From an article by Kenneth P. Green on energy policy. It explains why subsidy in any form is bad policy.
First, subsidies breed corruption. They don’t create incentives for honest people that already have a market-worthy product — such people can already sell their goods into the market easily. Rather, subsidies create a fertile garden for rentseekers who are unable to sell their goods competitively in a free-market, and prefer to tap the coercive and redistributionist force of government to lever their uncompetitive good into the market at the public’s expense. Rather than contribute to overall social welfare by giving consumers the best goods at the least cost, or even maximizing the efficient use of people’s taxes, rent-seekers undermine social welfare by foisting inferior or over-priced goods onto the market while taking money from people that could be used for other important purposes. This is a particular problem in countries with relatively weak property rights regimes, and countries with legal institutions insufficient to prevent it.
Full article at http://www.aei.org/publications/filter.all,pubID.26353/pub_detail.asp.