Nuclear energy is efficient, clean | | Brainerd, Minnesota

Nuclear energy is efficient, clean

Posted: July 17, 2012 - 5:37pm

When I begin teaching a new class on energy technology, I often start by writing a single word on the white board — scale.  We then look at the printed handouts that each student has received. They contain table 1.1 from the Energy Information Administration (EIA) which sets out total U.S. energy consumption in quadrillion British Thermal Units (quads). You need a big number like quads when you discuss energy for a whole country like the U.S. And the U.S. consumes about 100 quads of energy per year for all purposes like heating buildings, transport, manufacturing, etc. The purpose of reviewing this data is to give us perspective when we start to talk about energy use and its impact on our environment.

We learn from the table 1.1 that 88 percent of our 2012 energy comes from burning something — oil, coal, natural gas, and biomass including biofuels. Eight percent is from nuclear energy; 3 percent is from hydroelectric dams; and rapidly expanding wind and solar is just 1 percent. It’s the burning 88 percent that is producing green house gases like carbon dioxide (CO2) that are apparently warming our planet. It is clear that even if the wind always blew at the right speed and the sun shone round the clock, that 1 percent is not going to have much impact on the 88 percent anytime soon. The 1 percent is also limited because intermittent wind and solar energy is difficult to use by our energy infrastructure, and the high cost requires large subsidies from cash strapped governments. 

U.S. energy consumption has stabilized in recent years from increased efficiency and a slower economy. But the world as whole continues adding 450 billion kilowatt hours annually to electricity consumption. As energy analyst Robert Bryce notes, “That’s the equivalent of adding about one Brazil to the electricity sector every year. And the International Energy Agency expects global electricity use to continue growing by about one Brazil per year through 2035.”  Most of this additional demand is being met by burning coal in countries like China and India.

Whether more CO2 is a major hazard, or global warming is a real threat, the indefinite burning of a finite and polluting resource like fossil fuels is not possible. Recent improvements in drilling technology are opening new large resources of cleaner natural gas (NG). NG is mostly methane which has the formula CH4. Coal is mostly carbon (C) so its energy comes from making CO2 from carbon and oxygen. Methane’s energy also comes from producing water vapor by combining hydrogen (H) with oxygen, so it makes less CO2 per unit of energy than coal. NG also lacks pollutants such as the mercury and sulfur emitted by coal burning.

Many environmentalists hope that natural gas can be a bridge fuel to a clean energy future from sources like wind and solar. But those costly and intermittent sources simply lack the scale and reliability to meet the world’s future energy needs. Bryce and others are proposing a program called NtoN (natural gas to nuclear) to meet those needs. 

Fissioning uranium and plutonium in our nuclear reactors releases energy from the conversion of matter to energy per Einstein’s famous formula E=mc2. The amount of energy released in this conversion is millions of times the amount you get from normal burning of the same amount of matter. We don’t get all of that in our current generation of reactors, but we get a lot. A uranium fuel pellet the size of a finger joint lasts for five years, and it releases the energy of a ton of coal, while emitting only water vapor. The spent fuel pellets (nuclear waste) can be stored in a geologic facility like Yucca Mountain which has been delayed by politics, not geology. Or better, the spent fuel can be reprocessed with most of it recycled to new fuel as the French do at La Hague.

The world’s most popular new nuclear reactor is the Westinghouse AP 1000 which China has adopted. The U.S. is getting four new reactors in Georgia and South Carolina, all are AP 1000s. The AP 1000 cost about $3 billion to build in China, $5 billion in the US. It will produce 600 billion kwh over 60 years which is less than one tenth of a penny per kwh.

ROLF WESTGARD is a professional member of the Geological Society of America and the American Association of Petroleum Geologists. He teaches classes on energy subjects for the University of Minnesota Lifelong Learning program.