solar vs corn ethanol land use - Page 1
Forum section: electronics / general

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 27, 2025, 01:54:36 am
content: https://www.anthropocenemagazine.org/2025/04/new-study-compares-growing-corn-for-energy-to-solar-production-its-no-contest/QuoteSo making just the 10% ethanol in gasoline uses 3x as much land as solar panels, then EVs having a MPGe rating 2-3x that of the best hybrids pushes that to 6-9x! Then don't forget that processing corn into ethanol needs electricity that could instead be used to power an EV, pushing that figure up even more.

author: brucehoult
author_rank: Super Contributor
timestamp: April 27, 2025, 03:45:03 am
content: Clearly modern solar panels are far more efficient at converting a given amount of sunlight into moving vehicles than growing plants to product ethanol to burn in an ICE.Corn to ethanol had an overall efficiency around 0.1% to 0.2%. Ignoring distribution, an ICE then typically has around 25% efficiency, for an end to end efficiency of 0.025% to 0.05% i.e. 2000 to 4000 units of sunlight to produce 1 unit of moving a vehicle.With solar panels 20% efficiency is at the low end now with better panels claiming 23% or so when new, round trip in and out of a lithium battery is about 90% efficient, and then an electric motor is also about 90% efficient, so overall efficiency (again ignoring distribution e.g. a home setup directly charging your own vehicle) is around 15% to 20%.i.e. maybe 500 times better.Growing sugar cane instead of corn would be about five times better, where climate permits. Switchgrass is also better than corn, but not as good as sugarcane. Algae can be 10x more efficient than sugarcane, and some can produce ethanol directly.But that's ignoring several very important things:1) capital costs. For plants it's pretty much just the land itself. A half million dollar harvester can service a 1500 acre farm for 20 years, adding maybe $30/acre to the cost. Or you can use a contractor for $40-$50/acre. It's minor. Corn crops are worth around $600/acre, with seed costing $100, fertiliser $100, and pesticides $50.In contrast a solar installation is something like $500k per acre, so a 1500 acre farm converted to solar would cost $750 million.Or, converting 3 acres of a 1500 acre corn farm to solar to get the same vehicle miles would cost $1.5 million, with maybe $100k annual maintenance and depreciation.2) energy density. EV cars are pretty much ok these days, with acceptable range. But this is at the cost of a major weight addition. A Model Y LR weighs 2000 kg while my comparable Subaru Outback weighs 1530 kg. And even then the Model Y has significantly less range. Petrol cars devote a very small proportion of their internal volume or weight to fuel -- about 45 kg for the 60 litres of fuel in my Outback. If I wanted to, I could trivially put 500 litres of fuel containers into the cargo space of my Outback, below the level of the top of the seats, and still take 4 passengers and travel 6000+ km. Or I could tow a trailer with 2000 litres of fuel (1500 kg) and travel around 20,000 km.A Model Y battery is 771 kg. It could tow a trailer with two batteries, extending the range to maybe, being generous, 1800 km. It's just no comparison -- a 10:1 range difference when using all the load capacity to take extra fuel/batteries.As I said, this is pretty much acceptable for cars now. But it's not acceptable for long range trucks or for airliners.I have a number of times flown non-stop on an A380 between Auckland and Dubai, a distance of 14200 km. There are other routes even longer (not least Auckland to Doha 14500 km, London to Perth similar, Sydney to NY is 16000 and Singapore/NY 15350). Putting the same weight of batteries in an A380 instead of kerosine, you might get 1500 km.That's nowhere near even getting from Auckland to Sydney. You might just barely be able to do Norfolk Island to Brisbane, like in the old old days of the 1940s. Forget about anything like LAX to Hawaii (4000 km). From Auckland you could island hop to Norfolk Island, Fiji, American Samoa, Rarotonga, Tahiti ... and then you're stuck.So, it would be a very good idea to forget about ethanol for cars, but if one day we can't get dino-juice it would make sense to use it for even medium range airliners.

author: UnijunctionTransistor
author_rank: Frequent Contributor
timestamp: April 27, 2025, 04:08:47 am
content: You forgot the most important aspect of ethanol as fuel: the farmers who grow the corn also vote.The politician(s) who even dares to suggest that corn ethanol shouldn’t be used as an automobile fuel, he/she would be voted out of office faster than you writing the ethanol’s formula: CH3CH2OH

author: CatalinaWOW
author_rank: Super Contributor
timestamp: April 27, 2025, 04:22:07 am
content: BruceHolt correctly identified most of the comparison, but there is one additional issue. And I can't even start to correctly state the actual numerical values involved.That cornfield only operates part of the year. I would assume that is built into the calculation for how much sunlight is converted on a 31 hectare plot. But the ethanol produced can be put in a tank and stored for years and thus is ready for use at any time of the year.I don't know how the annual variation in solar output was computed (if it was even noted), but either the solar plant has to be sized to produce the amount of energy required on the worst days of the year, or very long transmission lines have to be built to bring southern hemisphere energy north and visa versa. That adds to the capital cost very significantly. There is no currently viable method for seasonal storage of electric power, and I am sure if one is developed it won't be free.None of this makes ethanol I wise choice, just points out the solar electric isn't as easy as some would say.

author: Andy Chee
author_rank: Super Contributor
timestamp: April 27, 2025, 04:26:54 am
content: Long carbon chain biofuels (ethanol and/or biodiesel) may still be required where batteries are impossible.The most notable example being aircraft fuel. A lesser example is ocean shipping, though I suppose they could revert back to using sails.

author: nctnico
author_rank: Super Contributor
timestamp: April 27, 2025, 11:19:01 am
content: Quote from: CatalinaWOW on April 27, 2025, 04:22:07 amIn Europe there is a lot of movement towards hydrogen as an energy transport and storage medium. Many European countries have contracts in place with north-African countries to develop hydrogen production from solar. You can google the reports and articles. For example:https://protonventures.com/news/morocco-netherlands-to-partner-on-boost-to-green-hydrogen-production/Growing crops just for fuel is not very efficient and wastefull. And it also has a large CO2 footprint as much of the fertilizer is made from natural gas or coal. Then again, some companies (like Poet-DSM) are quite far along developing processes (from harvesting the leftovers to fuel production) which convert the unused (non-edible) parts of plants into ethanol. That means better (more efficient) use of farmland and fertilizer. Last time I checked these project where scaled / shut down though due to lack of funding from the US government since 2019.

author: UnijunctionTransistor
author_rank: Frequent Contributor
timestamp: April 27, 2025, 03:09:27 pm
content: My grandfather had a saying; when there is a real interest in doing something, the money to do so will ALWAYS be found.What I read that some government program was shut down because of “lack of funding”, what I actually read is that some politicians were lobbied by (insert here your favorite villain) to cut the program’s budget.In 2019 Trump was still serving his first term. Just sayin’.

author: nctnico
author_rank: Super Contributor
timestamp: April 27, 2025, 03:27:15 pm
content: Quote from: UnijunctionTransistor on April 27, 2025, 03:09:27 pmThat sounds nice in theory but it doesn't work when new technology is needed to replace (deeply entrenched) existing technology. Think about subsidies for wind, solar, electric cars, etc. The government does have a special role to support and steer development of new technology in the right direction.

author: Kleinstein
author_rank: Super Contributor
timestamp: April 27, 2025, 04:19:21 pm
content: Quote from: nctnico on April 27, 2025, 03:27:15 pmOne problem here is that it is not even clear which direction is the right direction. Chances are we will need a mix of different renewable energies and methods of storage. It depends on how good the technologies get how well the compete with each other.For crops to fuel the best crop definitely depends on the climate an soil. Corn may work in some areas, but not so much in others. It is attractive to have some of this crop for energy, as this allows to switch to food or at least animal feed if really needed due to poor weather or similar conditions. Due to the relatively poor efficiency I don't see it as a main way for energy production.

author: nctnico
author_rank: Super Contributor
timestamp: April 27, 2025, 04:35:18 pm
content: Quote from: Kleinstein on April 27, 2025, 04:19:21 pmYes, but that is also why governments need to be involved in funding / developing new technologies (starting at universities and government associated research institutes) as actual business cases might be very unclear.

author: UnijunctionTransistor
author_rank: Frequent Contributor
timestamp: April 27, 2025, 04:46:26 pm
content: Quote from: nctnico on April 27, 2025, 03:27:15 pmPerhaps my post wasn’t clear enough.What I meant is that the “lack of funding” project cancellations are almost certainly politically motivated.And in the US, lobbying the Congress by large corporations is a national sport.

author: Siwastaja
author_rank: Super Contributor
timestamp: April 27, 2025, 04:54:44 pm
content: Quote from: nctnico on April 27, 2025, 03:27:15 pmBut governments rarely understand whatthe right directionis. Heck, even the best in the industry don't know it for sure, you don't know it, I don't know it.Best governments can do is:* Remove obstacles to business and innovation (e.g. very high taxation)* Support universities to do wide research, some has to be without any clear large vision in sight, just research different things* If subsidies are to be used, use them to inject noise in the system: support different types of ideas.Governments that pick some Chosen Right Technology for a Master Plan do the same mistake that happened in the Soviet Union: the choice is made with poor and limited information and is not constantly sanity-checked against real world needs and limitations.Hydrogen is a perfect example of a good servant but bad master. Apply wisely; pushing it as a generic catch-all solution for everything is a guaranteed failure, and only possible by very ineffective use of taxpayer money.

author: Kleinstein
author_rank: Super Contributor
timestamp: April 27, 2025, 07:32:18 pm
content: Hydrogen will very likely play an important role in longer time storage and using of production peaks. However the problem is not in how to use hydrogen, but foremost the production and storage. There is still a large amount of hydrogen produced from natural gas.With the introduction of a new technology on a large scale the money / capital can be an issue because of the scale. PV or wind power still have large upfront costs and the gains over a relatively long time. Already pushing the PV enough to bring the cost down took a lot of public money: some $100 Billon from German consumers, a similar amout from China and a little more from other countries. It was still money well spend to speed up the developement.

author: UnijunctionTransistor
author_rank: Frequent Contributor
timestamp: May 03, 2025, 01:08:47 pm
content: Does anyone know where Tesla’s solar panels are actually manufactured?Not assembled but manufactured.