Presdiential candidate John McCain last night outlined his energy and environmental policy, lashing out at Barack Obama's lukewarm support for expanded nuclear power and US oil drilling in an attempt to draw a distinction between the two candidates' green policies.

Speaking to the US Republican Party Convention in Minnesota, McCain echoed Obama's commitments to reduce dependency on Middle East oil, build more nuclear power, develop clean coal and increase investment in renewables and developments such as flex fuel, hybrid and electric cars.

"My fellow Americans, when I'm president, we're going to embark on the most ambitious national project in decades," McCain said. "We are going to stop sending $700bn a year to countries that don't like us very much. We will attack the problem on every front."

However, he also sought to outline differences between his campaign's energy policy and that of the Democrat candidate by attacking Obama's position on nuclear power and plans for an increase in oil drilling in the US. "Senator Obama thinks we can achieve energy independence without more drilling and without more nuclear power. But Americans know better than that," he said.

In his speech to the Democratic convention, Obama had made a commitment to " safely harness nuclear power" but provided no overt investment pledges. He has said that he is open to expanded nuclear energy, but has mentioned no numbers, citing concerns over the security of nuclear waste. He has also opposed the Bush administration's plan for storing waste at Yucca Mountain in Nevada, which Mccain supported.

In contrast, McCain is on record as calling for the construction of 45 new nuclear power plants by 2030.

He also reiterated his support for more oil drilling in the US yesterday, telling delegates that "we will drill new wells offshore, and we'll drill them now."

It is a stance that has attracted accusations of "flip-flopping" from the Obama camp, which has highlighted the fact that McCain supported the moratorium on offshore drilling during his first presidential campaign back in 2000.

But Obama has shown inconsistencies in green policy too. Despite his high-profile support for renewables, he co-sponsored legislation to subisidise the production of liquid coal in his home state of Illinois, albeit on the condition that the resulting fuel emitted 20 per cent less carbon dioxide than conventional fuels.

There was further evidence of differences between the two candidates in McCain's failure to mention biofuels in his speech. Obama had proposed investment in the "next generation of biofuels", but McCain said earlier this summer that he wants to eliminate biofuel subsidies.

McCain's voting record shows a reluctance to support tax credits as a way to spur greater use of alternative energies and energy efficiency. "When government jumps in and distorts the market, there are unintended consequences as well as intended," he told US businessmen in Washington in May.