I have been working on renewable energy (photovoltaics) for 16 years as a scientist at the National Renewable Energy Laboratory. It is quite obvious to me that abundant energy, in one form or another, has been the key to human advancement. This fact is not going to change. That is why it worries me when largely uninformed, irrational and panic drive perspectives on nuclear energy come to dominate the issue.
It was refreshing to see a more down-to-earth perspective on the radiation hazard resulting from the tsunami driven Fukushima disaster in yesterday’s Wall Street Journal. Here are a few glimpses of the article “The Panic over Fukushima” by Richard Muller.
Denver has particularly high natural radioactivity. It comes primarily from radioactive radon gas, emitted from tiny concentrations of uranium found in local granite. If you live there, you get, on average, an extra dose of .3 rem of radiation per year…The International Commission on Radiological Protection recommends evacuation of a locality whenever the excess radiation dose exceeds .1 rem per year…It is worth noting that, despite its high radiation levels, Denver generally has a lower cancer rate than the rest of the United States…Applied strictly, the ICRP standard would seem to require the immediate evacuation of Denver.
The “hot spots” in Japan [after the Fukushima tsunami disaster] that frightened many people showed radiation at the level of .1 rem, a number quite small compared with the average excess dose that people happily live with in Denver.In hindsight, it is hard to resist the conclusion that the policies enacted in the wake of the disaster in Japan—particularly the long-term evacuation of large areas and the virtual termination of the Japanese nuclear power industry—were expressions of panic.
OK, so maybe the Chevy Volt doesn’t really get 230 miles per gallon. Are such exaggerations justified because they serve a greater cause? The Chevy Volt will help save the world, after all, by reducing Co2 emissions, right?
In fact, in some cases the amount of CO2 generated per mile for the Chevy Volt is the same as a conventional automobile getting only 21 miles to the gallon. Read on…
When running on gasoline (known as ”charge sustaining operation”) the Volt will get 50 miles per gallon. According to the EPA burning one gallon of gasoline yields 19.4 pounds of CO2. That means the CO2 emitted per mile driven while running on gasoline will be 0.39 pounds.
( 19.4 lbs of CO2 / Gallon) / (50 miles / gallon) = 0.39 lbs of CO2 per mile
How much CO2 will be emitted per mile when the Volt is powered by energy from the electrical grid that has been stored in its battery? That depends on how the energy on the grid is generated. If you live in an area where the power on the grid is generated primarily with coal, then the amount of CO2 per kilowatt-hour generated is fairly high. If you live in an area where the power on the grid is generated primarily from nuclear, then the amount is fairly low. On the average, though, there are 1.34 pounds of CO2 pumped into the atmosphere for every kilowatt-hour of energy generated for the electric power grid in the United States, according to the Department of Energy (2000).
The fully charged lithium-ion batteries hold 16 kilowatt-hours of energy and will propel the Volt 40 miles. That works out to 0.4 kilowatt-hours per mile. So that means on the average, 0.54 pounds of CO2 will be put in the atomosphere for every mile that the Volt drives on energy drawn from the electrical grid, assuming perfect charging efficiency.
(1.34 lbs of CO2 per grid kWh) x (0.4 kWh per mile) = 0.54 lbs of CO2 per mile
But charging a lithium-ion battery off the grid is not 100% efficient. There are grid transmission losses and grid to battery conversion losses which add up to about 10%. So running your Volt off of electric grid power will yield closer to 0.59 pounds of CO2 for every mile your drive. That is 151% of the CO2 put in the atmosphere by the running the Volt off of gasoline.
How many miles per gallon must a conventional automobile get in order to put the same amount of CO2 into the atomsphere per mile as a Chevy Volt does when running off of grid power? That’s easy- about 33 miles per gallon. Here are some cars that will do better.
( 19.4 lbs of CO2 per Gallon) / (0.59 lbs of CO2 per mile) = 33 miles per gallon
If you drive in an area where the electric grid is primarily powered by coal, then the numbers are even worse. Burning coal to power the electric grid yields about 2.1 pounds of CO2 for every kilowatt-hour generated. Driving your Volt with grid generated power will yield about 0.92 pounds of CO2 for every mile driven (when 10% conversion inefficiencies are added in).
(2.1 lbs of CO2 per grid kWh) x (0.4 kWh per mile) x 1.1 = 0.92 lbs of CO2 per mile
That is the same amount of CO2 per mile as a conventional automobile that gets only 21 miles per gallon!
( 19.4 lbs of CO2 per Gallon) / (0.92 lbs of CO2 per mile) = 21 miles per gallon
So don’t be fooled by astronomical claims of miles per gallon for the Chevy Volt. And if you are worried about CO2 (I’m not), then don’t count of the Chevy Volt to save you - it won’t.
Here is a simple, fun, 10 question quiz that covers a sample of climate change and/or energy issues. Simply check the appropriate box and push the “vote” button for each question. After you have pushed the vote button you will see the accumulated wisdom of everybody who has answered that question so far. You can even leave a comment for any question, which I encourage.
Note that several of the questions requiring numerical answers have “order of magnitude” choices. That is, they require “back of the envelope” type approximations, not high precision.
At the bottom of the quiz you will find a link to a solutions page, with links to supporting evidence, and “back of the envelope” calculations. If you want, you can look at the solutions first and then take the quiz – but that would be cheating!
After enough people have answered the questions I will post the results at ClimateSanity.
Here are five false color images of the sea ice in the arctic. The images represent the ice on five year intervals on July 18th of 1988, 1993, 1998, 2003, and 2008. Your task is to use your knowledge of changing conditions in the Arctic to put them in the proper chronological order. Note that each image uses the same color scale (shown in the upper left corner of each image) to indicate the density of ice as a function of position.
In the fall of 2007, after the northern summer melt season, the Arctic sea ice extent anomaly reached its lowest level since satellite monitoring began in 1979. This was followed by warnings that the Arctic ice could be completely gone by the summer of 2012.
In 1979 the worst nuclear accident in US history happened at Three Mile Island nuclear power plant near Middletown, Pennsylvania.
A rising sea level is one of the feared symptoms of global warming. According to the Jason and Topax satellite tracking of ocean levels, the average sea level rise rate for the last 10 years has been about 3.2 mm per year. This is interpreted by some to indicate an accelerating sea level rise rate. IPCC expert Simon Holgate’s 2004 data (Holgate, S.J., and P.L. Woodworth, 2004: Evidence for enhanced coastal sea level rise during the 1990s. Geophys. Res. Lett., 31, L07305, doi:10.1029/2004GL019626.) was prominently featured in the IPCC’s Fourth Assessment Report (AR4, Working Group 1: The Physical Science Basis of Climate change, Chapter 5). In a more recent 2007 paper (S.J. Holgate, “On decadal rates of sea level change during the twentieth century“, Geophysical Research Letters34: GL019626 (2007)., Holgate reconstructed sea level rise rates from high quality tidal gauge data going back to about 1900.
The northern coast of Greenland is at 83.5 degrees north latitude. It is the closest land to the North Pole. Satellite data since 1979 has always shown this region locked in sea ice. If global warming were to result in an ice free arctic sometime during this century, it is believed that this area would be the last place to lose its summer ice.
Compact fluorescent light bulbs use only 25% of the energy of an incandescent light bulb to give the same number of lumens of light.
Since 1963 Africa’s Lake Chad has experienced severe shrinkage. While atmospheric CO2 levels have continuously increased since 1963, the surface area of the lake has dropped from about 25,000 square kilometers to about 1,500 square kilometers. This fact has been presented by Al Gore and others as a consequence of anthropogenically induced global warming. Of course, this evidence must be considered in comparison to how the lake was changing when CO2 levels were not increasing.