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How to Work with Limited Resources
by Paul Scheckel
Last week I was visiting some friends who have been working on reducing their overall energy use. They started down this path through their church, where a group got together to learn about the impacts of energy use, then help and encourage each other to cut down. Like any other support group, it’s more fun and rewarding to do things together; maybe even have a competition.
My friends have reached a place where they aren’t sure what to do next, so they asked for my opinion, “What’s your goal?” I asked. They know that saving energy has far reaching implications ranging from lower monthly costs to a myriad of environmental benefits, but they hadn’t really clarified their personal goals. I listed the most common: save money, reduce carbon footprint, increase comfort in the home, return on investment, reduced risk of exposure to future high energy costs and the growing scarcity of fossil fuels.
“All of that, but mostly lower our carbon footprint” was the answer. Now we could move ahead in planning a course of action. I reviewed their gas and electric bills and asked about driving habits. Food choice can have a substantial impact on carbon footprint as well. My friends are vegetarians and buy local food whenever possible, representing a low carbon diet. Their power use is a respectable ten kilowatt-hours (kWh) per day (I use my own power use of six kWh as a benchmark for potential). The only appliance left to replace was an avocado colored dishwasher. While they do most dishes by hand, I pointed out that the new efficient dishwashers use less water and water heating energy than hand washing. They’ll look into that, but its relatively small savings. Where are the remaining big-ticket energy savings in their lifestyle?
This family of four has about average energy use for heating water. “He’s thinking about a solar water heater but I like the idea of solar electric power.” Now is where I need to put on my professional hat and avoid being in the middle of a disagreement between spouses, both of whom I’d like to remain friends with. “Let’s take a look at the numbers.” I like numbers; they’re safe and devoid of emotion.
My friends drive about 12,000 miles each year in a mini van that gets 20 miles per gallon. About 20 pounds of carbon dioxide is produced for each gallon of gasoline burned, so that adds up to 6 tons of CO2 per year. Their electric use totals 4,000 kWh per year, and each kWh adds 1.2 pounds to their carbon footprint (I don’t know who decided that a footprint should be measured in pounds, but it seems to work metaphorically), for an annual total of 2.4 tons. Their gas water heater burns up about 240 therms of natural gas each year, contributing another 1.4 tons of CO2. Finally, their home consumes about 600 therms each year to keep it warm, which expands the annual footprint by another 3.6 tons.
It’s difficult not to let cost enter into the equation. We all want to put our money to good use and get good value for an investment. Here’s how the cost and carbon savings breaks down for my friends, it will certainly be different for you depending on fuels used and their cost, along with your family’s habits.
Improvement - Cost - Tons CO2 Reduction - Annual Cost Savings
improve home "envelope" - $30,000 - 2.7 - $810
Solar electric power - $20,000 - 2.4 - $720
more efficient car - $25,000 - 2 - $200
Solar water heater - $8,000 - 1 - $302
Based on this information, they have narrowed their choices to either a solar electric system or a more efficient car. Some additional factors they need to consider are that a solar power system will far outlast any car, won’t depreciate, requires almost no maintenance, and requires far less energy to produce than a car. Despite the favorable numbers associated with efficiency, the primary reason not to address major home improvements at this time is the disruption such work would cause.
My friend’s annual CO2 footprint is 13.4 tons for the family’s direct energy purchases. Their indirect footprint includes commercial and industrial aspects of their lives such as the products they purchase and the food they eat, all of which require energy to produce and transport. Average total CO2 footprint for an American family is about 20 tons. Some climate scientists indicate that to maintain a non-threatening level of atmospheric CO2, each of the nearly 7 billion inhabitants of earth would have a budget of about 4 tons of CO2. If you had a limited carbon budget, how would you spend it?
Paul Scheckel is the author of The Home Energy Diet (New Society Publishers) and a leading blogger on energy related topics (www.nrgrev.com) .