Solar is so cute and cuddly we can bear-ly stand it. But does this teddy have any teeth?

Is there a more lovable energy source than solar power?

Its fuel is light from the sun, which is free and available almost anywhere. It’s entirely clean to run. It’s easy to install and maintain. The big utilities can use it to generate green grid power, but you can also put it on your own roof to become your own utility or to go off-grid.

And did I mention that it’s powered by THE SUN?

(Full disclosure: I do some work for a solar power developer).

It’s no wonder that public support for solar power is high, with 92% of Americans in a 2009 poll saying that it’s important to develop solar energy resources. In particular, environmentalists love solar power best of all energy sources. It’s as clean as wind power, but solar is much less controversial.

Wind turbines make noise and spoil hillside “viewsheds” that bother the neighbors and the turbines’ huge spinning blades can kill birds and bats. But aside from a need for land and some use of toxics in manufacturing, solar has few environmental impacts. And so far, there has been very little NIMBY opposition to solar installations.

Itsy bitsy teeny weeny

But many experts in energy beg to demur. They admit that yes, solar power sure is cool. But they say that solar is not a practical source of electricity today. And they predict that it will probably never become practical in the future.

Skeptics have three main problems with solar. First, because it’s intermittent (the sun doesn’t always shine), solar power can’t provide the always-on power that we’re used to. So, every time you put up a solar power installation you also need to build or pull in a dirty fossil fuel or nuclear plant to back it up. That’s not so clean, is it? And it’s wasteful too, since you basically have to keep those backup plants running on standby 24/7.

Second, solar power is also expensive, not only because you need all those other plants just sitting around as back up, but also because making solar panels requires fancy-dancy materials like rare-earth minerals and costs money for many other reasons. Even with government subsidies, solar power still can’t compete today with coal or nuclear power rates.

Finally, even if you could store solar power at night or ship it over from sunny areas like Arizona to places that need the juice like New York City, the battery and grid technology is so far in the future that solar power won’t be able to scale up in any meaningful time frame to replace coal or nukes.

Solar panels look cool. But are they practical?

So, critics say, no matter how neat solar panels and reflector mirrors look gleaming in the noonday sun, solar power always seems to be the energy source of tomorrow. Put together, after decades of development photovoltaics and solar thermal power still can’t produce even one percent of America’s juice. Doesn’t that prove that solar will always be rinky-dink?

In support of this view, Tad Padzek of the University of Texas at Austin told the ASPO-USA conference in October that if you measure all electricity sources by the number of days worth of usage per year that each provides, solar is microscopic. If coal covers 176 days, nuclear power covers 72 days and wind power covers 5 days, solar power would account for only one puny hour of America’s electricity usage.

Another skeptic, Robert Hirsch, who also spoke at the ASPO event, referred to solar power in his book The Impending World Energy Mess as the “emperor’s underwear,” an energy source that is not a total fraud and does have some value, but whose power comes only at a very high price.

Growing, but without much love

“You have to start somewhere,” says Ken Zweibel, director of the GW Solar Institute at George Washington University.

Zweibel told the ASPO-USA conference that, although the US doesn’t have much more solar power today than we did ten years ago, we have yet to see a nationwide emergency program to ramp it up. Quite the opposite, in fact. Most of solar’s growth has taken place in a start-again-stop-again policy atmosphere where incentives were intermittent and investors had difficulty planning the true costs of a project. “We’ve seen a 3000-fold increase in solar capacity without really trying.”

“Recently, the numbers have started to grow, doubling over the year before,” Zweibel told me. “It doesn’t take many doublings for things to get pretty astounding.”

(Click image to enlarge.) Chart showing similar adoption curves for solar power and other sources of electricity. Image: Terry Peterson.

In support, Zweibel cites the work of researcher Terry Peterson, who did a study of the rate at which wind power ramped up to its current nameplate capacity of about 100 gigawatts worldwide. “Solar is now on the same increase curve as wind and also as both natural gas and nuclear power were in their big periods of growth.”

Zweibel cites another report, this time a forthcoming study by Robert Margolis for the Department of Energy, that in twenty years solar power could supply 20% of US electricity demand, an amount equivalent to the energy now used by America’s entire fleet of cars and light trucks.

And if wind power can ramp up to provide yet another 20% of US electricity in the same period, as many experts have also projected, then in 2030 nearly half of America’s power will come from these two clean, renewable sources, the sun and the wind. That’s definitely not chickenfeed.

GW Solar Institute’s Ken Zweibel.

Today, bigger and bigger solar projects are in the works. For example, in October California approved the world’s largest solar installation, a thermal plant capable of generating 1,000 megawatts of power using mirrors to heat water that would turn turbines to generate electricity.

Zweibel says that such projects could overcome the challenge of providing always-on power by pairing solar installations not with fossil fuel or nuclear plants, but instead with wind farms of appropriate capacity. Working together, solar and wind often balance out each others’ intermittency, since the wind often blows harder at night while the sun isn’t shining.

But to supply power from the sun that’s more consistently available, storage will have to greatly improve. Along with better batteries and other ways to store electricity such as compressed air and pumped water, Zweibel says that we can use the growing fleet of hybrid electric and all-electric vehicles as batteries-on-wheels, one of those neato ideas that seems to solve two problems at the same time.

“Electric vehicles can be brought online without adding much capacity,” Zweibel says. “EVs are storage which allow you to add more solar power without adding more cost.”

Your roof in Cleveland vs. that blinding Arizona sun

Zweibel sees a place for millions of panels on rooftops across the country. Those panels won’t be as affordable as doing solar at utility scale. But distributed solar will have the advantage of adding needed competition so far missing from most regions’ electricity markets. By requiring utilities to become more efficient, competition from home PV systems will drive down costs for retail electricity.

But Zweibel thinks that big solar will be more cost-effective in the long run. Large installations can turn the burning sun of the southwestern US into affordable juice for the rest of the country at competitive rates — 14 to 17 cents per kilowatt hour without any subsidies.

Can solar power become the grizzly bear of energy sources, ready to rip carbon emissions to shreds?

And in the future, Zweibel sees solar only getting cheaper because, viewed from every aspect of the energy business, solar enjoys the lowest risk. While coal, natural gas and uranium are sure to rise in cost as supplies deplete, solar has no fuel cost to pay. Instead, its main cost comes from manufacturing equipment, and that is likely to continue falling in the future. “Total prices today are 40% to 60% less than three years ago,” he says.

Operational and regulatory risks are both also low relative to other power sources, particularly those environmental bad-boys, coal and nuclear. Coal is sure to feel the wrath of carbon taxes along with additional costs from carbon sequestration, if the industry ever delivers on the so-far elusive promise of “clean” coal. And if nuclear begins to ramp up again as President Obama has promised, the public is likely to demand expensive measures to increase the safety of new plants and to store growing piles of radioactive waste.

Meantime, the break-even point on investment for solar PV has come down to ten years in the US southwest and 14 years in a moderately sunny East Coast state like Virginia, for example. Today’s solar panels are rated to last 30 or 40 years, and in the near future, panels could be built to last a full century, Zweibel says.  As simple to maintain as they are to assemble, the only major component of a solar system that needs to be changed out regularly is the inverter, a relatively inexpensive part of the whole setup.

So, what will it take to help the solar teddy bear grow into a thousand-pound grizzly, ready to rip to shreds high energy costs, polluting fuels and dangerous nukes?

Aside from new technology, Zweibel calls for certainty in deployment. Because they’re not predictable — one year they’re here and they next year they could be gone — tax credits have not been the most helpful form of incentive to invest in solar power. Also, tax credits favor Wall Street speculators over entrepreneurs and homeowners. “I hate these tax credit things. They bring in Goldman Sachs and firms like that while pushing out the rest of us,” says Zweibel.

He calls for outright grants over tax credits, and for public incentives that are locked in for a period of years to avoid the on-again-off-again syndrome and provide some predictability for investors to put their money into building solar installations.

Large installations of 100-year solar panels could be the Roman aqueducts of our generation. Photo: Wolfgang Staudt via Flickr.

“Simple, rugged, long-lived infrastructure like dams, harbors, aqueducts, schools and libraries differentiates great civilizations from failures,” says Zweibel.

And with peak oil coming on, if we can convert many of our cars, trains, and buses over from liquid fuels to electricity, then solar power could just help America find a cost-effective substitute for some of the oil that we’ll lose. This could help provide a much softer landing to our oil-soaked economy.

Because transportation is so key to our economy and our culture, powering transportation with solar could, by itself, make the America of the future a great civilization rather than a failure.

–Erik Curren, Transition Voice