Senators Lamar Alexander, a Tennessee Republican, and Jim Webb, a Virginia Democrat, say their bill was prompted by a shared belief that Congress is taking the wrong approach in trying to lower greenhouse gas emissions.

The Senate climate bill, which has White House support, would create a nationwide cap-and-trade system to cut emissions 20% by 2020 from 2005 levels. The House version passed in June seeks a 17% reduction. Both bills aim for an 83% improvement by 2050.

The Senate bill in its current form has no chance of passage, with Republicans unified in opposition and as many as 15 majority Democrats seeking major changes. In a bid to salvage it, co-sponsor John Kerry of Massachusetts is reaching out to opponents to find a consensus over content.

Alexander and Webb say that regardless of what support Kerry and the other co-sponsor, Barbara Boxer of California, can muster, they have strong doubts over cap-and-trade as a concept.

“And I have very strong reservations about the notion that we should apply different standards to ourselves in terms of global warming than other countries such as China,” adds Webb.

Speaking at the American Nuclear Society in Washington, DC, Alexander said their bill was separate from the Boxer-Kerry legislation. Unlike global warming skeptics in the Senate led by James Inhofe of Oklahoma, Alexander says he believes that climate change is an issue the US must address.

He argues the most effective way to slash carbon emissions is to double nuclear power generation and advance most forms of renewable energy. This would reduce dependence on coal, the leading source of carbon dioxide pollution when burned to produce energy, he says.

Alexander is a leading critic of wind power, arguing that wind turbines produce too little electricity for the space they occupy.

Proposed federal loan guarantees in the bill would go mainly to expand the number of nuclear power plants. The 104 current plants generated about 19.6% of US electrical output in 2008.

The Boxer-Kerry legislation does expand those guarantees to support financing of new nuclear plans, but not to the extent sought by Alexander and Webb.

Alexander estimates his bill would cost as much as $20bn over 10 years. During that period, the proposes to spend $7.5bn to research and develop advanced biofuels made from non-food feedstocks, batteries for electric cars, solar power, recycling spent nuclear fuel, and carbon capture and storage technology.

Alexander and Webb called those initiatives “mini-Manhattan projects,” recalling the US programme during World War II to develop the atomic bomb.

Their bill also would spend $100m a year over a decade to train and educate nuclear engineers and technicians