Energy storage is an indispensable technology in our transition towards a low-carbon future, helping balance electricity supply and demand minute by minute, as well as improving power quality by minimizing spikes, surges, or outages that damage electric equipment.
There are various forms of energy storage, from lithium-ion batteries found in phones and electric vehicles to utility-scale pumped hydro and thermal technologies. In this article, we will investigate these leading methods.
Batteries
A battery is an electrochemical device that converts chemical potential energy to electrical energy through electrochemical reactions. It consists of one or more electrochemical cells; with one cell acting as the anode and another serving as the cathode.
An anode and cathode are two separate metals or chemical compounds which facilitate redox reactions between electrodes, producing electrons which flow between them to generate current flow and increase voltage. As these reactions progress, electrons produced are distributed between electrodes as they produce current. This increases voltage.
Lithium-ion batteries are ubiquitously found in consumer electronics and electric vehicles, offering high energy density storage capabilities in an extremely small footprint. Not to mention they’re cost-effective and safe to handle!
Behind-the-meter batteries offer both businesses and homeowners an efficient way to leverage solar and other renewable energy sources, serving as backup power during outages while offsetting intermittent renewable sources like wind or solar power. Furthermore, these batteries allow companies to shift demand away from peak times for cost savings purposes.
Hydroelectric Dams
Hydroelectric dams store vast quantities of potential energy in reservoirs before using that energy to spin generators that produce electricity – they make up nearly 99% of global grid-scale energy storage capacity.
Pumped storage utilizes an electric motor-driven pump to move water between reservoirs during periods of excess electricity production, then back down again during times of high demand for electricity. Pumped storage systems require minimal land per gigawatt-hour of storage capacity while producing less pollution than battery systems.
Dams can present problems as well. A study led by Michigan State University social scientists led by Dr. Peilei Fan has shown that communities within 50 kilometers of dams experience worsened economic conditions, population displacement and green space loss after construction. Researchers are exploring other energy solutions which offer similar benefits without their negative repercussions.
Thermal Storage
Storage technology can play an invaluable role in helping stabilize electricity grids by fulfilling services currently provided by fossil fuel peaker plants that operate only during times of peak demand, such as heat waves. Many such plants sit near low-income communities that have historically suffered the effects of pollution and climate change; their deployment could help lower energy costs for these residents.
Thermochemical energy storage uses phase change materials like salts or waxes with significant thermal capacity at their temperature of change to store large amounts of power for extended periods. Such systems have great potential to store energy over long time spans but require significantly more space than electrical batteries.
Henry and his team have been developing what’s known as a “heat battery.” Like its conventional counterparts, this system converts electricity to heat when necessary but has much higher peak-power density; this would enable it to connect cheap, intermittent renewable energy with industrial facilities that require regular heat sources.
Electric Vehicles
As more EVs enter circulation, their batteries increasingly serve as energy storage sources.
Rate arbitrage allows utilities to compensate EV owners who use their battery storage capabilities to store electricity from the grid when prices are high, providing consumers with additional income without increasing utility rates.
Batteries found in electric vehicles (EVs) can provide other benefits to the grid, including primary and secondary power reserves, fast-frequency reserves, voltage regulation services and congestion management through load shifting and peak shaving – these services are known collectively as vehicle-to-grid or V2G services.
Though costs have fallen and energy density increased for electric vehicle batteries, remaining challenges include improving safety, hybrid electric powertrains, charging infrastructure and robust re-use regulations to integrate retired batteries back into the grid at end-of-life (EOL). To encourage consumer participation in V2G systems effectively. Strong policies and innovative business models will need to be in place to encourage participation by consumers in V2G projects.