Solar energy produced from one acre of land, compared to the ethanol energy produced from one acre of corn.
One acre of good corn growing land in America will produce about 140 bushels of corn during a one year growing season. As a matter of interest the all time record harvest is over 260 bushels per acre but we also have to remember that more often the all time low has been zero bushels per acre. A bushel is considered to be about 56 lbs.
The current corn harvest is only possible due to the artificial fertilizers, herbicides and pesticides that are routinely applied to America’s corn crop. A little over 2 lbs of fertilizer and chemicals are used for each bushel of corn grown. This averages about 1 lb of nitrogen, 0.4 lbs of phosphate and 0.5 lbs of potassium. The herbicides and pesticides amount to about 0.22 lbs of active ingredients per bushel. This might not sound like much but on Kentucky corn alone, pesticides and herbicides equal about 3 million lbs per year. Corn is responsible for a hell of a lot of toxic chemicals that have created untold difficulties.
The USDA estimates that it takes 53,000 BTU’s of energy to convert 1 bushel of corn to 2.8 gallons of ethanol and most of the new ethanol plants are using coal for this energy. The USDA vigorously supports corn based ethanol production; unfortunately they are using accounting methods that completely ignore any environmental impacts from the entire process. These are the same accounting methods that are currently wrecking the planet.
Then there are the energy costs associated with building the equipment the farmer uses to grow the corn, the energy costs that the farmer used himself, the associated production and transportation energy incurred to get seed, fuel, fertilizer and chemicals to the farmer, the energy to get the corn to the ethanol plants, the energy needed to turn the corn into ethanol and then the energy to get the ethanol into your car. There are many other energy costs that are directly attributable to the production of ethanol but we don’t count them for gasoline so why should we count them for ethanol? The answer is, because they exist. Ignoring all the little details to make gasoline or ethanol look better than they actually are is called fooling yourself. Many Americans complain about $3+/gallon gasoline but fail to realize that the true cost of a gallon of gasoline is currently about $20/gallon.
So the argument continues but it seems reasonable to conclude that gasoline, diesel and ethanol are much more expensive than the pump price. Smart guys have spent a lot of time looking at this and have come to the same conclusion.
So to keep this simple, 140 bushels of corn grown on one acre in one year can be converted to 392 gallons of ethanol. At 76,000 BTU’s per gallon this equals 30 million BTU’s per acre, per year, from corn, when it is converted to the liquid fuel ethanol. Some folks say that it takes more than 30 million BTU’s to produce this much ethanol, in which case this huge effort is a waste of time but the USDA ethanol guys say it takes just over 20 million. Nobody says you end up with a net 30 million BTU’s from an acre of corn, less than 10 million BTU’s actually produced is tops. All this means that the energy equivalent to at least 3 gallons of ethanol is burned to produce 4 gallons of ethanol. Therefore, we ultimately end up burning 7 gallons of fossil fuels to produce the equivalent of 3 gallons of gasoline (3 instead of 4 due to the greater BTU’s in gas and diesel than ethanol). Due to the similar amount of pollution created burning ethanol compared to gasoline,
Of course, there is a more important issue here that the West has been happy to ignore while it spends billions to create fuel from food. It must be considered reprehensible to convert huge quantities of food to fuel on a planet where 26,500 children die each and every day due to not having enough,
Fortunately, there is an eminently reasonable solution, which the fossil fuel gangs have rejected, simply because they have put their greed ahead of everything else. Governments have also rejected this solution because they seldom lead the way and they are also obsessed with short term gain and votes.
Let’s have a look at what 1 acre of land can produce using photovoltaic (PV) panels that are now up to 20% efficient. That means that 20% of the solar energy that reaches the panels is converted into electricity. Twenty percent is a reasonable number these days. The best conversion is 50% using prohibitively expensive equipment but 30% is also reasonable using solar energy to produce steam that can drive generators.
The sun conveniently delivers about 1000 watts of energy per square meter to the earth’s surface (at an angel of 90 degrees). At 20% efficiency each square meter of photovoltaic panel will therefore produce about 200 watts of electricity. We need 5 square meters of PV panels to produce 1000 watts. In 1 acre there are 4047 square meters. Divide that by 5, the area to produce 1000 watts and you get 809, x 1000 watts = 809,000 watts per hour of sunshine, or 809 kilowatts per acre. One kilowatt equals 3,400 BTU’s so in one hour, one acre of solar panels could produce 809 x 3,400 = 2.75 million BTU’s.
Naturally it makes sense to locate solar facilities where you get the most sunshine although corn growing areas are quite good. The Americans deserts receive over 7 hours of productive sunshine per day so 7 hours times 2.75 million BTU’s equals 19.25 million BTU’s per day per acre. Let’s reduce that to 15 million BTU’s to account for installation inefficiencies but you can see that after ONE DAY of solar electrical production we have at least 50% more energy than one year of corn energy from ethanol production. In the desert parts of America getting this kind of sunshine is possible for well over 300 days per year. This means that solar energy plants, that are commercially available today, can produce about 500 times more energy from the same area as ethanol from corn.
To be fair we also have to look at the input costs associated with producing this solar energy. In optimal solar locations, like the American deserts, it will take less than 2 years to produce the energy that was required to make the solar installation in the first place. The solar system will then go on to produce clean energy for decades. Like the ethanol gangs the solar gangs tell us that significant new efficiencies will emerge in the near future.
We should also mention that electrical energy is as useful as liquid energy. It is clean energy we need; the form of that energy is secondary. It is also worth mentioning that solar energy is not difficult to store so that solar energy can be available 24/7 however most energy is used during the day.
Of course all this begs the question. Why would anyone destroy a vast amount of food to produce a relatively insignificant amount of global warming energy when a clean, inexhaustible source of energy is going to waste? Currently humans produce energy equal to about 10,000 million tons of oil per year. That is equal to about 250 billion, million BTU’s per year. The good old sun produces vast amounts of clean fusion energy than we can access without wrecking the planet. On the land surface of this earth, solar energy equals about 100 trillion BTU’s per hour, 24 hours a day, 365 days of the year, 6000 times what people produce from all sources.
Could it be that because solar energy is “free” we humans have rejected it because less profit can be made? Could it be that we are that greedy and that foolish? Could it be?