Since I can’t leave my comment at the WSJ forums on this article (I guess the discussion is closed), I’ll have to do it here.
from the article:
Let’s Get Real About Renewable Energy
We can double the output of solar and wind, and double it again. We’ll still depend on hydrocarbons.
[snip]
Mr. Bush’s record aside, the key problem facing Mr. Obama, and anyone else advocating a rapid transition away from the hydrocarbons that have dominated the world’s energy mix since the dawn of the Industrial Age, is the same issue that dogs every alternative energy idea: scale.
Let’s start by deciphering exactly what Mr. Obama includes in his definition of “renewable” energy. If he’s including hydropower, which now provides about 2.4% of America’s total primary energy needs, then the president clearly has no concept of what he is promising. Hydro now provides more than 16 times as much energy as wind and solar power combined. Yet more dams are being dismantled than built. Since 1999, more than 200 dams in the U.S. have been removed.
If Mr. Obama is only counting wind power and solar power as renewables, then his promise is clearly doable. But the unfortunate truth is that even if he matches Mr. Bush’s effort by doubling wind and solar output by 2012, the contribution of those two sources to America’s overall energy needs will still be almost inconsequential.
and so forth…
Here’s the issue that I have with this article – the math:
For the sake of convenience, let’s convert the energy produced by U.S. wind and solar installations into oil equivalents.
The conversion of electricity into oil terms is straightforward: one barrel of oil contains the energy equivalent of 1.64 megawatt-hours of electricity. Thus, 45,493,000 megawatt-hours divided by 1.64 megawatt-hours per barrel of oil equals 27.7 million barrels of oil equivalent from solar and wind for all of 2008.
Now divide that 27.7 million barrels by 365 days and you find that solar and wind sources are providing the equivalent of 76,000 barrels of oil per day. America’s total primary energy use is about 47.4 million barrels of oil equivalent per day.
My rebuttal:
Politics aside, I believe that the math in the article is a little misleading.
It’s true that 1 barrel of oil contains 6119 MJ of energy, or 1.64 MWh of energy. However, electricity is highly refined energy, i.e. one must burn 3 MJ worth of coal to create 1 MJ of electricity (roughly the same for oil). The author’s math assumes that there is a process for converting all of the 1.64 MWh in a barrel of oil into electricity. At best the conversion rate is 30-40%. Looking at a barrel of oil in that light, one would consider a barrel of oil to “equal” 0.55 MWh of electricity. Or, conversely, a barrel of oil would be displaced for every 0.55 MWh of renewable electricity production.
Redoing the math:
45,493,000 megawatt-hours divided by 0.55 megawatt-hours per barrel of oil equals 82.7 million barrels of oil equivalent from solar and wind for all of 2008.
Dividing by 365, the numbers remain grim – 227,000 barrels of oil equivalent per day. Still a drop in the bucket of the roughly 19 million barrels per day of crude oil consumption, but much rosier than the picture that Mr. Bryce paints.
This is one of the tricky issues of energy conversion, and using “energy equivalents” in arguing your point – especially when comparing electricity to raw fossil fuels. I would expect that the economists and energy analysts at the WSJ would understand this concept, especially someone who is the managing editor at the www.energytribune.com website.