Before You Go Solar

Lengthwise — Tue, 20 Jan 2009 04:39:42 +0000

Don’t get me wrong, I like the idea of solar. We installed solar on our business and I plan to install solar on my home one day. But, before you install $20,000 ($7,000 after rebates) worth of solar PV panels on the roof, please perform an analysis of your current energy consumption habits. Check out what I did at the business to be more efficient.

Lengthwise Brewing Company, my workplace, installed a small solar system that produces 1.2 kWh per hour for five hours a day. After a quick investigation, I found that the system would not even provide enough energy to power the 25 track lights that provide ambiance lighting! Each track light bulb was a 50 watt halogen bulb. Therefore, the math goes like this:

Consumption Math (halogen bulbs)
25 bulbs x 50 watts = 1250 watts or 1.25 kWh
The lights are on for 12 hours a day
12 hours x 1.25 kWh = 15 kWh

Solar PV production Math
1.2 kWh x 5 hours = 6 kWh per day

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According to the info above, the track lights consume 15 kWh per day and the solar PV system provides 6 kWh per day. So, it appears that we need a larger solar array. Wrong. We need to install more efficient bulbs. All halogen track lights were changed out to compact fluorescent spot lights that consume 7 watts per bulb per hour but provide approximately the same amount of light. New math:

New Consumption Math (compact florescent)
25 bulbs x 7 watts = 175 watts per hour
12 hours x 175 watts = 2.1 kWh per day

Bulb change out cost
25 compact fluorescent spots x $8.00each = $200

Solar PV system after rebates cost
1.2 kWh complete system = $7,000

The point is this, reducing your energy consumption through efficiencies will by far out weigh a hasty solar PV installation. Our simple $200.00 bulb change will save us 12900 watts per day or 4,708,500 watts per annum!

Jeff Williams
www.greenerbakersfield.com

Greener Bakersfield » Solar

Before You Go Solar