Last week, the Department of Energy released a proposed rule that would be the death knell for the incandescent light bulb.  The proposed rule would implement the so-called “backstop” provisions of the Energy Policy and Conservation Act, and impose an efficiency standard for general service lamps of 45 lumens per watt.  In short, incandescent bulbs operate at efficiencies well below 45 lm/W and thus could not meet the new standard.

The legal issues behind the rule are about as arcane as administrative law gets and I’m not going to get into those issues here.  Instead, I want to emphasize two facts that I’ve been aware of for some time, but which I still find to be moderately amazing.  First, while I’ve seen different statistics, it is clear that incandescent bulbs generally turn less than 10% of the energy they receive into light, and it can be 5% or even lower.  Remember the historical claims that nuclear power was going to be too cheap to meter?  For years, the incandescent bulb was too cheap for people to care how wasteful it was.

The second fact, according to some commenters in the rulemaking, is that, for each month DOE delays in implementing the 45 lm/W standard, 800,000 tons of CO₂ will be emitted over the lifetime of all of the bulbs sold during that month.  That’s a pretty mindblowing statistic.

To me, the most significant issue here is, once again, the role of externalities and the power of definitions.  Since the invention of the light bulb, we’ve been wasting huge amounts of electricity.  This might seem perplexing, because one thinks of engineers as being pretty good at not being wasteful.  However, it’s all a matter of definition, and that’s where the role of externalities come in.  In our wonder of an economy, nothing counts as a waste until a cost is attached to it.  Because no one has ever cared about the cost of the inefficiency of the incandescent bulb, it did not matter.  Indeed, it’s as though it did not exist, because no one assigned a cost to that inefficiency.

The time has come to really put engineers to work to root out the inefficiencies in how we generate light.  The DOE rule will help kickstart that effort, though I note that it provides no incentive to design a bulb that produces more than 45 lm/W.