"You've got to be big in this sector, " he said.

He said the company was not considering investments in biofuels in central Europe or in Latin America, at least for now, although ethanol derived from Brazilian sugar cane is currently the most efficiently-produced ethanol.

The biofuels opportunity in the US, however, was as much about security of supply as about climate change. The US has no desire to replace dependence on oil from the volatile Middle East with dependence on biofuels from Brazil, he said.

He also ruled out entering markets for palm oil to make biodiesel. Palm oil extraction is considered among the most destructive practices for cultivating energy crops and is blamed for rapid deforestation in Indonesia and Malaysia.

NTR will also not be investing in "next generation" technologies for biofuels, which eventually promise greater yield from "cellulosic" plants such as switchgrass or forestry waste. Barry predicted that environmentalists would eventually have to choose between renewable, green biofuels and opposition to genetically-modified seeds, which would improve yields for ethanol production in crops other than sugar cane.

The energy and wastemanagement group posted results that pleased analysts.

The closely-held company that may float part of its business or a subsidiary, perhaps Airtricity, by 2009 as one scenario of a promised "liquidity event" for existing 43% shareholders the Roche family and Philip Lynch's One51 group, which owns 25.6%.

NTR reported overall group profits of 79.4m before tax and other factors. Revenues grew to 446.9m from 361.1m in the previous comparable 12 months.