The tradition in the solar industry is to compare system costs according to their “cost per watt” of capacity. “Capacity” is the ability of the solar panels to produce a certain amount of electricity when exposed to light. More specifically, it is a measure of how much electricity the panels will generate when they are at a specific temperature and are exposed to light of a specific intensity. For example, a solar array rated at 5 kilowatts (kW) will produce 5 kW of direct current electricity under standardized conditions. The amount of electricity created by the panels will vary if the temperature or intensity of light change.
(Before going further, it may help to understand the difference between a kilowatt and a kilowatt-hour.)
If you are comparing one installer’s proposal to put solar on your roof against another installer’s proposal to put solar on your roof, then comparing cost-per-watt is perfectly reasonable, as long as both installers propose to use similar quality equipment.
However, the Solaflect PV Tracker is qualitatively different from usual fixed-mount solar arrays. The advantage of the Tracker is precisely that it uses its solar panel capacity a great deal more effectively than do fixed-mount arrays. In particular, the Tracker ensures that the panels receive more intensity of light, because it keeps the panels facing directly at the sun at all times. Solar panels in a fixed orientation receive light from an indirect angle at virtually all times throughout the year, and therefore the light landing on them has less intensity.
As a result, solar panels with 5 or 6 kW of capacity in the Solaflect PV Tracker will deliver 40%+ more energy—measured in kilowatt-hours—than the same solar panels in a fixed array. (See “How does the Solaflect PV Tracker make more energy?” parts 1, 2, and 3.)
And energy is what you want. Capacity is merely a means to the end of producing energy. Your electric bill is calculated on the basis of energy—of kWhs. If you want to reduce your electric bill with a solar array, you want the array that will give you the most energy, the most kWhs, at the best cost.
Nine times out of ten, the most cost-effective solar option for you is going to be the Solaflect PV Tracker.
When you want to compare a proposal from Solaflect with one from another installer, ignore cost-per-watt since that is an apples-to-oranges comparison. Instead, calculate the cost-per-kWh using the expected kWh production from the first year. Of course, any solar array will continue producing energy long past the first year. Limiting this mathematical exercise to the first year is just to make it easier and quicker to get an apples-to-apples comparison.
To do this, look at the proposals and find the cost for the solar array, then divide this number by the expected kWhs to be produced in the first year. Using this value, cost-per-kWh, you can then make fair comparisons between any set of solar proposals.
A real-life example.
We recently provided a proposal to a Vermont resident for one Solaflect Tracker mounted with 320 watt panels (each Tracker is mounted with 16 panels with varying wattage depending on a customer’s energy usage) . This resident also received a proposal from another installer for an array that would go on the house roof. The homeowner has a gorgeous place, both as a home and for solar access with almost no shade at all from trees, buildings or ridge lines.
Here are the numbers to compare the two proposals.
|1. System cost (after tax credit)||$26,530||$31,375|
|2. System capacity||8,000 watts (8 kW)||8,520 watts (8.52 kW)|
|3. Cost-per-watt (traditional measure): Row 1 divided by Row 2||$3.32||$3.68|
|4. Solaflect cost advantage on capacity basis||9.8% less than the alternative|
|5. Expected energy delivered in 1st year||12,582 kWhs||8,470 kWhs|
|6. Solaflect energy production advantage||48.5% more than the alternative|
|7. Cost-per-kWh (first year production only): Row 1 divided by Row 5|
This is your apples-to-apples comparison.
|8. Solaflect cost advantage on energy basis||43.1% less than the alternative|
The precise values in this example are the result of the particulars at the home site, but they are indicative of the sort of value Solaflect customers receive. If you are thinking of going solar (and you should be!), and you have the space in your yard or field, it’s helpful to get an estimate for a Solaflect Tracker to compare to traditional rooftop solar pricing.
We love talking about all things related to solar, so please reach out to us or call us at (802) 649-3700 if we can answer questions and help you think about how solar can cover an ever-increasing share of your family’s power usage!