The decision to use natural gas rather than solar heat reduces costs: in part due to recent low natural-gas prices, it's far cheaper to burn that fuel than to build a field of mirrors to concentrate sunlight. The natural gas, in addition to heating the gasifier, will also provide a source of extra hydrogen. The ratio of hydrogen and carbon in biomass isn't the same as in gasoline—the hydrogen from natural gas makes up the difference, increasing the fuel yield from biomass. The other option would be a reaction that uses carbon monoxide to produce hydrogen from water—but that would lower yields and force Sundrop to truck in more biomass.
Switching to natural gas had another benefit. As with the decision to use conventional gasification technology, it has helped Sundrop finance its first plant. It attracted $155 million in funding from natural-gas producer Chesapeake Energy, which was seeking to fund technologies that would increase demand for natural gas.
The use of natural gas means emissions have increased, however. When Sundrop used solar heat, its gasoline resulted in 90 percent lower carbon-dioxide emissions than conventional gasoline. But the company says the emissions will still be 60 percent lower than with conventional gasoline.
The higher cost of the conventional gasifier will also make it difficult to run the process profitably—even with the benefit of cheap natural gas. "It barely works," Simmons says. "You wouldn't build a whole lot of these plants, because your equity return wouldn't be good. You do make a modest profit, but nothing like when you go to our
View the Original article
No comments:
Post a Comment