Why Is Tesla Building Giant Batteries?

Just 60 days after the intended start date of the 29th September, Tesla completed its giant array of batteries in Australia.

It was the largest industrial-scale battery pack in the world when it was first completed. This battery pack was of great importance to Australia, though Tesla had some issues taking it through parliament.

However, to really understand the fundamental importance of energy storage, we must dive deeper into one of the greatest problems with renewable energy.

What’s the Problem with Renewable Energy?

Based on public interpretations, renewable energy sources are shown to be a necessary step to avoiding irreversible damage to our natural environment from climate change. Although they provide energy without emitting CO2 or other harmful greenhouse gases, they have some of their own problems, most of which I will discuss in another post.

solar panels on green field
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A solar farm in the USA

Unfortunately, one of the largest problems with renewable energy is that they usually only produce enough power at peak times. For example, a solar panel produces peak power in the middle of the day when the sun is at it’s highest point. Additionally, a wind turbine produces peak power in heavy winds, thus making them the most viable offshore.

On the other hand, non-renewable energy sources such as coal, natural gas and nuclear all produce a steady level of energy output. However, this has it’s drawbacks too. Firstly, though each country uses different levels of power at different times, every country has peak times. In the UK, this is around 5PM-7PM.

Clearly, this window isn’t where solar panels are at their peak, so companies are finding ways to solve this problem by storing the energy. One of the particularly recent examples of this is batteries.

Why Batteries?

Recently, Tesla has been ramping up production of their Model 3 electric car. Since each individual car contains thousands of batteries, it seems that they can produce them with enough scale for industrial use cases.

In case you didn’t know, Tesla recently acquired Solar City, which was the largest solar leasing company in the USA. Incidentally, a solar company and a battery production company go hand in hand together and lend themselves to this kind of challenge.

Moreover, renewable energy sources such as solar are becoming more and more popular within the US, meaning that timing is optimal for Tesla to produce commercial battery packs.

Tesla's commercial array of batteries
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Tesla’s Commercial Array of Batteries. Source Tesla.

Advantages

One major advantage of battery packs is their rapid response to meet sudden energy demands from the grid. That’s just the nature of electricity. Energy is stored in the chemical bonds within the battery when peak production from renewables is high, then released from the bonds when production is low and demand is high. Here’s a case where batteries are useful:

Suddenly, there’s a surge in energy demand. In order to meet demand, the operators of the national grid have to start up another energy generator. However, these can take hours to get going. If some energy was stored, the grid would take care of itself and batteries would start putting energy back into the grid. This is far better than starting another generator.

Furthermore, batteries can be produced in vast quantities and Tesla is proven to be able to produce them on time.

So, in the UK, the batteries would be charging at midday and releasing energy at 5-7PM. Easy, right? Sadly, it’s not as easy as that due to the drawbacks of batteries. Here are a few of them:

Disadvantages

Expensive Earth Elements

Batteries contain elements like lithium which must be extracted from the earth for use. Currently, Chile is home to one of the largest lithium mining industry in the world.

However, mining is expensive and it destroys the natural landscape. Additionally, animal and plant habitats are destroyed.

Strangely, this is one of our main problems with fossil fuels, they have to be extracted from the ground. So, now we’re doing it with ‘renewable’ energy, it doesn’t sound all that promising.

Space

Having a battery pack large enough would require a vast amount of cells, taking up a large amount of space. This could be problematic in population dense areas like the UK where people don’t like companies building in the countryside.

In comparison to pumped storage, batteries seem like an inferior option. This is because pumped storage takes advantage of the natural landscape and doesn’t ruin the image of an area.

Leakage

Due to the nature of the chemicals in a battery, they slowly degrade and lose storage over time. You’ve probably experienced this with a phone battery. However, this poses a major problem.

Lithium batteries drain charge particularly fast in cold climates, whilst needing strong cooling systems to keep them cool when it’s warm.

You see, there are only 28 million tonnes of lithium in known reserves on the planet. The average electric car uses about 20kg of lithium. As a result, we have enough lithium to sustain about 23 years of an all-electric fleet of electric cars.

Unfortunately, that’s not the end of it because that is just electric cars. Now picture many countries installing these giant batteries and you’re well on you’re way to depleting the worlds lithium reserves in under 20 years. Then what do we do?

How Can This Problem Be Solved Using Batteries?

Fortunately, lithium batteries can be recycled, though not 100%. However, the figures which I used above are appropriate presuming that we are recycling the batteries. Completely depleting a natural resource can be devastating for the survival of certain ecosystems.

As humans, we would have to find ways to change battery chemistry in order to make batteries out of more abundant materials. Alternatively, we could make more energy dense batteries which use the same amount of lithium but with greater energy potential. This could mean that less lithium would be used.

An example of this is solid state battery technology. Cleverly, the otherwise liquid electrolyte is replaced with a solid one. Thus, energy density is increased and the battery decreases in size. Alternatively, it’ll be interesting to see what Tesla will be able to do with the recently acquired Maxwell technologies in order to reduce lithium consumption.

Excessive Dendrite Growth in Lithium Ion Batteries
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Excessive Dendrite Growth – STRN

Although these advancements in technology sound promising, solid-state batteries come with their own unique problems. One of these is the formation of dendrites. Dendrites grow from the anode and can cause the battery to short circuit if not protected. Subsequently, researchers have developed technology such as a nano-film of boron nitride.

Norway – The Lungs of Europe

In order to think about solving the energy storage problem without batteries, we should look at Norway, which gets over 90% of its power from hydroelectricity.

Norway is fortunate in that it’s got an abundance of rivers and steep, mountainous regions. Optimal conditions for hydroelectricity.

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A Hydroelectric Dam – Arizona

However, depending on rainfall levels, Norway’s electricity generation can vary. For example, in the summer, there is usually less rainfall than in the winter, so energy generation is lower.

On a smaller scale, Norway may experience a rather unusual period of drought, meaning hydroelectric production is limited.

In an effort to solve this problem, the Norwegians decided to supply the other 10% of the grid with other sources of energy like solar and interconnectors to Germany and the surrounding nations.

Evidently, this isn’t 100% foolproof because it involves either using other fluctuating power sources such as solar or relying on other countries for electricity.

So, What’s the Answer?

Pumped storage is the answer. Since Norway already has the existing terrain and infrastructure available i.e. mountains and hydroelectric power stations, it can store the energy as pumped storage.

grey concrete building
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First, when there’s a peak in energy production, the excess energy is used to pump water uphill to a reservoir up in the mountains. When the energy is needed, the water is released and it flows through the existing hydroelectric power station.

As it flows through the station, it spins a turbine which generates energy. Finally, the water ends up in another reservoir, before being pumped back up again when there’s surplus power.

Pumped storage has low environmental impact too. In fact, the majority in Norway would utilise existing infrastructure, requiring only a few miles of pipes to get one station going.

How Can We Apply This on an International Scale?

Each and every country has it’s own energy generating resource. For example, Iceland has geothermal, Norway has hydroelectricity and the UK has an abundance of offshore wind.

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However, not every country can afford to or has the required infrastructure to store power. That’s where places like Norway with pumped storage come in.

When it’s windy, the UK produces extra power due to the energy generated by wind turbines. If the UK and Norway were connected, this energy could be used to pump water up to a mountainous reservoir in Norway, with a fee from Norway for storing it.

When it’s nice in the UK and there’s not much wind, the energy can be released from pumped storage and put back into the UK national grid, creating a system where Norway is acting like the battery of Europe.

Fortunately, Norway isn’t the only place for this type of energy storage, but it’s certainly one of the best. Places like Switzerland could take part in this energy storage system.

What About an Intercontinental Grid?

One large grid covering the whole world and connecting everybody seems like a great idea. However, there are some major complications which would likely prevent it from ever becoming a reality.

Firstly, there are sometimes vast distances between continents, for example, North America and Europe. Even at a high voltage, a substantial amount of power would be lost as thermal energy to the surrounding stores.

Secondly, the cost of building such a project would be colossal! There would have to be many cables running under the ocean as the amount of power draw is vast. This means greater amounts of maintenance is needed to fix any problems that occur.

Finally, the contribution of electricity would be highly uneven. Impressively, India produces more power than the whole continent of Africa! So, Africa would be putting a very small amount of electricity into the grid, whilst taking more.

Could Individual Countries Adopt Pumped Storage?

What if each country could store it’s own energy? Well, in many places, they can. However, you may struggle to create a viable pumped storage solution in the Netherlands.

On the other hand, places like the USA could have one national grid which is connected. Renewable energy from solar panels in California could supply energy to Colorado where it is stored as pumped storage.

body of water across the mountain during sunset
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Colorado Landscape

China could use pumped storage. Energy generated from renewable sources could be transported to the mountains where it is stored. This would be a major industry in China, allowing for the creation of jobs in rural areas.

Pumped Storage Isn’t Perfect.

After reading this article, you’ve probably got the impression that pumped storage is superior to battery technology. Although this is true in some cases, Tesla has a great reason for building giant batteries.

It comes down to speed and instantaneous energy output. Pumped storage requires some time for the water to flow down the pipe to the hydroelectric station.

Due to the nature of electricity, batteries can provide instant metering to the grid, removing the dramatic effects of power fluctuations. Thus, a stable grid is created for everyone.

Conclusion – Why Is Tesla Building Giant Batteries?

Evidently, Tesla has a good reason for building the city-sized batteries. They’re a financially viable solution and they provide excellent rapid storage.

However, Tesla must consider the rapid usage of lithium. Depleting our deposits with no backup could cause serious damage to the human population, putting a halt on many parts of the economy.

Although nobody outside of Tesla is certain what they are developing, we can hope that they’re developing a battery technology which doesn’t involve lithium.

Perhaps a mixture of batteries and pumped storage is a good option. This combination would have a limited impact on the environment and would provide fast and stable storage.

You could visualise this system like a computer server with an SSD cache and hard disks for the bulk of the storage. Batteries would act as the SSD cache and pumped storage would act as the hard disks.

Similarly to a server, this balances cost and convenience, whilst having a fast system capable of performing the required tasks.

If you’ve got any thoughts, questions or comments, please leave them in the comments section below this article.

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