Well.....Covanta paid USD52 million for two plants in Maine that supplied 49/50 MW. Those two plants were roughly twenty years old. They also purchased those plants in California for around the same price...those plants supplied 75MW.

http://www.prnewswire.com/news-releases/covan...64237.html

http://www.businesswire.com/news/home/2007052...YMGD0arGEE

...so it's a starting point...eh?