Solar: Do-it-yourself vs. buying green power
EarthTalk
Tucson Green Times – Auguat 2009
Dear EarthTalk: I’d like to know the relative electricity cost of utility scale solar and wind plants versus rooftop residential solar. In other words, how can I know whether to subsidize my utility’s alternative energy plant or renovate my own home? − Randy Wilson, Flagstaff, AZ
Making such a determination is complex, but you could start with “In My Backyard,” a new online tool by the National Renewable Energy Laboratory (NREL). You first need to know your electricity usage and what size solar photovoltaic (PV) system or wind turbine you could install. Then, using Google Earth maps and data on the amounts of sunshine and wind at your location, the tool will estimate the electricity you could get from a certain size wind turbine or PV array installed on your property.
The costs to install renewable energy systems vary greatly by location, warn researchers at the Lawrence Berkeley National Laboratory, which is supported by the Department of Energy (DOE). And kilowatt hour (kWh) costs vary by utility, as do state and local financial incentives. One piece of good news: The federal Investment Tax Credit was expanded and extended this year. It allows for 30 percent of the cost of your system to be deducted from your federal tax bill, and is good through 2016.
Comparing the cost of going it alone to that of simply buying green power through your utility is not a simple equation, either. You can support your utility’s renewable power infrastructure by paying a premium on your electric bill, or you can buy renewable energy certificates—also known as green tags—even if your utility does not offer green power (green tags inject renewable energies into the grid even if they don’t come back to you via your own utility). To decide which equation is better for you, compare the costs of those programs over the same time period with the cost of building and maintaining your own system (minus any installation credits and/or revenues from selling your excess electricity back to the utility). That would give you the relative costs and return-on-investment.
But that’s still not the whole picture: Another question is whether your home system can continue to produce energy more cost-effectively than your utility, as it brings more and more green energy sources into its mix. Lawrence Berkeley says no, essentially. A February 2009 report summarizing the costs of PV from 1998 to 2007 concluded that larger systems averaged a 25 percent lower cost than the smallest ones.
The same is true for wind power, says the American Wind Energy Association. The group’s February 2005 report calculates that a large wind farm can deliver electricity at a nearly 40 percent lower cost than a small one. It also can take advantage of economies of scale in lower operational and maintenance costs.
The bottom line is this: Decades ago, when widespread use of alternative energy was still only a dream, building one’s own private source of home power was the only way to get off the carbon-intense grid and ensure that your own energy needs left little footprint. But today, with considerably more renewable energy sources coming online or about to do so in quantum leap measures—and at much greater efficiencies than can be achieved privately—the best bet may well be to forego the go-it alone path and support your utility’s efforts to generate green power not just for your own household but for everyone.
CONTACTS: NREL’s “In My Backyard” Tool, www.nrel.gov/eis/imby; DOE Green Power Network, http://apps3.eere.energy.gov/greenpower.
Dear EarthTalk: I’d like to know the relative electricity cost of utility scale solar and wind plants versus rooftop residential solar. In other words, how can I know whether to subsidize my utility’s alternative energy plant or renovate my own home? -Randy Wilson, Flagstaff, AZ
Making such a determination is complex, but you could start with “In My Backyard,” a new online tool by the National Renewable Energy Laboratory (NREL). You first need to know your electricity usage and what size solar photovoltaic (PV) system or wind turbine you could install. Then, using Google Earth maps and data on the amounts of sunshine and wind at your location, the tool will estimate the electricity you could get from a certain size wind turbine or PV array installed on your property.
The costs to install renewable energy systems vary greatly by location, warn researchers at the Lawrence Berkeley National Laboratory, which is supported by the Department of Energy (DOE). And kilowatt hour (kWh) costs vary by utility, as do state and local financial incentives. One piece of good news: The federal Investment Tax Credit was expanded and extended this year. It allows for 30 percent of the cost of your system to be deducted from your federal tax bill, and is good through 2016.
Comparing the cost of going it alone to that of simply buying green power through your utility is not a simple equation, either. You can support your utility’s renewable power infrastructure by paying a premium on your electric bill, or you can buy renewable energy certificates—also known as green tags—even if your utility does not offer green power (green tags inject renewable energies into the grid even if they don’t come back to you via your own utility). To decide which equation is better for you, compare the costs of those programs over the same time period with the cost of building and maintaining your own system (minus any installation credits and/or revenues from selling your excess electricity back to the utility). That would give you the relative costs and return-on-investment.
But that’s still not the whole picture: Another question is whether your home system can continue to produce energy more cost-effectively than your utility, as it brings more and more green energy sources into its mix. Lawrence Berkeley says no, essentially. A February 2009 report summarizing the costs of PV from 1998 to 2007 concluded that larger systems averaged a 25 percent lower cost than the smallest ones.
The same is true for wind power, says the American Wind Energy Association. The group’s February 2005 report calculates that a large wind farm can deliver electricity at a nearly 40 percent lower cost than a small one. It also can take advantage of economies of scale in lower operational and maintenance costs.
The bottom line is this: Decades ago, when widespread use of alternative energy was still only a dream, building one’s own private source of home power was the only way to get off the carbon-intense grid and ensure that your own energy needs left little footprint. But today, with considerably more renewable energy sources coming online or about to do so in quantum leap measures—and at much greater efficiencies than can be achieved privately—the best bet may well be to forego the go-it alone path and support your utility’s efforts to generate green power not just for your own household but for everyone.
CONTACTS: NREL’s “In My Backyard” Tool, www.nrel.gov/eis/imby; DOE Green Power Network, http://apps3.eere.energy.gov/greenpower.
Dear EarthTalk: I’m sure there are many good environmental reasons to build a rooftop garden. Can you enlighten? And also I’d like to know how to go about creating one and whether or not some municipalities might offer incentives to do so. – Linda, via e-mail
Indeed there are many good reasons to build a rooftop garden, or a so-called “green roof”—whereby layers of soil and plants on top of homes and buildings provide a host of environmental “services” for the living space below as well as for the surrounding ecosystem. Unlike traditional roofs, green roofs thrive on (and filter) precipitation, decreasing the amount of pollution-laden stormwater run-off draining into our waterways. And thanks to the process of photosynthesis, the plantings create oxygen, cleanse the air and absorb carbon dioxide before it gets into the atmosphere and adds to our global warming woes.
Green roofs also provide insulation: All those layers of organic material help keep a structure warm in the winter and cool in the summer, and help cut energy use and costs. Migrating birds and other wildlife have been known to take a shine to green roofs, especially in urban areas where natural habitat options are limited. Likewise, homeowners and building residents tend to view their green roofs as oases of peace and tranquility within otherwise noisy and concrete-laden urban environments.
According to Green Roofs for Healthy Cities, a nonprofit industry association, green roofs are gaining popularity. North Americans added some 3.1 million square feet of them to their buildings in 2008 alone—up 35 percent from 2007. Part of the uptick can be attributed to increasing awareness of the benefits of green roofs among urban planners, building owners and managers, and homeowners, all who have pressured policymakers to ease the burden of zoning and permitting for such beneficial projects.
Chicago now sports some 535,000 square feet of green roofs—the most in North America. Other leading lights in the green roofs movement include Washington, DC, New York City, Philadelphia, Baltimore, Montreal, and Vancouver, British Columbia. Dozens of smaller cities have also embraced green roofs. Grand Rapids. Michigan sports some 75,000 square feet of them, and Princeton, New Jersey and Newtown Square, Pennsylvania each play host to 50,000 square feet citywide. Inquiring at city hall is the best way to see if your city or town offers incentives for creating a green roof or greening an existing one.
Relief for the costs of installing a green roof might be on the way from the federal government. As part of the Clean Energy Stimulus and Investment Assurance Act she authored earlier this year, U.S. Senator Maria Cantwell (D-WA) is calling for residential and commercial property owners who install green roofs or retrofit existing roofs to recoup 30 percent of their costs in the form of a federal tax credit.
Do-it-yourselfers will find a treasure trove of information on how to create and install a green roof at the website Greenroofs.com. The site’s keyword-searchable directory offers links to manufacturers of kits to make installing your own green roof that much simpler, as well as to professional installers across North America and groups working on urban greening issues.
CONTACTS: Green Roofs for Healthy Cities, www.greenroofs.org; Clean Energy Stimulus and Investment Assurance Act, www.govtrack.us/congress/bill.xpd?bill=s111-320; Greenroofs.com, www.greenroofs.com.
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