Passive Home Design

Following up on passive design homes from Dr. Lang's lecture this morning:

The concept of the passive house, pioneered in this city of 140,000 outside Frankfurt, approaches the challenge from a different angle. Using ultrathick insulation and complex doors and windows, the architect engineers a home encased in an airtight shell, so that barely any heat escapes and barely any cold seeps in. That means a passive house can be warmed not only by the sun, but also by the heat from appliances and even from occupants’ bodies.

And in Germany, passive houses cost only about 5 to 7 percent more to build than conventional houses.

Via NY Times.

Low Hanging Fruit: Ripe for the Pickin'

Our efforts to reduce carbon emissions will undoubtedly utilize many different strategies. Pacala and Socolow of the Princeton Environmental Institute first illustrated the concept of stabilization wedges in 2004, in which they identified a desirable CO2 emissions rate and prescribed various existing technologies we can use to achieve emissions reductions (1). The wedge concept reiterates the important, and sometimes overlooked idea, that a diverse array of technologies and practices are necessary, and that we should emphasize the use of existing technologies to make emissions reductions. One of the wedges I would like to discuss is the Efficient Building wedge, specifically lighting as it is the lowest hanging fruit of them all.

The inefficiency of incandescent light bulbs is well known; about a 5% efficiency with the rest wasted as heat. Many countries have passed regulations to phase out incandescent bulbs, Australia, Brazil, Switzerland, U.S. (by 2014), and recently the EU (by 2012). The substitute lighting of choice for the majority of residential and commercial applications are CFL's. Lasting 10 times longer than incandescents (10,000 hrs) and using 75% less energy, CFL's will greatly reduce energy use and carbon emissions(2). But why stop there?

The promise of cost competitive light emitting diodes (LED's) may be closer. LED's boast even greater energy efficiencies and life spans (45,000 hrs) than CFLs, but up to this point have been prohibitively expensive. Recent production breakthroughs, noted in the latest Economist, may greatly reduce the cost of LED's. The breakthrough involves using cheaper silicon wafers instead of expensive sapphire-based wafers. Using silicon wafers means a lower cost for materials, and a production process that can utilize more economical 6 inch wafers and more common fabrication equipment(2).

The potential future energy savings of switching to LED's has been noted by the DOE. They estimate that LED's can reduce the electricity demand of lighting by half and avoid adding 130 new power generation facilities. DOE's Next Generation Lighting Initiative, started in 2003 and funded through 2011 with $450 million, sole objective is to "research, develop, and conduct demonstration activities" "based on white light emitting diodes" (3). The goal is to make LED's cost competitive with incandescents and CFLs, while maintaining desirable lighting qualities, by 2011. Identified by DOE as a major obstacle to meeting this goal is the cost of materials and manufacturing. Perhaps the recent production breakthrough is on their radar, and hopefully the commercialization of these LEDs is not far off. It would be ideal for LED commericialization to take place during the lighting replacments now mandated, instead of a second lighting renessiance further down the road.

(1) Pacala, 2004, Stabilization Wedges: Solving the Climate Problem for the Next 50 Years with Current Technologies, Science 305, 968, http://www.sciencemag.org/cgi/reprint/305/5686/968.pdf

(2) The Economist, 2009, A brilliant new approach, http://www.economist.com/science/displaystory.cfm?story_id=13315818

(3) EIA, 2002, Impacts of Energy Research and Development, http://www.eia.doe.gov/oiaf/servicerpt/erd/energy.html

Reuters: Wal-Mart introduces new generation of energy-efficient stores near Chicago

Summary:
Wal-Mart Stores announced it will open the first of 4 new stores that promise to "use 25% less energy than its supercenters that were in operation in 2005," beginning January 23 in Romeoville, Illinois. It plans to meet the goal by adding "energy conservation measures focused on the refrigeration system and water heating and cooling" to the new stores, as well as including "white roofs, low-flow bathroom faucets, LED lights and an advanced daylight harvesting system."

The move stems from two experimental stores it opened in 2005 in McKinney, Texas and Aurora, Colorado, where they experimented with the likes of wind turbines, PV panels, water-cooled refrigerators, and xeriscape gardens. Wal-Mart's CEO, in the recent past, has said their goal is to ultimately use only renewable energy sources and produce zero waste. Also in 2005, Wal-Mart announced goals to increase their truck fleet's fuel efficiency, reduce greenhouse gas emissions, and reduce solid waste, all within the next few years.

Opinion:
Is this a good sign towards progress in America? Does the world's largest retailer care about environmental stewardship or do they simply realize the economic benefits that will result from cutting their own energy use? Even if they don't care, will their moves have a trickle down effect in promoting energy conservation to the nearly 100 million American customers that visit their stores each week?

Wal-Mart is aiming for a reduction in their own energy consumption - in both electricity and fuel forms. Slightly off topic, is it okay that this new store in Romeoville, IL (~30 miles from Chicago), will be the 8th Wal-Mart in a 10 mile radius? Maybe that's Wal-Mart's brilliant plan: reduce America's fuel consumption by strategically placing stores on every corner. It might work.

-Brent