Renewable Energy, anyone would think, is the answer to all our energy issues. It’s all we seem to hear or read about. Indeed the climate change agenda seems to have hijacked any sensible debate about solving the energy crisis facing us – putting renewables forward as the first and only solution to minimising reliance on carbon based fuels. But are wind, solar and tidal power really the answer to affordable, plentiful and green electricity? And how do they measure up to other sources of power?
The facts:
* Only provides occasional or ‘chaotic’ power generation – when the wind drops or the sun goes down, the power stops – and so you need immediate back-up capabilities from other sources of conventional power
* Not as green as you might think when you take into account the complete lifecycle of each technology
* Very heavily subsidised – power generated is twice the cost of conventional power generation.
* Requires huge installations to deliver equivalent volumes of power
* Not able to offset the planned retirement of coal-fired and nuclear power stations
* The “quality” of our electricity is very important, since microprocessors and electric motors rely on the stable voltage and frequency of the supply to work properly. It was an important achievement of the 1926 Electricity Act to unify the voltage and frequency throughout the UK by joining up selected large power stations, working in unison through the “Grid”, to give us our present reliable high quality electricity. A multitude of turbines is reversing this process, and if continued to any great extent, would endanger the quality of our electricity and possibly cause power cuts.
Back Up Power
While the idea of free renewable energy sounds great as a concept, in fact self-renewing minimal carbon energy can actually be very expensive to produce as it can’t be stored and is only available at the time of generation.
The national grid relies on a steady controlled generation of power from generators and turbines which can be supplemented by occasional “chaotic” power generation but cannot depend upon it. To avoid black out and “crashing” the grid, wind power and other renewables must be supplemented at all times by a back up generation capability equal to 80% of the installed renewable energy capacity, so that when the wind drops, the tide turns or day turns to night, there is an 80% reserve to avoid failure.
Wind
Wind provides an inconsistent, chaotic and very dilute source of power requiring huge installations to generate the same output as a single power station – an equivalent wind farm would need to be in the region of a 1000 times bigger site (covering a lot more valuable land.) And, after 18 years’ development, wind power still produces only about 1% of the nation’s electricity. Take for example the Anglesey Wylfa Nuclear Power station and adjacent wind farm which takes up 1500 times as much land.
It’s both costly to set up and costly to keep running, and without the heavy subsidies that are available, many of the existing and proposed wind farms we currently see today would simply go away, since they would be uneconomic. The fact is the power generated is more than twice as expensive as that of conventional power. And on top of all this there is a large body of opinion that believes we shouldn’t be investing in technology on a scale that blights the landscape and damages eco-systems.
Solar
The issues with Solar energy are much the same as wind. It can only be collected 50% of the time ie during daylight, and only then when there is no heavy cloud cover. The fixed solar panels vary in output throughout the day, as sun rises to a maximum and then declines. Therefore efficiency is low until improved photo voltaic technology is developed. Heat collectors on the roof to warm up water for domestic or industrial use are useful, however they aren’t a recipe for self sufficiency. Even in perfect conditions, the amount of energy available has a modest upper limit.
Wave power – tidal streams
For tidal streams to generate a reasonable amount of energy ie 1000 MW, 1000 turbines are needed. The capital cost is quite high, the carbon emissions are low, but as the generation of tidal power is not constant and electricity can only be generated when the tide is running, it too has to be supported by 80% of the installed renewable energy capacity, to avoid black outs.
Biomass – burning wood for energy
Burning wood instead of fossil fuels has its own problems. To plant enough willow to keep a single 1000 MW (e) power station operating would cover an area bigger than Kent. As wood is cellulose, a carbohydrate, less than half of its weight (the carbon part) burns to produce heat, the rest evaporates as water; it is thus half as productive per tonne as coal, and while green, is actually poor in energy.
Current UK renewable energy accounts for less than 5% of UK power production and this is mostly from hydro-electricity (regarded as a fully-developed sector) and burning waste. Wind power still produces only about 1% of the nation’s electricity. This lags well behind Government targets calling for 10% of electricity generation by 2010 and 15% by 2015, with an “aspiration” of 20% by 2020.
Land requirements
To produce 1,000MW of electrical energy – the size of an average power station – nuclear requires the equivalent of a mere 10 soccer pitches. Wind (when it is blowing) requires an area the size of Dartmoor, and solar would need half as much again; biomass (wood) needs a forest the size of Wales. Britain needs at least 55 1000MW(e) power stations to meet peak demand and renewables come nowhere near to meeting the requirement.
So what to do? We certainly shouldn’t discount renewable energies. Where they make sense they have a useful contribution to make and help us to meet our green targets. But to deal with the energy crisis facing us in terms of the growing gap between capacity and demand we have to refocus the debate and look at a balanced power generation solution for the UK, embracing a mixture of technologies which above all includes Nuclear. The process has been taken much further in France where over 80% of their electricity is produced by nuclear power, and a further 13% from hydro-electric schemes. The UK imports electricity from France in times of high demand.
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