Speaking at the European Bioethanol Fuel Conference in Brussels, Mr Piebalgs said biofuels would be key to Europe meeting its new target to source 10% of its transport fuels from renewable sources by 2020.
"Biofuels are just about the only large-scale option currently available to diversify fuel sources in the transport sector," he said as he pointed out that 98% of transport fuel in Europe comes from crude oil.
<<but it wasn't reported what the other large scale options might be>>
But as he laid out Europe's biofuels ambitions, Mr Piebalgs downplayed last year's controversy over biofuels, in which claims were made that the rise in global food prices was a direct result of increased biofuels production.
Addressing another concern, about the land available to grow biofuels energy crops, the commissioner said Europe had enough capacity to hit the Directive's 10% target using its own domestic agriculture - although global free trade rules would prevent a domestic-only approach to biofuel crops.
<<dubious - a general estimate is that each 1% of fuel for transport in the EU requires 1% of EU land area>>
Along with greenhouse gas savings requirements, the new Directive's sustainability criteria also sets restrictions on using land with a high biodiversity to cultivate crops to turn into biofuels, as well as land with a high "carbon stock" - like rainforest or peat bogs.
The Commission has also said it will examine the issue of indirect land-use change - for example where biofuel crops could displace food crops, forcing them to be grown in areas with a high biodiversity - before making recommendations in 2010.