Can a Microgrid be a Resilience Superhero?

Steve Hoffman, president and CEO of Hoffman Power Consulting

By islanding during extreme events such as wildfires and hurricanes, microgrids add resilience to their list of potential benefits, including enhanced power reliability and quality, reduced electricity cost, and revenue generation.

But can a microgrid integrate additional resilience solutions, providing more resilience bang for the buck? This is a timely question as we endure unprecedented wildfires and a record-breaking Atlantic hurricane season – while constrained by COVID-19. Everybody wants more resilient electric power, but at a reasonable cost and in ways regulators can support. Here are five ways to boost microgrid resilience.

Building energy efficiency: More resilience per dollar

Almost every microgrid encompasses buildings, but are those buildings energy-efficient? If so, compared to inefficient buildings, they need less generation and storage to power them in island mode – improving the microgrid’s resilience. The buildings can stay cooler longer during a summer extreme event and deplete precious local storage less quickly. What’s more, energy efficiency is a local, decentralized resource that is less vulnerable to disruption than centralized generation – another resilience benefit.

According to Jules Nohra of Veolia North America, energy efficiency helps “make sure the microgrid is not oversized.” In 1982, Rocky Mountain Institute (RMI) Chairman Emeritus Amory Lovins called energy efficiency the solution that provides “the most resilience per dollar.” In 2018, Elisa Wood of Microgrid Knowledgecommented that “no kilowatt is cheaper than the one not used.”

Distributed renewable generation and storage

A second way to enhance resilience is to implement distributed renewable generation and electric storage in the microgrid. Rooftop photovoltaics (PV) arrays and distributed wind power – supported with local storage – are resilient because they do not rely on “outside” fuels. Most other power generation, including diesel and natural gas generators and fuel cells, is dependent on such fuel supplies, and hence less resilient. Even large-scale PV/wind, and distributed renewable generation not connected to the microgrid, are less resilient becausethey may not be available in an extreme event.

Graph: Hoffman Power Consulting

Vehicle-to-building and vehicle-to-microgrid storage

Incorporating electric vehicle (EV) charging in microgrids helps maintain mobility in an extreme event. But these EVs can also play a resilience role. They can act as an alternate source of electric storage, extending the availability of microgrid renewable generation and storage.

During an extreme event, recharged EVs can supply power back to homes or businesses (i.e., vehicle-to-building resilience). An RMI study showed that the 60-kWh battery in a Tesla Model 3 stores enough energy to power an average home for two days. Recharged EVs can also supply power and grid services, such as voltage regulation, back to the microgrid (i.e., vehicle-to-microgrid resilience).

Another benefit of integrating these additional resilience solutions into a microgrid is that regulatory agencies and city councils tend to like them, which can aid the project approval process.

Intra-microgrid demand response for resilience

During an extreme event, a microgrid could use demand response approaches to beneficially shift the timing of energy use, based on the limitations of the microgrid’s internal resources. For example, if a microgrid’s generation is primarily renewable, with storage capabilities limited to a few hours per day, microgrid demand response could shift load from nighttime to daytime (using energy available when the sun shines and the wind blows). This internal demand response would make more efficient use of the microgrid’s resources, enhancing resilience.

Naturally resilient solutions

Microgrids can also become more resilient using the following nature-inspired solutions (to name a few):

• White roofs (to reflect heat)
• Urban tree canopies (to provide shade and reduce heating load)
• Wetland and riparian resource restoration (to provide natural flood resistance)
• Green stormwater management projects (i.e., water gardens)

When incorporated into microgrid design, these solutions can reduce the impact of extreme natural events and decrease energy use in a manner similar to energy efficiency.

Improved regulatory acceptance, and more

Another benefit of integrating these additional resilience solutions into a microgrid is that regulatory agencies and city councils tend to like them, which can aid the project approval process. In addition, the clean energy aspect of some of these solutions is likely to appeal to businesses with carbon-reduction goals and communities considering community microgrids. These solutions can also provide everyday cost-reduction and reliability benefits (i.e., during normal operations, not just extreme events), further enhancing their value.

These additional resilience solutions apply to single-customer microgrids and multi-customer community microgrids. Microgrid developers can incorporate them by partnering with building energy management firms, solar system providers, EV charging system installers, demand response specialists, and others. This increases project complexity and requires coordination of more players, but has the potential to make the microgrid an energy resilience superhero.

Steve Hoffman is president and CEO of Hoffman Power Consulting, which provides client-tailored thought leadership and business content to microgrid developers and others. More information on this subject is available in Hoffman Power Consulting’s special report.