Tuesday, July 3, 2012

Offgrid Living In The Sierras

Off-Grid Living in the Sierras


There are two major types of solar electric system: grid-tied and off the grid. The first is tied directly into the utility, or grid, and makes the most sense for a residential user in an urban or suburban setting. But being grid-tied can be exceedingly expensive for someone living in a more rural setting--and especially for someone in the high, remote Sierra Nevada mountains. But that doesn't mean one can't have electricity! Indeed, an off the grid solar electric system can provide enough electricity to power an entire house. Here's set one up.


Instructions


1. Survey your house. You are looking for potential shade problems. Do tall trees cast long, full shadows on your roof? Is your roof shade-free? If there is no shade on your roof, then it is probably the best and most cost-effective place for your solar array (an array is a collection of solar panels). If there is shade on your roof, search your property for an open-to-the-sky spot that receive little or no shade. A stand-alone array could be located here, though it will cost a little extra.


2. Decide on the size of your system. To do this, look at your utility bills from the last year and add up the total kilowatt hours used over the last 12 months. Divide the result by 12 to discover your average monthly kilowatt hour usage. Use this number to size up your array properly. For example, if you use 200 kilowatt hours per month, you want an array large enough to produce 200 kilowatt hours per month.


3. Purchase your panels. You'll want to refer to your energy calculations from Step 2. A 2-kilowatt system (ten 200-watt panels), for example, produces 2 kilowatts of power for every peak sun hour--or, in the Sierras, about 7 kilowatt hours a day. That's 210 kilowatt hours per month, almost perfect!


4. Purchase an AC/DC inverter made for photovoltaics (solar cells). The sun's energy is turned into DC electricity by the panels, then run through the inverter--which turns it into AC electricity, the kind that powers most of the appliances in a typical house.


5. Purchase batteries. These must be batteries made specifically for a solar electric system--not like a car battery! These will store extra energy produced during the day by the system and your house will draw from them during cloudy days, storms, or at night.







Tags: kilowatt hours, your roof, hours month, kilowatt hours month, solar electric, electric system, into electricity