Alternative Energy Sources — A Quick Look

by George W. Zobrist

According to experts, oil discoveries peaked in the 1960s, while production in most countries has peaked or expected to peak sometime in the near future. Some estimate that our petroleum stores will run out in approximately 20 years, while others predict a supply that will last at least one 100 years more. Prognostications and arguments aside, it is reasonable to assume that someday energy usage will have to shift from petroleum to alternative sources.

The Department of Energy's Energy Information Administration (EIA), in its April 2004 International Energy Outlook, projects that world energy consumption will increase by 54 percent from 2001 to 2025, and that worldwide oil consumption will rise from 77 million barrels per day (Mmbbl/d) in 2001 to 121 Mmbbl/d in 2025. This growth, among other significant factors, has spurred investigation into the feasibility of developing and adopting alternative energy sources. Such alternatives fall into two major categories: nonrenewable and renewable. Nonrenewable sources include geothermal, coal, shale oil and nuclear fission. Renewable sources include wood, biomass, hydropower, solar/wind energy and fusion.

Each potential source of energy has its share of pros and cons, as well as myths and realities. The following is a brief overview of some of the more widely discussed alternative energy sources. These summaries are based, in part, on coverage of alternative energy sources in the Electronic Green Journal and Consumers Report (October 2004), the latter of which focused on alternative energy sources for vehicles. Keep in mind that when examining the alternatives, each source's interchangeability, or energy density, should be considered.

Nonrenewable Energy Sources

Oil Sands/Heavy Oils — Massive quantities of these oils now exist in Canada and Venezuela. They are true oils, but special treatment is necessary to recover the oil. One drawback to the process is that the net energy recovery is considerably less than that of conventional drilled wells. And to generate a useable amount of product would have a profound effect on the environment. Consequently, this group could only replace a small fraction of today's oil supplies.

Coal — A sizeable energy source. One significant drawback is its energy density, which is far less than that of oil. Coal is useful in producing electricity in a coal-fired plant, but to convert to a liquid form for automobile usage would require a massive mining effort due to its low energy density. Coal usage also adds to the greenhouse effect.

Shale Oil – Contrary to popular belief, oil shale cannot be used to create oil. Instead, kerogen — a hydrocarbon that occurs naturally in oil shale — can be converted to oil through a process called pyrolysis. However, that process requires large amounts of water, and the waste byproduct is much larger than the original shale mined, presenting a formidable disposal problem. Shell and Exxon-Mobil are both investigating ways to heat the shale while it's still in the ground, and then extract the oil. The largest oil shale deposits are in Colorado, which is not rich in the water resources. According to the Wall Street Journal (10 March 2005), the only people who have made money on oil shale ventures are the two caretakers employed by the Interior Department to patrol the land.

Nuclear Fission — Nuclear fission's end product is electricity, and on a mass scale, electric automobiles are still not ready for primetime. One researcher has determined that one gallon of gasoline (approximately 8 pounds) is equivalent to roughly 15 tons of storage batteries. Again, the energy density problem: how to provide enough energy from storage batteries to fly a jet across the ocean, or provide energy to a farm tractor on a 10- to 12-hour day of plowing? Electricity's limitations keep it from being an efficient replacement for petroleum.

Renewable Energy Sources

Hydroelectric/Solar/Geothermal/Wind — As we are discovering, hydroelectric is not really a renewable energy source, due to the eventual filling of sediment in the dam system. Geothermal energy can turn steam turbines to generate electricity, but there is a scarcity of sites. Solar energy is attractive because it is "unlimited." However, it is only unlimited in certain parts of the world. Solar energy is converted to electricity, but the amount generated is quite limited, and the conversion efficiency is quite low, some suggest approximately 12 percent. Again, like nuclear fission, the end product is electricity with all of its limitations. Wind power is similar to solar in that it is limited in availability. There are also aesthetic concerns and lately the Audubon Society has sought to limit wind farms, because they are often in bird flyways — which happen to coincide with wind patterns.

Wood/Biomass — Obviously, wood has been used as a fuel in both automobiles and homes for many years. Wood can also be converted to liquid, but the energy recovery is low. Biomass, such as corn, soybeans and sugar cane can be converted to alcohol or ethanol which subsequently can be used as fuel. The problem is that the process of converting the raw materials to the finished product is sometime "energy negative." Walter Youngquist says that it takes 71 percent more energy to convert corn to ethanol than can be obtained from the end product [Electric Green Journal, December 1998]. E85, which is a blend of 85 percent ethanol and 15 percent gasoline, gets approximately 25 percent fewer miles per tank than straight gasoline.

Another problem with using food stocks for fuel is that it depletes available food. This theory may sound absurd, but consider utilizing it for automobiles. Ethanol plants consumed about 12 percent of the nation's corn production last year. If oil prices fall, the “bubble” may deflate as it did in the 1990s (WSJ, 09 March 2005). Government subsidies, like a 5.4 cent-per-gallon exemption from the 18.4 cent-per-gallon federal excise tax, support biomass development programs. In Missouri, farmers receive a state tax credit for their ethanol investments, while plants receive payments from a state inventive fund (St. Louis Post Dispatch, 20 February 2005). Also, while reducing carbon monoxide emissions, compared to petroleum's output, it adds aldehydes and alcohol to the atmosphere. Ethanol has less energy per volume than gasoline. And considerable energy is used to plow, plant and cultivate the necessary corn crops. One needs gasoline, or some equivalent, to produce the crop to obtain the ethanol. A study by Giampietro et. al., published in BioScience (Vol. 8, No. 9, pp. 567-600, 1997), concluded that large-scale biofuel production is not an alternative to oil and not really an option to cover even a fraction of it.

Nuclear Fusion — Theoretically, nuclear fusion is an infinite source of energy and renewable. The problem is that it is essentially the same energy that powers the sun, and developing such an energy source requires working with extreme temperatures. Even if the technical problems can be overcome, electricity is still the end product.

Hydrogen/Fuel Cells — These are not primary energy sources. Hydrogen must be obtained utilizing another energy source, and fuel cells must be fueled with hydrogen or some derivative of oil. Consumer Reports reports that a fuel-cell car would cost approximately one hundred times that of an equivalent gasoline powered car. Another problem is where to get hydrogen, how to store it, and how to transport it. Presently, the most cost effective way to obtain hydrogen gas is to extract it from natural gas, which obviously depends upon fossil fuel.

Hybrid vehicles are becoming available. Hybrids are vehicles which combine a gas-electric hybrid power train. These vehicles cut emissions and improve fuel economy. The downside is that they cost more, weigh more, and their long-term durability is questionable.

The newly formed House Hydrogen and Fuel Cell Caucus believes that the time is at hand for weaning the nation away from foreign sources of oil. The bipartisan caucus declared 28 June "End Dependence Day" and staged demonstrations of hydrogen-powered motorcycles, a military truck, a van and a mock fueling station on Capitol Hill. "This is not science fiction — these hydrogen cars demonstrate that we have the technology right now," said Rep. Bob Inglis (R-S.C.), on the of caucus' four original organizers. Among the caucus' goals, the coalition:

• Advocates full funding of the Department of Energy's hydrogen programs, including existing demonstration programs
• Advocates funding basic science research to discover breakthroughs necessary for affordable hydrogen and fuel cell technology
• Promotes near-term use of best practices rather than premature standards that may quickly become obsolete.
• Advocates keeping hydrogen affordable and promoting means of making it widely available
• Promotes hydrogen as a safe, reliable, abundant and clean fuel

In Qatar, plants are being developed to turn natural gas into an ultra-clean automotive fuel to challenge the oil industry. The developers are hoping that by converting natural gas into a liquid their product will rival the efficiency of diesel fuel, but with virtually zero pollutants. Diesel engines get about one-third better fuel economy than gasoline engines and current diesel engines can “run” on this liquefied natural gas (Wall Street Journal, 15 February 2005).

Most alternative energy sources can be viewed as “niche” sources, but not as a  complete replacement for fossil fuels. And policy-makers and decision-makers must consider a host of factors when determining the best resources to pursue: energy density; availability; whether to generate fuel or only generate electricity; government subsidies to make the venture viable; impact on the food supply chain; and much more.

Oil will be difficult — if not impossible — to replace in its entirety. The end result would be a world much different than today.

A wealth of information on energy policy and position papers can be found on IEEE-USA's Energy Policy Committee Web page [www.ieeeusa.org/volunteers/committees/epc]. The committee's overall objective is to assist in the resolution of energy problems through the provision of rational, sound, technical and professional counsel, based upon the best resources which the IEEE is competent to bring to bear upon these problems.

Numerous websites have information on this topic, and you can also do a Google search for alternative energy sites.

Dr. George W. Zobrist is professor emeritus at the University of Missouri-Rolla, Department of Computer Science, IEEE-USA's Member Activities editor, and former editor of IEEE Potentials. Comments may be submitted to todaysengineer@ieee.org.