Solar

Is Solar Practical in West Virginia?

Yes! Ambitious solar programs in Canada, Germany and England are testaments to the fact that solar works anywhere there is sunshine. Both solar hot water heating and photovoltaics are viable options in the mountain state.

The National Renewable Energy Laboratory has calculated, "the annual average solar resource in Miami, FL is 4.8 kw-h/m2/day, and in Beckley,WV is 3.8 kwh-m2-day. Thus, to get the same energy from a rooftop in Beckley, you would need approximately 25% larger solar panel (or, 250 m2 rather than 200 m2). This would be for the annual average, at latitude tilt.

Insolation Data for Beckley, WV

Variable	I	II	III	IV	V	VI	VII	VIII	IX	X	XI	XII
Insolation, kWh/m²/day	1.82	2.47	3.39	4.47	5.01	5.65	5.50	5.03	4.16	3.09	2.03	1.66
Clearness, 0 - 1	0.41	0.42	0.43	0.46	0.46	0.49	0.49	0.49	0.49	0.47	0.41	0.41
Wind speed, m/s	4.89	4.92	4.77	4.35	3.80	3.53	3.27	3.20	3.59	4.04	4.67	4.82
Precipitation, mm	75	75	88	89	101	94	117	89	84	72	76	80
Wet days, d	15.8	14.3	14.5	14.1	13.5	11.9	13.2	11.4	10.6	9.8	12.3	14.4

These data were obtained from the NASA Langley Research Center Atmospheric Science Data Center; New et al. 2002 courtesy of http://www.gaisma.com/

Solar Hot Water

Solar water heating systems gather heat in a solar collector, transfer that heat to your water supply, and store the heated water until it’s used. The technology is simple and well tested. They are VERY inexpensive to operate and last up to 40 years. Payback on a solar hot water system is from 8-15 years, depending on the system you are replacing (shorter payback when replacing electric hot water heaters).

In West Virginia the recommended systems would include an indirect (closed loop) system or a drain back system, both with south facing solar collectors. An indirect system uses propylene glycol as the heat exchange fluid to provide freeze protection in the system. The drain back system uses water as the heat exchange fluid. In order to provide for freeze protection, the pump shuts off when the temperature of the collector cools down below that of the tank, and the water in the system “drains back” into storage reservoirs. The panel then fills with air protecting the system from freezing when the pump is turned off.

For both indirect and drain back systems, the solar collection loop is run to a heat exchange coil around a water storage tank. In that way, the systems are decoupled from the potable water supply.

Photovoltaics (PV)

The most important aspect in sizing your PV system is to analyze your energy use and complete any conservation and energy reduction strategies first. This is good for your wallet and good for the environment. For every $1 spent on energy efficiency, you can save up to $5 on your solar system cost. Start by reducing waste and then work to reduce consumption. Reduce Energy Use

It is practical to design your PV system for expansion. A system can be off-grid or grid-tied. We recommend at least some battery backup so you are independent of the grid and can use your solar system for backup power in emergencies.