Thursday, February 2, 2012

Greenpeace Knocks, part II

So let's think a bit more about those suggestions from those green-eyed folks at Greenpeace, specifically about "geothermal" energy.

In this context, "geothermal" means using the residual heat in the earth (about 6 ft underground is sufficient), and extracting this heat using what is basically refrigerator technology running in reverse. This technology has been around for decades and you can check out great explanations of it here and here. Ground-based heat pumps are quite a bit more expensive than a standard nat-gas furnace or electric baseboards, and in our corner of BC they have a long payback period ((it takes decades for the upfront cost of the system to be made up in fuel savings). So they are not popular. In the colder parts of the province, where heating costs are higher, you will find more of them.

In our part of BC, you can forgo using the earth and install much cheaper "air-based" heat pumps, which compress outside air and extract the heat to warm your home. These devices are much more efficient (use less electricity) than baseboard radiators, but they are more expensive to install. Also, they don't work when temperatures drop below about 5C, so you need a backup system (don't get rid of those baseboards just yet!). But they are cheaper and "pay back" much faster than the ground-based heat pumps (10 years?).

For new construction, the problem is that because of the high capital expense of both of these systems, developers won't install them. The vast majority of home buyers will not pay more for a house because of some high-end fancy-schmancy heating system. Slap in the baseboards! Of course, once the baseboards are in, changing them out for something else is expensive. Changing the building code to force heat pumps (or at least leaving room for their future installation) might be an option, but I'm pretty sure that this would have the effect of increasing new home prices.

In terms of retrofits, most homeowners will not upgrade because of the long payback of these systems (hands up, who is willing to shell out $15k for a furnace that will pay back in 15 years, when a high-effiency natural-gas furnace costs half of this?).

Heating apartment buildings or townhouse complexes centrally is known as "district heating". Instead of using individually-controlled baseboard heaters (current practise) one could install large heat pumps based either in the ground, around sewage pipes, or in the river, and distribute the heat to the various homes/apartments. For new construction, this is definitely possible (but more expensive!), but it is very difficult to retrofit into existing complexes unless the piping is already there.

So the message here is, YES, these systems are viable, they work, you can install them today. But they will cost you more, up front. It takes a long time to realize savings from them. And since our current "free-market" economy is built on 5-year payback cycles, until electricity and natural gas are more expensive, these systems will never become widespread unless they are legislated and/or subsidized.

Finally, there is this to consider: these systems will reduce the amount of natural gas and electricity you use to heat your home. They will have absolutely no effect on the amount of oil we use here in BC.

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