Tag Archives: Tom Murphy

Biofuel, Geothermal, Renewable Energy Sources

Fascinating Comparison Chart on Energy Solutions

This chart was created by Tom Murphy, who is an Associate Professor of Physics at the University of San Diego. He writes big picture physics analyses of energy solutions.

The chart points out that biofuels, of all sorts, are misspent if they are used for electricity. That’s because there are many ways to make electricity, but there are very few ways to make liquid transportation fuels. Click chart to enlarge.

Energy-score

Notice geothermal. It has the most positive attributes when one considers available hot spots such as we have here on the Big Island.

On top of that, geothermal is a low-cost alternative, says a September 2009 Wall Street Journal blog Environmental Capital. That article asks:

…What price would oil or gas have to be for each technology to be break-even without subsidies, using combined-cycle gas turbines as the low-cost yardstick?

Geothermal is the cheapest: It is competitive with natural gas at $5.16 per million BTUs or oil at $57 a barrel. Nuclear power breaks even at $6.26 and $69.

Traditional, onshore wind power breaks even with gas at $8.33 or oil at $92. Offshore wind still needs a push: It requires gas at $17.14 or oil at $189.

In contrast, solar thermal needs to see natural gas at $35.66 or oil at $393. And good old photovoltaic solar, like the kind on rooftops? Natural gas needs to be at $59.61 or oil at $657 a barrel.

Geothermal, Peak Oil, Renewable Energy Sources

A Humorous Look at How This Could All Play Out

Sun

Since the start of the industrial revolution, our energy use has grown about 2.9 percent per year. This article says that to keep growing at even 2.3 percent per year beyond 275 years, we would have to put solar panels on every square meter of land.

Considering the sun’s energy seems limitless, what happens if we could maximize its use?

The article, from Energy Bulletin (July 12, 2011), is Part One of a series that tries to bring large concepts into view by using simple estimations to their logical, and sometimes humorous, conclusions.

Galactic-scale energy

by Tom Murphy

…Surely in 275 years we will be smart enough to exceed 20% efficiency for such an important global resource. Let’s laugh in the face of thermodynamic limits and talk of 100% efficiency (yes, we have started the fantasy portion of this journey). This buys us a factor of five, or 70 years. But who needs the oceans? Let’s plaster them with 100% efficient solar panels as well.

Another 55 years. In 400 years, we hit the solar wall at the Earth’s surface. This is significant, because biomass, wind, and hydroelectric generation derive from the sun’s radiation, and fossil fuels represent the Earth’s battery charged by solar energy over millions of years. Only nuclear, geothermal, and tidal processes do not come from sunlight—the latter two of which are inconsequential for this analysis, at a few terawatts apiece…. Read the rest

Plant leaves are mini solar collectors. Can we convert the product of leaves’  work and convert that result into something that yields more usable energy than what the leaves manufactured in the first place? So far, we have not been very successful.

Most of the processes that involve biofuels have a low net energy result — energy-in versus energy-out. In fact, because there are fossil fuel inputs, there is a term that describes the result. It is called the “receding horizon.” The break-even point recedes into the horizon as fossil fuel prices rise.

While I am for using sun energy to help solve Hawai‘i’s food and fuel problem, I am also for emphasizing geothermal energy as a way to give Hawaii a game-changing energy/food/social advantage relative to the rest of the world. This is about positioning future generations for survival and prosperity all at once.

My Pop would say: Find three solutions for every problem and then find one more just in case. Now is the time to implement that special, geothermal solution.