Stephen Rees’s blog

Energy Bulletin Sept 11

“Heat Islands” may produce more energy consumption - or not. First of all, it depends on the ambient temperature, and how comfortable it is. Secondly how people behave.

I suspect there is a significant difference in Phoenix to downtown Toronto for example. But also some of these effects can be offset by techniques such as green roofs, better energy efficiency in the buildings (less heat loss) use of planting and landscaping and so on.

But mainly mixed land uses, so the people in the buildings do not feel quite so much need to drive everywhere.

Moreover “may add to global warming” also depends on the energy source and use. In a city like LA which gets a lot of its electricity to run HVAC systems from coal power, there could well be an increase in carbon emissions. But somewhere using existing hydro (like Vancouver) no increase in carbon emissions.

Many modern office buildings capture all their own “waste” heat - people generate a lot, and so do copiers and computers. If you have a dense urban core, mixed land use and a district energy system this heat can be used by other buildings in the vicinity, such as care facilities. North Vancouver has such a system in its new development at the south end of Lonsdale. Of course such places need careful urban planning.

So LA and Phoenix, with very low densities in general, poor transit systems, low energy efficiency buildings (a legacy of a long history of low energy prices) and the custom of not only having the a/c set to deep freeze but also sending the “waste” heat into the sky, probably do add to the problem. In a city like Toronto where there is significant need to heat many buildings in winter, but plenty of “waste heat” around which can be captured, plus a good transit system and much mixed land use near the core, the effect may not be so significant.

Of course, systems such as LEED are fairly recent innovations in North America, but rising energy costs mean that better buildings pay for themselves in lower operating costs. Lots of surface parking lots, paved with asphalt also create more urban heat effect than parks, planting and other urban amenities.

In Vancouver, our biggest issue in meeting the current challenge of reducing emissions is mainly going to be about transport. That is because we no longer have the large scale industrial users in the city. Indeed, BC has a much bigger challenge than say Alberta - which Vaughan Palmer pointed out yesterday. Our challenge is to reduce ghg emissions from driving ourselves around: some of that will come from better, smaller and more efficient cars and maybe better fuels. But much more can come from significant investments in transit - given that our transit system is over capacity and a lot more people want to use it than can. But mainly not building more freeways to encourage ever more low density sprawl up the valley and outside the Metro area and creating more motorised travel demand. “Build a compact urban region, with complete communities, protect the green zone and increase transportation choice.” (LRSP) That was a good formula before Gordon Campbell committed us to a 30% reduction in ghg - it is an even better one now!