Solve the right problem

Went to a very interesting talk on climate change and the individual actions needed to mitigate it. It struck me that it was an excellent example of ‘don’t do things right, do the right things‘. There are lots of things we can do, but you have to look at the bigger picture to understand what will have the most effect.

I’m not particularly interested in the wider arguments around international liability and ability to cut emmissions – I can’t do anything about that beyond my vote – but I want to make the most of any individual actions.

However there are so many green actions to choose from – for instance see the 75 on the BBC’s Bloom site. And, as the Bloom site points out, they vary greatly in their effect.

The degree to which actions (or solutions) vary in effectiveness is put into stark relief by the work of physicist David MacKay in his book Sustainable Energy.

For instance the media has noted the ‘problem’ posed by leaving phone chargers plugged in when not in use. A standard Nokia charger, not connected to the mobile, wastes 472 mW (or left connected to a fully charged mobile, wastes 845 mW). This equates to 0.01 kWh per day, the equivalent energy is used up in one second of car-driving. The energy saved in switching off the charger for one year is equal to the energy in a single hot bath.

So, while I should unplug my mobile, I could have a much, much greater impact by changing my behaviour in other areas. From skimming through David’s excellent book it would seem the best areas to target are heating/cooling, flying and car driving.

I’ve already put in the extra loft insulation, have a condenser boiler, cavity wall insultation and double glazing, and my freezer and fridge are new efficient models, so apart from turning the thermostat down next winter (turning down one degree can save 10% on your fuel bill) I can’t change much more on that front.

As I don’t take flights the key target for me is therefore driving. There seem to be three actions I can take to reduce carbon emmissions from my car (and as it happens save ongoing fuel costs – bonus!):

  1. Buy a new more efficient (or hybrid) car
  2. Use the car less
  3. Make journeys I take more efficient

I’m not in a position to buy and new car at the moment. My current car isn’t particularly big and is fairly new so has decent fuel efficiency. There are more fuel efficient cars, alternate fuel cars and smaller cars out there, but I simply don’t have the money to change at the moment and the payback period is too long.

I could use the car less. Unfortunately living in the country there aren’t many journeys I can make on foot, but as communting accounts for most of my driving I could try to do something here by talking my employer into having a work from home day once a week.

Making journeys more efficient seems the best option, particularly as it will also save money.  Car sharing isn’t a particularly easy option as I don’t think I live close to anyone I work with and my hours aren’t that consistent, but I should look into it.

Another option is reducing speed and braking. Fuel efficiency generally decrease with higher speeds.  ‘All cars demonstrated decreasing fuel economy beyond 65 mph (105 km/h), with wind resistance the dominant factor, and may save up to 25% by slowing from 70 mph (110 km/h) to 55 mph (89 km/h)’ [wikipeadia]. The Energy Savings Trust reckons it can save companies 15 to 20% on fuel costs by training staff to change their driving style.

However dropping speed will mean longer journey time.. or does it? Other research has shown that speeding does not save time (or not as much as you might think): driving at 38 mph rather than 30 mph over a five-mile journey saved 75 seconds.

So I’m going to try to put my energies into saving 15% of my carbon emmissions from driving rather than trying to remember to unplug the mobile charger.

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