Drax's vision of producing coal-free energy

The coal-powered plant, the UK's biggest single source of carbon emissions, said it is starting design work on converting one of its six units to burn only biomass – fuel derived from natural materials such as straw, wood and energy crops.

Drax already has capacity to generate 500 megawatts (mw) of electricity from biomass co-firing, and said it is progressing with plans to build three new 290mw biomass power stations.

Converting one of its 650mw units to burn only biomass would be a massive step to reducing the plant's carbon emissions. But Drax said this will only be possible with Government support and called for increased subsidies and regulatory change.

"What we could do over time is convert other units to burning biomass," said Drax finance director Tony Quinlan. "Over time we would have an option for Drax to be (solely) a biomass burner. It would be one of the biggest clean power stations in the world".

Drax said its biomass ambitions are held back by lack of Government support which makes burning biomass more expensive than coal. Production director Peter Emery said producing heat from biomass is around two to three times more expensive than generating it from coal.

The plant recently added 400mw biomass co-firing capacity at a cost of 80m, but said it is only viable to run it at 250 to 300mw due to high biomass fuel prices. Earlier this year Drax even threatened to take biomass plans abroad.

"What we feel is that both the amount of support and the quality of support is inadequate for biomass," said Drax chief executive Dorothy Thompson. "The problem is that we are prone to policy changes every few years because in the current framework there are no long-term policy provisions like we have in the offshore wind sector, and that is a huge risk for potential investors."

She said biomass generation receives only a quarter of the financial support enjoyed by offshore wind, and that support can be subject to change every four years. "That's too much uncertainty to underpin what's really a major investment," she said.

Mrs Thompson said that biomass carbon savings over coal generation are 75 to 95 per cent and savings over gas generation are 50 to 60 per cent

If the conversion goes ahead the unit would generate about 455mw or 70 per cent of its current capacity, and run initially as a demonstration. Mr Quinlan said conversion would cost much less than building a new plant, and would take about 18 months.

Drax plans to build three 290mw biomass plants under a partnership with Germany's Siemens Project Ventures at an estimated cost of 2bn. Mrs Thompson said sites have been selected at Selby and Immingham, and a third is yet to be decided.

Under Britain's renewable energy support scheme, the Renewables Obligation (RO), the amount of renewable energy that can come from burning biomass instead of coal is capped.

Drax last night launched its vision for biomass at the House of Commons with a paper called Biomass: the fourth energy source.

A spokeswoman for the Department of Energy and Climate Change said it is consulting on biomass support. "We welcome Drax's commitment to sustainable biomass and to further reductions in carbon emissions," she said.

"We expect to carry out a Renewables Obligation banding review starting October. This will assess the appropriate level of support necessary to support biomass co-firing and whether the cap should remain."

'The world's fourth largest energy resource'

BIOMASS is an organic plant-based material.

Drax argues it is the world's fourth largest energy resource, behind oil, coal and gas.

It can be derived from agricultural residue such as oak husks, straw and cocoa shells. Forestry also produces residue such as bark and branches, while materials destined for landfill also contain waste wood.

Farmers in Yorkshire also provide Drax with energy crops such as miscanthus or elephant grass which are specifically grown to be burnt.

Drax committed to only using biomass that is derived sustainably, and gives at least a 70 per cent carbon saving relative to coal.

It said this can be sourced from anywhere in the world.

The International Energy Agency estimates that by 2050 sustainable sources of biomass could meet 10 to 20 per cent of the world's primary energy needs.