Limits to Substitute Fuels

Limits to Substitute Fuels

Renewable energy sources will not be able to subsitute for fossil fuels at a level that would allow us to maintain current habits of energy use.

It’s important to have realistic expectations of the capacity of alternative fuels to fill the demand vacated by declining oil production, and subsequent declining gas production. There are major constraints to substituting alternative fuels at levels anywhere close to our current per capita energy consumption. The following draws on points made by Lawrence Berkeley Labs energy analyst, David Fridley, in a talk in June 2009.

Energy Return on Investment
It takes energy to produce energy. It takes the equivalent of one barrel of Middle East oil to pump 30 barrels of oil out of the ground, and refine it into fuel. That’s an energy return on investment of 30:1. The energy return on investment for solar power is around 3:1. That means the solar installation produces three times as much energy over its lifetime as it takes to produce the equipment. Put in another way, for the first 10 years of an expected 30 year lifetime of solar panels, the panels are “paying off” the energy debt that it took to produce them.

The energy return on investment for biodiesel from soybeans is about 2:1. That’s due to all the energy for fertilizer, pesticides, tractors, processors and transport. Energy ROI of ethanol from corn is about 1:1. That means ethanol from corn has no net energy gain. And the downside of using corn to produce energy is its direct impact on world hunger.

The era of cheap oil exiting the world stage. Society needs to spend a larger portion of its energy just to produce energy. Oil is now produced from places where it takes a great deal of energy for the extraction: tar sands in Alberta, or miles beneath the surface of the Gulf of Mexico. As more energy is used to produce energy, the amount of energy available for other uses shrinks.

Scale & Timing
For the promise of an alternative to be achieved, it must be supplied in the time frame needed, in the volume needed, and at a reasonable cost. Once the peak is reached, David Fridley predicts future world oil production will decline at a rate of  3.5 - 4 million barrels/day per year. Innovative ideas for energy sources such as wave and tide power, biodiesel from algae, airborne wind turbines, etc. need many years of research and development before their commercial viability can be determined.  Fridley concludes that these alternative energy sources cannot come online quickly enough or in sufficient quantity to replace declining oil production, let alone keep up with world demand for energy.

Substitution Feasibility
Switching energy sources often requires vast changes in infrastructure. Fridley predicts that with liquid fuels in short supply, there will be a switch to electrical energy for transportation of people and cargo. However, the current capacity of the electric grid in California would be able to power just 11% of current vehicle traffic. Unless there is a vast increase in coal fired power plants, there will be a lot less traffic on the roads of the future.

Materials constraints
The term “non-renewable resource” means just that. Minerals such as copper get mined until it is too energy-intensive and expensive to continue to try to extract it. Indium, a mineral used to produce thin-film solar panels, has proven reserves that will last 13 years at current rates of depletion. Lithium, used in electric vehicle batteries, has similar constraints. Even a switch to the dangerous alternative of nuclear power is limited by the amount of uranium reserves. At current rate of use, uranium reserves will be depleted in 59 years.

Conclusion
Cheap energy fueled the vast economic growth of the last 150 years. Neither political leaders nor the general public have a great deal of awareness that the end of cheap energy will result in a shrinking in consumption of goods of all kinds. Not only will energy be expensive, but so will products that require energy for their production and distribution.
 
Transition Initiatives focus on making the transition to a low-energy economy a harmonious and pleasant one. The alternative would be chaotic and violent. Transition Initiatives remind us that a life with low energy consumption was how our grandparents and great grandparents lived. And social indicators suggest that the high per capita energy consumption of the last 50 years has not made us happier.

The more we make current choices based on awareness of future energy constraints, the better off we’ll be. As someone said, “Planning works best when it is done in advance.”

With decline in oil and gas production, reduced hydroelectric power due to climate change in the Sierra's, and the retirement of Diablo Canyon Nuclear Power Plant, there will be pressure to build more coal-fired plants like this one in Arizona that serves California power users.

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