Gas vs. Electric

The two major sources of energy used in California homes are gas and electricity. In our home, for example, the stove uses gas, the water heater uses gas, the washer/dryer use electricity to spin and gas to heat, and the house heater uses an electric motor to push air over a metal tube heated with gas. It's no accident that the California's major utility company is called PG&E: Pacific Gas & Electric. I recently stumbled upon an interesting article about energy efficiency in home appliances. Among others, the article recommends using an electric room heater instead of running the home gas heater. I was generally under the impression that "gas is better" because it's cheaper and pollutes less (gas burns cleaner, whereas electricity is generally produced in coal burning power-plants that are far dirtier). So I decided to do some some research into the matter. For the baseline, I looked at the January bill from 2008 and 2007 (January is the coldest month around here, when one would expect the bill to be the highest, and this past January was especially cold):

• January 2007
• Gas: 53 therms @ $1.13
• Electric: 133 KWh @ $0.11
• Total: $74
• January 2008
• Gas: 49 therms @ $1.14
• Electric: 136 KWh @ $0.11
• Total: $71

Based on our usage patterns, I would estimate that roughly half the gas we consume is for heating the air in the home. So what would it look like if we used an electric Vornado heater instead? Based on the Vornado's specifications, it uses between 750 and 1500 Watts, depending on the temperature setting. I measured the wattage, and we're between 600 and 1200 Watts, since we never set it at the max (it gets too hot). For the purposes of this simple calculation, I'll assume the average consumption is 1000 Watts = 1 KW. We use the heater for a maximum of 5 hours per night (5pm - 10pm), so in one month, that's 30 * 5h * 1KW = 150 KWh. With this in mind, our January 2008 bill would have looked like:

• Gas: 25 therms @ $1.14
• Electric: 286 KWh @ $0.11
• Total: $56

That's a 22% reduction in cost! The heater would pay for itself in 3 months. In terms of quality of life, we've started spending more time in one room, with the door closed, in order to keep the heat inside. The Vornado works best in such a closed environment, and it often heats up the room far more than the gas heater. It takes a bit longer to get the room warm, but once it's warm, it consumes very little electricity to keep it that. I spoke to some colleagues at work about this, and the general consensus is that if you can thermally insulate individual rooms in the house, it makes sense to individually heat them using electricity, otherwise a gas heater is more efficient and economical for the entire house. What about the environmental impact? It turns out that in California, most electricity is also produced using natural gas, which is a reasonably clean way to do it. Some electric energy is lost in transmission, but it appears to be reasonably small (average 10%). The big upside, however, is that California is aggressively pursuing electricity generation using renewable energy: solar, wind, and so on, in which case electricity is definitely the way to go. You also have the option to offset the carbon used by your consumption, which is a nice bonus. In typical maverick fashion, San Francisco wants to become fully energy independent, and there are projects underway for that. In my case, it seems that electricity makes more sense than gas. At the end of the day, however, the most important thing is to be aware, measure the impact, and think about what makes sense. More on that, however, in another post.