Our species craves energy, and, as historical data shows, our energy demands are growing exponentially. This trend cannot be sustained for much longer, as the environmental issues and long-term risks we are facing are largely connected with the energy sources we currently use and the growing demand. In fact, if we continue with the current rate of energy consumption and its increase, 2500 years from now (even with a 100% efficient Dyson sphere and having the ability to travel faster than the speed of light), we would need a large galaxy of stars. *1
More problematic is that, out of the total energy produced in USA in 2015, 59.1% was rejected *2, and this trend is similar for other countries around the globe, which is quite odd, taking in account all of the issues we are facing. It would be significantly less harmful, if we could use the energy we generate more efficiently.
As can be seen on the graph, the U.S. currently wastes almost 2/3 of energy produced. For comparison, try imagining going to the supermarket and buying three bags of apples, then losing 2 of the 3 bags on your way back home. That is the amount of energy we currently waste.
Strangely enough, our energy waste habits almost exactly match our food waste habits.
Why do we waste so much energy?
There are several reasons, out of which we can highlight the following:
- physical limits
- inefficient technology
- current economic system
In terms of physics, when trying to convert one form of energy into another, we will always have some losses, and the more conversions we perform, the more losses we will have. For instance, to convert electric energy into motion, electric current is first transformed into an electro-magnetic field, which is then transformed into motion. Depending on the type of motor, this process can be very efficient — ranging from 80-95%.
Furthermore, if we imagine that we need to use coal, in order to get motion, we will have several transformations. When using a steam engine, first, we would burn coal (chemical reaction), and that reaction will release heat and boiling water, which will create steam and pressure in the boiler, which will push the pistons, which will eventually pistons turn the shaft. Each of these steps, due to technological limitations, will create losses. The overall efficiency of the entire process, depending on the steam engine design, will range between 1-20% efficiency, where most of the waste will be discarded in the form of heat into the environment. *4
This rejected energy sometimes appears as clouds of vapor coming off a steam engine cooling system, and, usually, it is not recoverable.
In terms of technological efficiency, there are a few measures we can use — those that are purely technical, which tell us how good our technology is and those that are economical and tell us how much value can we get for the effort invested.
For example, in residential properties, a large portion of energy is wasted, due to poor home isolation, dissipating large amounts of energy outside during cold winter nights. Improving the efficiency of our homes can be done easily by using a better isolation facade, better windows and doors, which will, in return, save energy and money for consumers. Although we waste 35% of the energy in our homes, that waste is significantly lower than the 80% we waste on transport or the 67% we waste when producing electricity.
Our transport means, especially cars, are hugely inefficient, and they are wasting huge amounts of energy. In order to calculate these losses, two measures are used: tank-to-wheel and well-to-wheel efficiency. *5
The first one measures efficiency after fuel is poured into a car’s tank, showing the efficiency of the vehicle; well-to-wheel efficiency measures the entire process, from ground extraction, refinery, transporting fuel to the pump, pouring fuel into the tank, and “burning” it inside the engine.
Let’s first check a few well-to-wheel efficiencies *6 in this table for different types of vehicles:
According to the above source (before Peugeot announced the commercialization of a Diesel-Hybrid car in 2006) diesel and diesel-hybrid cars in highway mode have equal well-to-wheel efficiency as electric cars.
According to Tatsuaki Yokoyama, “Progress & Challenges for Toyota’s Fuel Cell Development,” 2009 ZEV Symposium study, FCHV-adv (“Fuel Cell Hybrid Vehicle Advanced“) is 40% efficient , while the electric car is only 33% well-to-wheel efficient.*7
How is it possible that electric cars, which have significantly larger tank-to-wheel efficiency, have a smaller well-to-wheel efficiency?
Well, first we need to imagine that all cars are small power plants on wheels, and, as explained earlier, the more transformation there is, there more losses we will have while transforming energy into motion.
For the diesel and FCHV vehicles, they already have an entire power plant under the hood, so the transformation is “straightforward;” in the case of both comparisons for electric car energy, it is bit more complex.
To calculate electric car efficiency, first, we have to take into account storage efficiency, or how efficiently we can store and retrieve energy from the battery. Luckily, according to a Stanford curriculum, that number is very high — between 80-90% *8 *14 *15. Gasoline tanks also have loses: over time, fuel will evaporate, although it looks negligible, because of a large number of cars in the world, it is estimated that we lose 5000 metric tons of fuel a day *9. Then, there is motor efficiency, and electric motors are highly efficient — up to 98% — while most combustion engines have an efficiency of only 16%. That gives an overall tank-to-wheel efficiency for electric cars of around 83%, which is significantly above anything we have now, in regards to combustion engine cars.
Now, in order to get the well-to-wheel calculation, we need to transform some kind of source of energy into electricity and transport that to the tank. It is true that, after transporting fuel to the power plant, burning it, generating electricity, and transporting electricity via grid, well-to-tank efficiency will be significantly lower than the number we began with, as there will be many more transformations.
However, the data sources I have showed are biased and deliberately misleading — in both cases giving favouritism to their own solution, while undermining the electric car. We cannot look at electric cars without fixing the other side (well-to-tank part) of the equation, which, in this case, is highly inefficient.
In order to do that, we will look at another measure, the economic one: energy returned on energy invested (EROI).*10 The EROI shows us how efficient energy sources are by measuring how much energy we can return for unit of energy put in, in order to extract new energy.
The best way to imagine this is by imagining how much time we need to work, in order to grow food. If we work one day and then secure food for 3 days, taking into account that we will spend one unit (1 day worth) of food each day, it will give us an EROI of 3.
Here is the list of some fuels and their EROI values:
|2000.0||Thorium - Dual Fluid Molten salt - Molten lead Nuclear (estimate)|
|10.0 – 70.0||Nuclear|
|32.4||Geothermal (with hot water heating)|
|14.5||Oil and gas (2005)|
|10.0||Natural gas (2005)|
Looking at the table, we can see that there are sources of energy that can directly produce electricity, instead of converting other fuels into electricity, and they can stand shoulder-to-shoulder with fossil fuels. Wind, for instance, has a slightly higher EROI than Oil, and Hydro has a slightly higher EROI than Coal. Both have one major advantage: both Wind and Hydro are infinite, and they do not create CO2 as a by-product.
Instead of comparing the electric car with other types of cars by using oil as the primary energy source, we need to avoid all intermediate transformations and use electricity from sources that can generate electricity directly. In that sense, we would lose only a small percentage during electricity transmission over the grid; the high overall efficiency of electric cars will be maintained.
A few days ago, there was news about an invention around a sterling motor, capable of giving cars a range of 100mpg, *13 around 4 times higher than the current average mileage (24.6 mpg). This would give combustion engine cars an efficiency of around 64% (4 * 16%).
Should we do this — should we start mass-producing this type of engine and continue using oil?
The short answer is still “no;” for a longer version, please read the future article: “Electric vs. Other Cars.”
Currently, combustion engines are wasteful and largely inefficient, so why do we use them?
The reasons are many, but they are largely intertwined with the current economic system.
It’s been said that the only goal of market capitalism is to maximise a value for shareholders, and therein lies the paradox: If the only goal is just maximizing value for shareholders, then it seems that, for oil companies, it is reasonable to have less efficient cars. The less efficient cars are, the more fuel they will burn; the more fuel they burn, the more oil they will sell and the more money it will create for shareholders, which is exactly the opposite of what we need for resolving some major issues we currently have on the planetary level.
Economically, burning lots of oil would be ideal, if there were not two major hurdles. First, we live on a finite planet with limited amounts of non-renewable resources; therefore, what fuel companies are selling is limited and eventually will run out. Second, and far more dangerous, is the fact that the fuel we are burning is destroying our environment, and it has a huge impact on climate change and life on Earth.
Additionally, to complicate things even more, EROI data are misleading. One would expect that, at this stage of development, we would probably have accurate data, but that is not the case. Studies are largely influenced by money and politics, and nuclear energy is a prime example of this. It is almost impossible to find consistent EROI numbers, and most of the studies will ignore important things like decommissioning costs or nuclear waste storage costs (more about this in the separate article, “Real cost of Nuclear Energy”).
Having accurate data about efficiency and EROI is of huge importance for strategic decisions about where to spend taxpayers’ money, what subsidies to provide, and where to invest tax money in the future, so we could place our bets, as much as possible, on the way that would guarantee the best outcome for our future.
An example of a bad investment we made in the past and are still making is corn ethanol. Corn ethanol receives $7 billion in subsidies each year. As can be seen from the table, Corn ethanol's return on energy investment is just 1.3. Only 30% more energy is recovered from corn ethanol than went into producing it. *16
There is not any logic in investing in an energy source that has such a low yield and still pollutes our air in the same amount as oil, while there are other, much better, widely available energy sources. For example: solar cells’ energy return is 6.8 times. Natural Gas is 10 times. Wind is 18 times. Today's water-cooled nuclear energy is 10-70 times more efficient. Coal is 80 times. Hydropower is 100 times. The estimated return for a thorium-powered, molten salt reactor is 2000 times the energy invested in it.
Corn ethanol simply is not good enough, despite being called a green fuel; it still produces CO2 and poses risks to ecosystems and biodiversity. So, maybe we should stop subsidizing it and invest that money a bit smarter.
After the news a few days ago, declaring that Antarctic CO2 has hit 400 ppm for the first time in 4 Million years, *18 maybe it is time to look efficiency and EROI tables with additional care and invest money we have in a bit smarter way.
Notes & References:
1. “Robots Will Steal Your Job But That’s Ok” - Federico Pistono (Appendix B. Pg. 158-159)https://archive.org/stream/PistonoRobotsWillStealYourJob/Pistono%20-%20RobotsWillStealYourJob_djvu.txt