Amongst renewable energy innovation and a global movement towards a more sustainable future, new technologies and terms are emerging—often leaving the public uncertain about their meanings. You may have heard the word “microgrid” thrown around. Energy experts and scientists are advocating for microgrids as essential tools that communities, especially historically excluded communities, need. But what are they? And why do we need them? In this article, we hope to explain the concept of microgrids and explore their role in building a more resilient and equitable energy future.
What are microgrids?
Microgrids are small-scale, self-contained power grids designed to supply electricity to a specific local area, such as a neighborhood, campus, or industrial site. Unlike traditional power systems that depend on a centralized grid, microgrids can operate independently, making them especially valuable during power outages or in remote locations.
How are microgrids different from conventional power grids?
The main difference lies in structure and scale. Conventional power grids rely on centralized power plants that distribute electricity over long distances through an extensive infrastructure. In contrast, microgrids are decentralized systems. They generate electricity from multiple local sources—such as solar panels, wind turbines, or generators—store it in batteries, and are managed with local controls. This allows them to operate autonomously or in connection with the main grid.
The benefits
- Energy Resilience: Microgrids can keep running during main grid failures, providing backup power during emergencies.
- Sustainability: Many microgrids use renewable energy, reducing carbon emissions.
Efficiency: Local generation and distribution reduce energy loss from long-distance transmission. - Cost Savings: In the long term, microgrids can lower energy costs, especially when paired with smart controls and renewables.
The drawbacks
- High Initial Costs: Building and installing a microgrid can be expensive, especially with advanced storage and control systems.
- Complexity: Managing multiple energy sources and ensuring seamless operation requires sophisticated technology and expertise.
- Regulatory Challenges: In some regions, integrating microgrids with existing energy policies and utility systems can be complicated.
Despite these challenges, microgrids are gaining traction as a smart solution for cleaner, more reliable, and more flexible energy.
Credit Erik Jepsen.
Microgrids in San Diego
In 2023, San Diego began the installation of microgrids in municipal facilities to support California’s 2022 Climate Action Plan. The plan sets a goal to reduce energy at municipal facilities by 35% from a 2010 business-as-usual baseline by 2035. The installed microgrids are expected to save San Diego $6 million over 25 years!
San Diego Gas and Electric (SDG&E) has also contributed to the installation of microgrids. Currently, they have about 21 microgrid sites generating 335 megawatts of energy. This can power about 14,000 homes annually.
One of the most prominent microgrids in the region is operated by the University of California, San Diego, which runs a 55 MW campus microgrid integrating various energy sources and storage to power the university and stabilize the local grid.
Additionally, the Port of San Diego maintains a smaller but impactful microgrid consisting of a 700-kilowatt (kW) solar photovoltaic array and a 2,700-kilowatt-hour (kWh) lithium-ion battery storage system, which supports load shifting and peak shaving during daily operations. Collectively, these microgrids not only provide localized power and reduce reliance on the central grid but also support the integration of renewable energy and advance the county’s climate and energy goals.
Sources:
U.S. Department of Energy. (2016). The U.S. Department of Energy’s Microgrid Initiative. https://www.energy.gov/sites/prod/files/2016/06/f32/The%20US%20Department%20of%20Energy%27s%20Microgrid%20Initiative.pdf
Insight Distributed Energy. (n.d.). Microgrid vs. traditional grid: What’s the difference? https://insightdistributedenergy.com/blog/microgrid-solutions/microgrid-vs-traditional-grid/
Andersen, F. M., & Østergaard, P. A. (n.d.). What are microgrids? Aalborg University. https://vbn.aau.dk/ws/portalfiles/portal/188518763/what_are_microgrids.pdf
IBM. (n.d.). Microgrid. https://www.ibm.com/think/topics/microgrid
Lund, H., Østergaard, P. A., Connolly, D., & Mathiesen, B. V. (2018). Smart energy and smart energy systems. Renewable and Sustainable Energy Reviews, 85, 1379–1390. https://doi.org/10.1016/j.rser.2017.07.097
City of San Diego. (n.d.). Microgrids. City of San Diego Sustainability & Mobility.
San Diego Gas & Electric. (n.d.). Battery energy storage systems (BESS) and microgrids. https://www.sdge.com/major-projects/battery-energy-storage-systems-bess-and-microgrids
UC San Diego. (2024, April 3). UC San Diego to receive $7 million to power campus and strengthen state electricity grid. https://today.ucsd.edu/story/uc-san-diego-to-receive-7-million-to-power-campus-and-strengthen-state-electricity-grid
Port of San Diego. (n.d.). Port of San Diego microgrid project. https://www.portofsandiego.org/microgrid
