Solar energy: mention it and people are likely to recall images of vast sun-drenched desert tracts covered with solar modules or mirrors. Searching the Web for "solar energy" is likely to produce news stories of big projects in the Mojave, Sahara and Negev (Israel,) places that reliably receive a potent daily dose of sunlight, measured in what industry professionals call sun hours.
Photo: A concentrated solar thermal project near Barstow, CA. Credit: U.S. Department of Energy
These projects attract hundreds of millions of dollars worth of public and private capital, each generating anywhere from 30 Megawatts to over 370 Megawatts of power, enough electrical generating capacity to meet the needs of a half million Americans.
To make this work, the U.S. government lavishes loan guarantees and expedites the review of projects on public land for multi-Megawatt and even Gigawatt solar power plants.
From an energy policy standpoint, how much should we rely on these utility-scale solar projects in our effort to secure a more sustainable system of electric power supply?
I think that the current zeal for projects like these should be tempered by more localized approaches to supplying renewable energy, with more control given to the states and cities in determining how much they achieve their own energy self-reliance. Renewable energy does not have to be harnessed in a few desert areas and shipped across country. In fact, public support for clean energy may hinge on the opposite.
These big power plants unarguably generate clean, renewable energy at an economic cost but also share some of the same drawbacks their coal- and nuclear-powered brethren do.
Developing large tracts of wild lands often raises concerns about the destruction of valuable wildlife habitat. Even if developers can successfully answer these concerns, it adds significant time and cost to the projects--and negative public opinion about solar energy.
Generating power at centralized locations far from our urban population centers creates additional challenges in terms of reliability, cost and economic value to consumers. The larger the facility, the greater the likelihood of its causing a major disruption in service due to an equipment malfunction, human error, or (heavens forbid) terrorist attack.
Despite the financial support and attention given to these large solar projects, the majority of our current solar power comes from thousands of systems as small as 3 Kilowatts in size installed on rooftops, in fields, over parking lots and even along highway rights-of-way.
2.4 MWp installation, Maryland. Photo courtesy of Kohl's
Since 2006 -- the first time a big concentrating solar thermal electricity power plant was built since the early 1990s -- solar photovoltaics (PV) has added 13 times more capacity to the U.S. electric grid than concentrating solar power plants, and with much less hub-bub.
This alternative approach to solar distributes our generating capacity over every locality from Alaska to Florida and California to Maine (and Hawaii and Puerto Rico,) closest to where the energy is needed. Recent studies show how distributed photovoltaic power could provide for much of what we need, including all of the projected growth in our electricity demand, both technically and commercially.
According to the report: Energy Self-Reliant States: Homegrown Renewable Power, more than 40 states plus the District of Columbia could generate 25 percent of their electricity just with rooftop solar photovoltaic systems.
Image courtesy of the Institute for Local Self-Reliance
Questions about cost and economics always must be first addressed. Solar electricity is not cost competitive with bulk, baseload power generated from coal and nuclear plants— but it does not have to be. Distributed solar provides electricity when and where power is most limited and most expensive, during those hot sunny afternoons when the demand for electricity can reach critical peaks. At these times local utility companies have to supplement their base generating capacity with more expensive electricity sourced from special-purpose “peaker” power plants, or from the spot market.
Solar electricity also mitigates the risk of fuel-price volatility, as ratepayers can understand when they find those pesky fuel surcharges in their power bills.
By the way, when a utility company like Georgia Power compares the cost of alternative energy with their costs, they frequently fail to mention this or any of the other surcharges and fees which appear on ratepayer bills. Consumer beware!
I'll continue this article next week, when we look further into the challenges of transmitting and distributing large amounts of electricity from remote plants, the economic benefits of localized renewable energy, and recent product developments that make rooftop solar more practical than ever.
Until then, thanks for reading!
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