Solar technologies could provide more power generation than fossil fuels, wind, hydro and nuclear by 2050 if policymakers provide “clear, credible and consistent signals”, according to the International Energy Agency.

The IEA has today published two reports which show how solar photovoltaic systems could generate up to 16 per cent of the world’s electricity by 2050, while solar thermal electricity (STE) from concentrating solar power (CSP) plants could provide an additional 11 per cent.

But to achieve these gains, IEA executive director Maria van der Hoeven (pictured) stressed that policymakers must eliminate the “incoherence, confusing signals or stop-and-go policy cycles” that she said has dogged the solar industry to date.IEA Maria van der Hoeven

“The rapid cost decrease of photovoltaic modules and systems in the last few years has opened new perspectives for using solar energy as a major source of electricity in the coming years and decades,” she explained.

“However, both technologies are very capital intensive: almost all expenditures are made upfront. Lowering the cost of capital is thus of primary importance for achieving the vision in these roadmaps.”

She added that policy clarity was needed to lower deployment risks to investors and inspire confidence. Without this clarity, she warned that “investors end up paying more for their investment, consumers pay more for their energy and some projects that are needed simply will not go ahead”.

The IEA reports underline the complementary role of the two solar technologies. With 137 GW of capacity installed worldwide at the end of 2013 and adding up to 100 MW each day, PV deployment so far has been much faster than that of STE, mainly thanks to massive cost reductions. Under the scenario described in the roadmaps, most of the growth of solar electricity comes from PV until 2030.

However, the picture changes after that, when reaching shares between 5-15 per cent of annual electricity generation, PV starts to lose value in wholesale markets.

The IEA says that “massive-scale STE deployment takes off at this stage thanks to CSP plants’ built-in thermal storage, which allows for generation of electricity when demand peaks in late afternoon and in the evening, thus complementing PV generation”.

Under this scenario, the IEA predicts that PV will expand globally, “with China being by far the leading country, followed by the United States. Over half of total capacity is situated at the final consumers’ place – whether households, shopping malls or industries. STE expands in very sunny areas with clear skies, becoming a major opportunity for Africa, India, the Middle East and the United States.”