Hagadorn: Colorado, soul of solar?
September 22, 2016
The 2nd fastest growing industry in Colorado? Solar and renewable energy.
Unlike wind power, which may plateau in the near future, solar will continue to experience astronomical growth. This billion dollar industry is fostered by our favorable regulatory climate, sunny high elevations, and a bevy of savvy companies and labs that are pushing the frontiers of solar research. Like the National Renewable Energy Lab in Golden.
Photovoltaic cells, or PV cells, are the lynchpins of this industry. Such cells are microscopically thin silicon sandwiches that make energy from the sun. They're composed of a veritable tongue-twister of ingredients, blended together to turn incoming solar energy into electricity.
In other words – a PV cell is like an LED in reverse.
There are three categories of PV systems: i) utility-scale systems that consist of huge fields of PV panels connected together like a power plant; ii) commercial and residential systems dominated by roof-mounted solar panels; and iii) community solar systems, aka solar gardens, which are stand-alone PV arrays that folks who rent, have shady roofs, or are on a tight budget can buy into.
Most of these PV systems are tied to the grid via some type of electrical meter, substation, or the like, providing what's called "distributed power generation" to our society. Rather than having all our power come from one place that a single entity controls, PV allows power to be generated in little batches, closer to where it will be used, with excess being sent back out onto the grid to benefit neighboring users.
Today's PV technology is as mind-blowingly advanced as the stuff in an iPhone. Panel efficiency has risen while costs have dropped – just like occurred in computers and cell phones in recent decades. Panels are so efficient and cost-effective that modern utility-scale systems, like the Comanche Solar field near Pueblo, can produce power at about the same cost as a modern gas-fired power plant.
PV systems have other advantages besides being cost-effective. They're quiet, maintenance-free, don't use water like coal- and gas-fired power plants, and they help provide national and local energy independence. By offsetting fossil fuel emissions, they yield health benefits through cleaner air and reduce global warming. Homes with seller-owned PV systems sell faster, and for more money that those without.
Both residential and commercial rooftop PV systems reduce overall pollution and prices of electricity for everyone on the grid, even those without PV. That's because panels generate the most power during the summer months, at a time when utilities are forced to buy higher-cost, less-efficiently-produced power to offset a portion of society's air conditioning needs. And they last – even after 25ish years of Colorado hailstorms, PV panels still perform at incredibly high rates of efficiency.
What about downsides? Photovoltaic systems, like any piece of technology and equipment, cost a lot of money to bring online. Their predictability, like wind, is subject to the vagaries of weather. Most aren't coupled to electricity storage systems, so aren't dispatchable on a moment's notice, nor is their energy portable like jet fuel. PV panels also produce DC power, so an inverter is needed to convert it to AC power, resulting in energy loss. Utility-scale systems, which tend to be mounted on the ground, also have land-intensive footprints. But with a bit of foresight, like the giant array mounted atop an old landfill on Fort Carson, their impact can be minimized.
Payback time for a system that provides 100 percent of an average Colorado home's needs is five to eight years, after which all the electricity is free. For utility-scale systems that use ground-mounted arrays and newer cadmium-telluride thin-film PVs, payback can be less than a year.
So what's next? Keep your eyes peeled on giant lithium-ion and similar batteries for your home or business, or perhaps even at the utility-scale. Such batteries have the potential to make PV-generated electricity dispatchable and predictable, just like oil-, gas-, and coal-fired power sources. The future might also include a return to homes that operate on DC, rather than AC. To step into this future, we'll need to carefully manage our tangled electrical grid, to make sure that electrons from the sun are en route wherever and whenever needed. Microgrids, increasingly common in the northeast US and elsewhere, will almost certainly be part of that future.
And the fastest growing (pun intended) industry in Colorado? It's an electricity hog. But if it were to use LED lights fueled by rooftop PV panels, it could save money, help public health and the environment, and grow even faster. Something to think about.
James Hagadorn, Ph.D., is a scientist at the Denver Museum of Nature & Science. Suggestions & comments welcome at firstname.lastname@example.org