Clean & Offshore Energy

Introduction

The scientific community now almost unanimously agrees that burning fossil fuels for energy should be phased out as soon as possible.  There are two major reasons for this.  One is that the fuel is being used up at least ten thousand times faster than it is being produced, and, therefore, will only last a few more decades.  The other is that burning fossil fuels releases by-products into the atmosphere, some of which enhance the so-called greenhouse effect.  This is causing the planet to become warmer and our climate to become unstable.

Recreational water users like us will feel the effects of climate change more directly than most other people.  Rising sea levels will interfere with surf spots causing some to disappear altogether; episodic storm events will cause severe and unnatural coastal erosion; intense bursts of rainfall will drive land-based pollutants into the sea; and freshwater inflow due to glacial melting could interfere with ocean currents and radically alter coastal water temperatures.

The general opinion amongst scientists that action must be taken immediately to reduce the effects of climate change, is shared by SAS.  One of the most important issues to address is the development and implementation of renewable, clean energy sources.

‘Renewable’ means that the energy is replaced at the same rate as it is used by us and ‘clean’ means that the method of converting the energy does not release harmful by-products (particularly greenhouse gases) into the atmosphere.  One difficulty at the moment is that the devices we have designed to convert energy this way are still quite cumbersome and inefficient, and we are so energy-hungry that we need a vast number of them to replace fossil-fuel-burning power stations.  We have to be careful to make sure that their very presence does not degrade the environment in such a way that the environmental benefits are outweighed by the costs.

The other problem is that most renewable energy sources are intermittent.  While we can simply choose how much fossil fuel to burn in a coal-fired power station, we cannot control when the wind, the sun and or the waves will produce energy for us.  One renewable energy source that might well go a little way towards alleviating this problem is tidal energy.  Although the tides are not related in any way to our demand for electricity, they are, at least, highly predictable.  The tides can be predicted weeks, months, years and even centuries into the future.

The movement of water on the surface of the planet due to the tides causes (a) vertical water movements at coastal locations and (b) horizontal movements of water along the coast, called tidal streams.  The vertical movements are magnified in places where there is a funnelling effect, such as in estuaries, and the horizontal movements are magnified in places where the flow is constricted, such as around headlands and between islands.  Importantly, both of these water motions can be exploited to turn electricity-producing turbines, hence produce electrical energy in a clean and renewable way.

In the United Kingdom, tidal ranges are large and tidal streams are strong, which means that a considerable proportion of the UK’s electricity could be produced from the tides.  The best areas are the English Channel, the Orkney Islands, Northern Ireland and the Bristol Channel.  At around nine metres, the Bristol Channel tidal range is one of the largest in the world.

Types of tidal energy converters

The two types of tidal water movement can be exploited by tapping off a small proportion of their kinetic energy to turn electricity-generating turbines in a similar way to either hydroelectric or wind turbines.  Energy can be extracted from the rise and fall of the tide by blocking off an estuary with a tidal barrage, or artificially trapping water in a tidal lagoon, and then redirecting the trapped water through a turbine.  Energy can also be extracted from tidal streams if a turbine is placed directly in the water flow.

There are currently many different design proposals for each type of tidal energy converter, and each one will have at least some effect on the environment due to its mere presence in the water.  Each individual proposal will be evaluated by SAS on a case-by-case basis.

Tidal barriers:  These need to be very large projects if they are to produce a reasonable amount of electrical power.  The largest one in existence is at La Rance in Northern France, built in 1966.  It consists of a 0.8-km wall of concrete across the estuary and generates about 240 MW of electrical power.  The Severn tidal barrier near Bristol, which is still being considered, would consist of a 16-km-long wall and would generate around 9,000 MW – about five percent of the UK’s electricity requirements.  It would cost several billion pounds to build.  A huge tidal barrier like the one proposed across the Severn Estuary would have a significant affect on the environment, which, in the long term, might outweigh the benefits.  The presence of a giant wall across an estuary, with two different water masses communicated only by a small opening where turbines are located, will modify the existing ecosystem in several ways; these include (a) increased concentrations of pollutants, (b) altered phytoplankton growth and (c) elimination of migratory fish species.

Tidal lagoons:  These are smaller schemes than tidal barrages; they produce less power but have lower environmental impacts.  A tidal lagoon is a circular concrete wall, mounted on the seabed just offshore, which artificially traps water on the incoming tide and releases it through electricity-generating turbines.  It could be thought of as a kind of ‘tidal buffer’ whereby the tidal energy is stored as potential energy in the lagoon and then converted to electricity in a controlled manner.  However, tidal lagoons are very much an unproven technology and the environmental effects are still unpredictable. They would probably not only affect the ecosystem, but also the local wave and current regimes and, hence, the coastal morphology.  To achieve a reasonable power output, a large number of these concrete structures would have to be installed along the coast.

Tidal Stream Turbines:  These are simply turbines that are put in the middle of the tidal stream flow to extract energy, similar to the way a windmill extracts energy from the air.  They are much smaller devices than tidal barriers or lagoons, and would have lower environmental impacts.  However, their energy output per unit is also very low, so a large number of them would be required to produce a reasonable amount of power.  They would probably be mounted on the seabed, in large clusters some distance from the shore to maximize tidal stream velocities.  The sheer number of them required would mean that some environmental impact would be inevitable.  Also, even though the principle is very simple, several practical issues still need to be resolved before the design is standardized, which could take several more years of research. 

Summary

Surfers Against Sewage is supportive of the aims of tidal energy as it has the potential to generate clean, safe, renewable energy and thus contribute towards combating climate change.

Tidal barrages have the potential to produce a large amount of renewable energy, but the environmental impacts are potentially extremely high.  Tidal lagoons are more practical, but are completely untested and could end up being just as harmful as tidal barrages.  Therefore, due to the inherent risks and uncertainty, SAS would not currently tend to support the building of tidal barriers or tidal lagoons.

The tidal stream turbine, although still very much in the research and development stage, seems to be the most versatile and potentially the least environmentally impacting scheme, and is therefore supported by SAS. However, devices should be suitably sited to avoid impacting on sensitive marine areas and with each application being considered on a case-by-case basis to ensure other marine users are protected and/or able to co-exist harmoniously alongside such devices.  Comprehensive environmental-impact studies should be undertaken to see whether or not the coastal environment will be significantly affected, both biologically and physically.

The Problem

We need to be able to find more ways of creating energy without damaging the earth. If we are unable to do this then we will continue to cause pollution, we'll continue to run out of our natural resources and we'll allow the continuation of damaging climate change.

The Solution

Renewable energy and marine renewable energy devices can harness the power in wind, waves and the sun and transform this into 'green' electricity - electricity that is produced without creating waste products such as nuclear waste or CO² as a by-product. Just as we harness energy from the sea to surf or windsurf our same playgrounds can be used in creating cleaner and safer energy. SAS believe that the UK (and the rest of the world) must embrace renewable energy for a cleaner and greener future!

Renewable energy needs to be harnessed, as the UK is signed up to the Kyoto Protocol. The Kyoto Protocol commits 38 industrial countries to reduce their CO2 emissions to levels less than 5% of what they were in 1990. This means a 10% reduction for the UK by 2010. The US was originally signed up to Kyoto but the current government decided that the mountains of scientific evidence were not enough. The US is also the world's largest polluter and showing no signs of slowing.

The main advantages of renewable energy are:

• It's a clean fuel and the alternatives produce some very damaging by-products.
• The UK has renewable energy sources in abundance with wind and wave action a constant year round resource. They're also at a peak in the winter when energy demands are also at there highest, so more than enough to meet our electrical demand.
• It doesn't cost the Earth. The first offshore wind turbines in the UK are currently producing power cheaper than the newest nuclear power station. The UK Government has produced reports showing wind power will be cheaper than nuclear power by 2020.
• There are examples of renewable energy working around the world. Opponents of renewable energy will state that we will still need power stations to back up energy sources for when the sun doesn't shine, the wind doesn't blow and there are no waves (sounds like a horrid day), but this is the same for every energy source. Nuclear power stations need back up power stations as they regularly go 'down' and are unable to get electricity to the national grid.
• People will also argue that it will mean job losses, but it would also create jobs. If 10% of the UK's electricity were meet by wind farms, approximately 36,000 new jobs would be created.
• It is a popular method of electrical production as the public become more aware of the problems associated with climate change.

Whilst there has been some talk over whether or not offshore renewable energy devices will present a threat to nearshore wave quality and "our surf", it has been deemed by most that the impacts on surfing will be negligible. Waves provide us surfers, windsurfers and kayakers with a natural source of energy to indulge our passion. There are enough waves to go round for us not to feel threatened by offshore renewable energy devices. What offshore renewables will help to bring us, however, is clean, green energy. SAS is continuing to call for consistent modelling and research in relation to the potential effects and placement of offshore renewable energy devices on surf and coastal erosion. Within a few years we will have a better idea of which renewable source of energy delivers the best performance - both in terms of harnessing energy, protecting the marine environment and all who use it for recreation.

What can you do?

There is a lot to do, but we can all start making a positive change today, now! REMEMBER Fossil fuel burning power stations are major producers of CO². To reduce the amount of CO² released by these power stations we can all change the way we use electricity. Small things such as:

• Ask yourself: "Do I need to turn this on now?"
• Turn off lights when not in use.
• Use energy efficient light bulbs and look for energy efficiency when buying electrical goods.
• Watching less Television.
• Only put the water in the kettle you need.
• Use a kettle to boil water for cooking.
• Place switch plugs on applications that drain standby power.
• Unplug unused appliances.
• Turn down your refrigerator.
• Insulate your house, keep the heat in, in winter and out in summer.
• Clean your refrigerator coils and fan.
• Dry your clothes on a line or drying racks.
• Wash your clothes in cold water.
• Configure power management on your computers.
• Program your heating more conservatively.
• Using long underwear and more quilts in the winter.
• Creating a cross draft to avoid the use of fans and air conditioners in the summer.
• Shut off your gas pilots during the summer months.
• Riding a bike or public transit to work as often as possible.

All of these suggestions and many more will help save the planet and oceans, most of them will save you money!!! It's a win win situation!!

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