A DC Microgrid is an innovative stand-alone renewable energy system that is much more effective, reliable and affordable than an AC-based off grid system. This system was developed at Living Energy Farm, an intentional community and environmental education center in Louisa, Virginia, where a DC Microgrid has provided for the energy needs of a dozen people since 2011.
DC Microgrids are…
Effective because they leverage the strengths of renewable energy. Typical AC-based off grid PV systems are doomed to failure when they try to force a limited commodity (sunlight) to behave the same as an unlimited commodity (grid power).
Reliable because the emphasis is on providing useful services, not bulk energy production. Natural feedback mechanisms teach the user to conserve. The power never goes out completely; instead it weakens slowly, giving the user time to adjust their energy use appropriately.
Affordable because the hardware is simple and extremely durable. A DC Microgrid side steps inverters and AC (alternating current) electricity, and uses nickel iron batteries, a non-toxic technology that lasts 40 years or more.
DC Microgrid design is site-specific, depending on wind and solar resources, local climate and energy needs, etc. But the design principles are the same everywhere. These principles are:
1. Maximize conservation, efficiency and insulation. Solar energy is only useful when demand is minimized.
2. Minimize battery size by storing energy in forms other than electricity. Compared to other forms of energy storage, batteries are expensive and fragile. The bulk of the stored energy in a DC Microgrid takes non-electric forms such as a hot or cold thermal mass, pressurized water, or bio-gas.
3. Operate high-demand electrical appliances as daylight drive only. In daylight drive systems, DC (direct current) motors and resistive loads are wired directly to photovoltaic panels with no batteries or other hardware involved. These appliances are used only during the day.
Click here for more details about the DC Microgrid we have at Living Energy Farm.
Learn more about the advantages of DC Microgrids over grid-tie and conventional off-grid technologies.
Wondering who else is using DC Microgrid technologies? Click here to read about how we distributed Iron Sun Cabin kits free of charge to families in the Navajo and Hopi reservations.