A direct drive DC Microgrid (D3M) is a community-scale renewable energy system that provides modern energy services with a very low resource footprint, using conservationist design and increased user interaction to compensate for the intermittency of solar energy.
Conventional solar and storage systems try to mimic the unlimited nature of grid power by producing constant 120VAC power. These systems rely on large sets of lithium or lead acid batteries, which must be replaced every 5-10 years, and inverters that must replaced every 10 years. The system must be overbuilt, or backed up with a generator, to supply constant voltage to the inverter.
A D3M aims to provide services, not mimic grid power. The system teaches people to use solar energy when it is available by providing real-time feedback on the availability of electrical power. High standards of insulation and efficiency stretch a limited energy budget, while simple, low tech non-electric storage systems (like thermal mass and pressure tanks) keep demand on batteries to a minimum. The main components of the system- PV panels, nickel iron batteries, non-electric storage and DC appliances- will last for 30 years or more.
Every D3M is unique and begins with a design process. However, the main components typically include:
- Solar thermal and green building design for heating and cooling
- Direct drive DC circuits, for motors, pumps (including solar direct water systems), and other mechanical loads
- Durable nickel iron batteries to power lights and electronics
- Biogas digesters for cooking fuel