Solar energy is one option for reducing future greenhouse gas emissions. Offsetting 50% of all future growth in thermal electricity generation by photovoltaics (PVs) would reduce annual global carbon dioxide emission from projected increased levels by 10% in 20 years and 32% in 50 years. Several projects are under way worldwide to demonstrate the feasibility of PV systems. This paper examines the economic competitiveness of PV systems and concludes that even after including externality costs, without significant technological breakthroughs, the economics of PV applications are unlikely to allow for an unsubsidized, widespread adoption of this technology in the near future. Further, if the goal of PV transfer programmes is to limit future greenhouse gas emissions, there are larger and cheaper opportunities available in industrialized countries to achieve reductions. Alternative measures for ensuring a market for photovoltaics, hence providing manufacturers with opportunities to improve the current technology, include mandating that utilities install a certain quantity of solar technologies by a certain date. Finally, moving towards a renewable energy future that includes PV systems requires a sustained R&D programme that will lead to improvements in panel and other system efficiencies.