Clanton Associates just completed a study for wireless lighting control company Daintree Networks that compares first costs and energy savings for six different lighting control retrofit options for a typical 1970s office space. Not surprisingly, the study shows significant first-cost savings with the wireless systems, with higher equipment costs offset by the reduced labor for running wires. Energy savings for the two wireless options are comparable to that of wired systems with similar capabilities, with the most advanced systems saving 49% over an ASHRAE 90.1-2007 baseline and 35% over California’s Title 24-2008 efficiency standard. The modeling in the study also reveals that advanced controls can compensate for less optimal layouts. Even though it was focused on retrofit solutions, this study may also help inform designers considering options for newly constructed spaces. In new construction “there would likely be a bit less differential in first cost between the systems, but the energy study would remain the same, and the additional long-term benefits of installing a networked, addressable system may far outweigh the first cost and energy costs,” predicts study co-author Dane Sanders.

For more information, see: www.daintree.net/products/wireless-lighting-control/

By Emily CatacchioRE-Powering America’s Land, an initiative of the U.S. Environmental Protection Agency (EPA) proposes the development of renewable energy production technologies on “potentially contaminated sites.” EPA is looking for applications from states, tribes, regional governments, and communities interested in renewable energy development on current and previously contaminated sites. The Department of Energy National Renewable Energy Laboratory (NREL) will then conduct a feasibility study to evaluate the potential of development. NREL will determine which technology is most appropriate, its location on the site, its generating capacity, return on investment, and economic feasibility. EPA will accept applications from Superfund, brownfield, RCRA corrective action, and former landfill or mining sites by May 20th, 2011. For more information, visit www.epa.gov/renewableenergyland.

EBN Oct. 2010). The Maryland housing department and local governments are allowed to amend IGCC within their own jurisdictions. The bill, developed by the International Code Council and others, establishes a green model code focused on commercial buildings. For more information, visit mlis.state.md.us.

 

A recent study published in

Environmental Science and Technology reports that the actual rate of greenhouse gas production from septic tanks is half what has previously been estimated. One-fifth of the U.S. population uses residential septic tanks to treat wastewater; during this process, micro-organisms decompose the matter and produce greenhouse gases such as methane, carbon dioxide (CO₂), and nitrous oxide (N₂O). Estimates of 0.23 metric tons of carbon dioxide equivalents per user per year, made by the Intergovernmental Panel on Climate Change (IPCC), are based on how quickly microbes convert organic matter into methane. According to study participant Harold Leverenz, P.E., Ph.D, a post-doctoral researcher at the University of California–Davis, IPCC “assumes all organic matter entering the tank is converted under anaerobic conditions. [But the team] found that only a portion of the influent organic matter actually undergoes anaerobic decomposition.” Further, “the team found that dissolved organic matter which exits the tank in the effluent is converted under aerobic conditions to carbon dioxide,” which causes less methane and more CO₂ production, reducing the overall CO₂ equivalent produced.

 

By Paula MeltonU.S. homes expend far less energy on home heating than they did in the 1970s, but overall residential energy consumption remains virtually the same, reports the U.S. Energy Information Administration (EIA). According to EIA’s Residential Energy Consumption Survey, home energy use from appliances and electronics has surged by nearly 84%—from 1.77 quadrillion Btu (quads) in 1978 to 3.25 quads in 2009—despite higher efficiency standards for appliances. Energy consumption per household actually dropped an average of 31%, and net stability is due in part to an increase in the number of households. EIA points to several other factors that contribute to stable overall energy consumption, including dramatically increased ownership of clothes washers, dishwashers, and central air conditioners. Additionally, according to EIA data, 72.6% of households have at least one computer (39.4% have two or more), 88.6% have one or more rechargeable electronic devices (44.3% have four or more), and 98.5% own a television (more than half of households have at least three televisions). “Screen size and average energy consumption per television have continued to grow over time,” says the EIA website. For more information on the survey, visit www.eia.gov/consumption/residential.

By Paula MeltonFirst Solar has chosen an abandoned General Motors testing facility in Mesa, Arizona as the site of its second U.S. factory. The plant will create 600 jobs and be able to produce 250 MW worth of thin-film photovoltaic (PV) modules per year, according to the company, which expects to start shipping modules from the Mesa factory by late 2012. In a press release, First Solar also said the facility will have a 3 MW PV array on its roof and a ground-mounted PV array that would be used for testing. It will also recycle other First Solar modules as part of its production process. General Electric has also announced plans to build a new thin-film factory in the U.S., which it says will produce 400 MW worth of PV per year and employ 400 workers. The location of this plant has not been announced.

By Paula MeltonScientists have long known that when river water and seawater mix, as they do in river deltas and estuaries, the chemical reaction releases large amounts of waste energy. A recent breakthrough may enable the use of this reaction as a renewable energy source. Researchers at Stanford University, the University of Milan, and Penn State University created a device they call a “mixing entropy battery” that, when dunked alternately in seawater and river water, was able to store entropic energy created by the difference in salinity. According to an abstract on the website of the American Chemical Society ( www.pubs.acs.org), the battery achieved energy extraction efficiency of 74%. The researchers also claim that “the mixing entropy battery is simple to fabricate and could contribute significantly to renewable energy in the future”—up to 13% of global energy consumption, according to their estimates.