Decarbonization and concerns about energy security argue in favor of a decentralized electric power grid. The war in Ukraine with its power outages also clearly illustrates the importance of decentralizing the power grid and microgrids.
Beyond energy security, microgrids can also play a management role on a renewably supplied grid, which according to a new report titled “Can Decentralized Energy Get Good Enough, Fast Enough?” by Ernst & Young Global faces “multiple new challenges.”
One example of a utility-scale microgrid serves the Portuguese island of Graciosa. Energized mostly by renewables, it has slashed diesel fuel use by 70%. The microgrid’s configuration is unique in that all the energy from wind, solar, and diesel resources flows to the battery first, distributed from there to the power grid that supplies the whole island.
The U.S. now ranks first in attracting renewable energy solutions, according to the report, because of a combination of regulatory, financial and corporate support recently boosted by the Inflation Reduction Act of 2022, the bipartisan infrastructure law, and a 19% increase in solar installations above 2020. All these increase the need for microgrids to help balance a grid increasingly reliant on intermittent renewable energy.
Renewables and distributed energy resources can improve grid security and resiliency, but may also cause unstable network conditions that can damage and shorten the lives of grid assets by leading to voltage instability and capacity constraints when low demand coincides with high distributed energy production.
Distributed energy resources must not be allowed to cause sudden spikes and drops in the power supply, or the grid’s voltage and frequency levels will be disturbed, resulting in poor power quality. In the face of such challenges, network operators will be pressured more and more to find faster and less expensive ways to connect distributed energy resources to the grid.
Microgrids are a key to balancing intermittency wherever wind and solar play a large role on the grid. As these renewables ebb and flow through the day and night, microgrids quickly ramp up and down to help balance supply and demand on the grid. The more renewables on the grid, the greater the need for microgrids to manage intermittency. It is best to have the growth of renewables and microgrid growth go hand in hand.
Decommissioning of fossil-fueled baseload generation, such as coal-fired plants, and the addition of electric vehicle charging also put a strain on the grid, exacerbating the challenges of intermittent power sources. And it’s not only distributed energy resources that create imbalances; grid-scale renewables do as well. Fortunately, adding microgrids is getting easier, as barriers to them are removed by new regulations and business models, such as energy-as-a-service contracts.
The Inflation Reduction Act offers tax incentives for microgrids. New scalable, configured-to-order microgrid solutions are now coming to the market. These factors will soon make deployment of behind-the-meter microgrids commonplace and positioned to assist with grid resiliency.
In addition to addressing the intermittency of renewables, microgrids can boost grid resiliency by helping to cut usage during peak periods and providing clean electricity as an alternative to fossil-fueled generating plants. Some power plants are built to run only a few hours of the year to meet the peak demand of hot summer days when air conditioner use is high. Microgrids can provide less expensive and cleaner power and can also moderate electricity consumption during peak periods.
Electric vehicles incorporated into microgrids can also help integrate renewable energy. Electric vehicle batteries within microgrids can stabilize the grid by helping to smooth the energy use curve. Electric vehicles can be charged at night when electricity is less expensive; owners can then sell some of their batteries’ electricity back to the utility during peak load periods. Furthermore, when aging electric vehicle batteries can no longer efficiently power vehicles, they can continue to have a useful life as energy storage units.
Clearly, grid operators have considerable opportunities to manage their grids more effectively, not just to meet the needs of a hot world but also to support the transition from internal combustion vehicles to electric vehicles. Taking advantage of batteries, grid operators can even delay new power plant installations that may ultimately be required to manage growth.
In short, energy storage in microgrids can play an important role in integrating renewable energy. Microgrids can cut peak energy demand and fill the gaps of intermittency of renewable energy sources. They can play a critical role as more renewables are added to the grid on our way to a net zero future, all the while increasing resilience by decentralizing the power grid.
Advanced microgrids help mitigate voltage and frequency fluctuations and, by providing more distributed, near-the-user power generation, create a more resilient energy framework for region and country.
(Paul Kando is a co-founder of the Midcoast Green Collaborative, which promotes environmental protection and economic development via energy conservation. For more information, go to midcoastgreencollaborative.org.)