Saudi Arabia is investing in solar power and hopes to become the world's leading supplier in this sector, Saudi Arabian Oil Minister Ali Al-Naimi said on Monday.

'The world's largest oil exporter also hopes to be the world's leading solar power provider someday,' he said, suggesting the solar sector would broaden the kingdom's economic base.

However, he said fossil fuels will be vital for the world's energy for decades to come and must be made cleaner and more efficient.

'Given their massive scale, non-renewables will remain the world's energy workhorse for many decades to come,' he told an energy and environment conference.

'While the days of easy oil may be over, the days of oil as a primary fuel source for the people of the world are far form over,' said Naimi, speaking for the world's top oil exporter.

'... there is no excuse to pin our hopes only on alternatives which today are just supplemental energies,' he said. 'Our immediate focus, then, must be to make fossil fuels cleaner and more efficient.'    

'All energy sources will have a role to play in meeting future demand,' Naimi said.

 The minister had attended Opec's Sunday meeting in Vienna which had agreed to hold oil output steady. Naimi reiterated the group's view that investment in future energy projects was under threat due to the world economic downturn and low oil prices. -Reuters