A Zero Energy Microgrid Community

Project Description

Housing Initiatives Partnership (HIP) has a proven thirty year commitment to providing affordable housing in Prince George’s County.  In recent years they have increasingly focused their efforts on developing housing that is both healthy and energy efficient. This is not by chance; it is critical to their mission.  An asthmatic child staying home sick from the effects of poor indoor air quality can mean a lost day of work for a single parent.  A high monthly energy bill can break the budget of a family of limited means.

It is for these reasons that HIP created the first Passive House in Prince George’s County, located at 5424 Addison Road, Fairmount Heights, just around the corner from the proposed Fairmount Heights lots. The success of that pilot project inspired HIP to apply for, and win, a grant to move to the next step and create a DOE Net Zero Ready community of six adjacent homes.

Up until now, Net Zero Energy Buildings have been rare and expensive. This is primarily because they are not designed in an integrated way; solar panels are simply added, at considerable cost, to buildings built at or slightly above energy code minimums. This is not a viable approach in bringing net zero to the affordable housing sector.

This project presents a model for the logical way to build healthy and resilient net zero communities based upon a simple equation:

a super efficient building envelope + a minimal solar pv generation and storage system = an affordable net zero home

The envelope part of the equation is accomplished by using an integrated design approach based upon low- tech and economical solutions achievable by any careful builder. The result is homes with heating and cooling demands that are 50% lower than code built homes, needing much smaller heating and cooling equipment and much less electricity.  We know this approach works because we achieved it in the Passive House on Addison Road, which has a total energy bill of under $60/month. These homes will be built similarly to that project in terms of size and style, with variations in response to site and aesthetics.

a pilot direct current community microgrid with Pepco/Exelon and Emera Technologies
What makes this project unique, however, is the second part of the equation: our approach to onsite energy generation and distribution. Instead of installing six separate solar generation systems that link to the grid, we are building a neighborhood current microgrid. Unlike traditional PV systems, this microgrid system will not depend solely upon the regional grid to store energy when these homes are creating more energy than they are using. Rather, these homes will store that extra energy in an onsite battery system, which will provide power when the regional grid is down. Pepco chose to partner with Emera and HIP to create this “in-front-of-the-meter microgrid because they see its potential for the future:

  • The microgrid approach has the potential to bring initial investment costs down and drive efficiency of energy generation up;
  • It creates a more resilient community.
  • Most important from the utility’s standpont, it helps solve the intermittency problem created by solar energy. Presently energy demand from the grid grows lower and lower during daytime as more and more solar production comes online. This creates an increasing spike in energy demand in the evenings as people return to their homes and turn on lights and appliances. That demand spike creates the need for spinning reserves and peaker plants. The result is that the present grid has the potential to create twice the power it actually needs. Storing energy produced in the daytime in batteries to makes that surplus energy accessible in the evenings and can eliminate the intermittency problem.

What we are creating is a model for a future community-centric, distributed energy grid. At a time when the State of Maryland is formulating how it will incorporate microgrids into the energy mix, this project is a beacon. The Maryland Energy Administration generously provided a planning grant for the design of the microgrid.

2020 Covid19 delays made pushed back groundbreaking for this project until April of 2021. The silver lining of the delay is that it allowed time for Pepco and Emera to finalize their microgrid pilot plans.

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