the United Kingdom has plans to reduce costs of installing offshore wind farms by 2020. If that price reduction could be achieved, prices for wind power would almost reach the prices for natural gas-generated power:
Solar installations in the USA for the first quarter of 2012 took a big jump, partly due to sharp decreases in the costs of solar panels! But 2013 promises a slowdown, as tariffs take hold intended to protect US manufacturers from perceived "dumping" of solar panels from China.
The issue of tax credits from governments remains an issue as well. Here in the USA, the production tax credit for wind power is up for a renewal at the end of 2012, and there is a possibility that Tea Party Congresspersons could sink it, which would sharply slow the expansion of that industry.