Problems with Renewables

Over the last few decades the efficiency of renewable energy capture has steadily increased, while the cost of generating electricity from it has gradually fallen. Onshore wind power (captured on the land, rather than offshore – at sea), for example, costs 3-5 pence p/kwh compared to gas-produced electricity which is about 3 pence p/kwh. Yet despite this we are told that renewables will not be able replace fossil fuels. So the question is why not?

While some people object to wind farms as being noisy eyesores in an otherwise peaceful countryside, the main problem with them is that the electricity they produce tends to be intermittent – the wind doesn't always blow. And more consistent forms of renewable energy, such as wave power, are currently expensive, costing roughly 20 pence p/kwh, and they remain as yet unproven and impractical as a technology.

Also, despite the huge potential for wind and wave power in countries like the UK, critics argue that they don't scale well – filling the gap left by fossil fuels would require an unfeasible number of generators. And because of their intermittent nature it would not be possible to meet sudden peak demands in power.

Finally because much of the UK's renewable energy potential lies in remote locations, either onshore or offshore, efficiency of generation will be countered by energy required to transmit the electricity to denser populations.

Even hydroelectric dams, which are capable of producing huge amounts of easily regulated power, now have a question mark hanging over their 'renewable' credentials. Besides the creation of reservoirs damaging local ecology and often uprooting local people, there is now growing evidence to suggest that some hydroelectric dams actually produce several times more greenhouse gas than fossil fuel plants. The dams release both carbon dioxide and methane – the latter is of great concern since it is by far the most potent of the greenhouse gases.

Carbon dioxide is produced by rotting vegetation around the shoreline. As the water level falls and rises seasonally, vegetation grows, drowns and decomposes here, producing carbon dioxide. This 'drawdown' region can in some cases cover several thousand square kilometres.

Methane is produced by organic matter that is decomposing in the absence of oxygen under the water. Normally it remains dissolved in the water, but the churning turbines of the hydroelectric plant cause the gas to be released into the atmosphere.

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