Local Energy Production Builds Sustainable Neighborhoods
Reliable electrical energy is increasingly being seen as a basic human right, and this perspective is driving significant shifts in the way electrical energy is being generated, transmitted, and used.
Climate change and extreme weather events can increase disruptions to electrical power service with very personal consequences. At one extreme, power outages impact daily life when there’s a lack of connection to a reliable power grid, while at the other extreme, increased electrical demands on aging electrical grid infrastructures raise the risks for outages.
Interspersed with these challenges are the varying human needs and attitudes of electricity users across a range of socioeconomic issues and disparities. Examples include the disproportionate fixed cost of electricity to low-income households, growth in electric vehicle (EV) charging needs, critical community facilities (e.g. hospitals, fire protection, water treatment and schools), vulnerable manufacturing facilities, and the range of household and community commitments to reducing their carbon footprint.
Community microgrids tailored to meet shared, localized needs can solve these challenges.
The Community Microgrid
The microgrid is a small electrical grid that serves electricity needs within a defined boundary using local sources of supply. This defined electrical boundary can include neighborhoods, a campus, a village, a town, or multiples thereof, where the electricity users live, work, and perform services together, in which case the microgrid expands to a community microgrid.
Today, the microgrid can address a community need to reduce its carbon emissions through the efficient use of renewable and stored energy resources. It may operate connected to or disconnected (“islanded”) from the grid.
In remote areas, where energy poverty impacts survival, community microgrids have emerged as a possible solution.
In remote areas, where energy poverty impacts survival, community microgrids have emerged as a possible solution. In India, for example, the deployment of microgrids to villages on mountains, in deserts, and on islands has outpaced the government’s efforts to tie these communities to the national grid.
A Sense of Energy Supply Ownership
A community microgrid gives participants a sense of control and ownership over their energy supply, and not only serves individual households but also the needs of the community.
The greatest benefits are derived as the households learn how to interact with the microgrid and become aware of how their daily habits impact energy usage. The neighborhood microgrid is a “behind the meter” (quasi off-the-grid) where consumers of electrical energy are also producers, or prosumers, producing a net benefit to its users both individually and collectively. Such systems achieve a smart grid that forces cooperative use of rooftop solar and energy storage units that are distributed among participating households.
Among the factors for the most favorable neighborhood microgrid implementations, the number of participating households is key. Case studies show current favorable effects range from 20 to 200 homes. Weather and geographic location play a role as well, with implementations in a Mediterranean climate being the most favorable.
Neighborhood Microgrid Challenges
Nevertheless, the feasibility of a purely “behind the meter” or neighborhood microgrid is challenging, given the human factor and the all-important question: Who will shoulder the costs of installation and maintenance? Rules regarding net energy metering impose constraints on the size (and beneficiaries) of a microgrid; utilities must deal with the consequences of possible sub-standard implementations that interact in a negative way with the utility grid, with rules varying by state, such as in California.
The feasibility of a neighborhood microgrid is challenging, given the human factor and the all-important question: Who will shoulder the costs of installation and maintenance?
Even so, motivation for planned installations, such as “all-electric neighborhoods” in California are coming from mandated building codes. Recently, facilitators for large-scale community microgrid deployments, such as the Clean-Coalition, are advocating for “front of the meter” approaches that connect neighborhoods with commercial properties, essential community services, and include utility-focused partnerships. Utility partnership or ownership allows users to pay for electricity through their utility, making microgrid ownership and operation more transparent.
A successful example of neighborhood ownership and sustainment is the 37-home pilot project installed within the Medley at Southshore Bay residential development in Wimauma, Florida. This microgrid is utility owned and operated and is built upon an electrical system developed and installed by a Tampa, Florida, company, BlockEnergy.
Neighborhood microgrid installations will become more ubiquitous when the most expensive components, such as energy storage, are utility owned and when usage includes community service providers (such as schools, hospitals, fire departments, etc.) and commercial properties. In this way, costs and benefits are spread across a more diverse group of stakeholders.
Installation Energy Security
Community microgrids can play a significant role in achieving Installation Energy Security. Energy security depends on three pillars: reliability, resilience, and efficiency (see Figure 1).
Efficiency
The efficiency pillar includes what has been mentioned already: more efficient use of the electrical energy generated by environmentally friendly resources minimizes the detrimental impacts of fossil fuels increasingly being manifested through extreme weather events. These accelerate the pace of community microgrid adoption as a necessary solution—and here the other two pillars come into play.
Reliability
Reliability has to do with a service or a product functioning as expected as long as it is being used in the manner for which it was designed. Reliability of electric power means an electricity user can expect to receive uninterrupted service unless there is a disturbance causing voltage and/or current to stray outside of designed (rated or nominal) parameters.
However, there is a caveat—"for the life of the product.” As electrical grids age, their components—cable insulation, circuit breakers, and so forth—are weakened and become less reliable. The aging electrical grid infrastructure, costs to upgrade, and increasing consumer demands leads to a weakening of the grid’s ability to provide stable and clean voltage power to its customers.
The aging electrical grid infrastructure, costs to upgrade, and increasing consumer demands leads to a weakening of the grid’s ability to provide stable and clean voltage power to its customers.
Electricity is distributed through a grid within a specific geographic area. Patterns of ownership and operation vary depending upon the country and the level of government involvement in electricity generation and distribution. In the U.S., this grid is owned and operated by local utilities. Distribution voltages are typically in the tens of thousands of volts. Sometimes, power must be delivered to customers that are far from the generation source, and customers in rural areas often find themselves at a weak end of the distribution grid.
The weak grid problem is exacerbated by sudden shifts in loads that cause voltage dips and spikes. Lights may dim or buzz, or circuit breakers may trip unexpectedly, leading to the loss of essential life-sustaining services. A locally focused community microgrid is a solution for communities who dislike being at the weak ends of the grid.
Resilience
Resilience, another pillar of Installation Energy Security, addresses any disturbance or event that could endanger human lives or damage equipment if electrical power is not immediately removed, or isolated from affected or damaged parts of the system.
Community microgrids interface with energy utility electricity transmission through a utility substation. Transmission has to do with the transfer of electrical energy over much longer distances, and the voltage levels are hundreds of thousands of volts (high voltage). This is mentioned because future community microgrids will expand the definition of community beyond the neighborhood, city, and municipality.
An example of a great need for resilience is the Goleta Load Pocket, a 70-mile area along the Southern California coastline that is highly vulnerable to power loss. Communities along the Goleta Load Pocket are served by just one set of transmission lines hung on the same transmission towers and routed through 40 miles of mountainous terrain.
This is a disaster-prone region that has been subject to extreme weather events in recent years. A community microgrid solution—the Goleta Load Pocket Community Microgrid (GLPCM)—has been proposed that would interconnect planned and existing microgrids, energy storage, and solar PV installations in Goleta Load Pocket communities. Development of this multi-city microgrid is still in progress and is actively moving forward thanks to the efforts of Clean-Coalition.
Figure 2 shows a concept for a resilient community microgrid that interconnects multiple installations through either direct interconnection within a local community or through utility substation connections across multiple communities.
All these implementations share common features, such as a standardized approach to microgrid building blocks, that can be installed as the community grows. Each microgrid building block has localized controls and communications with proactive capabilities to learn from its environment and increase its resilience over time. It also has an autonomous reconfiguration capability so that if a power outage appears imminent, power can be automatically re-routed to keep the lights on.
Each microgrid building block has localized controls and communications with proactive capabilities to learn from its environment and increase its resilience over time.
Figure 3 shows an example of how the system would respond to an extreme weather event that, without this community microgrid concept, would result in losses of power to large sections of the serviced area. The system is self-learning and self-healing. Individual microgrid building blocks (the microgrid sub-stations) can “island” or disconnect themselves from the rest of the network and provide extended electrical service to the part of the community it services while repairs are being made.
The system determines what actions to take by receiving information from its nearest neighbor through high-speed communications with adjacently connected sub-systems and by coordinating with the energy utility. If communication networks are damaged, the system can use the information that it has to make the best decision as to which switches to open and what changes to make to its connection with its participants.
Adoptability and Sustainability
Public policy is key to building microgrids. Clean-Coalition provides a good example of an organization that not only designs and stages cutting-edge community microgrid projects, but is also involved in commissioning these installations and showcasing their value and feasibility. They are also involved in addressing barriers and gathering stakeholders through their work on public policy.
At the same time, utility-focused partnerships in project development and a “front of the meter” approach addresses long-term sustainability. Otherwise, individualized project endeavors (and even public-private partnerships with a community) can become subject to the hidden costs of maintenance contracts from commercial vendors of these systems. Obsolescence is an issue, as well.
Of course, microgrid developers are an essential element, but the more replicable and plug-and-play these systems become, the greater their market will become. Technological innovations, partnerships, and policy are all essential to the deployment of sustainable energy secure community microgrids.
With each new community microgrid project, the way forward becomes clearer.
*Robert Cuzner is Richard and Joanne Grigg Associate Professor for the Electrical Engineering Department at the University of Milwaukee, Wisconsin (UWM), the Director of the Center for Sustainable Electrical Energy Systems (SEES), and the UWM Site Director for the GRid-Connected Power Electronic Systems (GRAPES) Industry/University Collaborative Research Center.