THE cost of solar power in parts of NSW has for the first time crept below that of coal-fired electricity - seen as a key tipping point for the expansion of renewable energy.

New data shows solar power is edging towards ''grid parity'', after which it becomes cheaper than fossil fuel-generated energy such as coal and gas, even taking into account the upfront cost of buying rooftop solar panels.

Outsourcing ... Silex is to take cells from China. Credit:Ben Rushton

But it was one of the few bright spots for an industry suffering from a 93 per cent drop in rooftop panel installations since the boom late last year at the peak of the NSW bonus scheme.

Workers at Australia's only commercial solar cell maker, the Silex plant at Homebush in Sydney, were told yesterday that cell production would be outsourced to China.