An electric microgrid is a miniature electrical utility system that includes:
– a micro power plant (in this case solar electric PV panels on rooftops of houses),
– a means of storing this electrical energy (e.g. battery or flywheel storage),
– electrical cables and a control system to distribute and monitor the energy, and
– appliances that consume this energy, such as residential space heating and cooling, water heating, clothes washers/dryers and dishwashers.
If the regular utility power is disrupted or there is a power outage, the microgrid can supply power to the homes that are connected.

The project team will design the microgrid to best fit the neighborhood and existing utility structure. There are several options under consideration:

  1. Direct Current (DC) microgrid or Alternating Current (AC) microgrid. AC electricity is what utilities supply currently; DC electricity is what solar panels produce, and thus provides some efficiencies. A DC microgrid could serve large equipment directly (such as heat pumps for space conditioning and water heating) and also provide an inverter to supply AC to existing loads.
  2. Underground or overhead distribution of power. Another option is whether to put the interconnection cables underground or to use existing utility poles.
  3. Complete separation from the utility grid or parallel system. The project could simply add the microgrid and run it in parallel with the utility electric grid, or the infrastructure of the utility could be decommissioned and removed so that only the microgrid provides services to the participants.
In this hybrid AC/DC scenario, all houses power DC loads (such as heat pumps for space conditioning and water heating); some houses maintain their AC utility meter connection to power their AC loads and others use an inverter. Image Credit: Bruce Nordman, LBNL; Sascha von Meier, UC Berkeley

The project team will work with the participants to determine the best approach for this neighborhood.

Sample street section of the components of the EcoBlock microgrid. The DC microgrid consists of Solar or Photovoltaic rooftop panels, flywheel or battery storage, and Electric Vehicle changing at the curbside. Credit: Maika Nicholson, Sherwood Design Engineers; Therese Peffer, UC Berkeley 

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Urban Planning and Process
Design and Construction
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