People who follow the solar energy industry have long known that increasingly efficient photovoltaic technologies will allow clean energy to become more affordable than ever in the coming years. However, another area to focus on when it comes to holding down costs will be the materials that are needed to make renewable energy a reality.

A recent report from the United Nations Environmental Programme stated that an important part of the worldwide trend toward clean energy technologies will be the rate at which high-tech specialty metals can be recycled.

These metals include lithium, neodymium and gallium. Their uses range from solar photovoltaic panels to batteries for hybrid electric vehicles - but they also tend to be in limited supply.

The report noted that only about 1 percent of these important metals are currently recycled - and that failure to improve this situation and establish a stable long-term supply can make them "essentially unavailable for use in modern technology."

"Urgent action is now clearly needed to sustainably manage the supplies and flows of these specialty metals given their crucial role in the future health, penetration and competitiveness of a modern high-tech, resource-efficient Green Economy," said Achim Steiner, director general of the UN Environmental Programme.