A 2007 study found that the maximum share of energy consumption that could be produced in Luxembourg from renewable sources was 4.5%. Price guarantees and subsidies have sparked a notable increase in photovoltaic solar energy production capacity (from 54 kW in 1999 to 23 500kW in 2005). Thus, over the period 2001-08, investment in photovoltaic solar power received EUR 70 million in subsidies. It would be useful to reconsider the various systems in place for promoting renewable energy and to assess and review them from the viewpoints of economic efficiency and environmental effectiveness. Opportunity costs of the funds allocated to promoting renewable energy and those devoted to energy savings should be assessed. Luxembourg’s electricity prices before tax are the highest in the OECD, particularly for small companies and households.