From Earlham Cluster Department
Using a grid-tied system has the benefits of not having to store or use energy as it is created. The power company buys back the energy that is produced. The downside of this arrangement that in most areas this relationship is untested and the red tape involved in hooking up the box to the grid might be daunting. Our investigation into grid-tying our system is ongoing.
Power from the grid is AC while most renewable energy sources produce DC power which is more easily stored. AC is more easily transported in wires however as DC power suffers a higher degree of wire loss owing mostly to the lower voltages involved. Tables for calculating DC wire loss can be found here: http://www.nwes.com/Wire%20Loss%20Tables.htm
Ramping up the voltages from a 12V solar module can be done in several ways:
- by parallel linking multiple modules, this is limited by the number of modules.
- by inverter, which transforms 12VDC into 110VAC. These systems can cost several thousand dollars.
Fortunately for our purposes, we only need the power to travel about 200 feet to our box from our barn roof which is more ideally suited for solar module adaption than our house roof which has the potential for tree shadow in the winter.
needed additions: hooking up a DC system to an AC box.