by Chris Farmer
In June, residents of the Hut Hamlet became owners/users of the first electric microgrid at Earthaven! Chris Farmer designed the grid with help from Brandon Greenstein. Code for mastering, monitoring and metering usage was written by Jake Farina. Earthaven members produce electricity from sun and water, and are not tied into the Duke Power grid, so this is especially significant to folks choosing simplified lifestyles. Now bigger and smaller users alike will be able to meet their needs, each paying according to usage, the rates differing between peak- and low-usage times. The Hamlet microgrid is solely solar-powered at this time.
Before the microgrid, some Hamlet residents had barely enough power for a light and a laptop, while others had been able to upgrade their systems to power refrigerators and freezers. The new plan, which took many months and many minds to work out, and weeks of disrupted paths and phone lines, has been running smoothly for a few weeks and the future of power in the Hamlet looks, well, …brighter!
Microgrid Technical Points, courtesy of Chris Farmer (SunWorks Electric, 828-664-0268).
The MicroGrid presently powers 11 Huts, the neighborhood kitchen, and bathhouse. The system is touted to produce 31.5 kWh (kilowatt hours) of energy on an average day. (Note: In 2013 the average American home required 29.9 kWh of electrical energy per day.) All of the power available is not yet being utilized.
Hut Hamlet Microgrid Components
- An 8.16 kW Solar Photovoltaic Array (32 individual 255 watt Kyocera panels
- A 48 volt 950Ah (Amp Hour) flooded lead acid battery (HUP Solar One) that weighs 3500 lbs.
- Two MidNite Solar 200 charge controllers
- Two Schneider Electric XW6848 Inverters, each capable of 6.8kW of continual conventional AC power output. One inverter is asleep ~90% of the time, awakened only when the Master inverter needs help.
- Excess electricity produced is diverted to a 105 gallon, 240 volt AC, electric hot water heater.
- Each connection is individually metered. Capital and operating expenses of the system will be determined by users’ weighted impact.
- The system is backed up by a super quiet Honda EU7000is generator.