Commercial/Utility usage of wood pellets and other organic renewables in the continental US is not prevalent, but the economic viability of large scale usage is challenged by residential heating needs. Everyone that lives north of the Mason-Dixon line (and mountain people in the south) that reside near timber country in rural areas heat with wood, corn, and any other organic combustibles that may be handy. After people have used up the available resources heating their dwellings, there is not much left over for public utility districts or co-gens.

Regarding the use of biomass as a fuel source, if I understand correctly, Williams view is that there is not sufficient fuel to satisfy the needs of both residential heating, and commercial generation. While this MAY be accurate for the existing housing stock which was constructed without regard to the implications of energy consumption, energy efficient homes have been constructed for decades in harsh climates that use little to no energy for heating (and cooling for that matter). Construction that integrates solar gain, thermal mass, heat recovery ventilation, ground source heat pumps and insulation are in use around the globe. Granted, converting the existing housing stock and educating residents on behavior will need incremental changes. That's the stage we are in now.

Regarding the availability of fuel stock... wood and dead plant waste are being generated in numbers that exceed 100's of tons daily in virtually every medium sized metropolitan area. Urban and suburban green debris from parks, business centers, golf courses, hospital grounds, military bases, college campus, street tree trimmings, watershed lands, utility right of ways, and even highway median and interchange acreage could represent assets, not liabilities from a waste stream standpoint. Then there are rural the possibilities. Wildfire prevention shrub growth and removal of pest infested forest material represents tonnage that would dwarf urban green waste. Properly managed, these abundant renewable resources can bridge the gap to "renewable - on demand" power generation that solar and wind fail to address, much to the delight of the critics of renewables and the global warming nay-sayers.

Biofuels need not mean growing corn to drive a hummer. Diverting food on a commercial scale to become fuel is obscene, narcissistic and irresponsible. It ignores biodiversity, water and resource management and fundamental ethical issues. Managing plant stock and harvesting wild growth, and creating value from that process is a different issue.

I would invite anyone to take a trip to their local waste disposal facility or transfer station, and for 15 minutes, calculate how much wood and clean green waste make their way into the waste stream. In my small, semi rural community, it's tons per hour. And that is just the commercial side. During the permissive "burn days", plumes are seen across hundreds of square miles from small landowners keeping their property wildfire safe. I'd love to see much more discussion on this issue.