Mindless Renewable Energy Targets

In the almost mindless race to meet the United Kingdom’s emission targets the government has decided to subsidise, at taxpayer’s expense, the generation of electricity in a way which will mean the creation of far more greenhouse gas emissions.

This strange and dangerous decision has arisen because emission targets by the European Union and by the government make no distinction between clean renewable energy and dirty renewable energy. Clean renewable energy is, of course, a definition of relative cleanliness, not one of absolute cleanliness and dirty renewable energy is simply energy that produces relatively large amounts of emissions.

Clean renewable energy includes generating of energy by such means as solar water heating, wind turbines and photovoltaic energy, where you use the infinitely renewable resources of light and wind. Wave and tidal energy also falls into this category.

Dirty renewable energy is energy generated from sources that involve burning some kind of crop; burning ethanol derived from corn has been proved to be renewable but far dirtier, in terms of emissions, than burning oil. The fact that an energy source is renewable or potentially renewable does not make it benign as far as the environment is concerned, but governments fail to realise and act on the important distinction between clean energy and dirty energy.

The latest folly is the decision to burn wood at Drax power station in North Yorkshire, instead of coal. Burning wood is technically renewable because you can grow more wood. You cannot grow more coal. However wood burning creates as many greenhouse gases as coal burning so the harm to the environment will continue at Drax when they start to burn wood.

There is not enough locally grown wood to serve Drax. There is not enough British cropped wood to serve Drax. Wood, with its low calorific value in relation to its volume, will be shipped from all over the world and transported to Drax in order that it may burn there. Of course in most cases new trees will be replanted which will absorb some of the carbon dioxide emissions but overall the effect on the environment will be as damaging as continuing to burn coal.

Cutting emissions at Drax would be improved if instead of burning wood or coal the power station burnt natural gas, which produces about a third of the emissions per kWh that burning wood or coal produces. Burning woods does not count towards the emission targets, even though burning wood creates as many emissions as burning coal. A metric tonne of bituminous coal (the sort commonly burnt at UL power stations) yields 27-30 GJ or energy  A metric tonne of bone dry wood yields 18-22 GJ. The simple maths indicates that the fuel transportation environmental impact will increase by at least 50% when Drax starts to burn wood. This in itself will create more emissions than coal burning does at present.

All of which goes to show that the target becomes more important than the underlying rationale for the target.

Filed under: biomass, carbon emissions, climate change, electricity, energy, global warming, renewables, solar, solar panels, targets Tagged: clean renewables, dirty renewables, Drax Power station, energy policy, energy yield of coal in GJ per tonne, energy yield of wood in GJ per tonne, natural gas, renewables, wood burning, wood burning power stations