Energy Storage As Part of a Distributed Energy Storage System
Energy storage provides grid resilience to mitigate the duration and intensity of disturbances and power imbalances. It can be integrated at multiple levels of the energy grid including transmission, distribution, generator, and customer sites.
Energy storage can also prevent price spikes during peak electricity demand. This reduces carbon emissions, fossil fuel usage, and wear on infrastructure.
Battery Storage
Energy storage provides a number of critical grid services. It can provide energy to the electricity network at strategic times without requiring the use of transmission or distribution lines (as electricity is delivered from generation plants to consumers). Energy storage can also help balance renewable intermittency. It can be charged when renewable generation produces excess electricity and discharged when demand increases, helping match electricity supply with demand.
Battery storage systems can be installed at the system level, as with PJM’s large-scale batteries, or at the commercial and residential levels. Energy storage at the residential and commercial distributed energy storage system level allows customers to take control of their energy, reduce their bills, and provide emergency backup in case of a power outage. It can even allow homeowners to become self-sufficient and live off the grid.
In addition, because the storage units are able to quickly respond to changes or drops in electricity demand, they can help avoid outages and reduce the need for expensive investments in transmission and distribution capacity. Energy storage can also assist with electricity frequency regulation and voltage management, at both the system and local levels.
However, the high initial set-up costs and volatility of the lithium market (which is essential for EV batteries) are challenges to battery storage. Moreover, there are concerns about the environmental impact of the production and disposal of the batteries.
Flywheel Storage
In the field of energy storage, flywheels can achieve rotational speeds much greater than batteries and are able to store many more kilowatt-hours. They require very little maintenance and have a long lifespan. Furthermore, they don’t have the fire hazards or chemical corrosion that is found with some other energy storage devices and they operate in a wider temperature range than most batteries.
For renewable energy, a flywheel can act as an energy buffer and help stabilize power fluctuations. This can help reduce the cost of electricity during peak demand periods such as summers for air conditioning and winters for heating. It can also help reduce the need to use fossil fuels during these times, which are a major source of greenhouse emissions.
A flywheel system can be used as a microgrid in its own right or in conjunction with other renewable energy sources to provide long-term ride-through power. It can also be used to compensate for power outages in hospitals and other critical applications that depend on consistent voltage levels such as MRI or CT machines.
The global market for flywheel energy storage systems is expected to grow in the coming years. This is due to the increasing demand for distributed energy storage systems in countries with rapidly growing urban populations. These regions are often undergoing significant investments in power infrastructure improvement, which will need to be supported by an appropriate level of distributed energy storage.
Fuel Cell Storage
Energy storage enables the grid to respond rapidly to changes in electricity supply or demand, providing power system stability and reliability. It can also help to reduce greenhouse gas emissions and the need for coal, oil, or natural gas power generation. It can provide backup power for communities, and it can be combined with community solar or aggregated residential and commercial rooftop solar projects to create microgrids or resiliency hubs.
Distributed energy storage systems are located in multiple segments of the electricity grid-in transmission networks, distribution networks, co-located with wind or solar power plants, and at the customer level (commercial buildings and residential). They enable the grid to operate in island mode, facilitating restoration and re-energizing in the case of a disruption. They can also offer multiple services, including frequency and voltage regulation.
The use of distributed energy storage can increase the penetration of renewables distributed energy storage system in a power system, helping to mitigate climate change. However, the high carbon dioxide emissions from battery manufacturing may offset any positive impact resulting from increased use of these technologies. The high initial investment and cost of batteries has slowed growth of the market. The price of critical metals, such as lithium, has risen due to the Russian invasion of Ukraine and brisk demand from electric vehicles. The market is further challenged by supply chain disruptions due to shortage of cobalt, a key material in batteries.
Hydrogen Storage
As part of a distributed energy storage system, hydrogen can help to address the challenge of intermittency. The gas can be generated from renewable sources with the aid of electrolysis, and stored for use when solar or wind are not available. This can reduce the need to rely on fossil fuels for energy generation, leading to significant climate benefits.
Hydrogen can be stored in manufactured storage tanks or in natural geological formations such as salt caverns. It is flammable, and special safety precautions are required when handling it. It must be pressurized and cooled, or it can become explosive. It is also a brittle, corrosive gas that can cause embrittlement of materials and cracking of containers. It is therefore ideally stored in sealed containers under high pressure.
Unlike battery technology or thermal energy, which can only store electricity for a few hours to a few days at most, hydrogen can provide long term storage capacity. This will allow it to play an essential role in decarbonizing the grid by tackling the intermittency of renewable energy.
Distributed energy storage systems (DES) can be used by utilities and consumers to support the integration of renewables into the grid, as well as to provide backup power for critical infrastructure. They can be used to smooth out energy demand peaks and can also reduce emissions, fuel consumption, and wear and tear on equipment. They are a key enabling technology for solutions such as microgrids, net zero buildings, and grid flexibility.