Rick Wilkinson
OGJ Correspondent
ADELAIDE, Apr. 17 -- The most important trend in energy production over the last two centuries is decarbonization, a trend that will see methane overtake oil and coal to become the next two generation's primary fuel, said Jesse Ausubel, director of Rockefeller University's Program for the Human Environment. Ausubel spoke at the Australian Petroleum Production & Exploration Association (APPEA) 2007 Conference in Adelaide.
"On average, when one removes the water, biomass fuels have a ratio of 40 carbon atoms to 4 hydrogen," he said.
"Coal typically has about 8 Cs for each 4 Hs. Gasoline and jet fuel average about 2 Cs for each 4 Hs. Methane burns only 1C for each 4 Hs—one-fortieth the ratio of wood."
Ausubel and his colleagues plotted the history of fuel in terms of the ratio of carbon to hydrogen and found a strong trend towards decarbonisation, with carbon losing market share to hydrogen.
"The slow process to get from 90% C to 90% H in the fuel mix should take about 300 years and culminate about 2100," Ausubel told the conference. "Some decades have lagged and some accelerated, but the inexorable decline of carbon seems clear."
This trend is driven by the ever-increasing need for spatial density of energy consumption by the end-user, that is, the energy consumed per square meter, especially in urban areas.
"Fuels must conform to what the end-user will accept, and constraints become more stringent as spatial density of consumption rises," he said.
Green energy metrics
Ausubel also questions the green credentials of renewable energy forms. "They may be renewable, but calculating spatial density proves they are not green," he said.
"The best way to understand the scale of destruction that hydro, biomass, wind, and solar promise is to denominate each in watts per square meter that the source would produce.
"In a well-watered area like Ontario, Canada, a square kilometer produces enough hydroelectricity for about 12 Canadians, while severely damaging life in its rivers.
"A biomass power plant requires about 2,500 sq km of prime Iowa farmland to equal the output of a single 1,000-Mw nuclear plant on a few hectares.
"Windmills to equal the same nuclear plant cover about 800 sq km in a very favorable climate.
"Photovoltaics require less, but still a carpet of 150 sq km to match the nuclear plant.
"And a car requires a pasture of a hectare or two to run on biofuels—unwise, as the world's vehicle population heads towards one billion.
"No economies of scale adhere to any of the solar and renewable sources, so trying to supply India or eastern China would require increases in infrastructure that would overwhelm these already crowded lands," he says.
