A scenario where a modern society could collapse is if the energy returned from new energy sources drops below critical levels. Clearly, if you spend more energy to build a new reactor or solar farm than what the reactor produces overs its lift then your society will start a downward spiral and produce less and less energy. This is where energy out divided by energy in is less than one. Also, if the energy output divided by energy input drops below about 5-10 then a modern society would start to have pretty big problems.
The analogy is it takes more energy to scrape the bottom of the barrel. It is easy to scoop out the top of a full barrel or the top of a pot of food. Then at the bottom you are working harder to get less.
The Peak Oil people made a big deal about this around 1990-2005. They were extremely worried about the low energy return from the oil sands and from fracked oil.
EROI Varies Because of Calculation Methods and Actual Wide Ranges By Project
There is also concern that solar has a low EROI (Energy Return on Energy Invested).
The EROI numbers from solar, shale oil and oil from the oilsands are debated in the scientific and technical literature. The claimed EROI numbers can vary by ten times. Someone anti-solar could use the 1.6 EROI number or pro-solar could use the 12 EROI number. There is also an actual wide range of EROI for each depending upon location in the world and actual projects. EROI for solar is better in a middle eastern desert than in marginally sunny places (Germany, Canada) where solar farms were built only because there were massive subsidies. The same is true for some oilsand and shale oil projects. Some very inefficient oil projects were built because the builder got a lot of someone else’s money to make it.
The doomsday scenarios are that we would go 100% solar with low EROI solar or that we run out of high EROI oil and gas or that because of climate change risk we have to stop using high EROI energy and are forced to go use only low energy return.
Global Low EROI Is Barely an Inconvenience
The oilsands EROI increased as technology and processes got better.
The energy efficiency of gasoline cars and trucks has been low. It take a lot of energy to convert oil into gasoline and then to transport the gasoline to gas stations and then the cars engines are less than 30% efficient and there is efficiency loss in the wheels.
Electric cars are about 4 times more energy input efficient than gasoline cars. The Tesla Model 3, containing a 75 kWh battery, provides a 325-mile range. This translates to an efficient 0.9 megajoules of energy required to travel one mile (over 75% less energy required than the average competing 35 MPG sedan).
This shows that the EROI numbers are not dropping one way. It is clear that for oil shale and solar power to have bigger positions in the world economy then vast inefficiencies and problems will have be resolved for them to continue to grow.
There is huge areas for the world to get vastly more efficient. However, the world tolerated low-efficiency gasoline cars and trucks for about one hundred years.
40-60 MPG cars were available for over twenty years but 50% of people were choosing 8-20 MPG trucks and SUVs. People are switching to more efficient electric cars because Elon Musk made high-performance and desirable cars that happened to be electric.
The oil price shock of the 1973-1985 temporarily shifted significant numbers of people into buying small fuel-efficient cars in North America and some country in Europe have stayed with tiny fuel-efficient cars. The higher oil prices of the 2005-2012 period had far less impact on SUV and truck purchases.
The world society wastes a lot of energy. The world could easily become twice or even hundreds of times as efficient but we are choosing not to bother. There are easy gains on the energy usage side.
All of the multi-decade world society will collapse because we globally “run out” of “high-quality” energy, food or water are wrong.
The run-down scenarios are like saying that gasoline prices will go to $500 per gallon over ten years and because you currently drive 30,000 miles every year with 15 MPG SUV now then you will go bankrupt and starve when you are paying $1 million per year for your SUV.
You would stop using the SUV before it became that expensive. You would share rides or look at other options. A globally low EROI world would cause shifts to a lot more telecommuting, carpooling, buses, bikes, electric scooters, lighter and smaller vehicles and solutions.
It is not just that we will make better technology that does not require sacrifice or discomfort, but we can easily do things that are already are available options. Those options are 10X or 100X more energy efficient. We all know what they are but prefer being the sole occupant of a 3-ton Lincoln Navigator or Lexus LX 570 or a four-ton Ford F-250 instead of calling up UBER or a riding a subway or bus.
People put solar panels on their roof without battery storage even though they only were home at from 9pm to 7am. The electric company let the panels generate electricity and ran the power meter backward and gave them 10-20 cents per kWh of credit. This is despite the electricity burning off unused as heat at the first distribution node. The homeowner got tax credits for putting up the panel and a lower electricity bill despite no one using the actual electricity that was produced.
The world would not work if all people and all companies in the world were maximizing inefficiency and getting the current subsidies or corporate welfare to support their habits.
When things slide down too far into subsidized stupidity then the subsidies get phased out and the true costs get passed through.
The solar power subsidies and electric car subsidies are being phased out as solar power and electric cars become more mature. The shale oil companies are being forced to make profits instead existing on bank financing and government support.
Other people’s money runs out eventually. However, things can get pretty bad nationally and regionally with mass stupidity enabled with other people’s money.
There is also the aspect of Other People’s Resources. Using the global share of other people’s resources, water, energy, etc…