Net Energy-what Captain Cook didn’t know

By Mary Logan

In June of 1778, Captain Cook’s search for the Northwest Passage brought him to the later-named Cook inlet near my home, Anchorage, Alaska. As he sailed up the arm (fjord) and reached the end, he discovered that there was no outlet. After days of being stuck due to wind and fog, he had to TurnAgain, hence the name of the arm. Captain Cook never found the Northwest passage, and he never saw England again. He died the following year in the Hawaiian islands after picking a fight with Hawaiian Islanders.

We are not quite out of gas yet in the United States. But we keep steaming down fjords without outlets, turning randomly from one blind alley to the next in trying to adapt to our energy quandary. In Captain Cook’s case, he was exploring with zero information, so there was a good chance of failure. But when it comes to energy alternatives, we can avoid dead ends, since we have what Captain Cook didn’t have, information on the best alternatives. This post is about the science of net energy regarding those options.

We are now trialling many unworkable alternative energy sources, as a response to government subsidies and agendas promoted by various energy lobbies, often in pursuit of short-term profits for private companies. Should we be letting private energy companies with vested interests dictate future energy policy which could make the difference in continuing to exist as a country? Which so-called renewable energy sources have yielded practical returns on investment, withstanding the test of time? There is a 50-year body of research on the subject of net energy. Shouldn’t we be using science and not vested corporate interests to set energy policy?

In the last post, I suggested that if one doesn’t understand the problem of declining net energy (empower basis), then growth is not viewed as a problem. Even our oil companies now openly advertise that we have produced the easy half of the oil available to the planet, and we will be producing less in the future since we have peaked. Less oil and other resources means that our economy will have to contract in the future, since renewable energy suffers from lower energy density and quality. Since we are entering energy descent, practical energy sources are beginning to sort from the impractical. Because “the true value of energy to society is the net energy, which is what is left after the energy costs of getting and concentrating that energy are subtracted,” we must decide net yield to make proactive choices about the future (Odum, 1973). Odum developed the concept of net energy and then refined the idea over the span of 50 years. The name of the analysis changed several times beginning with the term net energy then to embodied energy and finally to the term emergy yield or net empower to account for more inclusive changes in method, so many don’t recognize that the terms were developed over time from the thinking of the same community of scientists.

The primary goal of this post is to suggest that many purported energy source predictions of net yield are overly optimistic dead ends–many of our current efforts won’t work. The second goal is to suggest more reasonable net empower estimates, and to briefly check the performance of renewables from the proving ground of time. How did these experiments in energy work out for us? Continue reading Net Energy-what Captain Cook didn’t know