April 21, 2008
What Can Building Retrofits Achieve?
Over the last few years we've heard a lot about how if just invested in efficiency, like retrofitting old homes, we would save huge amounts of energy and massively reduce our emissions (not to mention create millions of jobs, reduce inner-city poverty, stimulate the economy, etc.). This was the subject of an op-ed in the New York Times on Monday.
But today, the Times ran an interesting correction on the op-ed page:
An Op-Ed article on Monday, about renovating older houses to save energy, included an incorrect figure for the number of homes that would need to be retrofitted every year to save 200 million barrels of oil over a decade. The figure is 300,000, not 3,000.
I went and looked up some of these numbers. According to the U.S. Energy Information Administration, Americans consumed over 20 million barrels of petroleum per day in 2007. About half of that petroleum is in the form of gasoline and the rest is heating oil, industrial distillates, kerosene, jet fuel, etc.
Few houses, of course, are heated by petroleum, so the comparison is inexact. Moreover, I doubt the assumptions embedded recognize that people tend to use more electricity when efficiency lowers the total monthly bill.
The numbers provided by the Times offer a sobering view of how little retrofits will actually do. Here's what we find: If we were to retrofit 3 million homes over the next decade, we would only consume 10 days less petroleum (.27% less). If we were to retrofit 10 times as many homes, 30 million, (which is almost certainly not possible to do in 10 years), we would save just 100 days of oil over a 10 year period (2.7% less).
If these numbers are basically right, then it's safe to conclude that building retrofits will not contribute significantly to reducing overall global emissions. They might be good for other reasons, but they are hardly the basis for a strategy to mitigate warming.