# Calculating energy: return on investment.

I READ WITH INTEREST THE ARTICLE "BY THE NUMBERS: U. S. TO ACHIEVE ENERGY INDEPENDENCE," FEBRUARY 2013. I realize that it was pretty much a summary of the International Energy Agency's recent report but was disappointed that it didn't take an engineering approach to the data.

Let's ignore climate change, environmental impact, increasing population, and politics for a minute and Look at how our society uses energy. I say "energy" because we all know that energy can neither be created nor destroyed, just converted. Yet most of us still use the common terminology "energy produced" or "energy used." It's convenient.

Saying the U.S. will overtake Saudi Arabia by 2020 is only part of one side of the story, the supply side. In 1970 it took about one barrel of oil to extract 100 barrels of oil and our economy boomed. By 2000, it took about one barrel of oil to get 20 barrels.

Each new discovery of millions of barrels of oil continues to take more and more energy to extract it from the Earth.

With so much unconventional petroleum available does it really matter that it continues to take more energy? Yes.

Charles Hall has done some work and estimates that our current society needs an Energy Return on Energy Investment [EROEI] on the order of 15-20. Current conventional petroleum production is running at an EROEI of 10-15. Shale oils are running 2-7 and oil sands are around 5-7. Obviously these numbers depend on who runs the study.

Even if Hall's analysis is off by a factor of 2, we face major energy shortfalls without substantial conservation efforts.

If the EROEI is effectively cut in half, that is comparable to cutting production in half. Saying that we will have energy independence because we have access to twice the amount of oil means that we are breaking even compared to where we are today. Again, this does not take into account any environmental, impact, global markets or expansion of China, India, and Brazil. If the extraction is property performed environmentally, this would further decrease the EROEI.

Our society cannot sustain itself with returns of this amount without drastic reduction in our overall, energy consumption. To retry on unconventional petroleum and maintain any llfestyle close to what we currently have means that we need to cut our total consumption in half. This is not a per capita number but a total consumption number.

We continue to shuffle the deck within the same box. Society desperately needs the engineering community to step forward, man up (or woman up}, and thoroughly evaluate these situations to help the community at [large understand the seriousness of the situation. They also need to think outside the box to come up with innovative ways to solve the problem [our current behavior requires too much energy} instead of the symptom (we need more energy to support our behavior).

JACK SOL-CHURCH is a weatherization program manager at Neighborhood House Inc. in Wilmington, Del.

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