There is no real renewable energy. The sun uses many tons of hydrogen at 0,00000000001 efficiency or less for growing a grain of corn and potassium and other elements are removed from the soil. An analysis would show that growing permanent trees and storing the logs after many years in abandoned salt mines with the same expenditure of water and soil productivity and using more oil would remove more carbon from the air.

If humans were to leave the earth and leave it alone for a few million years, oil and coal deposits might be built up to the extent that have been used.

Most monies spent on "renewable" energy would be better lent to cities and commercial buildings and even homes for combined heating-power-Cooling units that use natural gas. It would save money which could be paid back to the loaning agency and would reduce CO2 release by a greater amount per dollar expended, and in fact most units would pay for themselves. It would be even better if the units' owners got a gas rate about the same as the gas rate for natural gas combined cycle power plants and they would be more energy efficient.

This is not to say that farmers should not produce methane from some wastes and use it on the farm to replace some fossil fuel use. The potassium remains on the farm as do some other elements. There is always the worry that nitrogen is being destroyed. Much nitrogen is produced by bacteria for crops with the energy from plant material left on the ground.

Instead of encouraging the use of biomass for energy production, the US could encourage the use of biomass for the production of charcoal to mix in with the soil to increase fertility and production. This process will sequester carbon from the air at far lower costs than the production of corn ethanol does.

A professor in Hawaii has developed a fast charcoal producing process that can be used with any plant material.

With computer controlled equipment, charcoal is almost as easy to burn for home fuel or even for auto fuel as propane is. The TORSTEN KALLE gasifier could be rebuilt with computer controlled pumps and controlled valves and every farm could be heated with charcoal and even water heaters operated. Electric generators can also run on the gas as well as pump engines.

Many years ago, I thought that plant material could be digested by cooking at elevated temperatures and pressures, and the discovery of existing wet air oxidation and then super-critical oxidation have confirmed this. When wet air oxidation temperatures are kept low material is produced that is suited for anaerobic processing. Supercritical water is decomposed into hydrogen and other gases by biomass.

The cooking stoves are best supplied with methane from an anaerobic digester It is too bad that anaerobic digestion does not yet produce propane or butane. Even Ethane would be an improvement. ..HG..

Henry, you make several good points. The conversion of some biomass to charcoal for return to the soil makes perfect sense. A simple step in the biofuel agriculture process.

And I regularly agree with you on the CHP issue. There should be a US city-designated test to demonstrate the efficacy of combined heat and power fueled by natural gas. Somewhere there are cold winters would be best (Chicago, Minneapolis.)

By installing Residential Power Units in a neighborhood we can reduce the demand on grids, remove overhead power lines, limit the number of new power plants needed, and greatly improve energy security.

The technology is coming. Japan is the leader so far. But Bloom portends a strong future with their low cost SOFCs. And CHP households should be given the best rate on NG possible.