Guest contribution by Willis Eschenbach
I’ve read some people’s claims that batteries are the key to a bright green renewable future. Of course, we wouldn’t need batteries if we didn’t try to rely on unreliable, intermittent sources like sun and wind, but let’s leave that question aside for now.
There are a number of ways to store energy that enable us to generate electricity as needed. Batteries, pumped water storage, compressed air, electromechanical flywheel systems, electrochemical “flow batteries” are in use at different locations. And there are “intermittent flow” systems that, while not representing storage, allow higher generation at certain times … including Niagara Falls, where the flow over the falls is reduced at night so more energy can be generated when it is not a tourist attraction. No storage … but still pretty cool …
Figure 1. Niagara Falls, without water.
Aside from Niagara, I thought I’d take a look at how much energy there is in the world. Here is a list of all the energy storage systems in the world, sorted by type.
Figure 2. Global energy storage systems with capacity in terawatt hours.
I love science because I am constantly amazed. In this case, the surprises are how much bigger pumped storage power plants are than any other. The sum of all other systems is around one twentieth of the pumped storage.
The next surprise was where lithium-ion batteries, the Tesla Powerwall batteries, fall on the list … second from the bottom.
Since I was curious, I thought I was just looking at the US storage systems. Figure 3 shows this result.
Figure 3. As in Figure 2, but for US energy storage systems, with capacity in terawatt hours.
The US pretty much mirrors the rest of the planet. Mainly pumped hydropower, little lithium-ion batteries.
It all looks impressive now … but is that really it? So I thought I’d compare the electrical energy storage shown in the images above to the amount of electricity that is consumed in a single day. I started by looking at the globe as a whole in Figure 4.
Figure 4. Global energy storage system versus global daily electricity consumption.
Hmmm … doesn’t look that impressive compared to the power consumption of a measly day. For example, all Tesla-style lithium-ion batteries in use would only cover the world’s electricity demand for … wait … two hundredths of a second.
And once again I looked at the corresponding US data, as shown in Figure 5 below.
Figure 5. As in Figure 4, but for US energy storage system compared to US daily electricity consumption.
Proponents of solar and wind power will be happy to know that lithium-ion batteries can power the US for about 50% longer than the global average … two hundredths of a second for the world.
If you look at that now, you’re tempted to think, wow, we could do it all with pumped storage power plants. But pumped hydropower has some major drawbacks:
• To do this, you need the right geographic setup with hills, a water source, and a place where a valley can be dammed up to form a reservoir.
• Such websites exist, but they are few and far between. And a number of countries do not have such websites.
• Often there are streets, cities or other immovable objects of value at such locations, which are located where the planned storage lake would run.
• Even if there are no cities or roads at the intended location, in California, as in many other locations, it is fundamentally impossible to build new dams because of feelings. The greenest liberals who insist on intermittent energy sources that need a backup don’t want us to drown a few worms and let a few squirrels and cute bunnies go to the nearest valley to get the backups they ask for – that would be krool to nature.
• Good locations are often very far from the electricity demand. You can put a conventional power plant or even a Tesla-style battery next to a city where there is a need for electricity … but that’s generally not possible with pumped hydropower plants. This results in very high transmission costs and transmission losses.
• Pumped storage power plants are not as efficient. You only get back about 70-80% of the energy you invested …
• The best pages are too often in use.
Subject to these caveats, pumped storage is the best of our bad choices so far. Some new ones are likely to be created, but probably only a few.
So this is the current state of energy storage for power generation. Short version? We are far from the fact that batteries or other storage systems can store and deliver enough energy to do something greater than compensate for short-term fluctuations in energy supply and demand.
All my best
w.
After written: As always, to avoid misunderstandings, I ask everyone to quote the exact words you are talking about. This way we can all know exactly what and to whom you are responding.
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