U.K. power producer ScottishPower plans to substitute energy crops grown by local farmers for coal burned today at Scotland's two coal fired power stations.

But it's apparently only expecting limited benefit for the investment.

Up to to produce 250,000 tonnes of purpose-grown biomass are to provide fuel for the company's Cockenzie and Longannet coal power plants.

ScottishPower already burns biomass such as wood at the stations as part of its renewable program.

Energy crops provide carbon neutral fuel, given that the CO2 that is released when the crop is burned is equal to the CO2 captured as the plant is grown.

The project is to use about 12 percent of Scotland's total agricultural land—roughly 35,000 hectares—yet is expected to displace only 5 percent of the company's coal requirements by 2013, the company acknowledged today in a statement.

The crops are to be a mix, including cereal crops and short rotational crop such as willow coppice.

ScottishPower, now part of the Iberdrola group plans to grow the crops on marginal land where possible, so as to minimize impact on food crops.

ScottishPower is the U.K.'s largest generator and developer and operator of on-shore wind energy.

The company calls the move "an excellent opportunity for farmers with ScottishPower offering support for the Scottish agricultural community."