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Topic 7: Wave energy system

Henry Tan's picture

Safety Engineering and Risk Management Debate 2012

  

Discussion Topic 7: Discuss safety considerations in wave energy system.

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JOHN BOSCO ALIGANYIRA's picture


Discussion Topic 7: Discuss safety considerations in wave energy
system.


Wave energy systems produce electricity without
emission of greenhouse gases and thus do not pollute the environment (2) which
is true when we only look at the normal energy conversion process however
during the manufacture of components used to assemble a wave energy plant, there
is a possibility of emissions being  produced. Antifouling coatings could also
result in emissions. The installation, maintenance and decommissioning phases
also have their own safety issues that cannot be under looked.


Other environmental safety issues associated with
wave energy include coastal erosion resulting from small solid objects mainly
sand being moved from the shoreline; device moorings  could impact on shipping if they break away or
causing traffic (2);acoustic noise and vibrations from on shore and near the
shore installations  can be a nuisance to
nearby residents and wildlife; offshore installations could affect fishing
operations due to disturbances in the sea bed, some marine species may become
endangered especially of offshore installations are done in their habitats and
also navigation could be impacted. The above possible impacts can however be
minimised and or even avoided by using better procedures.


Marine pollution and related concerns could arise
from installations especially due to bad practices for example schemes that use
oil-hydraulic systems resulting in spillages which could endanger aquatic species.
Spillages and sewage discharges can also originate from construction vessels
and may become a safety issue not only to the aquatic life but also human beings
using the water.


According to the available statistics ,there are no
major disasters and fatalities that have been reported on wave energy systems
unlike other energy production technologies, however like all other energy technologies,
wave energy has some environmental and safety issues thus measures have to be
in place to minimise the possible impacts for example by carefully selecting
the materials to be used on the wave energy plant ,a case in point is by using non-polluting
paints and biodegradable oils are desirable to reduce on pollution. There is
need to consider the above impacts right from manufacturing of the plant
components ,installation, operation , maintenance  and decommissioning phases to improve on the
safety of wave energy systems.


Regards,


John Bosco Aliganyira


Msc.Oil and Gas Engineering


References:


1.Ocean wave energy current
status and future prepectives [i.e. perspectives]
João     Cruz; SpringerLink (Online service) , c2008











2.Wave
energy conversion
Engineering Committee on Oceanic Resources. Working Group on Wave Energy Conversion.; ScienceDirect (Online service) , 2003

3.Ocean waves
and oscillating systems linear interactions including wave-energy extraction
Johannes
Falnes 1931- , ebrary, Inc. , 2002


4.Renewable
energy conversion, transmission, and storage
Bent Sørensen 1941- ,
ScienceDirect (Online service) , c2007


5.Renewable
energy its physics, engineering, use, environmental impacts, economy, and     planning aspects
Bent Sørensen 1941-
, ScienceDirect (Online service) , c2004





Richard Sedafor's picture

RS

John, I agree with the points outlined in your post. Wave technology indeed does have an effect on the ecology of the environment in which they are placed. Spillage of oil and lubricants and other  chemicals that are associated with the instalation and maintenance could be damaging. But as with all other technologies, can't it be improved to be more efficient? Can regulations be put across that will minimise hazards and ensure better safety compliance?

In a report titled "Non technological Barriers to Wave Energy Implementation", Waveplam, indicated that the problems hindering the advancement of Wave technologies goes far beyond the technical issues. Some of the hazards you that people claim are only perceived. More funding and research should be done to improve the technology.

 

Reference:

http://www.waveplam.eu/files/downloads/Waveplam_Del_2-2_Non-technologica...

FELIXMAIYO's picture

Wave energy is one of the newest form of energy and it’s in
its infancy stage much like wind energy 20 year ago. This form of energy has
its own advantages and also challenges.  Before
deciding whether a wave is suitable to generate energy a lot of factors have to
be considered ranging from the way it will affect humanity around there and
also the impact it will have on the environment.

Some of the considerations are its ability to withstand a
harsh ocean environment and its efficiency to extract the required energy that
is during normal operating conditions and also during extreme conditions e.g. a
strong wave.

The other issue is the impact it will have on the
surrounding marine environment including the concerns of the migrating aquatic
life along the region that we want to harvest the wave, the change in the
sediment transport and near shore coastal processes.

Socio economic concerns have been raised. The effect it will
have on the recreational facilities along the coastal shore because it changes
the pattern of the beach sand nourishment and may have an impact on the safe
navigation.

Noise has to be considered before setting up. From a report
it has been stated that noise from under water is a global environmental issue
if we are to harvest wave energy. http://news.cnet.com/8301-11128_3-20126414-54/ibm-listens-in-on-wave-energys-subsea-sounds/

Sources

http://en.wikipedia.org/wiki/Wave_power

http://nnmrec.oregonstate.edu/book/export/html/84

FELIX MAIYO

Marinos Ioannou's picture


Going through DVN (Det Norske Veritas) website, I
found the ‘’Guidelines of Design and Operation of wave Energy converters’’.
Getting a closer look at the guideline I noticed that a serious work and research
has been done in order to ensure the safety for any probable danger through the
whole procedure of designing and operating a wave energy converter. Also a very
important thing about the DVN Guideline is that it was commissioned as an
applicable standard by the Carbon trust during the 2004-05 Marine challenge and
it was published on May 2005.  


* DVN is an independent foundation that aims to safeguard
life, properties and the environment.


* Carbon Trust is a world-leading organisation that
helps businesses, governments and the public sector to achieve a low carbon
economy through several paths like: carbon reduction, energy-saving strategies
and commercialising low carbon technologies.


References:


http://www.dnv.com


www.boemre.gov


Marinos Ioannou

RossWinter's picture


Wave energy is part of the growing market
for renewable technologies, and as the United Kingdom is an island the
potential to harness wave energy has great potential for our future energy
needs. The devices used to harness the energy are limited to a normal working
range of weather conditions in the coastal areas, however whenever there is an
extreme storm the limits to the design will be tested and potentially with
severe storms becoming more frequent then the stress put upon the devices can
become too much and cause damage to the system. This then could lead to stray
bit of equipment floating around coastal areas, which would endanger local
shipping if not resolved quickly. However the type of storms which could cause
the damage would limit the recovery time due to the safety measures which would
need to be taken by the people involved.


victor.adukwu's picture


Discuss safety considerations in wave
energy system.


 


The placement of wave devices is a safety
concern for boat traffic, such as fishing and recreational boating. Also, for
wave devices set further out in the water, they could interfere with shipping
lanes. To address this safety concern, wave devices will be required to have
warning equipment, such as signals, radar, reflectors and lights.

When installing a wave device or removing an old one, marine ecosystems may be
impacted. Placing cables attached to the wave device disturbs the ocean floor
and the entire ecosystem. When a wave device is no longer operational and is
removed, the process disturbs marine life that has adapted to the device. For
example, birds might nest on the portion of the device that is above water and
they would lose their nesting ground.

Reference:


Safety
Concerns for Wave Energy Systems | eHow.com
http://www.ehow.com/list_6960521_safety-concerns-wave-energy-systems.html#ixzz28Nzh5lQf


Craig Donaldson's picture

I would imagine that any placement of a wave energy device would be out with busy shipping lanes and tend to be near the shoreline. However, to continue your post on concerns for ships and other sea users Pelamis [1] (one of the world's leading companies in wave energy) provide many measures for making other sea users aware. They have done this by carrying out a rigorous navigational risk assessment where they contacted all relevant partiers such as fisherman, ferry operators and the government. They used the information they gathered to select locations with low vessel traffic and discern which navigational aids would be most appropriate.

Features which have been put in place include; marker buoys at each corner of a wave farm which have lights and radar reflectors; sites are marked on navigational notices and issued to mariners. Furthermore each device is brightly coloured and has its own lights and radar reflectors.

In my opinion they have done a rather substantial assessment of the safety features required and implemented multiple different layers of redundancy to protect the safety of all concerned. For example if the mariner has not already seen the wave farm on his map, he should see the brightly coloured devices during the day or the lights at night and failing that his radar would pick them up.

[1] http://www.pelamiswave.com/

 

Kwadwo Boateng Aniagyei's picture

i agree with craig on his comments. in as much as i appreciate the fact that the installation of wave energy devices disrupts the ship routes; most wave farms are located in areas where there is little or no marine traffic at all. Moreover there are more measures in place to ensure that the wave farm doesnt obstruct ships. in the USA for instance; before a site approval is authorised for a wave energy project; the commanders of the US coast guard will have to determine whether it's going to be an obstruction in the navigable waters of the US. Just as you mentioned; warning signs are errected to notify other marines users of any dangers ahead. This i believe is a good safety practise as any potential hazard will be minimised.

Menelaos Michelakis's picture

(Topic : Tidal lagoons, safety considerations)

Introduction : ( nice to know...)

As i have explained in a previous post tidal energy is different than wave energy. Tidal energy comes from gravitational forces between Moon and Earth's water masses. It is also affected by Earth's rotation. On the other hand, wave energy is produced by a completely different mechanism. Sun makes wind and wind makes waves. What they have in common : In both cases, humanity generates energy, from the natural movement of water masses, so i consider wave energy and tidal energy to be closely related, and for that reason i did not create a new discussion topic. 

What tidal lagoons are ? There are places where we get energy from, taking advantage of the tide, by building walls in the sea. Requirements : Shallow waters, large tidal range. Building two instead of one : If two laggons are built in the same location, there is a construction method that allows us to generate energy at any time, independently of tide's state. It is fluid mechanics. One lagoon is designed to be the 'high' lagoon and the other one the 'low' lagoon. At low tide some power generated by the emptying high lagoon can be used to pump water out of the low lagoon, making its level even lower than low water. The energy required to pump duwn the level of the low lagoon is then repaid with interest at high tide, when power is generated by letting water into the lagoon.

Energy estimation : An engineer must always do calculations - i hate theory although it is necessary. Supposing an average of 4.0 W/m2, which is not an optimistic scenario, a tidal lagoon with total area of 350 km2, gives : 4*350 = 1400kw, which is a very good scenario, considering that after building the lagoon not other significant costs arise.

Safety considerations : No accidents have been reported. Actually, as much as i learn about energy from water masses, i believe it is the cleanest energy source, that humanity could have after the depletion of fossil fuels. Kinetic energy of water masses is turned into electricity. It is more environmental friendly even than solar energy, and there have been no accidents (deaths or injuries) reported during installation, unlike in wind turbines or solar panels (installed on roofs). There is no comparison to nuclear energy and fossil fuels, considering the environment or accident statistics, although it cannot be used as fuel. 

So, it is a good source of electricity, and when conditions favour such structures, they sould be built.

Increasing safety : [Lighting during night - avoiding a collision with vessels]

A thought i made is that these structures sould somehow be lighted during night, as oil platforms are lighted for example. Maybe a few small floating lights, would be enough, but maybe there are more lights needed, and the legislative regime sould be studied further. From country to country the legislation may be different but lighting of sea structures at night is essential, including energy systems that i have already described such as energy producing sea snakes and tidal stream farms.

Ref : JC Mackay (2008) - Sustainable energy - without hot air

Angelos Hadjiantoni's picture

Hello,

I agree with you on the point that marine energy might be the cleanest source and that is has minimal environmental impact.

The construction procedures associated with tidal barrages or lagoon will produce CO2 emissions. After the completion thought the operation is totally clean.  I think tidal stream turbines are the way forward to exploit marine energy since they are cheaper than a barrage and can be installed individually and gradually to increase the tidal farm’s output. Less CO2 will be produces during their construction and installation.

So far only the SeaGen S by Marine Current Turbines has reached full-scale commercial production. It has been installed in Strangford Lough and running since 2008.
During these 4 years and before the installation the activity of the marine life was tracked.  According to the Final Report regarding the environmental impact there were no mammals’ deaths associated with the operation. The rotating speed of the turbines is slow enough so that fish can go through without any problem.
The unit features a sonar system that can detect approaching mammals and shut down the turbines in less than 3 seconds.

As a result in my opinion each type of tidal turbines/wave devices should be studied separately about their safety issues.

Best regards,
Angelos Hadjiantoni
MSc Renewable Energy

Source:
http://www.marineturbines.com/sites/default/files/SeaGen-Environmental-Monitoring-Programme-Final-Report.pdf

leighmoreton's picture

I agree with Angelos where marine energy is potentially the cleanest form of renewable energy.  Although the marine environment can be a very harsh atmosphere, due to unpredictability. 

Many companies who operate renewable technologies offshore have to consider the issue of how to maintain their equipment in such an environment.  As most of the technologies need to be anchored to the seabed should any problems occur they need to employ a highly qualified diver to go into the potentially dangerous environment to retrieve or repair broken machinery.  This causes a serious risk to not only the diver by also to any maintenance crew with the support vessel.

As mentioned earlier by Angelos the SeaGen S has a feature which will severely reduce this risk.  The machinery is installed onto a monopile tower which is driven into the seabed.  If any maintenance is required on the equipment can be completed on the surface of the water as the turbines can be raised to the water level and support vessels can then easily access the devices.

Other marine technologies are also experimenting with this form of technology as it will greatly reduce their maintenance costs for equipment, and manpower, as divers may not be necessary.

Leigh Moreton
MSc Renewable Energy

Angelos Hadjiantoni's picture

Double post please Ignore

victor.adukwu's picture


Discuss safety considerations in wave
energy system.


 


Wave energy is an emerging clean energy source;
however, there are some safety considerations.
Wave energy raises concerns about fisheries and ecosystem health. At a
commercial scale, wave or tidal energy facilities will cover large areas.
Fishing areas may be disturbed by the wave devices. Each wave machine is anchored
and has cables to transport the converted power. The safety concern for marine
life is damage to ecosystems. Reefs and salt marshes are sensitive to
environmental factors and small changes to the silt and sand may pose safety
issues for sea creatures in the area. Another concern is for organisms that are
sensitive to electrical magnetic energy fields very close to the undersea
cables.


Each wave unit does contain hydraulic fluid
that could release into the water and impact the ecosystem. Monitoring programs
and secondary containment designs will minimize any potential chemical spill
concerns. Another potential toxic consideration is the use of biocides, which
are chemicals used to stop marine organism growth. Wave technology is still
being developed and these safety concerns are based on potential safety issues,
not on actual incidents.

Reference:


Safety Concerns for Wave Energy
Systems | eHow.com
http://www.ehow.com/list_6960521_safety-concerns-wave-energy-systems.html#ixzz28Nzh5lQf


Kii Cajetan Barisi's picture

OCEAN WAVES HAS BEEN ESTIMATED TO SUPPLY 13 PERCENT OF THE ENERGY DEMANDS WORLDWIDE. THIS ASSUMPTION IS HOWEVER BASED ON ULTILIZINGJUST 1 TO 2 PERCENT OF THE GLOBAL WAVE SUPPLY.

ALTHOUGH I RESPECT THE SAFETY CONCERNS OF MY COLLEAGUES ABOVE, I HOWEVER DISAGREE WITH SOME SAFETY COMMENTS REGARDING WAVE ENERGY. WAVE ENERGY IS ONE OF THE SAFEST AND CLEANEST FORM OF ENERGY. IT DOES NOT CO2 TO THE ATMOSPHERE SO DOES NOT POLLUTE THE ENVIRONMENT.

THERE HAS BEEN LITTLE OR NO REPORT AS YET AS TO ANY FATAL ACCIDENT INVOLVING WAVE ENERGY INSTALLATION WORLDWIDE AND NONE REPORTED IN THE UK. UNLIKE THE OIL AND GAS SECTOR THAT HAS CLAIMED MANY LIVES AND COST BILLIONS OF POUNDS, TIDAL OR WAVE ENERGY HAS NOT BEEN INVOLVED IN SUCH ACCIDENTS.

IT ALSO PROVIDES A BREEDING GROUND FOR FISHES IN AS MUCH AS IT DISTORTS THE ECOSYSTEMS AND PROVIDE HABITATS FOR BIRDS AND A SENSE OF COMMUNITY TO OTHER AQUATIC LIVES.

WITH GOOD PLANING ALSO, WAVE INSTALLATIONS WILL POSE LITTLE OR NO HARM TO SHIPPING AND BOAT ACTIVITIES AS BOATS' ROUTES CAN BE FAR AWAY FROM WAVE INSTALLATIONS.

WAVE INSTALLATIONS ARE FAR AWAY FROM HUMAN SURROUNDING AND SO DOES NOT POSE ANY DIRECT RISK TO HUMAN LIVES. 

 

KII CAJETAN BARISI 

Kwadwo Boateng Aniagyei's picture

i strongly agree to the concerns raised by kii. Wave energy is a very clean source of fuel with no CO2 emissions and hence does not pollute our environment. it is not catastrophic as its fellow fossil fuels. One mjor concern is that it interferes with ship routes. However this issue is well managed by various marine authorities and permits are only issued for wave farm constructions when they are away from the routes of ships and boats. When a wave farm is installed; the main impact will come from increased operational procedures. A potential effect is the wave hydrodynamics; which transports sediments along the shorelines. Though this destroys the existing ecosystem; it creates another artificial habitat to serve as a breeding ground for acquatic life. However; wave energy poses other environmental issues; which in my opinion is relatively insignificant compared to the environmental effects of fossil fuels. These are visual effects and impacts on recreational activities like jet skiing and scuba diving. Just as kii opined; a well planned and regulated framework will ensure proper and safe installations of wave energy devices.   

Menelaos Michelakis's picture

(Topic: Oscillating water columns, how they work, safety considerations)

One of the most widely used, wave energy systems, is the OWC - (oscillating water column). What is an OWC and how it works ? An oscillating water column is mainly consisted of a chamber. Inside this specially designed chamber, the rise and fall of the waves, produces air waves that give motion to an air turbine. The air turbine is connected to a generator and electricity is produced that way. There are such plants installed around the world, even in Scotland. Although wave energy technologies are not fully developed, scientists and engineers around the world have understood their significance.

Safety considerations : I could hardly imagine a technology safer than oscillating water columns, for the environment as well as for humans. No accidents have been reported during the installation of such wave energy systems. I have never seen an oscillating water column in action, so i would not like to make comparisons, although it not hard to state a few things such as : 1) there is no hidden pollution, 2) there is no impact on marine life, 3) It belongs in the group of renewables that are ideal for countries such as UK and Ireland because of the Atlantic Ocean West.

Ref : G.Boyle, B.Everett, J.Ramage (2004) - Energy systems and sustainability, power for a sustainable future.

Menelaos Michelakis's picture

(Topic : Safety considerations - the impact of salinity)

Something that has not been mentioned in previous posts, is the corrosion of most wave energy and tidal energy systems, caused by salinity. As everyone knows sea water contains salt, which is extremely corrosive for all metallic constructions and mechanical parts of every machine or engine. This means that corrosion, as time passes, is inevitable, even if we use other materials to protect metallic parts, because they will be affected by salinity too.

I shall set an example in order to be better understood. Wind turbines placed on dry land - onshore - are not affected by salinity as wind turbines that are placed offshore. The fact that they are placed onshore, increases their life for many years, compared to offshore wind turbines. In the second case - offshore wind farms - certain parts must be replaced every few years or months, depending on the construction and climate. This means, more money spended for offshore wind farms, but also safety is redused, (because workers are involved), when changes or repairs take place.

By this aspect offshore wind turbines are far more expensive and dangerous than onshore wind turbines. This is also proven, by the fact that some people have drowned, while repairing or installing, offshore wind turbines. The place where they are situated in conjunction with salinity makes the difference. Two things can be concluded, salinity decreases safety and increases costs.

Salinity affects lesser or more all wave and tidal energy systems that have described in previous posts, such as OWCS, energy sea snakes, tidal stream turbines, etc., increasing costs and decreasing safety. Although salinity affects in a negative way all wave and tidal energy systems, they still remain a very attractive energy solution for the future.

Ref : No references are set - general knowledge

RossWinter's picture

I would have thought that the manufacturers of these devices had considered this as a problem. Therefore i would have expect they would have used either non-corrosive metals in their designs, for example stainless steel, or they would have coated the device in some sort of protective element, like graphene. However as you said, corrosion is inevitable but with the right design and plannig strategy, they can be monitored and when the calculated lifetime of the design is up , workers can check to see if the sea and weather conditiions are safe for retrieving and replacing the device.

Ross Winter Msc Renewable Energy

Mark Nicol's picture

I don’t think they would use any corrosion resistant material’s due to the costs involved. It’s usually the more exotic duplex type materials that are used subsea, or various types of Inconel for cladding the inside of pipelines.

 These types of materials are only used when there is no alternative, due to the corrosive nature of the fluid that the pipeline is transporting. I don’t know for sure, but I would have thought that wave devices would be constructed with some type of structural carbon steel.

This wave devices would be cathodically protected by way of aluminium zinc anodes. This would be a much cheaper option than exotic materials as anodes are relatively cheap to buy.  

References:

1.      DNV-RP-B401    Cathodic Protection design

Andreas Kokkinos's picture


Wave
energy systems are quite new a type of energy source which is still in the
experimental face of its timeline. Like the offshore wind farm energy system;
wave energy is considered a green energy source as well. Additionally the
theory between wave and wind energy is the same but instead of wind, the WEC
(Wave Energy converters) use the waves in order to spin turbines for power
generation.


According
to the HSE (Health and Safety Executive); wave energy shares the same health
and safety risks as the offshore wind farm projects such as: [1]


·        
Construction
and major repair


·        
Operation,
maintenance and minor repair operations


·        
External
hazards either from sea or air (such as small boats, ships, aircrafts)


o  
Shipping
lanes safety concerns due to the placement of wave devices which may interfere
with boat traffic such as fishing or recreational boats and even large ships.
[2]


Some
environmental challenges emerge due to the environmental impact on the marine
environment such as noise pollution which may act negatively to the marine life.
[3] Additionally, toxic chemicals are stored in each wave unit in the form of
hydraulic fluid which could be released into the water either by a simple leak
or a greater damage. [2]


To
sum up, wave energy has a great potential as a new renewable energy source
since requires no fuel and also no greenhouse gases are produced. The safety
considerations associated with the wave energy are not as hazardous as other
sources of energy (e.g. Oil and Gas Industry) and currently no accidents or significant
incidents were recorded.


[1]
http://www.hse.gov.uk/


[2]
http://www.ehow.com/list_6960521_safety-concerns-wave-energy-systems.html


[3]
http://en.wikipedia.org/wiki/Wave_power#Challenges


 


Andreas
Kokkinos


MSc
Oil and Gas Engineering


Elle Allswell David's picture


Waves are caused by the wind blowing over the surface of the ocean. Energy is transferred from the wind to the waves. Wave energy has the potential to be one of the most environmentally gentle forms of electricity generation. It is a clean and renewable energy source and its potential is huge [ http://www.pelamiswave.com/wave-power].

The safety consideration in wave energy involves the following:

  •   The installations and Decommissioning of equipment.
  •   Conflict with other sea users
  • Visual appearance and noise.
  •   Reduction in wave height from wave energy converters.
  •   Marine habitat could be impacted negatively or positively.
  • Toxic releases related to leaks or accidental spills.

In order to have a good wave energy industry the above listed safety issues should be considered and included in the design process of the equipments.

References

1. Technology white paper on wave energy potential on the U.S outer continental shelf [ May 2006]

2.  Ocean wave Energy   http://ocsenergy.anl.gov/guide/wave/index.cfm 



 


Oluwatosin A. Oyebade's picture

Wave energy is derived from the winds as they blow across the oceans, and this energy transfer provides a convenient and natural concentration of wind energy in the water near the free surface. Once created, waves can travel thousands of kilometers with little energy loss. Wave energy is generally considered to provide a clean source of renewable energy, with limited negative environmental impacts. In particular, wave power is seen as a large source of energy not involving large CO2 emissions. The limited experience with wave power schemes makes it possible to form only an incomplete picture of possible environmental effects caused by wave power devices.  Thorpe summarizes the environmental impacts of wave energy conversion technologies as follows:

ENVIROMENTAL EFFECTS

                                                                     SIZE 

 Land use/sterilization
                                                                        S

 Constuction/maintenance site
                                                                        S

 Recreation
                                                                      S-M

 Coastal Erosion
                                                                        S

 Sedimetary flow patterns
                                                                        S

 Navigation harzard
                                                                        S

 Fishing and marine biota
                                                                        S

 Acoustic noise
                                                                        S

 Working fluid losses
                                                                        S

 Endangered Species
                                                                        S

 Device/mooring damage         
                                                                      S-M

KEY: S: small; M: Medium

 

It has been established that 100% safety cannot be attained so the ALARP risk measures should always be the target. From the above table, the environmental impacts of wave energy are relatively low compared to other energy sources and if managed adequately would pose no serious hazard to the community at large.

 

References:

 A. Cle´ment et al. / Renewable and Sustainable Energy Reviews 6 (2002) 405–431

J. Falnes, L. Lovseth. Ocean wave energy. Energy Policy, 19 (8) (1991), pp. 768–775 

RossWinter's picture

As with all energy production there is an element of risk and hazards associated with the extraction of the raw material and conversion to make power and Wave energy is no different. However with all other forms of energy production there has to be some level of risk or there wouldn't be and energy produced at all. Of all the renewable energies, wave energy has the highest energy density (2-3kW/m2) compared to solar (0.1-0.3kW/m2). The safety risks to people are very low due to nature of the technology. Unlike oil and gas production which need people based on rigs in dangerous situation, for wave technologies people are only in potential danger when the device is being constructed, installed and whenever repair are needed.

Ross Winter Msc Renewable Energy

Clement, A et al. 2002. Wave Energy in Europe: Current status and perspectives. Renewable and Sustainable Energy Review 6 pp. 405-431

Aaron McKenna's picture

I wish to extend on this prior point made by Ross regarding human interaction with wave energy systems. Obviously, as stated by Ross, by eliminating the necessity of people manning the technology daily, a great number of hazards are avoided. Additionally without the constant need for human interference wave energy facilities also detract from the risks involved with human error. As we have seen from a number of the studied incidents in the past, human error and negligence is a recurring factor in on-site failure. If people are only required sporadically in the running of the technology, then the systems safety more often than not directly translates to the reliability of the design and the materials involved in the building the facility, which when compared to the inevitability of human performance is a much safer situation. Another reason why if we could overcome the dangers of construction, installation and repair of such systems, then wave energy technologies may potentially be one of the safest energy systems.

Lee Soo Chyi's picture

Wave and tidal
energy offers promising prospects for the UK, as highlighted in The UK Low Carbon Industry Strategy,
published by the Government in July 2009. 
Wave and tidal stream technologies are comparatively new and largely
unexplored compared with solar and wind energy. To fully realise the potential
for marine energy, several technologies challenges must be tackled. The
challenges are:

1)     
Improving
the reliability and performance of wave and
tidal stream energy generating devices.

2)     
Reduce
the cost of energy

3)     
The
development of wave and tidal energy must not happen at the expense of marine
biodiversity and marine environment.

4)     
Shortage
of skilled scientists and engineers in the workforce

5)     
Installation
problems faced in harsh marine environment

6)     
Lack of
clarity of Government policy

 

It has been difficult to scale up the
designs for wave machines to produce large amounts of electricity. Tidal
barrages destroy the habitat of marine species. The rotting vegetation
underwater releases methane, which is a greenhouse gas [2].

To balance the requirement of project
developments, with environmental protection effectively, consideration beyond
simply identifying “sensitive areas” will be needed [1]. Environmental Impact
Assessment and Habitats Regulations Assessment [1] must be conducted prior to
commencement of the project. The other safety issue is the marine
transportation would be affected by the devices (normally the device is huge). Developer
also needs to manage public engagement effectively.

 

For your info, the following link shows the
vide of new giant wave energy device known as the Oyster 800 has been hailed as
a major step forward for Scotland’s renewable energy industry.

http://www.bbc.co.uk/news/uk-scotland-14152878

 

References:

[1] The Future or Marine Renewables in the
UK: Government Response to the Committee’s Eleventh Report of Session 2010-12.

[2]http://www.bbc.co.uk/schools/gcsebitesize/science/aqa_pre_2011/energy/mainselectricityrev4.shtml 

 

 Best Regards,

Soo Chyi, Lee

Emmanuel Mbata's picture

There are many advantages of wave energy, primarily the minimal environmental impact, high efficiency, and low construction costs associated with it. Until recently wave power was mostly theoretical but more real world examples are showing its viability as a utility scale power source. The main disadvantages of wave energy are its unreliable energy production and inability to be obtained inland from oceans. but besides that it is relatively safe of the environments. below are some of the advantages associated with it;

  • Capable of high efficiency (60-80%) in ideal conditions.
  • Renewable energy source obtained by wind via the Sun’s heating of our atmosphere.
  • Minimal environmental impact when properly placed.
  • Low operation and maintenance costs after construction.
  • Low upfront construction costs.
  • No emissions during operation.

 Reference: Renewable Energy index

Mykola Mamykin's picture

Most of the wave energy capturing technologies are primarily offshore and far offshore installations, which will be situated in deep water, typically of more than 40 meters

In addition to earlier mentioned oscillating water column, possible technologies like:

- point absorber, which is a floating structure with components that move relative to each other due to wave action (e.g., a floating buoy inside a fixed cylinder). The relative motion is used to drive electromechanical or hydraulic energy converters.
- Attenuators, which are long, multi segment floating structures oriented parallel to the direction of the waves. The differing heights of waves along the length of the device causes flexing where the segments connect, and this flexing is connected to hydraulic pumps or other converters.
- Overtopping devices, which have reservoirs that are filled by incoming waves to levels above the average surrounding ocean. The water is then released, and gravity causes it to fall back toward the ocean surface. The energy of the falling water is used to turn hydro turbines.
- seagoing vessels can also capture the energy of offshore waves. These floating platforms create electricity by funneling waves through internal turbines and then back into the sea.

All have similar environmental considerations, including:

• Positive or negative impacts on marine habitat (depending on the nature of additional submerged surfaces, above-water platforms, and changes in the seafloor);
• Toxic releases from leaks or accidental spills of liquids used in those systems with working hydraulic fluids;
• Visual and noise impacts (device-specific, with considerable variability in visible freeboard height and noise generation above and below the water surface);
• Conflict with other sea space users, such as commercial shipping and recreational boating;

REFERENCE

http://ocsenergy.anl.gov/guide/wave/index.cfm

 

Giorgos Hadjieleftheriou's picture

                                                                       Topic
7

Discuss
safety considerations in wave energy systems

Like every system, in the wave energy systems there are some
dangers that can be produce if safety plans don’t be applied.

The biggest danger is in the transportation of those systems
because are big and the installation because of the area that must be
installed. Workers must be vary careful or else the might be hurt.

Constructing wave systems can produce a lot of carbon
dioxide in the atmosphere because they require substantial energy.

Wave power generators can produce problems at any migrating
fish like whales for example. Fishes might collide with the generators and get
sever damage.

Regarding safety in the wave energy another problem has to
be concerned, Electromagnetic energy. This kind of energy can be transmitted
from the generators that produce high voltage throw the cables into the water
and harm the animals.

http://debatepedia.idebate.org/en/index.php/Welcome_to_Debatepedia%21

Kyeyune Joseph's picture


Wave energy is harnessed directly from water surface waves
and pressure fluctuations below it. Waves can be short term, seasonal, or long
term with variations in height and direction. Wave energy is caused by winds
blowing over the surface of water. Wave energy converters are used to exploit
wave power thereby generating electricity or mechanical power. Some of the wave
energy converters include Power Absorbers, surface Attenuators and Oscillating
wave surge converters. These can be installed offshore or closer to coastlines.


Due to nature of the waves (can be strong and long term with
force to cause fatalities and destroy ship hulls) and environment of operation (offshore),
some of the safety considerations in wave energy systems may include;


Type of electric generators used as these may necessitate
disruption to the sea floor thereby affecting marine life. Additionally,
leakages of hydraulic fluids from them may also impact the environment
negatively.


Safety of shipping lanes is also crucial. With power cable
installations especially offshore and other equipment, distraction of sea
traffic may be eminent. Activities like fishing may be affected drastically.


 


Impact of electromagnetic field waves from power cables to
marine life is also crucial. This may affect their reproduction as well the
entire ecosystem.


Bad weather especially offshore may distract activities like
installation, testing, commissioning and maintenance of wave energy systems and
as such needs serious attention during the planning phase.


In lieu of the above, it is therefore important that a
through environmental impact assessment is done so as to avoid any
eventualities. Additionally, use of non-toxic fluids in generators and use of
reflectors, radars and lights to warn sea traffic may also be vital.


References:


Bellamy, N.W. 1999, "Wave
Energy Prospects", The International Society of Offshore and Polar
Engineers, 30 May-4 June 1999. ISOPE Conference paper 1-99-020, Available at
onepetro


Wave energy potential in the US Outer Continental shelf, report available at
http://ocsenergy.anl.gov


Keqin Chen's picture

As an emerging renewablewave energy has been paid much attention by more countries. Different kinds of wave power stations has been established by Portugal, Japan, UKNorway and other countries with more mellow wave power conversion technology.

As to the safety concerns of wave energy, the
biggest concern is the
Bad impact on ocean ecosystem, which is detailed
below:

Usually, wave farm of
small scale will not do harm to the ocean ecosystem. However, at a commercial
scale,
the wave farm may lead to bad
impact to the ecosystem:

Firstly, various facilities such as dedicated devices, the
related anchors and cables will take a large coverage of sea. The existence of organisms
in ocean such as plankton will be influenced definitely, and the fishery will
be damaged. At the same time, the ecosystem could be affected by the noise and the
electrical magnetic energy fields caused by the facilities of wave energy.
Lastly, other biophysical impacts (flora and fauna, sediment
regimes) of scaling up the technology are being studied.

Reference:

1. Sustainable Energy: Wave Energy

http://www.maati.tv/2012/03/10/sustainable-energy-wave-energy

2. Safety
Concerns for Wave Energy Systems

http://www.ehow.com/list_6960521_safety-concerns-wave-energy-systems.html#ixzz29UhryS9H

 

 

 

Aaron McKenna's picture


The point above made by Keqin, makes for a very interesting
situation. Proponents of renewable energy resources believe that we have, or
will have, the ability to fuel ourselves completely by renewables. This would
necessitate a massive scale up from current facilities. However, as Keqin
points out this will have a potentially very damaging effect on the ocean
ecosystems. In scaling up it is therefore extremely important to understand the
risks that we may be taking with regards to this. I feel this would also be
true for wind power also. It appears then that in an attempt to stop global
warming and reduce CO
2 emissions we may have to be willing to jeopardise
our ecosystems. Is this a fair trade off? Or would the potential ecosystem
damage be enough to keep our power supply from wave energy relatively low and
cause us to look elsewhere for “green” energy?


Sineenat Kruennumjai's picture


Discussion topic 7; Discuss safety consideration in wave
energy system


Wave energy system is seem to be a safety energy resource
for human life, yet it has some environmental impacts, such as marine life
impact, the release of the toxic chemicals, the conflict of sea space, and the
impacts from installation and decommissioning. First of all, the facilities
which are used in wave energy generation are covering large space then they
disturb fishing areas. And the electrical magnetic energy fields can affect the
organisms that are living very close to the subsea cables. Secondly, regarding
to hydraulic fluids which are used in the wave devices, they might release and
pollute sea water and impact the ecosystem. Thirdly, the conflict of sea space
user, such as commercial shipping, is the once of the impacts from wave
devices. The placement of such facilities could interfere with shipping lanes.
Last but not least, installation and decommissioning processes can disturb the
ocean floor and the entire ecosystem. For example, coral reefs might be
destroyed by the anchor of wave devices.    


Source;        http://www.ehow.com/list_6960521_safety-concerns-wave-energy-systems.html#ixzz29GrFKLJE


 


 


chukwuemeka uzukwu's picture


The combination of an increasing energy market and
depletion of natural gas and oil reserves in the world has resulted in renewed
interest in developing renewable sources of energy, including the conversion of
ocean waves and currents into usable forms of energy. The ocean is an appealing
source of renewable energy because of its high power density, meaning it can potentially
produce large amounts of electricity.


 Potential
environmental considerations for the development of wave energy include the
following:


-       Positive or negative impacts on marine
habitat (depending on the nature of additional submerged surfaces, above-water
platforms, and changes in the seafloor);


-      
Toxic releases from leaks or accidental spills of liquids used in those
systems with working hydraulic fluids;


-      
Visual and noise impacts (device-specific, with considerable variability
in visible freeboard height and noise generation above and below the water
surface);


-      
Conflict with other sea space users, such as commercial shipping and
recreational boating;


It is therefore necessary to carry an environmental impact assessment
prior to installing any wave energy systems to curtail any eventualities


SON CHANGHWAN's picture


As mentioned about tidal energy, Tidal
energy is one of wave energy. It requires for some level of tides, so only few
location could be applicable for feasible energy generation. Once the barrage (flood
control gates) is constructed for blocking a bay, the gate will control the
flow and generate electricity. It needs an inherent geographical feature and
high CAPEX but operation cost is cheap. In overall, it is environmental friendly
energy source. But once barrage will control natural flow, it will influence on
sea level and population number of the coastal vegetation. [1] In South Korea, one
public enterprise announces plan for tidal energy power station in bay of In-Cheon
at 2005. Local communities and NGO express their concern whether its operation’s
impact could be minimized. Governmental plan is only performing regular monitoring
and alternative habitat, so impact on ecosystem in site and local fishing
community is inevitable. [2] At 2012, government rejects their development plan
because high risk in environmental impact on foreshore area finally. Some risk
could be lowered if they use tidal stream generators. It would be interesting
how they will improve their technical solution from environmental risk.


 


Ref.


[1]http://curriculum.cna.ca/curriculum/cna_world_energy_res/tidal_energy-eng.asp?bc=Tidal%2520Energy&pid=Tidal%2520Energy


[2] http://www.koreatimes.co.kr/www/news/nation/2012/08/117_118297.html


[3] http://www.kihoilbo.co.kr/news/articleView.html?idxno=483594
(Korean Article)


 


SON, CHANG HWAN


Harrison Oluwaseyi's picture

The increasing
population of man and gross domestic product (G.D.P) is proportional to the
energy demands. Several power generation techniques have been used in the past two
centuries, but there have been either financial constraints or negative
environmental impacts associated with them. Wave energy is one of the few
systems classified as renewable energy. The wave energy system use a principle
similar to that of the hydro-electric where the potential energy in water
falling from an elevated height is converted to electricity but for the wave
energy system, it uses energy from waves on an ocean surface.

Like every technology,
the wave system has a number of short comings but these problems tend towards
it efficiency, location etc and they include:

1) Effects on
marine life.

2) Variations in
wave timing and intensity.

3) The safety of
workers during installation and decommissioning.

4) Production
and maintenance of wave energy converters.

Mentioned above
are a few concerns associated with this system but it is still classified as
one of the safest energy generation techniques known to man.

REFERENCE

1)2009, B. Drew, A.R Plummer, M N Sahinkaya "A Review of Energy Converter Technology"

2) www.wikipedia.org

Kingsley ENEM's picture

The kind of energy which is delivered by ocean surface waves is known as wave energy and valuable in many ways like electricity generation, water reservoirs etc. Machinery which is used to work over wave energy is known as wave energy converters. Wave power is different from tidal power and ocean currents power.

When wind passes by the surface of the ocean, waves are generated. Provided the waves flow is slower than the wind speed, wind keeps on transferring energy to the waves. Wave height is determined by wind speed, the duration the wind has blown and the area over which the wind has excited the waves. Bigger or greater waves are more powerful and they are also determined by the air speed, wavelength and density.

Wave energy technology is still in its infancy. Many Wave Energy Conversion (WEC) devices have been established but no particular technology has been proven superior. Only a few full-scale devices have been deployed in the world.

Main technical considerations for wave energy development comprise its capability to tolerate a harsh ocean environment and efficiency for take-out energy from the resource, both of which are considered key to its economic success. The main technology challenges are related with not only electrical generation and output, but mechanical systems, mooring and anchoring, survivability, predictability (wave forecasting), and integration of the generated power into the present electrical grid. Other biophysical impacts (flora and fauna, sediment regimes and water column structure and flows) of scaling up the technology are being studied. Social and economic concerns have also been raised, with worries voice about loss of commercial and leisure fishing grounds and other leisure activities including surfing and kayaking. All of these considerations are or soon will be under study through research and through testing these devices in lab and field (ocean) facilities.

References:
1. http://www.maati.tv/2012/03/10/sustainable-energy-wave-energy/
2. http://www.ehow.com/list_6960521_safety-concerns-wave-energy-systems.html
3. http://nnmrec.oregonstate.edu/book/export/html/84


Kingsley ENEM

William J. Wilson's picture

The design of energy wave systems means that the majority of structures have a very low profile when sitting in the water.  Pelamiswave state that their structures extrude from the surface by approximately 1.70m  Given that small yachts and other recreational sea craft are low in the water too it could be difficult for a mariner to see the structure, especially during adverse weather conditions and this could spell disaster, with potential loss of life, if there was a collision.

So far there have been no reported collisions between any small craft and wave energy systems, but as we know human factors can affect decisions that mariners make which could navigate them towards a wave energy device.  However, I the RYA have stated that any structure should be clearly seen in all weather conditions and Pelamsiwave and similar companies have done so with their wave devices by:
• Painting the structure red and yellow to maximise visibility
• Installing flashing lights visible at 2 nautical miles
• Radar reflectors
• Future installations will have cardinal markers to identify the direction of the hazard
• Accurate charting of structures (especially partially submerged devices)

Risk of collision is real and the consequences are high (if you account for potential loss of life) but it has been managed well and I would consider it to be within the Low ALARP region.

References:
http://www.rya.org.uk/Pages/Home.aspx
http://www.pelamiswave.com

 William Wilson

MSc Subsea Engineering (DL)

Liu Yishan's picture

Although wave energy is one of clean energies, it still has a few problems on the sea usage and limited environment effects. The hydraulic fluid which is used in capture devices may contain toxic chemicals that could release into the sea and impact the ecosystem of oceans. These spilled toxic liquids would bring dangerous to the marine organism. The biocides which are used to stop marine organism growth are also sources of toxic releases. A few monitoring programs have concerned the potential toxic chemicals to the environment. As this safety issue in wave energy, more than monitoring should be done to keep wave energy to be true clean energy.

Reference: Technology White Paper on Wave Energy Potential on the U.S. Outer Continental Shelf, 2006, http://ocsenergy.anl.gov 

Oluwatadegbe Adesunloye Oyolola's picture

Waves are caused by the wind blowing over the surface of the ocean. In many areas of the world, the wind blows with enough consistency and force to provide continuous waves. There is tremendous energy in the ocean waves. Wave power devices extract energy directly from the surface motion of ocean waves or from pressure fluctuations below the surface. Wave power devices are used to collect the wave energy. It is impossible to harness wave energy in all nooks and corners of the world

Wave power varies considerably in different parts of the world, and wave energy can't be harnessed effectively everywhere. Wave-power rich areas of the world include the western coasts of Scotland, northern Canada, southern Africa, Australia, and the northwestern coasts of the United States.

Environmental and Safety Concerns of Wave Energy

Wave power stations are not found in abundance because it is very hard to harness energy from tides (the system depends on the blowing wind) and then to transform it into electricity. There are some environmental factors which must be kept in mind.

Let us have a look at them.

1.     Installation of these waves based power stations is quite expensive. Its maintenance is also complex due to huge compartments.

2.    If pollutants or other chemicals get discharged in case of accident than the aqua life is directly affected. Strong measures with constant monitoring must be maintained to avoid any critical situation.

3.    A very common problem with these stations is the noise made by the wind. These voices can be only avoided by silence filters. Waves themselves create a lot of noise.

4.    Additional submerged surface of the stations also affect the marine life. The sea level also shifts as a result of these wave power stations. Ways should be discovered to save the habitants of ocean from getting in touch with the power station and the electricity generators.

5.    The stations are also troublesome for those who love to spend their leisure time within sea. Thus these stations suffer criticism from recreational and tourist departments.

The system of extracting power from waves will be mature very soon and it is expected that some of the coastal areas will be able to fulfill the ever increasing demand of power for their population. This is an expensive but a natural source of collecting energy and will be utilized for the greater benefit of mankind.

Reference:

www.dnv.com.sg/binaries/WECguideline_tcm163-270406.pdf

www.bwea.com/pdf/safety/Marine_HS_Report.pdf 

www.lipower.org/pdfs/company/papers/report-wave0107.pdf

 

Adesunloye-Oyolola O.

MSc Oil and Gas Engineering

I strongly believe that wave energy is safe to a large extent. From a number of articles I have read, there are some issues regarding wave energy's saftey. However, I believe these are not major concerns. Safety issues of wave energy are as follows:

First and foremost, boats and ships may collide with the installations of wave energy in the sea. An other risk related to wave energy is the toxic fluid which can be released to marine environment during installation, maintenance, operation and also decommissioning. It can also pose risks to ecosystem and destroy it in the sea where equipments are installed.Last bot not least, I would like to  mention noise pollution caused by wave energy operation.

I believe that these concerns which are raised are minimal and can be easily reduced to ALARP  level with risk management.

 

Sources:

www.oceanrenewableenergy.com

www.guardian.co.uk

Leziga Bakor's picture

Wave energy is a renewable source of energy. It has some safety concerns. The major concerns are summarised below.
• Marine life impact: Carrying out wave energy development on a commercial scale will cover a large area and this will disturb marine life. Also reefs and salt marshes are sensitive to small changes in their environment and this poses serious safety problems for them. Transporting the electricity generated will induce electric magnetic energy fields close to the cables transporting the electricity and this will affect organisms in marine environment.
• Toxic chemicals: The units used to harness the wave power contain hydraulic fluids and if there is a leakage, this fluid will escape and is toxic to the marine ecosystem.
• Shipping lanes safety: Installing wave devices out in the sea could cause problems for ships if they collide with them. The collision could cause serious damage. Also the installation of this device on the sea will mean a major change in shipping routes.
• Installation problems: Installing wave devices out in the sea also is dangerous to the people installing it as they put their lives in danger. If they fall into the sea they could injure themselves. It is a risky job.
The wave is a good source of energy and it does not introduce greenhouse gases into the atmosphere but it has some safety issues among others. Some have been highlighted in this comment.

Oluwasegun Onasanya's picture

Waves originate when air and water surface temperatures are not the same.Waves tends to be more powerful because water is 832 times
as dense as air, so once a wave gets moving, it packs a heavier punch.
Waves keep rolling once they build momentum and can be forecast as far as three days away.

Considering the systems that utilises waves to generate power, the following below can be attributed,
1. Make little noise.
2. Rotating parts are either self-contained or so slow moving that marine animals should be able to avoid them.
3. Waves sytems do not interfere with aviation or radar and require far less space.

As every form of energy has its own unique safety issues, so also the wave energy system, is not left out. Below are some of the
safety issues that are pertinent to the wave energy system.

1. Marine Life Impact: At commercial scale, wave energy system will cover large areas, as this brings a safety concern to damaging
of the ecosystems. Organisms that are sensitive to electrical magnetic energy fields very close to the undersea cables may be affected.

2. Release of toxic chemicals: As wave unit contains hydraulic fluid, there may likely be fluid release into the water and impact
the ecosystem.

3. Shipping lanes safety: Wave devices that are placed in waters is a safety concern for boat traffic, such as fishing and recreational
activities. Shipping lanes can be interfered with.

REFERENCES:

1. Energy forum/ Alternative energy. www. discovermagazine.com

2. Safety concerns for wave energy systems. www.ehow .com.

OKEKE FRANCIS's picture

Wave energy accounts for about 12% of the UK's electricity generation. This renewable source of energy technology is not widely employed commercially. The basic concept of wave energy is the process of using waves generated as a result of wind passing over the surface of the sea to drive wave power machines which generates electricity.

As every renewable, clean energy technology, wave energy has its own safety challenges:

1. Some wave power systems work with hydraulic fluids, leaks or accidental releases from this liquid can be of adverse effect to the marine habitat.

2. Waves energy structures are either floating or near the water surface. This can conflict with other sea users like the fishermen, recreational boating and the commercial shipping lines.

3. It causes noise pollution.

4. Waves energy installations can be very expensive to install and maintain. The installation process can also be very dangerous.

References 

http://www.decc.gov.uk/en/content/cms/meeting_energy/wave_tidal/wave_tec...

http://ocsenergy.anl.gov/guide/wave/index.cfm

 

OKEKE FRANCIS N.

OIL AND GAS ENGINEERING

xingyuan.fu.12@aberdeen.ac.uk's picture

Tidal phenomenon caused by changes of the lunar gravity, which lead to sea levels periodically lift. Tidal energy is caused by the seawater fluctuation and tidal flow. Compared with the hydropower, tidal energy has low energy density that equivalent to the power level of the micro-head.
There is vast reservoir of energy stored in the tides of the ocean. During the Fluxes process, seawater has great kinetic energy and with the rise of the sea level, we can transform great kinetic energy into potential energy. This is the same in the ebb process, the water level gradually reduced, potential energy convert into kinetic energy. Despite the tide is very complex, but it can be accurate forecast. The common utilization of tidal energy is for power generation. Tidal power is to take advantage of favourable terrain such as bays and estuaries, people build dam as a water reservoir, and next to the dam, to construct the hydroelectric power plant room to generate electricity through hydro-generating unit.
To use Tidal power for generation must have two physical conditions.
1. Tidal amplitude must be large, at least a few meters.
2. The topography of the coast should be able to store a lot of water and can carry out the construction.

 

ZHANGYANAN's picture

Discussion Topic 7: Discuss safety considerations in wave energy system.

Wave energy

Wave energy power is a kind of energy which is able to convert the kinetic and potential energy of the waves into a mechanical energy, the gas energy or the liquid energy. And then through a transmission mechanism, the turbine or the hydraulic motor drive generators.

Wave energy conversion can be classified into three different kinds of machine: mechanical conversion, pneumatic conversion and hydraulic conversion. Always, people site the installation on a place which has heavy waves. But, these places are always in unsteady situation. That leads to the poor working stability.

Although it is relying on the mechanical transmission of energy, but there is still some hazards.1.       It may have negative impact on the sea environment surround.2.       It has poor reliability because the facilities are always very cumbersome.3.       The working facilities may cause the noise pollution.4.       It is harmful to the sea animals.

There is a potential impact on the marine environment. Noise pollution, for example, could have negative impact if not monitored, although the noise and visible impact of each design varies greatly. Other biophysical of scaling up the technology is being studied. In terms of socio-economic challenges, wave farms can result in the displacement of commercial and recreational fishermen from productive fishing grounds, can change the pattern of beach sand nourishment, and may represent hazards to safe navigation.  

Reference:

McCormick, Michael E., and R. Cengiz Ertekin. Mechanical Engineering-CIME 131.5 (2009): 36. Expanded Academic ASAP. Web. October 5, 2009.

 

Marine Renewable Energy Programme, NERC Retrieved 2011-08-01. Zhang Yanan      ID: 51233945

 

MSC IN OIL AND GAS ENGINEERING UNIVERSITY OF ABERDEEN

Ernest Appiah's picture

Wave energy is one of the cleanest and sustainable sources of energy which supplies 13% of the world's electricity demand. Despite the fact that wave energy is clean and an emerging energy source, there is some safety concerns associated with this technology. Some of the concerns are about:

  • Marine Life Impact- there are concerns about fisheries and ecosystems, that fishing areas may be disturbed by the large area covered by the wave energy devices and also that there will be damage to the ecosystem as a result of the small changes in silt and sand.
  • Installation and decommissioning of devices may have a negative impact on the ecosystem.
  • Shipping Lane Safety-that the wave energy devices could cause interference to fishing and recreational boats.
  • Toxic Chemicals.

There have been solutions to some of these issues and also since wave energy is still emerging, these safety concerns are based on potential safety issues and not based on actual incidents or accidents.


Reference
  Safety Concerns for Wave Energy Systems | eHow.com http://www.ehow.com/list_6960521_safety-concerns-wave-energy-systems.html#ixzz2DHTGkFWm

a.bhardwaj.12's picture

I agree about the points stated above. The technology no doubt is growing at a very high rate and so is the investment made in the same by UK government. But do you think that the controlling and validation authorities are so developed. The wave energy device developing companies are at the maturity level of having in house validation. The safety norms and engineering verification is done by in house engineers. I believe that the third party verification in the case of such developing industry is very essential. Modern wave energy harnessing devices such as subsea pumps and catterpiller wave capurer hold huge amount of fluids to actuate the turbines.If they are not commissioned by controlling authorities and certified so they may cause environmental damage. As far as present validation softwares such as multiphysics simulators are available, so they reduce the risk of failure but controller validations and commissioning hold a important place in technology launch in sensitive environments. 

 

a.bhardwaj.12's picture

As UK is making huge investments in the field of wave energy, also the development is quite exponential. But some of the technologies are poteltially harmful. As discussed earlier some devices hold huge amount of lubricating oil or oil for micra turbines. 

As UK plans to invest money for North Sea area hence it holds huge amount of risk as incase of leakages the devices cannot be repaired in rough waters thus converting this risk into an uncontrollable risk.

Present industry or Intellectual Property Banks do not have the satisfactory wave data which increases the uncertainity incorporated with the technology. As the technology is new hence governements didn't care to record the wave data in last decades. Hence the question still stands with the risks involved in deploying wave energy harnessing techonologies in North Sea.  

Marinos Ioannou's picture


The
safety concerns about Wave Energy do not affect directly the mankind, but can
cause serious environmental and sea life hazards. The main problems that may be
caused by wave energy can be grouped in four general categories. The first and
the most common is the ‘‘Marin life Impact’’, where the sea life can be
disturbed and polluted by the undersea installations. This can happen due to
the fact that many sea organisations are sensitive and can be affected by the
electromagnetic field that is generated by the system’s wires. Another major
hazard appears when toxic chemicals are released in the oceans from the wave
energy systems. Although that this source of energy is characterised by its
renewable and eco-friendly form, the energy transform systems include hydraulic
parts that can release those hazardous chemicals in the sea. Anyway, this can
be prevented or controlled by a continuous and systematic check and
maintenance. The marine ecosystem can also be affected during the installation
or decommissioning of wave energy devises as the wires and the device parts can
disturb the sea life of the area occupied by the wave energy farm. The last and
maybe more directly affective hazard of the wave energy farms is the fact that
they can cause crushing accidents with passing ships or boats with the wave
devices. This can be controlled by controlling the ship routes from diverting the
ships from those areas or by putting signals above the surface round the
restricted areas.


http://www.oceanenergycouncil.com


http://www.ehow.com/


Marinos Ioannou

Tianchi You's picture

Wave energy is an efficient kind of energy, if people can make full use of wave energy, ocean waves can supply 13% of electricity demand worldwide. However, since more and more countries have paid attention on wave energy, there are some issues about safety behind wave energy appearing.

  • Wave energy raises concerns about fisheries and ecosystem health
  • Each wave unit does contain hydraulic fluid that could release into the water and impact the ecosystem
  • When installing a wave device or removing an old one, marine ecosystems may be impacted
  • Efficiency drops significantly in rough weather due to safety mechanisms

Reference: http://www.ehow.com/list_6960521_safety-concerns-wave-energy-systems.html

Regards,

Tianchi You

51233959

Oil&gas engineering

Angelos Hadjiantoni's picture

Hello,

Even though there is a lot of argument in this topic for wave power in general,
 I will concentrate in wave tidal systems that actually are being tested and studies are carried out
about their safety and impact on the environment. Oyster by Aquamarine power is such a device.
One impact of marine devices being anchored on the seabed is their effect on the microorganism.
 According to the Environmental Study for a 40MW project the life on the seabed that will be lost, will be recovered by colonizing the devices.
Regarding the mammals and fish life, the chosen location has relatively low number of marine life passing by.
 As a result the danger on impact with the devices is low and it is further minimized by the fact that these devices move slow enough for seals and sharks to avoid them.
Also the need for possible drilling for pipelines might impose a danger of underground water contamination.
This will be handled by using water and non-oil based drilling fluids.
I believe that because marine energy’s impacts are site specific, a general statement that they are safe or they are not is not very reliable.

Best regard,
Angelos Hadjiantoni
MSc Renewable Energy


Source: http://www.aquamarinepower.com/sites/resources/Reports/3172/Lewis%20Wave...

amaka.ikeaka's picture

Wave energy is a renewable source of energy that
captures ocean waves directly from surface waves or from pressure fluctuations
below the surface. Wave powered devices are used to extract the energy from the
surface waves or below the surface. It is a non-polluting source of energy, as
it produces no gaseous, liquid, or solid emissions during its normal operation.
Although it is a renewable and non-polluting source of energy, it has some
negative environmental and safety issues which includes:

  • Noise:The
    noisy nature of wave energy devices especially during rough conditions may have
    implications for the navigation and communication of certain animals especially
    seals and cetaceans. These noise emissions could be directed into the
    atmosphere in order to reduce their impacts on seals, cetaceans, whales etc.

  • Device
    moorings: Interference with mooring and anchorage lines with commercial and
    sport-fishing; careful design consideration will minimize this

  • Navigation
    Hazards: Possible threat in navigation collision due to the low profile of the
    wave energy devices thereby making them undetectable

  • Disruption of
    marine life by the wave energy devices

  • Toxic
    Chemicals: Potential for the release of hydraulic fluids from wave unit into
    the water which has adverse effect on the ecosystem

Reference

Thorpe, T.
W. "A Brief Review of Wave Energy." (1999).

amir masoud bayat's picture

The safety concern in wave energy is for marine life which damage to ecosystem. Every wave unit contains hydraulic fluid which can release into the water and have negative effects on the ecosystem. Salt marshes and reefs are very sensitive to environmental damages and any changes can pose a lot of safety issues for the sea creatures. In addition, wave machines have cables to transport the energy and another safety concern is for sea creatures which are sensitive to electrical magnetic energy fields which are close to these cables.Also, the placement of wave structure is another safety concern since it may interface with shipping lanes. Moreover, the removing or installing a wave device can have negative effects of marine ecosystem.  http://www.ehow.com/list_6960521_safety-concerns-wave-energy-systems.html#ixzz29yoQpvFrwww.attask.com 

charlesggeorge's picture

Hi Amir,

  i agree with your points your have mentioned. i also like to add some of the other point with that. According to OCS Alternative Energy Programme studies, Mostly the wave generators are fixed or attached to seafloar or the shore which can cause disturbance in the sea florr aswell as marine ecosystems. And also these generators  can cause noise pollution and aslo disturbance to thoses living close by aerias.Some times wave generatores in the sea can cause major probelm to the commerical shipping and other boat in the ocean. This can cause potensial collision hazard and can cause problems for the safety to the people in boat and also to the wave enery generators. some times the collision may cause hydraulic spill which u mention   which can became an enviornmental hazard.

 

Charles George

Msc in Oil and Gas Engg 

sreehariprabhu's picture

As John introduced in the beginning, wave energy is a renewable source of energy and doesnt emit any greenhouse gases on its operation. But it is important that the safety measures are studied and applied. One of the safety concern was regarding the collision of marine vessels with the installations. In oreder to prevent this, before installations, a perfect place must be selected where not much marine vessels approach. It is also good to collect datas from the fishermen who will have the idea about upto what area they will be going. Once a place without much vessel movements is found, it is suitable to fix the installations there. Also inorder to ensure safety more, each system must have its own lighting and radar systems. Also it will be better if the information on the installations is given to marine workers so that they will be alert when they are in places near the installations.

Moreover like any systems, inspections must be carried out periodically to ensure the proper working. It should be also made sure that marine life is not harmed. If we can ensure that these problems are minimized, we can produce electricity from a cleaner source which will make a great advantage in the future.

Oghenekevwe Ovbije's picture

This is the use of the energy contained in the movement of water (hydrokinetic) to generate electricity. This technology is currently unproven for generating a substantial amount of electricity. The energy produced is a renewable, clean and has no emissions. Generating this form of energy causes different problems that can be classified as unsafe to the environment. Below are a few of the problems associated with the generation of wind energy [1][2]

•Marine impact – disturbance of fishing areas and marine areas may also be damaged especially organism that are sensitive to electrical magnetic energy fields.
•Release of toxic chemicals – leakage of hydraulic fluid into the sea from the production unit or effect of using biocides to deter the growth of marine organisms.
•Wave hydrodynamics – transportation of sediments and debris along the shoreline
•Noise pollution
•Visual obstruction
•Creation of artificial habitat – attachment surface for a variety of algae and invertebrates
•Marine navigational issues- change of migration route for marine animals affects the movement of fishes, marine mammals and organisms
•Installed cables obstructions
•Obstruction of recreational activities like jet skiing, surfing, scuba diving, swimming etc.
•Disturbance of the sea floor and ecosystem due to the installation and decommissioning of production unit

Reference
[1] Safety Concerns for Wave Energy Systems | eHow.com Available at: http://www.ehow.com/list_6960521_safety-concerns-wave-energy-systems.html. Accessed 12/8/2012, 2012.

[2] Anne Maczulak PD. Chapter 5 - Innovation in Clean Energy. Renewable Energy Sources and Methods: Infobase; 2010. p. 109-114

Maxwell Otobo's picture

Wave energy is a clean fuel and can produce a significant amount of energy with no greenhouse gases associated with it. 

However, there are a few drawbacks and safety issues associated with it which are;

 

  • technology - the technology is not yet perfect. The wave converters are very expensive to build and the ones readily available at the moment are not always dependable.
  • At a commercial scale, wave energy facilities will cover a large area of the ocean which may likely disturb fishing.
  • Shipping lanes safety - wave devices could interfere with shipping lanes and this is a safety concern for boat traffic and recreational boating (danger of collision). Warning equipment such as signals, reflectors and lights could be used to address this issue.
  • Toxic chemicals - pollutants and other chemicals can get discharged from the wave equipment in the case of an accident and this affects the aqua life directly by hurting or killing valuable ocean plants and animals.
  • Noise impacts - some wave energy devices are noisy. the high level of noise generated by this device especially in rough weather conditions can travel long distances under water which affects the navigation and communication systems of certain marine animals such as cetaceans or seals. 

 

With these safety issues addressed accordingly, it will be safer to operate wave energy systems.

References

1. http://www.appropedia.org/Wave_energy

2. http://renewableenergyindex.com/energy-kids/wave-energy-kids 

 

Wave energy has great contribution  in world energy needs. It one of the main renewable energy. ocean wave energy can produce clean and renewable energy. But still there are some safety issues regarding the wave energy. 

 

Wave energy plant can create bad effects on ecosystem and in fisheries. Large scale wave energy facilities can affect the fishing area. The ecosystem arounnd the area in which the wave energy machines, cables are installed is affected. The safety risk of the marine life will increase. 

 

Hydraulic fluid are used in each units of wave energy device. The release of this hydraulic fluid can damage the ecosystem. Biocides are toxic chemicals used to stop the growth of marine organisms. This can also increse the safety concerns. Placement of wave device can leed to safety issues regarding shipping lanes. Installation and decommissioning of the wave device will also increase the safety issues regarding ecosystem.

Fungisai N Nota's picture

 As the above stated the wave technology is clean on the environment
once it is built and running but like every technology out there as it is being
constructed there will be some carbon footprint but it is then offset by the operating
life of the technology there we can now compare it to others and see that it is
better but well prove to be less economical as with most of the marine
technology have low yield than other technologies. There are risks yes with the
hydraulic fluids if they do leak into the ocean and that of the environment with
the sea life if the systems are built within the path of travel or migration.  

Fungisai Nota BEng(Hons) MIET

Thomas James Smith's picture

If we can harness the power of the sea safely, and without having any adverse effect to the ocean environment, then this like wind power is a system that appeals to me.  

The issue that threatens its green credentials is the size and scale of the systems that would be required and the effect on the fisheries and ecosystem health.  Each system is anchored and cabled run back to the beach (carrying the power). It is likely that the onboard hydraulic fluids would leak into the ocean however any risk associated with leaks could be mitigated against by using non toxic fluids.  

All in all with proper planning, hazard and risk identification, environmental impact assessments these devices could be installed and would produce power with minimal affect to the environment.

Justice J. Owusu's picture

In search of knowledge

Andrew Strachan's picture

Wave-energy systems on a large scale are unproven over the long term therefore I see the largest risk as environmental, with potential damage to marine ecosystems. This may be low impact for the current level of planned wave-energy installations but to make a substantive contribution to the UK's energy mix many miles of coast line or near shore areas will need to be consumed for this purpose [1] and this may cause indeterminable lasting damage to our coastline.

This risk needs to be balanced against the urgent requirement to establish low carbon, sustainable energy sources in the UK.

[1] Sustainable Energy Without The Hot Air, David JC Mackay, 2009

 

eddy itamah's picture

Wave energy is an emerging clean energy source, which is not without some safety concerns. The following however explain some of the safety issues that is considered to be associated with wave energy.

1. Impact on marine life: Wave energy raises concerns about fisheries and ecosystem health. At a commercial scale, wave energy facilities usually covers a large area, thereby disturbing fishing areas. Each wave machine is anchored and has cables to transport the converted power, which invariably affect the ecosystem and thus damage the marine life. Reefs and salt marshes are sensitive to environmental factors and small changes to the silt and sand may pose safety issues for sea creatures in the areas.

2. Toxic chemicals: As a result of the hydraulic fluid contained in each wave unit, there is every possibility of release of toxic substance into water which invariably affect the ecosystem of the marine environment. Another potential toxic considerations is the use of biocides which are chemicals used to stop marine organism growth.

3. Visual and noise impacts (i.e) device - specific with considerable variability in visible freeboard height and noise generation above and below water surface

4. Conflict with other sea space users, such as commercial shipping and recreational boating.

5. Installation and Decommissioning: When installing a wave device or removing an old one, marine ecosystems may be impacted placing cables attached to wave device disturbs the ocean floor and the entire ecosystem. When a wave device is no longer operational and is removed, the process disturbs marine life that has adapted to the devce.

 

References:

www.ehow.com

www.ocsenergy.an/gov/guide/wave

 

 

 

 

 

 

 

 

 

 

Justice J. Owusu's picture

Sea wave is a source of renewable energy caused by wave currents passing over the ocean. Wave energy systems are used to capture this energy and transform it into useful energy. There are different types of wave energy system technologies. The anticipated hazards are environmental related, and that depends on the system technology, the physical and ecological features of the sea site. In order to utilize this energy sources, an environmental and economic impact assessments, among other things, need to be carried out. Regulatory bodies must demand pragmatic impact statements from potential developers that identify and assess hazards, and measures taken to avoid, reduce or compensate for latent impact.

Justice J. Owusu's picture

This is still a grey area with lots of potential, but some environmental impacts that need monitoring include:

1.       Noise level and system visibility – depends on technology type. The system must have warning devices such as conspicuous painting, lights, radar reflectors, etc. to reduce navigation hazards. Improved design can reduce the noise level.

2.       Aquatic habitat – depending on the ocean site, the system may have positive or negative impact on aquatic lives. For example in areas where there are sea lions, the surfaces of the system may provide a habitat for them. Underwater surface devices may interfere with movement by marine lives.

3.       Clash with other marine users – Possible interference with other ocean users such as ships, commercial fishing boats, recreational boats, etc. will have a negative impact. Site selection needs to be done carefully.

Pollution – accidental spill or leaks of the systems’ operating hydraulic fluid will have a negative impact. Choice of operating fluid is important and also adequate spill responds plans need to be in place.


The application of wave
energy infrastructures in the marine environment requires the consideration of
several safety issues. There are many varied systems designed to extract energy
from waves, all of which have their respective environmental safety concerns
(Carbon Trust Report, 2005).


 


Wave energy systems can
consist of devices such as ‘snakes’ that remain offshore and generate
electricity through undulations resulting from the local waves. These systems
could represent safety hazards for regional shipping activity. The moored
devices present an obstacle for vessels if positioned in areas of high marine
traffic. Furthermore, if a period of adverse weather is suffered, producing
effects such as particularly high storm swell waves, the potential exists for
the mooring tethers to fail. Therefore, the entire infrastructure will be
freely floating and will be transported by local currents, possibly into areas
of shipping traffic. Therefore, it will be necessary to apply safety exclusion
zones in the vicinity of the structure to attempt to eradicate risk to fishing
vessels, for example (
EPRI Report,
2004; Long Island Power Authority Report, 2007
).


 


There are also devices
that are positioned on the coast itself. These systems can generate
environmental issues regarding affected sediment transport regimes in the area
surrounding the installation. The altered patterns of distribution may
significantly impact other areas of coastline and develop issues such as
coastal erosion or habitat destruction.


 


Biological issues are
presented by the development of wave energy devices. The installation of
cabling and seabed mooring structures can directly affect local habitats and
thusly species success. The noise generated from such a development will also
possess the potential to impact on local ecosystems and could result in the
loss of motile species groups (
Long
Island Power Authority Report, 2007
).


 


References


 


Carbon Trust Report
(2005). Guidelines on design and
operation of wave energy converters
. Det Norske Veritas.


 


Long Island Power Authority Report (2007). Long Island Tidal and Wave Energy Study: An Assessment of the Resource.
E3 Inc. Energy and Environmental Services.


 


EPRI Report (2004). Offshore Wave
Power in the US: Environmental Issues
. Virginia Tech University.


James Parry
MSc Subsea Engineering

Mehran Vakil's picture

Personally speaking, I would like to say that each and every types of energy technology accompany by risks. Albeit, it is extremely important to consider the impacts associated with risks, it is more valuable to find some innovative methods to alter the conventional ones. As time goes by, introducing renewable energies for supplying energy have been reducing environmental impacts. But, it is an inescapable fact that more or less, all types of technology for producing energy are related with risks. Even Wave energy!!!
Generally it is true that the construction of any kind of structure in offshore has negative aspects on marine species and their habitats. Increase of this order of magnitude, causes worse effects as a result. It is also influenced by the characteristics of the mentioned region and their dwellers (Boehlert et al. 2007). The species which are in the most dangerous and unpleasant situation are seabirds. By virtue of food shortage, the researches reveal some reports about reducing in breeding by 53% (BBC 2012).
However, leakage of toxic materials during construction, exploitation and even decommission are the leading cause of water contamination (Ocean renewable energy 2012).Such a selfish humankind!!!!
But personally I would like to make an announcement for following these types of method for producing energy. Nonetheless they have some disadvantages, but these are inevitable.

REFERENCES:
1)BBC. Marine renewable 'risks' to seabirds studied [Online]. Available: http://www.bbc.co.uk/news/uk-scotland-highlands-islands-20407260 [Accessed 11/24 2012].
2)BOEHLERT, G. W., MCMURRAY, G. R. & TORTORICI, C. E. 2007. Ecological Effects of Wave EnergyDevelopment in the Pacific Northwest [Online]. Available: http://spo.nmfs.noaa.gov/tm/Wave%20Energy%20NOAATM92%20for%20web.pdf [Accessed 11/24 2012].
3)ENERGY, O. R. 2012. toxic chemicals in the marine environment [Online]. Available: http://www.oceanrenewableenergy.com/content/chemicals [Accessed 11/24 2012].

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