Production capacity is increasing. A factory in Ohio is being built to provide 100MW annually of thin ﬁlm cadmium telluride cells. Another just opened in Germany to produce 10-12MW of polycrystalline cells. The company responsible for the plant expects the cost of PV power to be halved by 2010(3). To put these ﬁgures into perspective the world currently needs 10,000GW of power(4). So we have a way to go. One report estimates that factories with annual output of 500MWp would lower PV prices to levels competitive with conventional power due to high levels of automation and economies of scale(5).