Russia has taken a step towards opening its energy sector to foreign investment at the G8 meeting in St Petersburg.
Many fear that the use of fossil fuels is harming the environment
The group agreed to "open, transparent" energy markets and to nuclear energy as a power source for those who want it.
Russia had faced calls from the EU and US for increased international energy co-operation, amid fears Moscow may use energy as a tool of foreign policy.
However Russia, a major oil and gas producer, did not ratify the Energy Charter, an international rulebook.
But the G8 leaders did express, in principle, their support for the Energy Charter treaty, which calls for open access to energy resources and transport infrastructure.
The European Union has been pressing Russia, which supplies a quarter of the continent's gas, to fully ratify the charter which it has signed.
G8 SUMMIT: 15-17 JULY
The world's seven richest nations - the US, Japan, Germany, France, Britain, Italy and Canada have met annually since 1975
Russia joined in 1998, turning the G7 into the G8
2006 summit to be held in St Petersburg - the first time Russia has hosted the G8
Energy security, infectious diseases and education are on Russia's agenda
Mid-East crisis, Iran, North Korea, and international terrorism are also likely to be discussed
"Energy is essential to improving the quality of life and opportunities in developed and developing nations," the leaders' statement said.
"Ensuring sufficient, reliable and environmentally responsible supplies of energy at prices reflecting market fundamentals is a challenge for our countries and for mankind as a whole," it added.
The statement comes after months of rising oil prices - including a new spike following the Israeli action in Lebanon.
Concerns were also raised earlier this year when a dispute between Russia's monopoly supplier, Gazprom and Ukraine over prices threatened gas supplies to Europe.
A BBC World Service survey of 20,000 people in 19 nations in early July found that, on average, 45% trusted Russia as an energy supplier.
It is against this background that the UK government recently announced the go-ahead for a new wave of UK nuclear power stations, as part of the mix of energy supply for the next 40 years.
"Those of us who have or are considering plans relating to the use and/or development of safe and secure nuclear energy believe its development will contribute to global energy security, while simultaneously reducing harmful air pollution and addressing the climate change challenge," the G8 said.
Most G8 countries have been looking again at the development of nuclear energy as an alternative to fossil fuels, but Germany is not supportive and plans to phase out nuclear energy by the early 2020s.
And German officials have been keen to stress a phrase on the G8 statement that says: "We are committed to further reduce the risks associated with the safe use of nuclear energy."