Energy storage: what are alternatives to batteries?
From home batteries to neighborhood batteries
Power you can't use right away, how do you save it for later? The most obvious solution is: store it in a battery. These batteries are increasingly being placed in our power grid, both on an industrial scale, and in the form of so-called neighborhood batteries, and also in people's homes as their own “home battery. Whereas about ten years ago most batteries were still lead-acid batteries, there is now a clear preference for lithium-ion batteries: that is therefore the type of battery you can buy from Zonnefabriek. Lithium-ion has the advantages that it has a high energy density, allowing you to store a lot of power in a relatively small volume, that it is comparatively inexpensive, and that it lasts a long time.
Are there any alternatives?
Read more about lithium-ion battery alternatives below.
An alternative to lithium ion are so-called saltwater batteries. In this technology, salt water is used as the electrolyte. This reduces the amount of rare minerals and toxins needed to make them, which would make these batteries better for the environment. The technology would also be safer, with less risk of fire. On the other hand, the energy density is lower, so you need a lot more space for installation. There are not very many providers of these types of batteries yet, but it is an option to keep an eye on.
Storing power in the form of hot water to be used for showers or heating at a later time is an application we've talked about before. At times when there is “too much” solar power, we can turn up the heat pump or heating element a notch, and store the heat produced in a well-insulated boiler tank.
A more exotic solution is to store energy in “molten salt. This material can reach and hold very high temperatures. The trick is then to later convert it back to something we can use, either heat or yet again electricity. This is being researched in several places.
In a “pumped hydro” storage system, excess power is used to pump water uphill, from a low-lying reservoir to a high-lying basin. When the demand for power increases again, the locks can be opened and the water flows back down through turbines, generating large amounts of power very quickly.
Pumped hydro is already widely used. In Europe, it is mountainous countries with reservoirs that can play a major role here. Switzerland, for example, wants to become the ‘battery of Europe'.
Unfortunately, of course, this is not so easy with us. In the Netherlands there is more talk of either underground 'waterfalls' in unused mine shafts or in large reservoirs the IJsselmeer for example.
Something very different is the storage of energy in a flywheel: A wheel that you give a 'push' with an extra amount of electricity; so that it starts spinning very hard. Under ideal conditions (low friction), once cranked, the wheel keeps spinning non-stop until the energy needs to be 'taken out' again: At that point, you reconnect the wheel to a dynamo and the stored kinetic (= movement) energy turns back into electric current.
There has been much interest recently in “green” hydrogen, i.e. hydrogen gas (H2) made from water using green electricity (as opposed to “blue” or “gray” hydrogen made from fossil fuels). The gas is stored and later converted back into electricity through fuel cells, or it is used in place of natural gas for cooking and heating. Because you can store hydrogen gas for a long time, it would even allow us to store solar power from summer until winter.
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Salt water
An alternative to lithium ion are so-called saltwater batteries. In this technology, salt water is used as the electrolyte. This reduces the amount of rare minerals and toxins needed to make them, which would make these batteries better for the environment. The technology would also be safer, with less risk of fire. On the other hand, the energy density is lower, so you need a lot more space for installation. There are not very many providers of these types of batteries yet, but it is an option to keep an eye on.
-
Warm water
Storing power in the form of hot water to be used for showers or heating at a later time is an application we've talked about before. At times when there is “too much” solar power, we can turn up the heat pump or heating element a notch, and store the heat produced in a well-insulated boiler tank.
-
Warm salt
A more exotic solution is to store energy in “molten salt. This material can reach and hold very high temperatures. The trick is then to later convert it back to something we can use, either heat or yet again electricity. This is being researched in several places.
-
Pumped hydro
In a “pumped hydro” storage system, excess power is used to pump water uphill, from a low-lying reservoir to a high-lying basin. When the demand for power increases again, the locks can be opened and the water flows back down through turbines, generating large amounts of power very quickly.
Pumped hydro is already widely used. In Europe, it is mountainous countries with reservoirs that can play a major role here. Switzerland, for example, wants to become the ‘battery of Europe'.
Unfortunately, of course, this is not so easy with us. In the Netherlands there is more talk of either underground 'waterfalls' in unused mine shafts or in large reservoirs the IJsselmeer for example.
-
Flywheel
Something very different is the storage of energy in a flywheel: A wheel that you give a 'push' with an extra amount of electricity; so that it starts spinning very hard. Under ideal conditions (low friction), once cranked, the wheel keeps spinning non-stop until the energy needs to be 'taken out' again: At that point, you reconnect the wheel to a dynamo and the stored kinetic (= movement) energy turns back into electric current.
-
Hydrogen
There has been much interest recently in “green” hydrogen, i.e. hydrogen gas (H2) made from water using green electricity (as opposed to “blue” or “gray” hydrogen made from fossil fuels). The gas is stored and later converted back into electricity through fuel cells, or it is used in place of natural gas for cooking and heating. Because you can store hydrogen gas for a long time, it would even allow us to store solar power from summer until winter.
The more the merrier
Of all the above technologies, there will certainly be some that will play an important role in our future energy supply. For storage in the home, apartment building or business, lithium-ion battery and hot water production are currently of particular interest. And let's not forget that you can also use the battery of the electric car.
For a truly sustainable future, we still need many new ideas and applications. Zonnefabriek is keeping an eye on it, and should there be a product that is of interest to you and us, we will be happy to seek it out.
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