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Renewable Energy

The Mynydd Llansadwrn Action Group recognises the need to reduce reliance on fossil fuels, but, in our view, the way forward is not highly-subsidised large-scale wind power installations. The wind turbines being proposed for Mynydd Llansadwrn and across Wales are huge industrial machines; installing them, building the concrete bases, the access roads, the cable trenches and pylons needed to connect to the national grid would inevitably have damaging effects on wildlife and the local environment. Once turbines are up and running there are the problems of bird kills, light flicker and noise pollution, especially low-frequency noise. The damage to the landscape and the lives of the people who live near these turbines far outweighs their effectiveness

The argument for wind farms is the need to reduce carbon dioxide emissions. But wind power is an intermittent and unreliable source of energy and, therefore, needs total backup from gas, oil, coal or nuclear power plants. Not one conventional power plant will be closed as a result of building wind farms.

We argue that wind farms, because of their relatively low and intermittent output and their high environmental costs, are the least viable form of renewable energy. Electricity generated by wind farms is also the most expensive when costs of duplicate plants needed as backup are taken into account. There are more effective and cheaper options available.

Here is a brief summary of some alternative forms of renewable energy under the following headings:


Photovoltaics


Photovoltaic cells convert solar radiation - daylight - directly into electricity. The technology, first used for powering satellites, is increasingly used to meet electricity needs, particularly in locations without access to a grid. Photovoltaic cells provide clean, silent electricity at point of use. It has been estimated that if all the available roofspace in the UK were covered in photovoltaic cells, there would be enough electricity generated to meet all our needs.

Although the technology is expensive, the price continues to fall. Even now it is cheaper to cover office buildings with photovoltaic cells and get free electricity from the sun than it is to cover them with cladding. The cost of photovoltaic cells for the average house is between 8,000 and 16,000, but there are 50% grants available.

Solar panels have been installed along a 50-metre stretch of the M27 near Portmouth. The electricity generated will be fed back into the local electricity grid and used locally for street lighting, street signage, or sold back to electricity suppliers

Woking, in Surrey, is entirely energy self-sufficient, with groups of homes hooked up to roof- mounted photovoltaic systems and integrated with combined heat and power systems. At night when photovoltaic cells are not operating, the combined heat and power plant starts up. The town also has solar- and wind-powered street lamps and solar-powered parking machines.

In order to get around regulations that protect privatised power stations, Woking Council had to install its own wiring to all the properties that take its electricity. Despite this added expense, electricity in Woking cost 1p less per unit than energy from the grid. Woking now saves an estimated 974,000 a year in energy bills.


Fuel cells

The fuel cell, invented in 1839 by British physicist Sir William Grove, produces electricity and heat by combining hydrogen and oxygen in an electrochemical process. Fuel cells are similar to regular batteries except that the fuel and oxidant are stored externally, so they can continue operating as long as the chemicals are supplied. In most cases, the oxygen is taken directly from the air, so only the fuel has to be stored. Hydrogen that burned off at oil refineries is a perfect fuel for fuel cells.

Developers of fuel cells claim that in the future households will be able to produce their own electricity using this technology.

Fuel cells have virtually no emissions; water is their only by-product. The electricity is generated close to where it is used, reducing transmission losses.

The only fuel cell power station in Europe is in Woking, Surrey. Here, the power station provides a steady supply of pure water as a by-product of combining oxygen and hydrogen to produce electricity.


Biomass

Burning wood - biomass - is the oldest form of renewable energy. Biomass is carbon-based so it generates carbon emissions when burned as fuel, as do the fossil fuels such as coal, oil and gas. However, the biomass used for power generation is supplied from living, sustainable stocks such as fast-growing willow, wood chippings, forestry wastes and agricultural wastes, which means that the carbon released during combustion is subsequently re-absorbed during the growth of replacement crops. Burning biomass is part of the earth's carbon cycle. Burning fossil fuels, on the other hand, releases carbons that are not part of the carbon cycle and, therefore, add to the carbon burden of the earth's atmosphere.

Recent developments in biomass technology have increased combustion efficiency, so more energy is being recovered from the same amount of fuel compared to a few years ago. There is currently a straw-fired power station in East Anglia.


Biogas

Biogas technology uses landfill gas, mostly methane, to generate electricity. Biogas energy plants in Europe use pig slurry, horse manure or sewage sludge to produce energy. Development of domestic refuse digesters that produce compost and biogas offers potential for electricity generation for local use, while at the same time reducing the need to burn rubbish.


Tidal power

Tidal barrages exploit the natural rise and fall of coastal tidal waters to generate electricity, in much the same manner as traditional hydroelectric power plants. The incoming tide fills a dam structure and then the water is let out through turbines to generate electricity. Because tides are predictable, tidal-power production is reliable and predictable. Conditions under sea are not affected by storms and waves as are offshore wind turbines, and tidal turbines are out of sight and produce no noise. However, barrages are expensive to build and there are environmental concerns associated with them.

Tidal lagoons generate electricity in the same way as barrages, but they are constructed in exposed or very shallow areas of the seabed and, therefore, do not block the entire estuary. The world's first tidal lagoon is being designed for Swansea Bay.

Undersea tidal turbines are like underwater wind turbines, but they are out of sight and have a predictable output. Trials of the Seaflow tidal power project show that a 1MW tidal turbine can access 5 to 10 times more energy per square metre of rotor than a 1MW wind turbine, resulting in a smaller and potentially lower cost machine.

Wave power

Wave power is concentrated wind energy, with the added advantage that waves are still there even when the wind drops. Wave-energy devices, operating either on the shoreline or in the deeper waters offshore, convert wave energy into electricity.

For the latest developments in wave power see this article from The Economist newspaper's Technology Quarterly dated June 7, 2008. Click here to download the article in MSWord format.

The most common device is the oscillating water column. A partially submerged hollow structure encloses a column of air on top of a column of water. Waves in the water column alternatively compress and decompress the air column, which drives a turbine to generate electricity.

The first commercial wave-power station, using the oscillating water column system, was installed on Islay in Scotland in 2000. The surplus power from the station is used to charge up an electric bus for the island.

Test are underway for other offshore wave-energy devices such as 'sea snakes' - floats that bob up and down to generate electricity.

According to the government's Performance and Innovation Unit, by 2025 there will be enough wave-power technology available to provide 10% of the UK's electricity needs.


Hydroelectricity

Hydroelectricity exploits the potential or kinetic energy of flowing water - from reservoirs, rivers or tidal currents - to drive a turbine connected to an electricity generator. Hydroelectric power accounts for about 2% of the UK's total installed electricity generating capacity.

Large hydroelectric dams are always controversial because they flood valuable land, but there are many opportunities for small-scale hydroelectric projects that use the thousands of old mill sites.


Wind energy - Offshore

For the latest developments in offshore wind see this article from The Economist newspaper's Technology Quarterly dated June 7, 2008. Click here to download the article in MSWord format.

The government has recently announced a 6 billion programme to build giant wind farms in three places off the UK coast. The advantage of building offshore is that the wind strength is more constant than onshore, and the turbines themselves can be even larger than those built onshore. However, it is more expensive to build offshore and power grids have to be built to bring the electricity ashore, wasting some of the power along transmissions lines. There are also recognised environmental problems and disruption to seabird nesting and migration patterns.

A mini wind turbine, developed by a Scottish inventor, is designed to fit on roofs, walls, chimneys or independent supports and supplement the electricity supply coming into a building. Spiral turbines are also being developed to operate on office buildings and homes; these can operate in turbulent wind conditions that could damage traditional turbines.

Small turbines still have problems of intermittency and noise but they can provide a valuable supplementary supply of electricity to homes and offices; on a local scale they could be used to power street lamps and signage via a battery.

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Mynydd Llansadwrn

What the politicians say

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Wind Turbine Facts

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