Vegetarians gazing at their Christmas tree lights may be forgiven for feeling a little queasy. The electricity used to power the decorations may have been generated from a power station using rendered animal fat, or tallow, as a fuel.
Generators, trying to meet their climate change targets and qualify for financial incentives under the government's renewable energy scheme, have been burning an increasingly esoteric range of products.
Aberthaw coal-fired power station in Wales, owned by Npower, a subsidiary of RWE, the large German utility, employs tallow - used for centuries to make candles and soap - as a substitute for heavy fuel oil to ignite the coal.
Sawdust, another so-called biomass fuel, which qualifies for renewable obligation certificates is also mixed with the coal at Aberthaw to help the company get even closer to its climate change target. Government requires electricity suppliers, such as Npower, to generate or acquire at least 10 per cent of their power from renewable energy sources by 2010. Burning biomass products such as straw or wood qualifies as the products are carbon-neutral, emitting no more carbon dioxide than is taken in when they grow.
The Royal Commission on Environmental Pollution has estimated that biomass could produce up to 12 per cent of the UK's energy needs by 2050. Tallow, produced from cows and other grass-eating animals, however, will cease to qualify as a renewable energy fuel at the end of next year as European Union rules say it must be classified as waste.
Scottish Power, which burns about 45 per cent of Scotland's sewage sludge - enough, it says, to power a town of 100,000 - at its Longannet power station is considering appealing aga-inst a similar EU ruling that would stop the dried sewage pellets qualifying as an organic fuel.
This would still leave plenty of other organic materials generators can burn. Npower incorporates sawdust and palm nut kernels at its coal-fired Didcot power station in Oxfordshire and also burns palm kernels at Tibury in Essex.
Powergen, owned by Eon, another large German utility, incorporates cereal waste at its Kingsnorth power station in Kent, while the French-owned EDF Energy consumes about 400 tonnes of olive cake and 35 tonnes of woodchip a day at stations in Nottinghamshire.
Government, by allowing power stations to mix organic fuels with coal, hopes to encourage farmers to grow green energy crops for dedicated biomass-only power stations.
To encourage the transition, the proportion of biomass which can be co-fired with coal is set to fall from 25 to 10 per cent in 2006 dropping to just 5 per cent between 2011 and 2016. From 2009 at least 25 per cent of biomass fuel must come from purpose-grown crops rising to 75 per cent by 2011.
Growers will require the financial security of long-term contracts before they plant new crops, Lord Whitty, farming minister has warned. Npower has signed a 10-year agreement for at least 30,000 tonnes a year of fast-growing willow for its Didcot power station.
