The Australian and United States governments have pledged to make solar energy cheaper in the next five years.

The Federal Government is investing $50 million on joint solar power research projects with the US, to cut the cost of the technology to that of conventional power sources.

The US secretary of state, Hillary Clinton, says solar energy should be more affordable by 2015.

"We have a common goal of making solar energy competitive with conventional sources by the middle of this decade, 2015," she said.

"The good news is that the price of photovoltaic modules have dropped about 50 per cent in the past three years. But to meet our goal, we have to drive the price down even more."

Prime Minister Julia Gillard and Ms Clinton met in Melbourne today.

Ms Gillard says solar technology has real potential, but needs a boost.

"The price of solar technology has come down in recent years but we need to accelerate that trend," she said.

Ms Clinton also says US president Barack Obama's decision to abandon his climate change policy should not stop other countries tackling the issue.

Mr Obama conceded he has little chance of passing his cap-and-trade plan after the Democrats fared poorly in the US mid-term elections.

Deputy Opposition Leader Julia Bishop has seized on the comments.

"There'll be pressure on the Labor Government to drop its price on carbon policy," she said.

But Ms Clinton has stressed the president was only referring to the situation in the US.

"Decisions in Australia are up to the Government of Australia and the people of Australia," she said.

Julia Gillard agrees, saying the Government is still determined to put a price on carbon.

"We will determine our own national strategy in our own national interest," she said.

Ms Clinton spent this morning answering questions on climate change, Afghanistan and gay marriage at a public forum at Melbourne University.

This afternoon she took time to meet Opposition Leader Tony Abbott.