Electricity from trees 'dirtier than coal'
Last modified: 12 November 2012
Burning whole trees in power stations can be dirtier than coal, a new report by environmental NGOs (1) concludes.
The report uses the UK Government’s own data to show that burning whole trees to generate electricity is worse for the climate than coal: generating power from conifer trees results in 49 per cent more emissions than burning coal.
The report follows a series of announcements from major coal power stations in England (2) that they intend to switch over from burning coal to burning wood. In Scotland, there is already one large-scale biomass plant, near Lockerbie, and another approved near Markinch, with several others proposed, although one controversial proposal, in Leith, has been withdrawn.
RSPB Scotland is calling on both the UK and Scottish Governments to ensure they do not subsidise burning whole trees in coal power stations and new ‘biomass only’ power plants. Instead, they want Government to focus on building a small-scale bioenergy sector based on sustainable UK feedstocks, including wood waste and arisings from forestry, as well as continued investment in clean, green renewable energy such as solar and appropriately located wind and wave power.
The report would follow the Scottish Government’s Draft Electricity Generation Policy Statement which “strongly advocates the deployment of biomass in heat-only or combined heat and power schemes, generally prioritised in off gas-grid areas, at a scale appropriate to make best use of both the available heat, and of local supply” (4).
Stuart Housden, Director, RSPB Scotland said:
“When trees are burnt in power stations, CO2 comes out of the chimney, just like it does when you burn coal. The difference is that the wood is less energy dense and is wetter than coal, so it takes a lot more energy to harvest, transport, process, and finally burn it. Governments have justified burning trees in power stations by claiming the chimney emissions are offset by the carbon that the forest takes up when it re-grows after being harvested, but this is misleading. It can take decades, if not centuries for the trees to recapture that carbon, leaving us with more emissions in the atmosphere now – when we least need it.
“Worse, the idea that there is enough wood to keep our lights on without endangering the world’s forests is equally misguided. If Government subsidies go ahead, this report shows that we will be burning 30 million tonnes of wood each year. That’s six times the total UK harvest. (5)
“This massive demand for wood will result in traditional industries that depend on wood –for furniture and building materials which ‘lock up’ the carbon they contain over many decades, for example - losing out and instead having to use other materials like plastic and concrete, which are worse for the environment. We want to see Government excluding the burning of whole trees on subsidies, and focusing instead on supporting clean, green renewable energy, including small-scale bioenergy schemes and the use of wastes such as waste wood and forestry arisings in energy generation
“Both the UK and Scottish Government’s are currently consulting on biomass subsidies (6). The Scottish Government’s consultation is to be commended in rejecting the idea of subsidies for large-scale, electricity only plants over 10MW. However, as proposed, there are loopholes that would allow large scale biomass burning if linked to very low standard CHP, or when co-firing oil or coal plants. We hope the Scottish Government will continue to follow its positive approach – while closing any loopholes – and that the UK Government will follow suit.”
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