One reason is the fiscal aspect of sustainability and renewable energies. Fiscal conservatives believe that there should be little to no government intervention in the economy, and renewable energy currently requires a large amount of government subsidies to be competitive.
A push for environmentalism also requires greater government control and regulation. Taxes on power plants for the amount of CO2 they emit, the Clean Air Act, and any regulation from the EPA are evidence of that. Conservatism generally points towards a smaller government with less government control, and so this idea goes against the conservative idea.
Another reason relates more closely to the idea of global warming, which leads some of the pushes for "green" technologies such as wind or solar.
Conservative think tanks and since the 1990s have opposed the concept of global warming; they challenged scientific evidence, publicised what they perceived as beneficial aspects of global warming, and stated their strong beliefs that proposed remedies would do more harm than good. [1]
For as to why liberalism has had a greater tendency to support increased environmental regulations:
Environmentalism appealed to the well-educated middle class, but aroused fears among lumbermen, farmers, ranchers, blue collar workers, automobile companies and oil companies whose economic interests were threatened by new regulations. [2]
[1] Aaron M. McCright and Riley E. Dunlap, "Challenging Global Warming as a Social Problem: An Analysis of the Conservative Movement's Counter-Claims," Social Problems, Nov 2000, Vol. 47 Issue 4, pp 499-522 in JSTOR
[2]Hays, Beauty, Health and Performance (1987) pp 287-328