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Carbon Zero

6 Oct 2009

I'm playing with the CarbonZero household calculator which helps you calculate the greenhouse gas emissions for your household.

The calculator asks for either a monthly or yearly value for various consumption types:

• electricity/gas/coal (kWh, litres, kg)
• car travel (km or $)
• bus and train transport (km by type)
• planes transport (km by type)
• waste and recycling

The end result for September 2009 was: 172 kg estimated total CO₂-e emissions. They provide the ability to instantly buy offsets for $33.70 per tonne (1000 kg).

Then I added in data for every month going back to January 2004.

What is most useful about this exercise is the graph below. The spikes are almost all car related - holidays to see friends and relatives. In January 2009 we had a cash-flow crises so we went cycle touring rather than drive to family. Then in June-July a friend lent us their grunty car and we enjoyed the convenience - a lot.

Source: http://en.wikipedia.org/wiki/List_of_countries_by_greenhouse_gas_emissions_per_capita) 2005 data. Note that these country numbers are just the national total carbon emissions (including agriculture and industry, etc) divided by the population. I don't know what the average New Zealand household emissions are - so it's a bit unfair to compare them.

Limitations

There are a lot of qualifications needed at this stage:

• The calculator is easy to use - that means there are lots of average numbers in the formulas, eg
  • it doesn't differentiate between Meridians hydro electricity vs Genesys coal electricity - although, in reality the NZ grid is managed as a national entity so the electrons come from "the system" rather than a particular electricity retailer
  • it doesn't ask how much "stuff" you use/consume (so a vegan using a solar oven is equivalent to another person eating imported caviar every night)
• My transport data is mostly guesswork before Oct 2009. My electricity data is accurate) - I've factored in holiday driving trips but my bus and train usage is an educated guess. I'll go back and re-factor those number once I've got some more real data on what public transport I use now. Although I'm a bit softer than I used to be - I don't ride in the rain much these days.
• It took me a while to properly work out how to use the calculator - I know I've make some errors. Once you've paid to offset a months emissions you can't go back and edit it. [I've discovered you can delete a months data after it's offsets have been paid. Then you can create a new months data and pay to offset it again. You'd have to be pretty obsessed to do that though.]
• The tool doesn't have an option to buy more credits than you "need". It would be interesting to pre-pay for my 2010 emissions on 1 Jan 2010 and then live to the target. What should my annual household "ration" be?
• There is a school of thought that emissions trading is "a market based solution" and therefore a BAD THING (because the global economy depends on growth - and we have/will outgrow the planet). I'm inclined to think we need everything we can throw at the carbon emissions problem. So "market based responses" along with a whole bunch of other responses is what we need. Some of which are blindingly obvious; Reduce, Reuse, Recycle. It may be that it depends on your definition of the word market: "globalisation" or "how people swap/exchange things/services"?

I don't mind if the calculator is not perfect at this stage, and I don't mind that my previous data was lacking. It's a step in the right direction. The more I do this the better at it I'll get.

My next steps:

• I'll start collecting accurate transport data
• I'll pay for offsets back to 2005 over the next few months

Notes

I'm not sure where Mr Spratt got these numbers from - the Australian number doesn't match up with the IEA number in the chart above. And he doesn't say if he's talking about carbon emissions of CO2 equivalent emissions. I'd love to have a robust estimate of the global capacity to absorb carbon. I'll keep looking.