What Is an Energy Storage System?
Energy storage systems capture surplus power in electric grids and store it in chemical, mechanical or thermal form. They support the integration of renewable energy sources, ensure grid stability and optimise electricity utilisation.
They can help businesses and households become more self-sufficient, and provide backup power during blackouts. They can also reduce carbon emissions and help combat climate change.
Reliability
Energy storage systems can store a variety of forms of energy: chemical, thermal, kinetic, and electrical. They can convert this energy to electricity when needed. They can also provide ancillary services such as frequency regulation. In addition, they can help defer expensive transmission upgrades and provide backup power. The reliability of an energy storage system is measured by its state of charge (SOC), which reflects the amount of stored energy and the rate at which it can be discharged.
Many commercial and industrial electricity customers deploy ESSs to reduce their demand charges, which are based on their peak load levels during high-demand periods. Residential battery storage also helps to align the more variable output of wind and solar generation with power demand.
While PHES and lithium-ion batteries are the most popular storage technologies, other forms of energy storage are also being deployed. For example, compressed air, superconducting magnets, underground pumped storage, and hydrogen are all in various stages of development. Many storage vendors are technology agnostic, and they can use software to dispatch different technologies depending on the project needs.
Empirical studies on energy storage utilization in power systems have found that they can improve system reliability by minimizing the need for transmission line upgrades. Moreover, they can support the integration of renewables into the grid by alleviating intermittency problems. Historically, North America was the pioneer of reliability improvement through energy storage systems, but Asia is now taking over with its large population and commitment to increasing renewables.
Flexibility
Energy Storage Systems (ESSs) provide a range of flexibility services for electric power grids. These services include storing and providing energy on demand, smoothing renewable generation, providing backup power, reducing end-user electricity demand charges and supporting grid infrastructure. In addition, ESSs can also reduce the need for expensive fossil fuel generation.
ESS technologies vary in the power and duration they can provide, Energy Storage System as well as how quickly they can respond to system balancing requirements. Flexibility can be on a second-by-second basis for sudden surges in TV use or months at a time managing the differences in energy demand and supply between different seasons.
A large-scale battery, for example, can be dispatched to function as either generation or load to help balance fluctuations in demand and supply on the grid. This increases grid efficiency, alleviates transmission congestion, and provides more flexibility in power system operations.
Using an ESS to smooth and shift renewable generation to the evening peak hours also helps avoid curtailment of these resources when their availability exceeds electricity demand or power transmission line capacity. Additionally, ESSs can be co-located with solar or wind power plants to improve the economics of these projects by increasing their reliability and availability.
The most widely deployed ESSs are lithium-ion batteries with a variety of sizes and capacities, but other technologies such as compressed air, super-conducting magnetic storage, underground pumped storage and hydrogen storage are also in various stages of development. Several of these projects are being integrated into microgrids, allowing them to operate independently from the larger grid and to provide services within that community.
Cost
Many state and federal incentives, such as investment tax credits and demand response payments, can help reduce the upfront cost of energy storage systems. Businesses can also save money by leasing the system or entering into a power purchase agreement (PPA).
The key to making renewables cost-competitive with fossil fuels is low-cost storage, which can enable them to dispatch at critical times when the grid needs additional capacity. For example, in some markets, electricity prices spike during summer heat waves. Energy storage can mitigate these price spikes by reducing peak demand and thus lowering the need for fossil fuel-powered peaker plants to run during those high-demand periods.
Battery costs have declined rapidly in recent years, thanks to technological and manufacturing innovations. Increasing global demand for lithium-ion batteries from consumer electronics and electric vehicles drove more investments in production capacity, further lowering the cost per kilowatt-hour of the Solar Applications technology. Meanwhile, efficiencies in inverters, wiring, containerization, and climate controls led to declining balance-of-system (BOS) hardware costs as well.
Smartly deployed energy storage can also reduce or defer the need to build out expensive transmission and distribution lines. In addition, the ability to increase local and system resiliency during critical times can eliminate or delay the need for costly infrastructure upgrades.
Environmental Impact
Battery energy storage systems are a key component of the clean energy economy. They provide flexibility to renewable electricity sources and enhance grid stability. They also support electrification and Net-Zero emissions goals. Moreover, they can also help reduce power demand during peak usage periods and reduce the need for costly energy infrastructure upgrades.
Energy storage systems are available in a variety of sizes and capacities. They can be found in both front-of-the-meter and behind-the-meter applications. Front-of-the-meter systems are used by utilities to alleviate grid congestion and extend the life of aging assets. They can also be integrated with EV charging stations to optimize charging times and reduce demand charges. Behind-the-meter systems are paired with rooftop solar installations and can be used for backup purposes.
The most common battery technologies are lithium-ion batteries, which are also used in mobile phones and electric vehicles. These batteries are environmentally friendly and can last up to 15 years with a proper maintenance plan. They are also recyclable, which makes them an excellent choice for the circular economy. Additionally, reusing batteries provides substantial economic benefits as well.
Energy storage can also be used to improve the reliability of solar and wind energy generation. This is because of their intermittent nature and the need to manage electricity demand. It can also help prevent these resources from being reduced or curtailed during a grid emergency. Moreover, energy storage systems can help improve the efficiency of existing peaker plants. They do this by enabling the plant to respond quickly to supply requests from the grid operator.