On and Off the Grid

â"Zero-Energyâ" home plans, in the city or in the sticks


by Matt Edens

Living â“off the gridâ” in a home that uses superior efficiency and renewable sources to produce all its electrical needs without plugging into the power grid has long been a goal of environmentalists and conservationists everywhere. Today, that goal is essentially achievable, and you don't have to be a tree-hugger living deep in the forest to do it.

This past weekend, the Southern Alliance for Clean Energy hosted a workshop at downtown's Lawson McGhee Library on its â“Zero-Energyâ” home plans. The product of a partnership between SACE, the Tennessee Department of Community and Economic Development, the Oak Ridge National Laboratory and Knoxville's own Elizabeth Eason Architecture, the plans are ready-to-build using proven technology such as high-efficiency heat pumps, solar hot water systems, photovoltaic electrical systems, controlled fresh air ventilation, high performance windows and superior insulation to produce a home whose net energy costs run less than a dollar a day.

Those estimates aren't just an academic exercise, either. Starting in 2002, ORNL's Building Technology Center teamed up with Habitat for Humanity to build four demonstration homes outside Lenoir City. Built for less than $100,000 each, those homes' daily energy costs averaged out to a mere 82 cents a day compared to the $4-$5 of an average Lenoir City home. They weren't entirely â“off the grid,â” but at times, their meters more or less ran backwards. Credit for excess electricity contributed back to the power grid trimmed an average of almost $300 off each home's annual utility bill.               

Other than some solar panels perched on the roofs, these homes were all but indistinguishable from the conventional houses Habitat builds. And, with a few finish upgrades, they could easily mix into most existing subdivisions and neighborhoods (the plans are available in both 1,320 and 2,640 square foot models). But while the demonstration project proved that drastically cutting home energy consumption is an achievable goal, there's one piece missing.

Sitting on a cul-de-sac not quite two miles outside the center of Lenoir City, these four â“zero-energyâ” demonstration homes were plugged into the power grid, but way off the street grid. Walking most anywhere would involve a long hike alongside or even across busy U.S. 321. And, since they are in Lenoir City, transit isn't really an option. The owners of the homes may be paying little for electricity, but how much are they shelling out for gas? Maybe Jimmy Carter could start a new charity: Hybrids for Humanity?

I see no reason why, instead of being built on greenfield sites, these net-zero- energy homes couldn't be constructed as urban infill. With shorter trips and the option of using their feet, riding a bike or a bus, owners could save on gas as well as their KUB bill. A growing center-city population would also attract more services, including retail and employment, increasing the advantage of proximity. Plus, rather than nibble away at the metro area's ever shrinking rural land, center city Knoxville certainly has plenty of vacant/abandoned land to accommodate considerable growth.

Luckily, the city has been taking steps lately to make living â“on the gridâ” easier and more attractive. Last month, City Council passed an ordinance allowing homes in areas zoned industrial or commercial (what's known as a pre-existing non-conforming use) to be rebuilt should they be damaged/destroyed by fire or any other disaster.   The change, while it might seem minor, will allow owners to obtain conventional mortgage financing for hundreds of homes left high and dry a half century ago when their neighborhoods were rezoned in hopes of attracting smokestack industries that never materialized.

This month, Council is likewise considering an ordinance to, within Knoxville's center-city Empowerment Zone, waive building permit fees for the renovation or construction of owner-occupied residential units in H-1 Historic Overlay or NC-1 Neighborhood Conservation districts. The idea, first floated by Fourth District Councilman Rob Frost, is indirectly â“greenâ” by encouraging revitalization and growth within the center-city's existing historic neighborhoods (and perhaps spur additional neighborhoods to seek historic status).

â“Household recyclingâ” on a grand scale, re-inhabiting Knoxville's underutilized urban core, could address a whole host of conservation and environmental issues. Couple that with â“zero-energyâ” concepts and the potential environmental payoff is that much greater. Although it does leave me wondering what Knoxville's Historic Zoning Commission will do when faced with a homeowner wanting to put solar panels in a historic district.


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