Snippets on Energy #5
People always wanted to be mobile. At first we have used our feet, then horses and finally motor vehicles to move further and faster. The same is true for transporting goods — one of the cornerstones of the economy. Fossil fuels were an (if not ‘the’) ideal companion on this trip: starting with coal fired locomotives, then continuing down the path with gasoline cars, diesel trucks and ships, not to mention planes flying high on kerosene. These fuels were dense, portable and storable.
Fuels derived from oil were absolutely on top in energy density. Each gallon of gasoline contained 120 million Joules (or 33,333 Watt-hours) of energy — in the form of “condensed fossilized sunlight”, an equivalent of jamming 40 acres of wheat into your tank. Being a noncorrosive liquid, it required nothing else than a steel tank to carry it around. Sometimes a cheap plastic bottle did the job just as fine. It could also be transported via pipelines — one of the cheapest (most energy efficient) means of forwarding goods of all times.
This is our baseline. This is what powers our ships, airplanes, locomotives, cars, trucks today— in one word: the economy. This is what keeps our civilization going — while being one of the biggest threats to it at the same time. This is what we have to replace.
According to the mainstream narrative electrification is the key to leave fossil fuels behind. One thing rarely gets accounted for though: the problem of storage. It is something which gets usually handled with a shrug: “we have batteries — problem solved”. Lithium-ion is the often touted answer to our mobility question. But have you ever wandered how little it can store in terms of energy?
In fact, batteries store less then a fifth of the energy what a potato, yes, a dumb uncooked potato, can hold (1).
How does this performance compare to gasoline? Batteries, found in the Tesla Model S P100 hold 75 times less energy than gasoline per a unit of weight. When factoring in engine efficiency (2) electric vehicles are still 25–30 times worse than their gas or diesel counterparts. This is why you don’t — and probably will never — see jumbo jets and large semi-trucks running and flying on electricity (3). Batteries are way too heavy: they are taking up more than half of the payload, which makes transportation of goods on long distances using batteries uneconomic to operate (not to mention the upfront cost).
The other thing regarding batteries — which is almost completely left out of the public debate — is their resource intensity. Here are two factoids from the Manhattan Institute to consider:
- The energy equivalent of 100 barrels of oil is used in the processes to fabricate a single battery that can store the equivalent of one barrel of oil.
- A single electric car battery weighing 1,000 pounds requires extracting and processing some 500,000 pounds of materials. Averaged over a battery’s life, each mile of driving an electric car “consumes” five pounds of earth. Using an internal combustion engine consumes about 0.2 pounds of liquids per mile.
As we have seen, high resource intensity tends to drive down EROEI. (Not to mention how this increased mining activity destroys remaining ecosystems.) This is especially true in a depleting world, where you have to dig away more and more earth and rocks to get the same amount of metals. Cobalt. Copper. Nickel. The mining of these metals requires ever greater amounts of ever lower EROEI fossil fuels. Combine this with a drastically reduced storage efficiency — meaning that you need 20–30 times more material to store the same amount of energy — and one can quickly realize that we are heading in the wrong direction.
Batteries might not be the ultimate solution to our energy storage and portability issue… What about hydrogen then? Well, think of it this way: since H2 cannot be found in nature, you have to invest energy into generating it, so that it can power your machinery and other high power processes in return. Put this way, hydrogen is nothing else, than a gaseous battery. Energy in (electricity to convert water into H2) — energy out (electricity from fuel cells). As simple as that.
The same holds true for obtaining heat or other forms of energy from hydrogen. According to the laws of physics however, you cannot get more energy out of a storage medium — be it a gas, or a liquid full of Li-ions — than what you have put into it in the first place. As a result you are losing energy whenever you are using Hydrogen (4). And not an insignificant amount. Add up all the losses in the process — generation, compression, transportation, leakage, conversion into electricity, or combustion — and you get 50% of the energy investment back in the end at best… If Hydrogen were an energy source, it would have an EROEI less than one!
There is one more thing: in order to efficiently separate H2 from Oxygen (the splitting of water molecules) you need iridium cathodes — again a rare metal, which is not growing on trees. The same goes for fuel cells: this technology requires platinum to be effective enough. Of course, you can replace these rare and expensive metals in the process, but there goes your (already poor) efficiency with them…
Again, in a world of lower and lower energy returns on investment for primary power generation, wasting half of the hard earned energy during conversion and storage is not a winning strategy. The same goes for e-fuels, synfuels, ammonia, bio-fuels etc. These “solutions” are all energy sinks just like H2 — sometimes even worse than that. It is absolutely no wonder that the “Hydrogen economy” did not took off yet — it is a net waste of energy, effort and raw materials.
It pains me to write this, but as it stands today, there is still no alternative to diesel when it comes to powering trucks (both on roads and utilized in mines), ships and agricultural machines… And without these vehicles the future of our civilization as a whole becomes questionable.
Yes, fossil fuels are emitting tons of CO2 and wreck our climate. No doubt. Yes, it is unfair to compare condensed sunlight (in the form of oil) to bright, clean virgin solar panels. Still, it is undeniable that these dirty fuels are superior in energy density and portability to anything we have ever encountered. And most probably this was the only reason we got so far with civilization.
I believe that this is the fundamental misunderstanding when it comes to the energy transition. We believe that we can manufacture our way into a clean future, while not giving a single thought to how fossil fuels were an energy windfall in creating modern civilization... A gift… A polluting and planet-wrecking gift, but a gift nevertheless. We are not, and in fact never was “producing” oil — this terminology has completely mislead us. It was the Sun and the plants working together on it for many millions of years. All we did is that we’ve found it and put it into our cars. We broke into nature’s treasure trove and stole everything — then burned the house down.
We have lived up a once in a lifetime inheritance of free, dense, portable and storable energy — and heated up the planet with its pollution. Now we’ve made ourselves believe that we can replicate the same economic miracle by “producing” “renewable” energy and hydrogen at massive losses and with ever worsening returns on investment. This is a dangerous delusion. A myth. It is confusing physics with psychics — at the cost of disregarding the laws of our very existence.
It is time to accept, that in order to stop this destruction we need to power down. Relax. Do less. Mine less. Build less. Buy less. This won’t happen overnight — it is going to be a long journey… but for now, use these last couple of weeks in 2021 to power down and experience what matters the most in life: human relationships.
Until next time,
(1) A single kilogram of uncooked potatoes contains 770 kCal of energy, which is equivalent to 3,222,168 Jules or 895 W/kg. A Li-ion battery of the same weight holds 265 Watts at best. In real life, a Tesla Model S P100 is running on batteries which are delivering a mere 160 W/kg performance (equivalent to 250 W/liter) or 946 Watts per a gallon of battery volume. A gallon of unleaded gas on the other hand weighs 6.1 pounds (or 2.77 kg) and thus has an energy density of 12,033 W/kg — 75 times than that of a Tesla battery.
(2) An average car has an engine efficiency of around 33% according to the MDPI of Basel, and 50% for diesel (the rest is turned into waste heat). Electric drives, with charging and electricity conversion losses (none of which apply to internal combustion engines), is around 80% in total (90% for the engine, 90% for the charger / inverter). EV efficiency is therefore some 2–3 times higher compared to gas or diesel engines.
(3) A semi-truck carries around 125 gallons of fuel, weighing 875 pounds or 397 kg. Considering engine efficiency you would still need a battery pack 30 times heavier than that, weighing almost 12 tons. This is more than half of the valuable payload (which is 20 tons or 44,000lbs)!
(4) If you are interested in the details, here is a great article with many references.