Archive for June, 2010

Transition to a Green Economy 3

Thursday, June 3rd, 2010

Before I get going, I want to make an assertion: we should be investing more in low-carbon energy sources rather than compromising on lifestyle!  Many plans for reaching a low or zero carbon economy assume significant degradation of lifestyle, particularly travel.

Personally, I don’t want to return to a world where travel is the preserve of the rich.  I want a world where people have access to simple, cheap, personal and international transport and where people have many electrical and electronic devices in the home.  So I want to show that this is possible and feasible!

So let’s reassess the need for that extra 187GW. Will we really need that much?  Clearly if we compromise on lifestyle, savings can be made.  But I want to examine whether this number accounts for known trends I previously glossed over.

I derived the figure from estimated 2012/13 production (~95GW) and the proportion of GHG emissions produced by electricity generation, transport and heating. This calculation still holds, but I missed several factors.

  1. Population growth. I assumed essentially zero growth. In reality, our population is expected to grow, with ONS projections putting the population as high as 71.6 million by 2033 – i.e. 16% growth.  Presumably these extra people will need electricity, so I’ve underestimated significantly.
  2. Increased numbers of electrical / electronic devices per household.  As should be obvious to everyone, there has been an explosion in the numbers of electrical and electronic appliances over the last 30 years.  I expect this trend to continue as more people buy additional computers, printers, TVs for other rooms, etc.  However, I think this is likely to be offset by increased efficiency of these devices.   For example, LCD TVs are much more energy efficient than plasma, and LED-backlit TVs are even more so.  As technology improves, it will use less power (I know, it’s my job!).
  3. Standby efficiency of electrical / electronic devices.  Current devices have very high standby power, by some estimates this accounts for about 8% to 10% of household consumption.  The technology exists to reduce this to almost zero.  As people’s behaviour is difficult to change, legislation on the standby power of new devices seems the best way of achieving this reduction.
  4. Increased efficiency of domestic lighting.  Roughly 19% of electricity (18GW) is used on domestic lighting, most of which is incandescent.  Incandescent bulbs are about 5% efficient, so with 100% efficiency this could be reduced to 900MW.  Current low-energy bulbs are about 30% efficient and LEDs are about 80% efficient, so it seems reasonable to assume <5GW will be needed for domestic lighting (assuming a reasonable uptake of LED lighting).  This adds up to a saving of ~13GW (about 7%).
  5. Increased thermal efficiency of housing.  At present, only 8% of housing is rated in bands A – C for energy efficiency and62% is rated in bands E – G.  As space heating accounts for ~60% of household energy demand, any improvement here will significantly reduce the electricity demand.

I think that is as quantitative as I can get!  Population growth will add ~16% to the total required; standby efficiency improvements will reduce it by ~8%; use of LED lighting will reduce it by ~7%.  That is, these factors roughly balance out.  This leaves improvements in housing, where I can’t find any good estimates.

One concrete thing we can do is on labelling of devices.  When the EU energy label for “cold” appliances was introduced in 1999, it improved the average efficiency of these by 15% in 15 months (see here, box 4)!  Introduction of similar labels for TVs, computers and other items should have a similar noticeable effect.

In summary, I think I’ll stick with my initial estimate though it is fraught with uncertainties.