Understanding Battery Energy Storage and its Impact on the World
Battery energy storage systems are big batteries that capture the surplus energy generated by renewables or other sources and release it when the demand is high but supply is low. It makes renewable energy reliable, smooths out the ups and downs of energy production, and keeps the power grid stable.
When we say they’re really big, we mean really big batteries! Take Fluence’s 2000 series, for example—these stand about 2.5 meters tall and stretch a solid 7.5 meters long. To put that in perspective, it’s basically almost the size of some school buses we see rolling around in India.
These big batteries and the surrounding components are generally a Battery Energy Storage System or BESS for short.
Now, the question is... How does this work?
At their core, BESS units operate like supersized versions of the battery in your phone. When the power grid has an excess of energy (say, during a sunny day with tons of solar power), the BESS charges up, storing that extra energy for later.
The stored energy is held in specially designed battery cells within the BESS. Unlike your phone battery, these cells are built for high power capacity and efficiency, meaning they can store large amounts of energy over long periods.
Source: Hyosung Heavy Industries
Like any system, even battery systems need a brain, and this brain is called the battery management system or BMS. The function of a BMS is to keep an eye on the battery’s health, making sure it doesn’t get too hot, too cold, or overcharged. It keeps all the battery cells balanced so they work together smoothly, checks if they’re running low, and makes sure they don’t get damaged.
To support the brain, the battery system has PMS or Power Management System, The PMS manages the flow of energy between the battery, the grid, and other connected systems (like solar panels). It determines when to charge the battery, when to discharge it, and how much energy to send to or draw from the grid based on demand.
Now, one thing to note is that batteries store energy in the form of Direct Current (DC), while most of the electrical systems run on Alternating Current (AC). That’s where the Power Conversion System (PCS) steps in! It converts the DC energy from the battery into AC so it’s ready to power things like lights, TVs, and other gadgets. And if it’s the other way around, say the battery needs to store some incoming AC power, and the PCS converts it to DC so it can be stored correctly.
But batteries get hot while in usage or charging, just like the batteries on our phones, that is why to maintain optimal temperatures these systems have HVAC (Heating, Ventilation, and Air Conditioning) systems. If the battery starts heating up from all the energy moving in and out, the HVAC system cools things down. And in cold weather, it might warm things up a bit to keep performance steady.
How do we know how much power these batteries have?
In our homes, we are generally familiar with the term Units, when discussing electricity bills and checking how many units were consumed. 1 unit is equivalent to 1kWh, or in simple words, 1 kWh is the quantity of energy consumed by a 1kW (1000 watt) electric appliance in 1 hour.
In a BESS, energy is typically measured in megawatts (MW)/megawatt-hours (MWh) or kilowatt (kW)/kilowatt-hours (kWh).
The system's power is usually measured in MW or kW, with MW being the larger scale (Scale = Gigawatt (GW)>Megawatt (MW)> kilowatt (kW)).
For example, a 10 MW battery can output up to 10 megawatts of power at once.
The Energy Capacity, or how much energy the battery can store over time is measured in megawatt-hours (MWh) or kilowatt-hours (kWh). So, if a battery has a capacity of 20 MWh, it can deliver 20 megawatt-hours of power in total. How long it lasts depends on how fast the energy is used. A 20 MWh battery running at 10 MW would last around 2 hours (because 20 MWh / 10 MW = 2 hours).
How big or small are these systems generally?
A typical small energy storage system can power your home for several hours. For instance, Tesla's Powerwall can store around 13 kWh of energy, which is sufficient to keep a household running for a while now, if we take the example of the earlier mentioned Fluence Grid Stack Pro 2000 series, which can store about 2.4 MWh. That’s enough energy to power hundreds of homes!
Global Energy Storage Progress
Due to the growing importance of renewable energy and the need for a consistent power supply, countries around the world are racing to expand their energy storage capacities to ensure a reliable and clean energy supply throughout the day.
Information and Analytics firm BloombergNEF forecasts that by 2030, the global energy storage market will see an annual growth rate of 21%, reaching 137 GW/442 GWh.
Let us take a look at the top 3
1. United States: The U.S. is on a mission to supercharge its clean energy landscape, throwing over $369 billion into it thanks to the Inflation Reduction Act of 2022. And it seems to be paying off! According to Analytics firm Wood Mackenzie, total energy storage deployments in the country in 2023 across all segments reached 8.7 GW and 25.9 GWh.
2. China: China’s not about to let the U.S. have all the fun with energy storage! They are speeding ahead with their own impressive setup, boasting a whopping 44.4 GW of new-type energy storage capacity by the end of June, this year expanding 40% compared with the end of last year, the National Energy Administration (NEA) said recently. Lithium-ion batteries accounted for 97% of China's new-type energy storage capacity at the end of June.
3. Europe: Europe is also going all in on energy storage. By the end of 2023, Europe’s total operating BESS fleet reached around 36 GWh, and the overall installed BESS capacity in Europe is projected to expand more than sevenfold to reach 260 GWh of battery storage by 2028.
In India, our solar capacity is increasing at a rapid rate, and we too are looking at energy storage solutions to store the excess generated. Although we are new to this technology, India’s policymakers have recognized the importance of energy storage systems (ESS) to the country’s evolving power landscape and have already awarded more than 8 gigawatts (GW) of such tenders, allocating 60% of these in 2023 alone, according to a new joint report by the Institute for Energy Economics and Financial Analysis (IEEFA) and JMK Research & Analytics.