Sustainable Energy NZ #13 – making light work of savings at home

Welcome to the thirteenth post in the Sustainable Energy without the Hot Air – A New Zealand Perspective series. After our previous posts on hydro power, geothermal and wind (and a summary on the big three), solarbiofuelsmarine and waste energy, we’re now looking at answering the question:

How can we achieve a BIG reduction in our personal and national energy consumption?

We covered the breakdown of where we use this energy in the last post. Today we’re dealing with commercial and residential building energy use. Be sure to check out our treatment on road and air transport from the last few days.

A few notes before we begin: as before, the units are in kWh/day/person – ie. if you ran a 40W lightbulb for 24 hours, it’d take ~1 kWh over the space of a day. We then divide it by person to give you a sense of the scale of the resource proportionate to the size of the population. Be sure to check out the methodology. For reference – we’ve been looking to replace around 55 kWh/d/p of energy currently generated by fossil fuels.

Commercial and Residential Energy Use

Making sense of the commercial and residential energy use in the Energy File is more complicated. All the commercial energy to light, heat, and power our gadgets both at home and at work amounts to 21.2kWh/d/p. Compare this with a UK usage of 37kWh/d/p for heating and cooling. A couple of caveats about these figures though. First, “industrial” energy use almost certainly includes some workplace heating, lighting and gadgets, so the real number is certainly higher. The number includes 5kWh/d/p of firewood but excludes firewood obtained from non-commercial sources. Using MacKay’s estimates as a rough guide, we would break this down as follows.

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In defence of banning the bulb

I see Canterbury University economist Eric Crampton politely disagrees with my post on the failure to ban incandescent light bulbs. I’d like to comment on a couple of the points he raises. The first concerns the non-priced carbon embodied in the production and distribution of fluorescent and LED bulbs, and the possibility that it may be so large as to negate the advantages of lower carbon emissions during the lifetime of the bulbs.

Crampton admitted he had no clue, but assumed that the more complex efficient bulbs would have a higher carbon footprint in their manufacture than the incandescents. However, he allowed that the longer life of the efficient bulbs probably gave them the overall advantage. I had no clue either, though I’m familiar with the need to take embedded carbon into account when making comparisons and guess I assumed that was not something that had been overlooked in the advocacy of CFLs and LEDs. However I had a look to see what I could find, and came across this assessment of CFLs from a writer initially inclined to be sceptical about them, and this report on LEDs. It doesn’t look to be an issue.

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