Doug Rokke wants you to believe installing solar energy at a home or business is almost certainly a waste of money. He’s wrong, and my goal here is to tell you why.

In his recent commentary in these pages, Rokke uses a dazzling jumble of jargon like “insolation” and “non-ionizing radiation” to impress readers when “sunlight” would fit the essential meaning just as well. His actual science is surprisingly spotty.

But the really devastating error Rokke makes in his essay on solar affordability is mistaking his own stew of astronomy and physics for a modern understanding of solar energy and economics, which he basically ignores. I should know. I own a solar array. Rokke doesn’t.

There are several reasons to consider putting solar on your rooftop or in your backyard. Contributing to cleaner air and less global warming is one factor in most decisions, but the biggest reason people decide to have a solar energy system installed is to save money on future energy bills.

The truth is, the price of home solar is lower than ever. Efficiency of solar panels has improved steadily while their cost has fallen drastically in the past decade. In addition, generous federal and state incentives designed to spur widespread adoption of renewable energy can offset 60 percent of the total costs, and systems tend to quickly pay for themselves through savings on electricity bills.

As one example, Solar Urbana-Champaign reports that 183 properties added solar through its group-buy program in the past three years. Among those program participants, the average time it takes for a homeowner to recover their investment by generating their own electricity is as little as six  years, not the 31 years Rokke estimates. A solar system can easily last 25 years, and (again, contrary to Rokke), many companies now warrant their parts for that entire period.

Rokke regards his knowledge as so vast and his expertise so deep that he concludes arguing with him would be like arguing with the laws of the universe itself. That a man who likes to be called “Dr. Rokke” could display such a spectacular misunderstanding of the topic is mystifying. Until you learn that he flashes the words “PhD” and “physics” so fast that it has often escaped notice Rokke holds only a bachelor’s degree in physics. He has a doctorate in Education. He is not a professional physicist or scientist of any kind.

So what did Rokke get wrong in his hit piece on solar last week? Literally almost everything but the first third of his verbiage, which concerned celestial mechanics (Rokke is an amateur astronomer). 

Yes, the Earth does indeed revolve around the sun, which from our 40 degrees northern latitude on a rotating planet tilted 23.5 degrees from the plane of its orbit, appears to swing around the southern sky east to west. Yee-haw. He got that mostly right.

And then he goes off the rails with paragraph after paragraph of sweeping generalizations and pure hokum loaded with so many (often irrelevant) constraints as to make home solar seem all but impossible. He labors to paint a picture of the strictest physical, structural and spatial requirements when, in fact, modern solar panels are designed to work even under less-than-ideal conditions. Why does Rokke want you to be so discouraged?

His piece is littered with utterly bogus claims like this, “Therefore, the sun as seen from the collector always must be visible along the entire ecliptic.” Baloney. A solar system can produce a lot of energy overall even if a few or even all its panels are occasionally in shade.

Inverters —what Rokke calls “rectifiers” — are about 99 percent efficient at converting the direct current (DC) produced by solar panels to the alternating current (AC) used in homes —far more than the 80 percent efficiency Rokke lowballs.

Please understand, I don’t have the space to expose every error Rokke makes. At one point, Rokke strongly implies a solar system must provide 100 percent of a home’s energy needs at all times. Not true. Most solar systems are connected to the grid and can draw supplemental electricity from it at any time. They can also feed the grid excess solar-generated electricity.

He writes that a solar array will not operate without line voltage, when the truth is a solar array tied to a utility grid is designed to automatically cease producing electricity in the event of an outage so linemen don’t get zapped. It doesn’t physically need external energy to make energy; it’s a disconnect required for safety.

He smears contractors by claiming they don’t distinguish true south from magnetic south and saying the 2 degrees of difference between these is “crucial” to pointing an array. Guess what? It isn’t, unless you’re a utility and need to squeeze every single watt from a multi-million-dollar investment.

Some of what Rokke writes about is important to consider. A lot of it isn’t. You don’t need an expensive tracking system to turn your solar array throughout the day and year because it’s far cheaper to just build a fixed-tilt system using more panels to collect more sunlight.

His example of initial cost is not greatly exaggerated, but he never does the math to compute the final cost. He seems to pull an electric bill from thin air and claim a 10 kilowatt solar array will save a mere $75 on an electric bill. In fact, it would save a monthly average closer to $120. Furthermore, he assumes savings on an electric bill will remain the same in future years. But this doesn’t take into account that utilities often raise rates. Over the three-decade lifespan of a solar energy system, electric costs will rise, and the homeowner’s monthly energy savings will increase as well, accelerating the investment’s break-even point.

Most important of all, Rokke leaves out any mention of the various government programs designed to spur solar’s growth. These include a 30 percent federal tax credit (dropping to 26 percent next year) you can take right off the top of your tax liability, spread over as many as five years. It includes a state incentive program that reimburses about a third of a small system’s cost to the owner with a nice check based on the total energy the system is projected to generate over time.

And then there are such state programs as Community Solar, Solar for All and Low-Income Solar, all designed to extend solar energy to the reach of more people. Many companies offer solar loans at low interest. There are even companies that install solar on qualified homes for free and lease energy back to the homeowners at less than utility rates.

Not every home, budget or situation can benefit from solar. But many can. If you happen to be thinking about it, do some digging. Call one of the solar companies that operate in the area, such as New Prairie Solar of Urbana, which helped install my system, or StraightUp Solar in Bloomington. You can even get started using the PV Watts solar calculator developed by the National Renewable Energy Laboratory at https://pvwatts.nrel.gov .

When solar energy is a good choice for many homeowners, why are some people intent on blowing smoke?

Chris Powers is a resident of Rantoul.