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Grid Scale Solar More Efficient than Rooftop

McLeodWith more than 300 days of sunshine every year, Arizona is a natural for solar power. In fact, the state was recently ranked number two for total solar energy capacity. Some of the benefits of solar energy are clear. This clean, renewable energy source has no carbon emissions and uses no water.

Solar power is an important resource helping to power our customers’ lives; however, we must make sure we are getting the most bang for our buck. Grid-scale solar (large solar farms that typically contain solar panels that track the sun across the sky), in a direct comparison, produces more, costs less and helps the environment far more than private residential rooftop. In addition, grid-scale solar means all APS customers are solar customers, not just the ones who can put panels on their roof.

For the past five years, APS has been hard at work overseeing the construction, maintenance and delivery of solar energy from nine solar plants around the state that are part of our AZ Sun Program. All but one of these plants has hundreds of thousands of panels that rotate to face the sun, enabling them to capture the power of the sun far more hours of the day than rooftop, including late afternoons when our customers need the most energy.

That’s why, for an equal hypothetical $20 million investment, grid-scale solar in Arizona could generate 28,500 megawatt-hours (MWh) in a year, compared to residential rooftop at just 12,400 MWh. Using the same example, when it comes to environmental impact, grid-scale solar avoids a whopping 25.6 million pounds of carbon emissions in a year, while residential rooftop avoids just 11.1 million pounds. Water savings from grid-scale solar are 8.9 million gallons per year, while residential rooftop saves just 3.9 million gallons. And as we desert-dwellers know, maximizing water savings is critical to our future.

The overwhelming, evidence-based consensus, according to recent reports from MIT, Harvard and the Brattle Group, confirms that grid-scale solar power generation is more cost-effective than rooftop. Put another way, both grid-scale solar and rooftop solar could achieve the same environmental benefits, but the cost to do so with grid-scale solar would be much lower.

Why does grid-scale solar cost less and operate more efficiently? Three reasons. The first, and perhaps the most obvious, has to do with the economies of scale gained by building a plant with thousands of panels, as opposed to the average residential rooftop. Second, these large scale solar plants can be optimally situated in areas of peak sunshine, not wherever a home happens to have been built. And third, as mentioned earlier, the technologies used at grid-scale solar plants incorporate optimized panel placement and sophisticated tracking mechanisms, so panels move to face the sun throughout the day.

At APS, we understand how important solar is to our customers and to our state. We also understand the importance of the environmental benefits solar power brings. Our question is: Why pay more for the same sun? FBN

By Tammy McLeod, APS Vice President, Resource Management

Tammy McLeod is the vice president of resource management at Arizona Public Service and currently a Ph.D. student in sustainability.


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One Response to Grid Scale Solar More Efficient than Rooftop

  1. APS_is_a_monopoly_who_hates_the_public August 8, 2016 at 5:27 PM #

    Wow Tammy, you’re a complete bigot. Next thing you know APS will be endorsing Donald Trump.

    APS wants to control all electricity and make sure they make as much money providing it to the citizens of AZ as it can. Let’s not forget APS is supposed to be a public utility company, looking out for the best interests of the public instead of themselves. They have failed miserably doing this.

    Instead, APS wants to become the all-powerful provider of electricity, making sure every nickel and dime they can take from you is theres. Thats why instead of being a pioneer in the solar industry, they are pushing for more and more changes that would allow the solar industry in AZ to plummet. Increasing demand charges, discontinuing the use of Net Metering, and allowing their peak energy to gauge out any financial incentive for homeowners to go solar has shamed APS and all those fighting for solar.

    While the cost of installation these solar farms does allow for economies of scale to reduce costs for its implementation, APS already believes it needs to charge its customers even more to “maintain” the grid, and are blaming residential solar users. These are people helping to supply power to the grid, which for those with common sense understand reduces necessary supply from utilities which allows you to use resources instead for your maintenance.

    If maintenance is really such a large issue, wouldn’t the costs of maintaining large scale solar farms, most of which have any moving parts which produce much more wear and tear than rooftop solar arrays. Not to mention any power produced by these solar farms would still be sent to consumers who would then have to pay much higher rates to get renewable energy than that produced by the non-sustainable ways APS continues to use even though they understand the environmental impact this has.

    Tammy you’re a disgrace to the solar industry and everyone who is working so hard to helping people switch to a reliable, clean, renewable source of energy.

    If you want to understand the important environmental benefits solar power brings, like you claim, push to drop the rate changes that will take away incentives for homeowners to go solar. Fight against SRP who has modeled what APS want, where solar installations have dropped 90% over the last 6 months. Fight against legislation like that in Nevada, where solar installations have almost dropped to nothing.

    Make solar available to everyone instead of trying to control it for yourself.

    Most importantly, stop representing a monopoly who has no interest in the benefits of the customers required to be serviced by APS.

    You should be ashamed, this is a complete disgrace to everyone working hard to change our world to a more economically and environmentally sustainable way. You are a horrible representation of the great push solar has had, and you’re an embarrassment to the entire solar industry itself. Please stop ruining the progress that’s already been made. Please stop slandering solar. Don’t be an albatross to the industry.

    Learn more about how unfair APS has been by reading:

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