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Exaggerated Claims

Page history last edited by Malcolm 11 years, 5 months ago

I am all in favour of serious efforts to achieve real and substantial reductions in carbon emissions, and I accept the arguments as to why this is urgent.  But I am not in favour of our chasing false goals.  So it seems to me that we need to account quantitatively for energy usage and carbon emissions, and we need to look hard at claims made.

In that context, I am sceptical about the overall carbon emission reduction claims made for electric cars.  Am I missing something?

Using published data for the current average carbon emissions at generation time of electricity supplied in the UK (around 500 gms CO2 per kWH), and assuming that:

1.      50% of the electrical energy purchased gets through the charging system, the battery and the motor to the driving wheels.

2.      Both an electric car and a diesel powered car of a similar size will need the same average power (say 40 DIN or 30 kW) delivered to the driving wheels to travel, for, say 1 hour over the same terrain.

In that time, the electric car will account for around 30 Kg of CO2 emissions whilst the diesel car will account for around 8 Kg of CO2 emissions.  Fuel costs to the consumer will be slightly lower for the diesel car.

For the electric car to compete on CO2 emissions, let alone get ahead, average carbon emissions at generation time of electricity supplied in the UK will need to reduce to below 125 gms CO2 per kWH, i.e. 100% wind or wave power.  This goal is some way off.

I am a member of Carrick U3A based in Cornwall.
Best regards
Ed Tozer

Comments (2)

Malcolm said

at 3:36 pm on May 21, 2009

Dear Ed,
Your skepticism is right in the context of the minor reductions in emissions being proposed in the short term.
I believe electric cars may make sense in the context of the massive 80% or more cuts we seem to need to reverse the warming and acidification trends we have started.
If we think of emissions being 3 roughly equal portions for residential, transport and industry then there are some very hard choices to face. I cannot see how deep cuts can be made unless all power is green. This is what Gore's "Repower America" proposes in 10 years and I think it is the right priority.
Without this, ground source heating does not make much sense and neither do electric cars, but with it we could almost eliminate combustion completely.
I would like to know how others see it.


Ed Tozer said

at 5:50 pm on May 21, 2009

The issue of incremental or radical carbon emission reduction is irrelevant. I think I’ve shown, using published data, that as long as we continue to generate electricity by burning carbon, we’re fooling ourselves if we think that we will reduce carbon emissions by substituting electric power. By doing so we’re actually INCREASING carbon emissions per kWH by at least a factor of three.
Look at the Parliamentary office of Science & Technology report on the Carbon Footprint of Electricity Generation, report no 268 Oct 2006 http://www.parliament.uk/documents/upload/postpn268.pdf
Ed Tozer

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