I read in the Kapiti Observer this morning about council plans to distribute 34,000 fluorescent lightbulbs free to every household.  This will involve a $74,000 interest-free loan from the EECA.  The report contained estimates that the bulbs will save Kapiti residents $5.8 million – that’s a huge return of $74 per $1 spent over the life of the bulbs.

Now, I know that these lightbulbs can save money; that’s why we have them in our flat.  I have seen three of the bulbs burn out within two years, though – they definitely don’t last forever.  But the magnitude of the supposed saving sounded totally astounding to me. 

SoI decided to check up on the figures.  First of all, the Kaptiti Observer didn’t get the number wrong.  The estimate of a 1:78 cost:benefit ratio is contained in this council report.

Wikipedia suggests that a cost:savings ratio per lightbulb over their lifetime of between 1:12 and 1:47, depending on the cost of the electricity.  For the Kapiti bulbs to be magically twice as beneficial as the best-case scenario presented in another estimate seems unlikely, even if the council are able to get the bulbs for a great bulk rate ($2 per bulb).

Another factor is that US studies include in the benefits’ side of the equation is the fact that less heat is generated by the efficient bulbs, so air conditioning units don’t have to work as hard.  This wouldn’t be a factor on the Kapiti coast; in fact, in the winter, a small amount of additional heating will be needed as the bulbs will be generating less heat than incandescent bulbs.

What I suspect they are doing is assuming a massively best-case scenario.  Electricity is super-expensive.  The two lightbulbs in each home are running 24/7.  The home has advanced air conditioning as in the US.  The home is forced to pay handymen to climb up on ladders to replace lightbulbs on a contract rate of $18 per bulb.  Incandescent bulbs are the most expensive ones available in the supermarket, rather than the cheapest ones at the Warehouse.  Maybe petrol to drive to the supermarket and buy new incandescent lightbulbs is included.

What the cost-benefit analysis doesn’t seem to include is the cost of printing leaflets, lightbulb storage, distribution and administration for the program.  I guess the council is ‘donating’ these costs as part of its pro-energy-efficiency budget.  We can also throw in the cost to the EECA (and taxpayers) of providing the $74,000 loan.

All of these assumptions, multipled by 17,000 households, produce a misleading savings amount, to say the least.

The other assumption being made is that households can’t run their own cost-benefit analysis – as have I, and most households I know – and installed their own CFL lightbulbs using their own money.

The program is relatively small, but the aggregate cost of all of these feel-good council programs makes up your total rates bill: thousands of dollars a year.

All I can say is, there ain’t no such thing as a free lightbulb.

Posted by Luke H on Friday, July 31st, 2009 at 1:22 pm.