Perfect Power Solar - Phoenix, AZ

SubPrime Solar Energy, Solar By The Pound, An Expensive Myth

by The Energy Doctor©

John R. Balfour, BS, MEP, Ph.D., LEED Accredited Professional

Would you ever buy a car or a home by determining the value in “dollars per pound”? It just doesn’t make sense. It’s like buying a car based on color or tire size. All red cars cost the same. In the solar electric world, residential, commercial, industrial and financial buyers use dollars per DC watt as a similar “Goofy Measure of Value” (GMV). The GMV results in what we call SubPrime solar.

Photovoltaic (PV) Technology converts solar energy into usable electric Kilowatt hours (kWhs), not DC watts. It may start out as DC power, but that is not how we tend to use it. When did you ever buy a DC watt? The fact is you haven’t! Do you even know what a DC watt is?

Actually almost nobody does! It is a PV measurement, a rating, it does not have a commercial value like a kilowatt hour does. We all buy kWhs from our utility companies. Please, check your bill.

There’s no line for dollars per pound or color for coal, oil, uranium or DC watts. When someone sells you a PV system by $/DC watt, their lack of knowledge of how PV technology works probably cost you a lot of money. You bought with questionable measure if not a negative value, GMV. There are a “handful” of people in the solar industry that agree with me.

Panels are certified in DC watts per panel at 77 degrees F, This has little relationship to how panels operate as a system in the real world. It puzzles me that utility companies, government agencies, the PV industry and almost all private buyers of Photovoltaic systems favor a misguided and misleading measure to purchase or size a solar system. When your business, school district or city buys a system based on the wrong specification or standard, you just made a poor decision on bad information! Generally, in PV they have purchased Subprime solar.

How do we get value?

The true measure of value is called PV System Performance (PVSP). It is measured in kilowatts per dollar spent (kWh/$).

We prefer to use a 20 year life as a realistic measure because while we design for a 40 year life, most systems are designed for a 10 to 15 year useful life.

Performance includes all the costs over those 20 years.

Kilowatt hours per dollar spent is a true and accurate measure! Performance based systems pay faster, have a better ROI and last longer.

The solar industry has been encouraged by the utility industry pushing the GMV myth that the true value of PV is based on first cost. Utility companies along with other energy industry advocates and protagonist do not use first cost in their world for power plants or other large capital projects. (They use heavily subsidized dollars per kilowatt hour produced.)

We are naïve in accepting the fanciful notion that PV panel cost will come down like processor computing costs in the IT industry. It’s like saying the cost of tomatoes will come down if we eat more. The results are a growing number of PV systems that will become disposable prematurely because of poor design and selection of equipment for system continuity and local conditions.

Temperature is the number one killer of equipment and performance. Yet, it’s not important to most designers. You can design PV systems for first cost or for performance but not both! Effective design does not require “Thinking Out of The Box”, a limp cliché. It requires getting rid of the box and starting from the basics of how technology works as a system, not just combining cheap components.

Unless you apply the right specifications and standards for your PV system and installation, you are cheating your family, business, school district, city, utility and nation. The USA is spending billions of dollars on technology which could be very good thing, if done well. Yet, with a three decade commitment to improving the PV industry I ask you to question if we are spending it properly today.

These words may seem harsh. However, subprime solar in a harsh environment is a harsh reality.

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SubPrime Solar Energy, Solar by the Pound, an Expensive Myth

Would you ever buy a home by determining the value in "dollars per pound"? It's like buying a car based on color or tire size. In the solar electric world, buyers use dollars per DC watt as a similar "Goofy Measure of Value".