DON STROBEL
HomeRun
Using insulation to reduce energy use Insulation is near the top of the list of the many elements involved in creating and maintaining a safe and healthy home with minimal impact on the environment. In addition to helping combat global warming, insulation helps provide comfortable temperatures and humidity levels in a residence. It reduces the amounts of energy and money otherwise necessary to achieve these levels. Before insulating, however, residents should first get an evaluation, or energy audit, by a seasoned professional who determines where to insulate and air seal. Then, after air sealing the building envelope, or filling the holes in walls, windows, and doors, residents should insulate their homes.
Order of events Homeowners should first increase the amount of insulation in the attic, and then, if the basement is unfinished, insulate the ceiling above it and above the crawlspace, in between the basement and the home. To determine whether an area of the home already has enough insulation, measure the insulation’s thickness, according to the U.S. Department of Energy’s (DOE) Web site (www1.eere.energy.gov/ consumer/tips/insulation.html). Contractors use R-values to identify insulation’s effectiveness; the higher the R-value, the better the ability of the insulation to protect a home from heat transfer. The best R-values for a home depend on the climate in which it is located. Guidelines include the following: the foundation wall R-10, the slabs below grade R-5, standard walls R-16, windows R-1.7, with low-E film recommended, and floors R-19 insulation. Most attics in the United
Applying weatherstripping can help stop air leaks around a doorway.
States should contain insulation between R-22 and R-49, with at least 6 inches of cellulose or 7 inches of fiberglass or rock wool, according to the DOE’s Web site. The two places that should be insulated first include the attic (because oftentimes this is where heat is lost) and the basement, especially if your remodeling plans include finishing the basement, or crawlspace.
What’s your type? There is a huge movement in the green world today to utilize foam in place of standard insulation. Higher R values per inch are possible, and it provides soundproofing, too. The application of these products is usually done professionally because it’s too technical for most homeowners. Some of the foam insulation products are soy-based so they contain no VOCs and are very green. Foam insulation products are particularly
Insulation Guide ff
Foundation wall R-10
ff
Slabs below grade R-5
ff
Standard walls R-16
ff
Floors R-19
ff
Attics between R-22 and R-49
well suited for the hot, humid climates in the South because they allow the entire envelope, or house, to be wellenclosed and protected from moisture. Insulating the home is one step in a series that will help to decrease energy use and cost. is a design/build contractor who is a Green Certified Professional through the National Association of the Remodeling Industry (NARI). For information, please access nariremodelers.com.
Don Strobel
scliving.coop | JULY 2009 | SOUTH CAROLINA LIVING
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DRIVIN on the
Is an era of 100-MPG cars and dollar-a-gallon gas about to bloom? By SCOTT GATES
Today, a small fleet of
specialized electric cooperative demonstration vehicles, drawing on the power of both gasoline and electricity, are currently wheeling down rural roads. Under optimum conditions, they can travel 150 miles on each gallon of gasoline. Sound far-fetched? The Cooperative Research Network (CRN), an arm of Arlington, Va.-based National Rural Electric Cooperative Association, has been conducting a project involving these cars, called plug-in hybrid electric vehicles (PHEVs), for the past two years. The U.S. Department of Energy’s Idaho National Laboratory and seven electric co-ops across the country have joined the effort, with at least a dozen cars on the road. “Part of the program is gaining real-world data on what it’s like to drive one of these vehicles day to day, and part of it is public outreach,” explains Alan Shedd, who logged 45,000 miles in a plug-in as a commercial-industrial marketing engineer at Jackson Electric Membership Corporation in Jefferson, Ga. Shedd picked up the co-op’s PHEV, a retrofitted 2004 Toyota Prius painted two-tone green and white, from a conversion shop outside Los Angeles in February 2007. He adds: “You can’t really drive anywhere without people asking about it. It’s kind of flashy—especially
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SOUTH CAROLINA LIVING | JULY 2009 | scliving.coop
NG Cuttıng Edge with ‘100+ mpg’ painted right above the gas tank.” In its study, CRN hopes to determine how PHEVs will perform as part of an electric co-op fleet. Any positive attention co-ops enjoy as a result provides an unexpected bonus. “It’s really great that electric cooperatives got involved in this technology early on,” comments Shedd. “Participating co-ops deserve a lot of credit for getting out there and making this initiative happen.”
Hybrid versus plug-in The public exposure Shedd and others provide by displaying the cars at co-op meetings, fairs, and other community events in South Carolina and elsewhere lets them explain what PHEVs actually do. Today’s hybrid cars, which many automakers are now offering, achieve greater fuel efficiency by adding an electric motor and 1.3-kWh nickel-metal hydride battery that takes over for the gasoline engine at low speeds. The
gas engine kicks on during long cruises, or when the battery gets used up. Both the gas engine and a regenerative braking system constantly recharge the battery pack. Plug-in hybrids, though, take the idea a step further by replacing the nickel-metal hydride battery with a 9-kWh lithium-ion model — a much larger version of those used in cell phones and laptops — that delivers more electric power and better fuel economy. A plug-in charging system that can be accessed above the car’s left rear bumper is then installed. When the battery runs down to where a onethird charge remains, the PHEV starts acting like a regular hybrid, using the gasoline engine to maintain that level. But the engine and brakes don’t recharge the battery much more. Instead, a full charge requires a regular 110-V outlet. Before being converted to a plug-in, Shedd’s off-the-shelf hybrid averaged 45 to 50 mpg. He now gets 75 to 90 mpg driving the same routes.
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“ In charging, the car draws less energy than a hairdryer.” Jackson EMC
Alan Shedd plugs his PHEV in at home and monitors how much electricity it draws with a small voltmeter. In recharging, the car uses less energy than a hairdryer.
On trips in-town of less than 20 miles, the car can average between 120 and 150 mpg. That means far fewer trips to the gas station, as long as Shedd can plug his car in at the end of the day. “When plugged in, a PHEV can recharge in four hours,” says Ed Torrero, CRN executive director. “Doing so consumes around 4 kilowatthours, or about 40 cents, of electricity. It’s cheaper to fully recharge the battery this way than charging it with the gasoline engine.”
Plug-in promise Charging can also be done at night, when demand for electricity is low. A PHEV can run on the equivalent of $1 per gallon for gas — a price not seen in this country for a decade. Plug-ins also offer the promise of reduced reliance on imported oil and lower greenhouse gas emissions. Combined, electricity generation and transportation account for close to 18
three-quarters of U.S. greenhouse gas emissions, blamed as a principal contributor to climate change. Even in a scenario where few changes are made to the nation’s current electric generation mix — with coal continuing to provide about half of all power produced — widespread adoption of PHEVs could reduce carbon dioxide emissions by as much as 500 million metric tons a year by 2050, according to a recent study by the Palo Alto, Calif.-based Electric Power Research Institute, a nonprofit research consortium for electric utilities, and the National Resources Defense Council in New York City. That’s equal to permanently taking more than one-third of cars off the nation’s roads. At the moment, plug-in hybrid electric vehicle development remains hampered by costs and still-evolving battery technology. Nickel-metal hydride batteries, for their part, are plagued by low energy density — the
SOUTH CAROLINA LIVING | JULY 2009 | scliving.coop
charge held relative to size. On the other hand, lithiumion batteries, such as those being deployed by CRN, are not yet proven. However, a report by the California Air Resources Board found them “making impressive technical progress worldwide,” especially in regards to longevity and safety. Another technical hurdle involves electric utilities’ ability to handle a surge of electric-driven cars. If PHEVs are charged during times of low electricity demand, the current power grid could “fuel” as many as 180 million without the need for new generation, according to the U.S. Department of Energy Pacific Northwest National Laboratory in Richland, Wash. But a rapid and more widespread adoption of the technology could severely strain distribution systems, such as those owned and maintained by your local electric co-op. “Plug-ins have the potential to create the greatest end-use product, and greatest challenge, for electric utilities since air conditioning was introduced in the 1950s,” explains Torrero. “Air conditioning load grew much faster than expected and caught a lot of utilities unprepared. This research project is contributing to an early understanding of the technology so we can avoid any similar unintended consequences.” When driving his PHEV, Shedd often fields questions along these lines. A popular concern is: if everyone on my block drives a plug-in hybrid, and comes home from work and plugs in at the same time, won’t we have brownouts? “In my opinion, it’s a non-issue,” insists Shedd. “In recharging, the car draws less energy than a hairdryer. And we don’t have brownouts in the morning when everyone is getting ready for work, drying their hair, and
Fuel of the future?
BIOELECTRICITY Switchgrass: next energy crop?
offer an alternative to petroleum for powering our cars, but growing energy crops to produce them can compete with food crops for farmland, and clearing forests to expand farmland will aggravate the climate change problem. How can we maximize our “miles per acre” from biomass? Researchers writing in the online edition of Science magazine say the best bet is to convert the biomass to electricity, rather than ethanol. They calculate that, compared to ethanol used for internal combustion engines, bioelectricity used for batterypowered vehicles would deliver an average of 80 percent more miles of transportation per acre of crops, while also providing double the greenhouse gas offsets to mitigate climate change. “It’s a relatively obvious question once you ask it, but nobody had really asked it before,” says study co-author Chris Field, director of the Department of Global Ecology at the Carnegie Institution. “The
BIOFUELS SUCH AS ETHANOL
kinds of motivations that have driven people to think about developing ethanol as a vehicle fuel have been somewhat different from those that have been motivating people to think about battery electric vehicles, but the overlap is in the area of maximizing efficiency and minimizing adverse impacts on climate.” The researchers performed a life-cycle analysis of both bioelectricity and ethanol technologies, taking into account not only the energy produced by each technology, but also the energy consumed in producing the vehicles and fuels. For the analysis, they used publicly available data on vehicle efficiencies from the U.S. Environmental Protection Agency and other organizations. Bioelectricity was the clear winner in the transportationmiles-per-acre comparison, regardless of whether the energy was produced from corn or from switchgrass, a cellulose-based energy crop. For example, a small SUV powered by bioelectricity could travel
making coffee.” Jackson EMC recently retired its PHEV when the odometer reached 103,000 miles, and Shedd has since moved on to work as a Southern regional manager with the National Rural Electric Cooperative Association.
nearly 14,000 highway miles on the net energy produced from an acre of switchgrass, while a comparable internal combustion vehicle could only travel about 9,000 miles on the highway. Average mileage for both city and highway driving would be 15,000 miles for a bioelectric SUV and 8,000 miles for an internal combustion vehicle. "The internal combustion engine just isn't very efficient, especially when compared to electric vehicles,” says Campbell. “Even the best ethanolproducing technologies with hybrid vehicles aren't enough to overcome this." The researchers found that bioelectricity and ethanol also differed in their potential impact on climate change. “Some approaches to bioenergy can make climate change worse, but other limited approaches can help fight climate change,” says Campbell. “For these beneficial approaches, we could do more to fight climate change by making electricity than making ethanol.” The energy from an acre of
But wanting to continue his participation with CRN, Shedd “put his money where his mouth is” and bought the car from the co-op. “I’m a huge fan of the technology— it works very well,” Shedd concludes. “This car and I, we go way back.”
switchgrass used to power an electric vehicle would prevent or offset the release of up to 10 tons of CO2 per acre, relative to a similar-sized gasoline-powered car. Across vehicle types and different crops, this offset averages more than 100 percent larger for the bioelectricity than for ethanol. Bioelectricity offers more possibilities for reducing greenhouse gas emissions through measures such as carbon capture and sequestration, which could be implemented at biomass power stations but not individual internal combustion vehicles. While the results of the study clearly favor bioelectricity over ethanol, the researchers caution that the issues facing society in choosing an energy strategy are complex. “We found that converting biomass to electricity rather than ethanol makes the most sense for two policy-relevant issues: transportation and climate,” says Lobell. “But we also need to compare these options for other issues like water consumption, air pollution, and economic costs.”
Scott Gates writes on technology and energy efficiency for the National Rural Electric Cooperative Association, the Arlington, Va.-based service arm of the nation’s 900-plus consumer-owned, not-for-profit electric cooperatives.
scliving.coop | JULY 2009 | SOUTH CAROLINA LIVING
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