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Secret Mega Batteries: How Utility-Scale Batteries Could Support Electrical Grids
- According to a March 2021 report, Tesla is building a secret mega battery in Texas, USA. The gigantic battery will potentially power around 20,000 homes on a hot summer day.
- Utility-scale battery storage systems are vital in moving from fossil fuels to variable renewable energy. In addition, battery storage will assist with frequency regulation, flexible ramping and black start services for the system operators.
- Utility-scale battery storage systems offer a better solution for frequency regulation services than those traditionally used. Unlike conventional plants, which can take several seconds to minutes to respond, it takes milliseconds for a battery storage system.
- When renewable sources gain access to the grid, the load curve changes dramatically. Utility-scale batteries can help the electrical grids meet these ramping requirements and flatten the duck curve.
- When there is a grid failure, the generation plants need power to start up again—known as a “black start.” Diesel generators typically provide power restoration, but battery storage systems could do the same job faster and in a more energy-efficient way.
In March 2021, Tesla hit international headlines for apparently constructing a secret mega battery in Texas, USA. The equipment at the site has been kept under covers, and workers are discouraging any onlookers. Still, the Tesla logo on the workers’ hard hats and public documents have helped confirm the company’s role in the project.
Now revealed, Gambit Energy Storage LLC—a Tesla subsidiary—is building a 100 plus megawatt battery connected to an ailing electric grid in Texas that nearly collapsed in February 2021. The gigantic Tesla battery could power about 20,000 homes on a hot summer day.
Utility-scale battery storage systems will need to play a significant role in facilitating the energy transition to more variable renewable energy (VRE). These storage solutions can assist greater penetration of variable renewable energy into the grid by storing the excess generation and firming the renewable energy output.
For the system operators, battery storage such as the one constructed in Texas can help provide grid services such as frequency regulation, flexible ramping, and back start services. Furthermore, when paired with renewable generators, batteries help provide reliable and cheaper electricity in isolated grids and off-grid communities. Many of these communities currently rely on expensive imported diesel for electricity generation.
Supporting Frequency Regulation
Utility-scale battery storage systems are a much better solution for frequency regulation services.
A disparity between power supply and power demand can cause a dip or rise in grid frequency outside the specified limits. Traditionally, thermal power plants provide frequency control services, but this can be inefficient and costly. The hike in cost is because the process involves many generation plants to be either put on standby or required to run at capacity levels that do not use fuel efficiently.
Utility-scale battery storage systems are a much better solution for frequency regulation services. Compared to conventional plants, which can take several seconds to minutes to respond to the system operators’ instructions, it only takes milliseconds for a battery storage system to respond.
Meeting Ramping Requirements
Adaptable technologies such as utility-scale batteries can help the electrical grids meet these ramping requirements and flatten the duck curve.
When VRE starts to gain access to the electrical grid, particularly solar photovoltaic (PV) penetration, the load curve changes dramatically—into what is known as a “duck curve“. Very high ramping requirements characterize the duck curve.
The system must ramp downwards in the morning when solar generation increases and ramp upwards in the evening when solar generation decreases and consumer energy demand increases. Adaptable technologies such as utility-scale batteries can help the electrical grids meet these ramping requirements and flatten the duck curve.
Black Start Services
It is possible for large-scale battery storage systems to provide black start services in cases of grid failure, just like diesel generators.
When there is a grid failure, the generation plants need power to start up again, known as “black start.” This power restoration is typically provided by diesel generators co-located with the generating plants. Large-scale battery storage systems can provide black start services in cases of grid failure, just like diesel generators.
Suppose the battery storage systems are installed on the sites of generation plants. In that case, they will also provide other ancillary services to system operators when not being used for black start support. This would offer additional revenue to the utility-scale battery systems.
The advancement and implementation of utility-scale batteries are critical to the clean energy transition mission. As more and more renewable energy is added to the grid, we can decrease the risk of disruptions by boosting capacity in long-duration, grid-scale storage. Storage is also essential for areas where they require electrical distribution via microgrids. These microgrids can then work separately from the large national grids and help improve a nation’s overall system resilience.
Frequently Asked Questions (FAQs)
What is the electricity grid, and how does it work?
The network which delivers electricity to consumers is known as a power grid. It comprises various elements, including generator stations, transmission lines and towers, and individual consumer distribution lines. National grids tend to be owned by regional transmission companies.
How big are utility-scale battery storage systems?
The size of a utility-scale battery storage system varies and typically has a storage capacity ranging between a few megawatt-hours (MWh) to hundreds of MWh. The world’s largest utility-scale battery is in California (USA) and has a total capacity of 400 MW/1,600 MWh. Lithium-ion (Li-ion), sodium sulphur and lead-acid batteries can all be used for grid applications.
How does renewable grid-scale battery storage work?
Battery storage systems are charged by electricity generated from renewable energy sources, such as solar and wind power. Intelligent battery software uses algorithms to coordinate energy production and determine when to reserve energy and release it to support the grid.
Why are batteries essential for renewable energy?
Grid-scale batteries have given renewable energy the ability to provide baseload energy to the electrical grid. Baseload is the minimum amount of electric power needed to be supplied to the electrical grid at any given time. These mega batteries have eliminated the last major hurdle for transitioning away from fossil fuels.
What happens when solar storage batteries are full?
When a solar battery system becomes full, it will simply stop absorbing and storing power from the solar system. The solar panels themselves will continue to generate voltage but will not be used or stored until there is better space or available energy demand.