Diffrent types of grid scale energy storage systems

In this article, I am going to try to give you an overview of the ways we currently store energy and what might come in the future.

To look at the different ways to store energy, we are going to assume that they all have the same origin of energy. So, for example, if one gets energy from coal and the other from wind, it doesn’t matter how effective the wind energy storage solution is as it will always be less environmentally friendly.

Your energy usage on a time graph shows how renewable energy produces energy. Of course, we exclude nuclear energy, as it works in pretty much the same way as coal, natural gas, or oil in producing energy when we need it. One of the biggest advantages of conventional power generation forms of energy is that it is easy to transport, unlike electricity. It is hard to freight electricity around, but not so much with coal. You can just put it on a train or on a ship and then bring it to where you need it.

But going back to renewable energy, humans don’t use the same amount of energy throughput the whole day. At some parts of the day, we use more energy than others, and sometimes this matches with how much the wind blows or how much sun is out. However, what if it isn’t? That is the big problem with renewables; they are intermittent, which means they are not so predictable and consistent as the conventional power sources. So what we need is a way to store power when we are producing too much of it and then be able to take that stored power when we aren’t producing enough electricity. That is where industrial-scale batteries come into play, where we can store power on a grid-wide level.

There is one major player in this field that has pretty much dominated the sector, which are dams. I think dams are great, and if we could put dams everywhere to solve the problem, we should. Yet we are running out of good places to put dams, and the places we are putting dams are getting less and less optimal. For example, China just built the world’s biggest dam, the Three Gorges Dam. This is a great way for China to store its electricity that it is producing with its wind farms, where China is on top of the list of countries that produce the most electricity through wind in the world. Yet what has been somewhat forgotten is that 1.2 million people had to move to make this dam work, as cities and villages upstream got flooded by the dam.

Another somewhat established player is lithium-ion battery farms; they have set up a farm in Australia next to a windmill farm so that the harvested energy can be used when it is needed.

In this article, I am going to try to give you an overview of the benefits of these energy storage systems and then show you some new technologies that are up and coming and that might help us move into renewable energy.

Existing technologies

Industrial lithium-ion batteries

Explanation:

A battery has a few main parts:

• Cathode: The cathode is the positive end of the battery.
• Anode: The anode is the negative end of the battery.
• Electrolyte: Electrolytes are a fluid that lets the electrons and protons flow easily from one side to the other.
• Porous separator: As the name suggests, it separates the cathode and anode.

It is important to note that in lithium-ion batteries, we don’t use lithium in its elemental form but combined with something. A common example is lithium-cobalt oxide (LiCoO2).

So, how can I power my phone with all of this? When you are using your phone (marked as Load), electrons are used as the system shifts sides between electrons and protons.

Pro:

• It can provide spinning reserve, like any industrial energy storage solution we are going to look at.
• It has a fast response time.
• You can absorb power instantly.
• It can store electricity of high quality.

Spinning reserve: Spinning reserve is the term used for how much extra power your electrical system can produce if needed. In the picture below, we have three generators, each with their own motor or power source. If each of your generators has an optimal production rate of 4MW and you have three generators, then you have a total optimal power of 12MW. Let’s say you have a city that needs to be powered by these three generators. The industry consumes 6MW of power and the residential district consumes 3MW of power. Then you have 12MW-9MW, a spinning reserve of 3MW. But let’s say one of the generators breaks down. Now, the two remaining generators need to run at 4.5MW each, which is overloading the system. The generators can do this for a while but not long without causing major damage.

If you have a battery that can provide 5MW for 15 minutes, then you have 15 minutes where you can fix the generator. If it isn’t fixed by then, you can still overload the generator from then. But it buys you 15 minutes, which can be crucial.

Cons:

• Most experts argue that it will never be cheap enough for industrial scale. It is not cheap now but the prices have been dropping.
• Their ability to hold a charge fades over time.
• They pose a fire risk.
• The materials are hard to get and expensive, there have also been records of human rights abuses and they are known to destroy the local nature.
• They are expensive to recycle.
• There aren’t any that really meet the DOE requirements for a grid-scale energy storage system.

DOE Requirements for grid-scale energy storage: The battery needs to be able to charge and discharge 20 kilowatts of power per hour. Be capable of at least 5,000 recharges. Have a useful lifespan of over 10 years. Such a battery should cost less than $100 per kilowatt-hour.

Dams: Dammed water is one of the oldest forms for humans to generate electricity. It is pretty much what powered the industrial revolution. It works, as you most probably know, by letting water that is higher up or flowing through a river, go through a turbine or in the olden days a water wheel. Which then turns a generator to produce electricity.

At some point, humans started to store that energy and have it on demand. That was the birth of the dam. Nowadays, we can use most dams not just to hold water back and then let the electricity flow out when we need it, but we can also store energy that comes from other sources and then use that energy whenever we need it.

We do this by having a dammed body of water higher up and a body of water at the bottom, also called a lower reservoir. This lower reservoir can still have a flow point, yet there needs to be enough water there to pump it up when you have excess power.

Switzerland has just built Europe’s biggest battery, connecting two mountain lakes and thereby making solar and wind a much better option in the nation and for the surrounding grids. Plus, there is a massive upside for the Swiss population. With this new “battery”, Swiss electricity providers can buy cheap excess renewable energy from neighboring countries and from within the country, and thereby sell it cheap throughout the day. Plus, it is renewable energy.

So let’s come to some of the pros and cons:

Pros:

• Can store energy with very little energy loss (high efficiency)
• Cost-competitive even though building the dam can be a big upfront cost
• It is reliable
• Can help with flood control
• Can be a great way to control water supply

Cons:

• Can destroy/alter the surrounding nature
• Can be an eyesore, some argue that they destroy the scenery in the mountains
• Because a lot of cement is used in construction, it is not a carbon-neutral process

Compressed-air energy storage (CAES):

A compressed air energy storage system works by compressing air into a container, often underground or in a large tank, using energy from an external source. When energy is needed, the compressed air is released and expanded through a turbine, generating electricity. This system is similar to a traditional gas turbine power plant, but instead of burning fuel to heat compressed air, the energy is stored in the compressed air itself. One advantage of this system is that it can use existing infrastructure, such as natural gas pipelines, to transport compressed air. However, the efficiency of compressed air energy storage is generally lower than other types of energy storage, such as batteries or pumped hydro.

Pros: Can use existing infrastructure, such as natural gas pipelines Low maintenance costs Can be located in urban areas where space is limited

Cons: Lower efficiency compared to other energy storage systems Limited by geography, as it requires a large volume of space to store compressed air (Undergrounds, so it can be in a city, you just need space underneath for the system) Requires specialized equipment and controls, which can be expensive Can be noisy and create vibrations Potential for air leaks and contamination

Flywheel: The Flywheel is one of the oldest technologies on this list. This tech was invented in the industrial revolution and was a popular way to store energy in places where access to a running stream was not an option. There are two types of Flywheels, heavy ones that don’t spin as fast or lighter ones that spin faster. Nowadays, there are flywheels that can go all the way up to 10,000 RPM.

The Flywheel is a great way to store energy on a short-term basis. However, it doesn’t make sense to store energy with a flywheel for a long time as friction between the parts and aerodynamic drag causes the flywheel to slowly lose power. Their main purpose in the future is going to be in stabilizing energy fluctuations on a small scale. They aren’t practical for storing energy for the transition from fossil fuels to renewables.

Pros:

• Can provide quick bursts of power over short periods of time
• Useful for backup power during brief outages or smoothing out fluctuations in energy supply and demand
• Has a long lifetime of 20+ years
• High return on energy (95%), although this dwindles very fast

Cons:

• Require significant amounts of space to be effective on a grid scale
• Can’t store electricity for very long

Upcoming new ones:

The ones I have talked about are all already in some commercial use. Now I am going to give you a short overview of some upcoming technologies. Here, I will explain how they work. However, most of these still need a lot of improvement to work in the “real” world.

Thermal Energy Storage (TES)

TES systems use electricity to store energy as heat. For example, this can be done with salt, also known as molten salt energy storage systems or in synthetic oils. There are two examples I want to look at closer: one being a sand TES system and the other being a TES system that uses bricks as a heat storage medium. Some TES systems can produce electricity again by making steam and then powering a turbine. Other systems don’t have that ability and can only produce heat, which can be used to heat homes and industry.

Pros:

• Can be used to heat homes or industry, or be used to generate electricity again
• Have a high energy density per cubic meter used

Cons:

• Can be expensive as this type of system needs maintenance (although not all systems require maintenance)
• There are TES systems that use hazardous materials as their storage medium

Sand Power bank

Polar Night Energy is a Finnish start-up that was founded by a team of experts in the energy storage community. They were trying to figure out some of the problems Finland is going to be facing in the transition to renewable energy. Mainly being the cold winter, where the sun doesn’t shine. They wanted to create a solution that doesn’t use any rare materials so that it can be scaled and more accessible for the general public. So they came up with a solution that uses low-grade sand to store energy. The advantage being that they can heat the sand to 1000°C. With this kind of sand being cheap and readily available, there is nothing in the way of making this a large-scale operation. A disadvantage this system does have is that it can’t convert the energy back into electricity, only heat.

Rondo’s Brick Energy Storage

Rondo’s energy storage system uses a special kind of brick to store its energy. These bricks are then stored in an insulated container. The system is built in a modular way so it can be scaled up or down how ever need to make the solution work for the costumer. A major advantages of this system being that I can produce heat and send it of to heat other systems as well as being used to generate electricity again with it.

1. Cheap excess power is bought and used.
2. The bricks are heated using thermal radiation up to 1500°C.
3. The heat that is stored can be delivered at any time as heat.
4. If the system needs electricity, it will heat up the coil with water and produce superheated air or superheated steam.
5. Air and/or steam is delivered to the industrial process or used to make electricity.

Hydrogen as a energy storage system

Most of you have heard of hydrogen as an energy source, either for cars or bigger things like planes or container ships. Yet, hydrogen has another major advantage compared to electricity stored in batteries: it can “easily” be transported. What I mean by that is you can produce wind power far out in some mountain range, convert it to hydrogen up there, and then transport that hydrogen into the industrial zone to use the energy there. This becomes especially useful when you are producing power very far away. For example, you have a solar farm in the Sahara and want to use the power in England. Then, shipping hydrogen becomes a lot more viable compared to making a power line that has to transport it all the way there.

So how does it work? To make hydrogen, we use a process called electrolysis. In that process, we turn water into oxygen and hydrogen. This process uses energy, so when we are creating energy with, for example, a windmill, we can use that energy to make hydrogen by splitting the molecule into its elements. This is not to be confused with splitting an atom, which is a very different process. Once you need the power again, you can then recombine the hydrogen with the oxygen, and you will get an energy release from that. So your only output is water and energy, and no greenhouse gases are released. Plus, hydrogen is the most abundant element on the planet.

How does electrolysis work? 2H2O → O2 + 2H2

This hydrogen can then be used for methanation. This is when you use hydrogen to convert CO2 into methane. Hydrogen can improve this process from 55% energy conversion to 99% energy conversion. This biomethane can then be fed into the natural gas supply and burned to power the grid.

Another use case is to not convert the hydrogen at all for electricity and feed it straight into cars or ships and use it as a new fuel source. This cannot be done with gasoline cars, but there are cars now on the market that run on hydrogen, and there are more and more vehicles that are able to run on hydrogen power.

There are, of course, plenty of other solutions out there being worked on, and I will try to incorporate them into my next articles.

I hope you found this article helpful. Thanks for taking the time to read it.

Sources:

https://www.ge.com/renewableenergy/hybrid/battery-energy-storage — GE website for there battery farms

https://youtu.be/EoTVtB-cSps — CNBC video on new ways of storing energy

https://youtu.be/9eAFEU7pMwU — Basic video on how and why we store energy

https://youtu.be/q8HmRLCgDAI — Video on basic Hydropower

https://youtu.be/D11iFUw_ImU?list=PL7b293q4n8alo87lK74wa2iuJRVGmBxvH — Video baisc of energy efficinecy

https://youtu.be/4JGMm8qDfxw — Video in energy storage solutions (about hydrogen energy storage)

https://youtu.be/lz6ZB23tfg0 — Video about gravity energy stoae soluctions

https://gravitricity.com/making-news/ — Gravitricity website

https://youtu.be/8X2U7bDNcPM — Video about a Flywheel as a energy storage system

https://news.stanford.edu/2018/04/30/new-water-based-battery-offers-large-scale-energy-storage/ — Article about Standford researchers that have developed a water based energy storage system.

https://medium.com/thinking-digitally/glass-batteries-an-energy-storage-breakthrough-65a7532ad252 — article about Glas batteries as a energy storage breakthrough

https://medium.com/the-dock-on-the-bay/energy-storage-the-sand-battery-8f9142209abf — Heated sand as an energy storage system

https://www.energy.gov/sites/prod/files/2017/01/f34/Deployment of Grid-Scale Batteries in the United States.pdf — Paper by the department of energy of the USA, on the deployment of Grid-scale batteries in the US,

https://energystorage.org/spinning-reserve/ — article about spinning reverse by the Energy storage association

https://youtu.be/PXy-H4iJqMY — Video about Spannung Reserve

https://medium.datadriveninvestor.com/energy-storage-now-6d49a401ab8f — article about energy storage solutions out there

https://youtu.be/9dnN82DsQ2k — video about the problem behind lithium batteries

https://www.youtube.com/watch?v=XWq-Mq1Uqpw — Video talks about the fires tha have been cause by lithium-ion batteries.

https://phys.org/news/2021-05-electricity-seebeck-device.html — article about Generating electricity from heat using a spin Seebeck device

https://polarnightenergy.fi/news/2022/11/24/sand-batterys-efficiency-explained-polar-night-energys-sand-battery-has-efficiency-up-to-95-per-cent — Article about Sand Batteries efficiency

https://www.bbc.com/news/science-environment-61996520 — BBC article about Sand batteries

https://www.wired.com/2017/03/dont-blame-batteries-every-lithium-ion-explosion/ — Article about lithium-ion fires

This figure is by the DOE

This figure is by the DOE

https://www.energy.gov/sites/prod/files/2017/01/f34/Deployment of Grid-Scale Batteries in the United States.pdf — Paper on development of grid scale batteries in the US by the DOE

https://letstalkscience.ca/educational-resources/stem-in-context/how-does-a-lithium-ion-battery-work — Article about how a lithium-ion battery works

https://www.upsbatterycenter.com/blog/intercalation-work-batteries/ — Article about intercalation in lithium-ion batteries

https://youtu.be/a6Dw9vtnwns — video explaining what Electrolytes are

https://www.energy.gov/energysaver/articles/how-does-lithium-ion-battery-work — article about how lithium-ions batteries work form energy.gov

https://energystorage.org/why-energy-storage/technologies/compressed-air-energy-storage-caes/ — Article explaining how compressed air energy storage works by Energy storage association

https://sinovoltaics.com/learning-center/storage/compressed-air-energy-storage/ — Article about

CAES.

https://rondo.com/how-it-works — website of Rondo energy