Finding the Best Place for Solar

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Some places actually have “better” sun than others for producing solar power, but identifying those places isn’t always intuitive.

Contrary to what I would have guessed, Hawaii does not have the best sun for solar energy production. Factors like cloud cover, water vapor and atmospheric pressure determine how effectively the sun’s energy can be converted into electricity, so even places one might consider to be “sunny” aren’t necessarily the best for electricity production.

Follow the sun

According to the National Renewable Energy Laboratory, the San Luis Valley in southwestern Colorado has “better” sun than Hawaii for producing solar energy.

It also has 50 percent higher average “direct normal solar irradiation” (read: good sun for producing energy) than Denver does. From a power production perspective, that explains why it’s more efficient and cost-effective to site large solar generation plants in ideal locations.

My house in Denver has a great orientation for solar generation and a shade-free roof, but it’s not as efficient or cost-effective as arrays near Alamosa that can produce 15 percent more energy annually with the same solar panel.

Many utility-scale solar arrays have trackers that tilt toward the sun as it moves across the sky. SunPower’s trackers, used in its much larger San Luis Valley installations, can generate 30 percent more energy than a fixed-angle array the same size. And that’s on top of the production increase afforded by an ideal location. The additional cost of the tracking feature can be justified in larger installations, but probably not on a system like the one on my home, which has a static array.

Utility-scale sun power production growing

To make the most of that great sun in the San Luis Valley, SunPower just completed building the largest PV solar plant in Colorado (19-megawatts), and it has another even larger plant (30-megawatts) in the works. That definitely makes the beautiful drive through the valley on Colorado Highway 17 more interesting for all.

I like our home’s little array because it produces clean energy and lowers my family’s electricity bills. The utility-scale arrays are great because they’re more cost-effective while they produce clean energy for all of our customers.

Check out a time-lapse video of construction at the 19 MW plant in the San Luis Valley.

T20 Construction and Timelapse – Mosca, Colorado from SunPower Insider on Vimeo.

Article by Sheila Knudtsen, appearing courtesy Xcel Energy Blog.

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