Coal-fired power station operator, Drax, has announced a 28% jump in first half pre-tax profits.The company said that for the six months to the end of June profits before tax had risen from £132m in 2010 to £169m.It said the results were underpinned by strong hedging and continued good operations.However, it warned full year underlying profits would be lower than in 2010, something it said had already been recognised in market forecasts.Drax is pushing up it's interim dividend by 13%, from 14.1p in 2010 to 16.0p this year.Chief executive, Dorothy Thompson, said the firm had delivered "excellent performance across the business in the first half of 2011".The firm also said it was ready to expand its renewable capacity significantly as long as the Government provided the "appropriate incentives"."Drax generated around 6% of the UK's renewable power in the first half of 2011; double the renewable output of any other facility," Thompson said."Biomass burnt at Drax delivers carbon footprint savings of over 50% compared to a typical gas-fired generating plant," she said."However, we continue to operate at less than our installed renewable capacity because of the current low level of regulatory support for electricity produced by burning sustainable biomass instead of coal."