Interesting. Although, you've got to be very careful accounting for all costs with systems like these. It took a while, but I finally found their estimated payback period on the website - at least 4 to 5 years. They talk a lot about how much electricity it will save you but nothing about how much the natural gas will cost you to run it.

My dream system, assuming I found the time to tinker with it, would be a slow-speed diesel "Lister" engine clone running a generator with its cooling system piped into my hydronic heating system and run on free waste vegetable oil.