Organic waste from human activities or natural swamps contains energy. Many societies already produce methane from cow dung or even human waste. Low-tech companies have sprouted up to make biofuels from deep-fry oil, left-over beer, or even onions. Almost all of these efforts are to produce fuel for transportation, which has already been treated in this chapter. There is only one application to general energy production. This is to mix biomass with the fuel in a fossil-fuel plant. The same amount of power can be generated with less coal.89 Small plants burning only biomass would be very inefficient.

Artificial photosynthesis is an interesting development that does not generate energy. Using chlorophyll, plants convert water, carbon dioxide, and sunlight into carbohydrates and oxygen. Daniel Nocera at the Massachusetts Institute of Technology has been able to split the water molecule in the laboratory using special catalysts and energy from solar cells (or the grid). Two electrodes, one of indium — tin oxide and the other of platinum, are immersed in a solution containing cobalt and potassium phosphate.90 When a voltage is applied, oxygen bubbles came out at one electrode and hydrogen at the other. The catalysts reform themselves. This process does not produce energy; it produces hydrogen, which can store solar energy during the night.

Wild Schemes

The inventiveness of the human mind has spawned a large number of crazy ideas for generating energy or slowing global warming. Some ideas are described in the Solar Power and Geoengineering sections. For instance, there is a plan to put square miles of silicon solar panels into synchronous orbit around the earth, convert the solar power into microwaves, and then beam the microwaves back to earth. Another is to place a huge mesh of wires at the point where the sun’s and earth’s gravita­tional fields cancel. The mesh scatters sunlight so that not as much falls onto the earth, thus reducing global warming (and perhaps trigger the next ice age). There are wind scrubbers that catch CO2 as it comes by in the wind. Dumping huge amounts of iron filings into the ocean would spawn huge blooms of plankton which absorb CO2. These ideas appear often in the popular literature.919293 Astute readers will recognize the ridiculous ones and have a good laugh.