Chapter 25. Chapter 25: Biofuels

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1) The average annual fuel costs for passenger cars in 2010 was around $1,600 (assuming 15,000 miles/year). If your annual cost is about $1,700, congratulations! You get above-average fuel efficiency! If your costs are $1,600–$1,700, sorry! Your mileage is less than the national average.

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1) Conventional biodiesel is probably a good choice. It has the pros of being EPA certified and producible on a small scale. So the city could start recycling its restaurants’ frying oil and use it to fuel vehicles. Environmentally, biodiesel is at least carbon neutral, if not negative. The cons are that biodiesel can only be used in diesel engines, and using 100% biodiesel may cause engine issues for unmodified engines and void warranties. This could add cost to the proposition. The biggest regional consideration would be if local agriculture focused on oil crops.

2) Corn Bioethanol has a higher EROEI now than when it was first introduced, but it is still more-or-less carbon neutral and does not produce as much energy as many other sources. It would probably only be a sensible option in corn-growing areas, but government subsidies may make it more attractive elsewhere. Improved pricing still does not solve the lower-than-average environmental friendliness, however.

3) Switchgrass bioethanol has a much better EROEI than corn, especially if grown as part of a LIHD system. Moreover, if it is grown on marginal land instead of farmland, it avoids the issue of competing with food production. It is also very good in terms of carbon output, usually being far on the carbon-negative side. Drawbacks would be that the technology has not yet developed to reliably meet supply demands and the fact that switchgrass should be growable locally to prevent using fossil fuels to transport it.

4) Besides the cons listed for conventional biodiesel, algae biodiesel really isn't commercially available yet, so unless the mayor wanted to sponsor a development program, this wouldn't be a good option. To reduce freshwater usage, it would be best to locate an algae operation where saltwater could be pumped readily as well, so this may not work in a landlocked area.

5) Harvesting methane from landfills is a well-established technology used by many cities already. The only regional considerations would be if the local landfills would be appropriate for the methane operations. If the sole goal of the fuel search is to find a fuel for vehicles, then methane isn't the best choice unless the city were preparing to adopt electric vehicles since a common use for methane is to burn it to produce electricity. Environmentally, reclaiming methane is a sound idea since it is a much more potent greenhouse gas than carbon dioxide. (Carbon dioxide receives more attention because there is a lot more of it in the atmosphere, making its total effect greater.)

6) This option is a great way to reduce the amount of waste going into landfills and circumvents the social problems associated with the other proposed use of recycling sludge: using it as fertilizer.