Energy Storage: a key driver for energy autonomy and efficiency
Energy storage is one of the core factors in achieving energy efficient systems. The ability to store energy and use it later has significant importance, as it is a solution to the problems of unstable or expensive power grids, and it is a critical tool for increasing the usage and integration of renewable energy.
A variety of technologies exist to store electricity; batteries, compressed air and chemicals, and pumped hydro storage are amongst the most common for large infrastructures. The growing need for flexibility and autonomy, where consumers are also becoming energy producers, is driving innovation in energy storage to produce a broad range of new solutions. Some emerging storage technologies, such as batteries, are gradually becoming more competitive for individual users (householders, buildings and small facilities).
The most relevant storage technologies for commercial and industrial facilities are batteries that store electricity, or thermal energy storage systems that store chilled water, ice, or provide heat. These can operate as stand-alone systems or work jointly with solar PV systems.
Battery Storage: Battery cells undergo a chemical reaction to store and release energy. Inside the battery, two materials exchange charged ions. This flow of ions generates an electrical current and a voltage which provides power. An inverter then changes the energy from direct current (DC) to alternating current (AC). The battery storage sector uses mostly lithium-ion chemistry, which features high energy density, efficiency, and a long life cycle.
Thermal Energy Storage: The most common types are chilled water or ice storage. During off-peak hours, water is cooled or frozen into ice, and then during peak hours, cooling loops extract the cold to provide space conditioning and/or refrigeration. Thermal storage can store heat as well, through heating salts, for example.
Main benefits of energy storage:
Flexibility: Energy storage creates new, flexible possibilities for managing the flow of energy within the framework, which is especially important for consumers. Usually, with users on a grid system that adopts photovoltaics, there is strain on the grid as the sun goes down and at peak times, creating steep changes in electricity demand, and incurring considerable costs for ramping up and down electrical power. Energy storage can help mitigate these issues by reducing peak demand, using stored energy during in those hours, and avoiding paying higher tariffs on peak hours.
Efficiency: By improving the overall efficiency of the power grid, storage accelerates the broader adoption of renewable energy. Energy storage could help balance the electricity supply, by choosing when to generate electricity for their own use and when to rely on the electrical grid for the residual balance. The user can also charge batteries in off-peak hours and use them in peak hours, cutting energy costs considerably.
Resilience: Planning for emergency backup power is an essential part of a resilience plan. Historically, the facilities that were used as emergency back-ups were expensive fossil fuel generators, but these can now be upgraded to new battery systems that provide money-saving and money-making solutions.
Demand response: Energy storage can enable participation in demand-response markets, offering lower net unit pricing in exchange for reduced power consumption during peak periods, without impacting normal facility operations. This will result in increased financial returns.
Although energy storage is poised to be a fundamental driving force for new energy efficient systems, there are still some challenges to face. The main barriers are potentially high upfront costs, but it is important to educate users that initial costs will be compensated for with future savings. Additionally, digital platforms and software can be integrated with energy storage systems to help owners know when to charge and discharge batteries (charge batteries when demand is low and discharge when demand is high), and coordinate peak demand events.