Letter to the Editor

Shedding light on incandescent bulbs The Canadian government appears to be making a bold move towards energy efficiency by following…

Shedding light on

incandescent bulbs

The Canadian government appears to be making a bold move towards energy efficiency by following Australia’s lead and announcing that incandescent bulbs will be banned.

But is it so bold? Is it so wise?

On the surface, it appears to make sense.

Any steps made to improve energy efficiency and reduce waste should be good.

Most of the energy (about 90 per cent) produced by a standard incandescent bulb is heat.

Certainly in Australia, this truly would be “waste heat.”

Air conditioners would need to work even harder to remove this extra heat, thus compounding the wastefulness.

But, in the Yukon, for at least eight months of the year, we need to provide supplementary heat to make our homes livable.

During these times, so-called “waste heat” from incandescent bulbs simply contributes to the energy input needed to heat our homes.

During the summer months, heat from incandescent bulbs may truly be “waste.”

On the other hand, the demand for lights in the summer is relatively miniscule.

Let’s look at some numbers.

Assume that the average monthly energy consumption is 1,000 kilowatt hours over the eight “cold” months, when supplementary heat is required.

Assume that 20 per cent of this energy used is used for lights and that all lights are inefficient incandescent. Thus 200 kilowatt hours per month is used for lighting.

Also assume that compact fluorescent bulbs are four times more efficient, (i.e. a 15-watt compact fluorescent bulb produces the same number of lumens as a 60-watt incandescent bulb).

If the incandescent bulbs were replaced by compact fluorescent bulbs, there would be a saving of 150 kilowatt hours of electrical energy per month.

In other words, less heat would be produced.

One hundred and fifty kilowatt hours is equivalent to 512,000 BTUs of energy.

The heat not given off by the efficient fluorescent lights needs to come from somewhere, typically from an oil-fired furnace, in order to keep the house comfortable.

Assuming that the furnace is 70-per-cent efficient, an extra 732,000 BTU of heat would be created by burning diesel fuel — an extra 21.8 litres /month, and thus an extra 174 litres of oil during the eight months.

One litre of diesel produces 2.65 kilograms of CO2. Thus, over the eight months, 461 kilograms of CO2 would be produced by the furnace to provide the extra heat that once came from the incandescent lights.

Most of the Yukon’s electricity is generated by hydro.

Thus a reduction in energy demand — due to replacing incandescent bulbs with more efficient lights — would likely result in a relatively small reduction in diesel consumption (at the power plant). 

However, even if we assumed that all the electrical energy saved would have been supplied by diesel, and assumed that the efficiency of the diesel generators were equivalent to the efficiency of the home furnace, the net effect (in diesel burned and CO2 produced) of substituting bulbs would be zero.

The reduction in diesel burned at the power plant would be offset by an equal amount of diesel burned in the home furnace.

In the four summer months, the heat generated from the incandescent bulbs is wasted.

However, at this time of year, overall demand for electricity is less, and hydro electricity supply is greater, more than enough to meet the demand.

Thus, in the summer, diesel does not need to be burned either in the house (to supply heat) or at the power plant (to supply the extra electricity needed for the inefficient bulbs).

Also, the energy required for lights/month over the four summer months is perhaps one-third that required during the other eight months, thus about 67 kilowatt hours/month with incandescent bulbs, or 17 kilowatt hours/month with compact fluorescents.

Using all the above assumptions, over the span of a year, a homeowner who switched from incandescent to compact fluorescents would use 1,400 kilowatt hours less electricity (saving about $170) and burn 174 litres of additional diesel (costing about $170). Thus there would be no net financial benefit to the homeowner making the switch.

So, although it would seem reasonable to strive for energy efficiency, banning incandescent bulbs, particularly in the Yukon, will achieve little, if anything at all, towards either reducing CO2 production, or providing savings to the consumer. 

And, if General Electric’s news is true, they will soon have a high efficiency incandescent light, comparable to the efficiency of compact fluorescents.

Perhaps government should insist that light bulbs, of whatever ilk, be of a certain efficiency rating.

But, to simply ban incandescent bulbs is rather simplistic.

Jim Gilpin