Some Arithmetic About Alternative Energy
Here are some back of the envelope calculations about alternative energy.
1. Biodiesel: Canola (rapeseed) yields about 122 gallons of oil per acre. If the USA planted all of its arable land, 407 million acres, with canola, we could produce 188 billion liters of oil per year. The bad news, we consume 1207 billion liters of petroleum per year. Oil seeds can never solve our energy problem, and ethanol from corn is even worse.
2. ANWR: USGS suggests there is likely 10.4 billion barrels of oil in ANWR and the local undersea shelf. The USA consumes 7.6 billion barrels per year. We should drill in ANWR, but it's not going to have a huge impact on our energy problem.
3. Nuclear: The Department of Energy estimates US Uranium reserves at 1155 million pounds (yellow cake) at $50 per pound mining and refining cost or less. Our 103 nuclear power plants consume about 40 million pounds per year of this fuel. That is 29 year supply of fuel, plus reserves. Unless we invest massively and quickly in breeder reactors, we will run out of cheap nuclear fuel before we run out of cheap petroleum.
4. Solar power: With 10% efficiency, one can optimistically expect an average of 30 watts per day per meter square from conventional photovoltaic panels. To supply the US average energy usage of 3.3 terawatts, we would need 110,000 square kilometers of solar panels, about 1.2 percent of the total land area of the USA. Anyone want to estimate the cost?
1. Biodiesel: Canola (rapeseed) yields about 122 gallons of oil per acre. If the USA planted all of its arable land, 407 million acres, with canola, we could produce 188 billion liters of oil per year. The bad news, we consume 1207 billion liters of petroleum per year. Oil seeds can never solve our energy problem, and ethanol from corn is even worse.
2. ANWR: USGS suggests there is likely 10.4 billion barrels of oil in ANWR and the local undersea shelf. The USA consumes 7.6 billion barrels per year. We should drill in ANWR, but it's not going to have a huge impact on our energy problem.
3. Nuclear: The Department of Energy estimates US Uranium reserves at 1155 million pounds (yellow cake) at $50 per pound mining and refining cost or less. Our 103 nuclear power plants consume about 40 million pounds per year of this fuel. That is 29 year supply of fuel, plus reserves. Unless we invest massively and quickly in breeder reactors, we will run out of cheap nuclear fuel before we run out of cheap petroleum.
4. Solar power: With 10% efficiency, one can optimistically expect an average of 30 watts per day per meter square from conventional photovoltaic panels. To supply the US average energy usage of 3.3 terawatts, we would need 110,000 square kilometers of solar panels, about 1.2 percent of the total land area of the USA. Anyone want to estimate the cost?
posted by DonPMitchell at 9:30 PM
7 Comments:
I don't know the numbers but there is a refining cost of any biofuel that must be included in its price.
"Biodiesel: Canola (rapeseed) yields about 122 gallons of oil per acre. If the USA planted all of its arable land, 407 million acres, with canola, we could produce 188 billion liters of oil per year. "
"Current economic uranium resources will last for over 100 years at current consumption rates, while it is expected there is twice that amount awaiting discovery. With reprocessing and recycling, the reserves are good for thousands of years."
http://www.world-nuclear-news.org/ENF_Exploration_drives_uranium_resources_up_17_0206082.html
Matthew, estimates depend on how far you go in including more expensive low-grade sources of uranium.
I think a better solution is to use breeder reactors, because the use of U-238 and Thorium will extend the fuel supply by a factor of 500 or so.
Hi, Don! :)
It would be nice to know the arithmetic for sugarcane ethanol.
The Economist has a nice summary upon Brazilian sugarcane ethanol:
Biofuels in Brazil: Lean, green and not mean
Even Brazilian media has not written similar lines when it comes to our native sugarcane ethanol. Its jugdment, often, points to apocalyptical and devastating future - slave labour, Amazon Rain Forest destruction, less farmland for food crops, USA and Europe tariffs charged on Brazilian ethanol, and so on - if Brazil goes on cultivating sugarcane plantations.
By the way, I would like to suggest you an interesting link concerning energy:
Project ArBAS: Hydrogen production by means of an Artificial Bacterial Algal Symbiosis
Berwian (BERlin WInd ANemone)
I wonder what will happen to those oil corporations - Shell, Texaco, ELF, etc. - when the oil resources come to an end. How will the world look like without fossil fuels? What about all those machines and devices which have relied on fossil fuels?
Weird...
I was about to make a blog entry about whole-plant biofuel.
There are several references showing considerably more U reserves than that. There has been a glut of U for some time so there has been very little exploratory activity.
Present reactors are refueled not because the U235 (or Pu239) is spent, but because fission products build up and poison the reaction. Even without breeding, reprocessing would recover a lot of U (and Pu) that would otherwise be stored or buried in "plutonium mines".
That said, I'd still like to see the Integral Fast Reactor revived. Fast neutrons can burn plutonium and other actinides while slow neutrons always breed them. The IFR does all reprocessing on site; only the fission products leave for burial, and without long lived actinides they decays to U ore levels in a few hundred years.
One of the great things about solar power is that existing rooftops can be used. A typical single family residential house can easily supply its own needs from the sunlight hitting its roof. Commercial and industrial buildings are more energy intensive but they do have some existing real estate (parking lots, etc) that could be covered with solar arrays. My own array is small, but I often have a surplus during daytime business hours.
Nothing says any particular alternative energy source has to supply 100% of our needs. We now have a mix, and we should always have a mix, probably nuclear, solar, wind and geothermal. We just have to get rid of the fossil sources.
According to some scientists (e.g., Richard Garwin), only about 20% of the nuclear fuel supply can be recovered by reprocessing fuel.
It's all about economics. Uranium is going for about $75/kg now, and reprocessed fuel costs about ten times that.
The same is true for mined uranium. If you want to spend vast amounts of money, you can extract uranium from granite and other very low grade ores, which is where some folks get figures that make it look like there is an unlimited supply of fuel.
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