Vehicle Scrappage & Efficiency Curves

May 18, 2009 by
Filed under: Education Matters 

My Dad is thinking of trading in his ten year old Renault Scenic under the government’s car scrappage scheme which launches today, and gives you £2000 to spend on a new car when you trade in your ten year old banger. The aim is to aid the economy by getting people spending, and to get older, more polluting, cars off the road in favour of clean new ones.

The scheme reminds me of when I was a design student and signed up for a course in “Environmentally Sensitive Design“, taught by Prof. Billett, which was the only final year option that had three hour lectures that felt like they flashed past in 30 minutes. One lesson that stuck in my mind was that the most environmentally sensitive behaviour is not always to keep stuff as long as possible – sometimes there is an environmentally optimum lifespan for a product.

This is often the case when a product consumes resources (like energy or water), and successive iterations of that product result in decreasing energy consumption. Ann Chalkley’s paper uses data about energy consumption of building and running a dishwasher and fits exponential curves to them, showing that the optimum lifespan of a dishwasher built in 1990 was 6.97 years, and predicting that the optimum lifespan of a dishwasher bought in 2009 will be 8.67 years.

It’s an interesting idea, but I’m not sure how universally applicable it is. I tried to work out the curves for my Dad’s Renault Scenic, but the fuel consumption for 1.9 diesel Scenics doesn’t follow the same pattern: the ’97 to ’99 model was 40mpg, the ’99 to ’03 did improve to 49mpg, but then the ’03 model spoilt it by dropping to 47mpg.

Which technologies are gradual enough to fit curves to? Can we design products that drop apart after their environmentally optimum lifespans and would we want to own them? Which cars are the period of ten years chosen by the government based on?

Comments

  • Charlotte Morton (Founder, Whi

    The Government’s scrappage scheme is shortsighted and ill-considered given the issues presented by Peak Oil and Climate Change. As Prof David MacKay’s recent Guardian article (www.guardian.co.uk/environment/cif-green/2009/apr/29/renewable-energy-david-mackay) showed, using public transport, joining a car club, walking and cycling rather than driving everywhere is one of the best things we can do to reduce our individual energy consumption. Whilst new cars may be more efficient and pollute less than old ones when they are being used, this saving is dwarfed by the amount of energy involved in manufacturing a new car (according to David MacKay’s book, Sustainable Energy – without the hot air, about 76,000kWh). The fact that the recession has reduced the number of new cars being manufactured is great news for the environment. Instead of encouraging people to buy new cars, the Government should be supporting and promoting public transport, car clubs, cycling and walking.

  • Charlotte Morton (Founder, WhizzGo)

    The Government’s scrappage scheme is shortsighted and ill-considered given the issues presented by Peak Oil and Climate Change. As Prof David MacKay’s recent Guardian article (www.guardian.co.uk/environment/cif-green/2009/apr/29/renewable-energy-david-mackay) showed, using public transport, joining a car club, walking and cycling rather than driving everywhere is one of the best things we can do to reduce our individual energy consumption. Whilst new cars may be more efficient and pollute less than old ones when they are being used, this saving is dwarfed by the amount of energy involved in manufacturing a new car (according to David MacKay’s book, Sustainable Energy – without the hot air, about 76,000kWh). The fact that the recession has reduced the number of new cars being manufactured is great news for the environment. Instead of encouraging people to buy new cars, the Government should be supporting and promoting public transport, car clubs, cycling and walking.

  • matthew taylor

    I like the idea of an energy consumption life cycle curve. It would be interesting to plot different products on the curve. Presumably there would be some electrical goods where energy consumption has stayed constant (radios?), some where it has fallen (like your dishwasher example) and some where it has probably increased (mobile phones). This would make an interesting article I think. Presumably the energy cost of disposing the existing and making the new appliance is factored in across the life cycle?

    • http://www.thersa.org/projects/design Jamie Young

      Yeah, I’d like to see the curve for various technologies too. The phone example is interesting, as I’d guess the energy consumption has risen because of the extra “features” that phone manufacturers stick in them. Web browsing means faster data comms and larger screens etc. Guess you’d need to take account of how the consumption changes according to the services provided by the object – rather than just thinking of it as a phone.

  • matthew taylor

    I like the idea of an energy consumption life cycle curve. It would be interesting to plot different products on the curve. Presumably there would be some electrical goods where energy consumption has stayed constant (radios?), some where it has fallen (like your dishwasher example) and some where it has probably increased (mobile phones). This would make an interesting article I think. Presumably the energy cost of disposing the existing and making the new appliance is factored in across the life cycle?

    • http://www.thersa.org/projects/design Jamie Young

      Yeah, I’d like to see the curve for various technologies too. The phone example is interesting, as I’d guess the energy consumption has risen because of the extra “features” that phone manufacturers stick in them. Web browsing means faster data comms and larger screens etc. Guess you’d need to take account of how the consumption changes according to the services provided by the object – rather than just thinking of it as a phone.

  • matthew taylor

    PS your links to other RSA blogs are out of date…..

  • matthew taylor

    PS your links to other RSA blogs are out of date…..

  • Mark Young

    I know radios have actually gone up – FM is less efficient than MW, and DAB is even less efficient than FM. I have to be feeling particularly energetic to listen to FM on my wind up radio!

  • Mark Young

    I know radios have actually gone up – FM is less efficient than MW, and DAB is even less efficient than FM. I have to be feeling particularly energetic to listen to FM on my wind up radio!