EnviroStats!

The “car” is a popular CO2 energy conversion unit, but it’s so huge and is only useful for mass energy use or massive energy use from one source! Here is a more practical system to put things into context.

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The computer is a good small context unit.

1 kWh per day (Treehugger.com and other sources)

1.55 lbs or .705 kg of CO2 per day (Energy Star)

365 kWh per year or 566 lbs (257 kg) of CO2 annually, taking 0.049 cars off the road.

There is no peripherals like monitors and printers since way too many factors contribute to a huge value range if one calculated such a thing.

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The fridge is a good medium-small unit.

3.79 kWh per day (Union of Concerned Scientists, quoted per year)

5.87 lbs or 2.67 kg of CO2 per day

1,383 kWh per year or 2144 lbs CO2 (974 kg) annually taking 0.18 cars off the road.

The fridge takes up 11-14% of household energy consumption so it’s practical for a lot of every life things (US Dept of Energy says 14, NRCan says 11 - probably colder in Canada so more energy consumed per house so bigger base in Canada).

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The tree is a good medium unit.

17 kWh electricity generated from fossil fuels absorbed per year (from data just below)

26 lbs or 12 kg CO2 absorbed annually (United Nations Environment Programme, UNEP)

Trees are so different in their CO2 absorption abilities, and varies over their life times individually, that it is almost ludicrous to get an “average” tree. However, UNEP endorses this stat so let’s hope they’ve done their research since the source is not known to me.

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The home is a good medium-large unit per day.

Canadian home at 34.5 kWh/day or 2.0 trees/day or 739 trees/year, based on fridge value and % above.

American home at 27.1 kWh/day or 1.6 trees/day or 581 trees/year (158 trees difference to Cdn value)

Weighted average, 10:1 US to Can population, would be 27.7 kWh per day (1.6 trees/day, 595 trees/year)

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The car is the big unit, but only because it’s a per year stat.

11,560 pounds or 5,255 kg CO2 per car per year (Energy Star)

438 trees a year

0.74 homes per year

CO2 from cars is direct, whereas homes consume energy indirectly from electricity from fossil fuels, or burn logs to produce CO2 directly.

Minh Tan, Envirostats author