How Solar Could Free Up 29.8 Million Acres of Prime US Farmland
Corn is a Shitty Solar Panel: 160x more energy from an acre of solar than an acre of corn ethanol
Around 30 million acres of prime US farmland is used to grow corn for ethanol production. Ethanol is a liquid fuel added to gasoline to make it “greener”. (A 2022 study in Proceedings of the National Academy of Sciences disagrees.)
The US could get the equivalent amount of vehicle fuel from a mere 200,000 acres of solar panels.
The vehicle fuel from solar would be electricity to power electric vehicles.
Yes, 200,000 acres is a heck of a lot of land for solar panels. But it is a lot less than 30 million acres of corn that no one nor any animal eats.
The energy from those solar panels would enable a vehicle to travel the same number of miles as turning 15 billion bushels of corn into ethanol. (Detailed calculation below.)
Need-to-Know: Plants are shitty solar panels.
The reason you can get the same amount of energy to move a vehicle from a tiny fraction of the land area (just 0.65%!) is that plants are really, shitty solar panels.
It’s easy to understand: The sunlight-to-energy conversion of plants is 0.023% versus 20% for a solar panel. (That’s nearly 1000x better.)
Advantages of solar panels over ethanol:
Solar energy is emission-free. Burning ethanol emits CO2, NOX, VOCs, and other air pollutants.
Growing corn requires enormous amounts of fertilizers, pesticides, and water.
Corn needs to be planted and harvested year after year. Solar panels cost a lot to plant the first year but they’re virtually cost-free for the next 20 to 30 years.
Processing corn at ethanol plants uses tremendous amounts of fossil gas. It can take a gallon equivalent of fossil energy to produce a gallon of ethanol. Without government subsidies, hardly any ethanol would be made.
Need-to-Know: If solar replaced ethanol in the US it would free up 29.8 million acres of prime farmland
The biggest advantage of solar over ethanol is the millions of acres used to grow corn for ethanol could grow food for people and lower food prices.
Given this, it seems pretty crazy that corn ethanol has received more than $100 billion in government subsidies. It continues to receive a massive subsidy in the government requirement that ethanol be added to gasoline.
For example, Iowa, with 8 million acres devoted to corn ethanol, passed a law in 2022 that forces gas stations to sell gasoline with 15% ethanol blends. Now the Republican leadership wants to make that a 40% ethanol blend. It’s a giant subsidy for an ethanol industry dominated by agribusiness corporations.
Need-to-Know: Farmers can harvest crops and green electricity for a win-win!
Here’s an even better idea: Agrivoltaics
Elevate solar panels two to four meters (6 to 12 feet) above cropland and grow food crops underneath. Farm workers and tractors can work underneath the panels.
The panels will help crops grow with less water. And the plants help the panels stay cooler so they produce up to 10% more energy, according to studies.
Livestock can also graze underneath and benefit from the shade.
Win. Win.
Vehicle Fuel Calculation: Corn Ethanol vs Solar Panels
Note: I’ve had this reviewed by energy experts and it is considered a conservative comparison.
An acre of high-yield corn in the US midwest can be converted into 500 gallons of ethanol on average. If a vehicle could run on 100% ethanol, it would travel 8,750 miles on 500 gallons. (Ethanol has 30% less energy than gasoline.)
An acre of solar panels produces an average of 350 megawatt hours (MWh) in one year. That’s enough electricity to be able to drive a Tesla Model 3 some 1,400,000 miles. (Model 3 uses 62 kilowatt-hours to travel 250 miles.)
That is 160X more miles from solar on the same acre of land in this tank-to-wheels comparison. Among the reasons a Tesla could go 160x further is the 400% better energy efficiency of electric motor vehicles than gasoline or diesel-combustion which produces lots of waste heat.
In other words, to match the annual travel distance of EVs recharged from 1 acre of solar requires 160 acres of corn converted into ethanol. (Even accounting for losses from electricity transmission, battery charging, and grid storage.)
Who the hell ever thought ethanol and biofuels were a smart way to power vehicles?
Need-to-Know: 90% of crops grown in the US are used for ethanol, biodiesel, or animal feed.
Of all the wheat, rice, corn, rye, oats, barley, and sorghum grown in the US every year a mere 10% is eaten by people. The rest is for animal feed and biofuels. (It is roughly the same proportion (+/-10%) in Canada, Australia, and most of Europe.)
Globally, some 70 million acres of food-producing land is devoted to ethanol and biofuels that provide less than 5% of the world’s transportation fuels.
Reclaiming some of those millions of acres to grow food could be a big part of solving an ever-worsening food crisis.
Keep all this in mind the next time someone says solar panels take up too much to provide the energy we need.
Until next time. Be well.
Stephen
yes, but somehow the political aspect that makes growing biomass more lucrative for farmers than does growing food, must be defeated.
Burning food as fuel is so 'last-century'.