Dare to Share:
The purported savings in greenhouse gas emissions (see endnote for one such assertion) are based on the gas not burned by not commuting by car. But in estimating net emission reductions a lot depends on where the telecommuter works when he or she is not in the office, on how he or she commutes to the office, and on the climate.
- If the worker would have commuted by shared transportation (carpool, bus, subway or the like) then his or her commute might have virtually no carbon footprint. The marginal emissions from one more rider are essentially zero. If he or she would have walked or bicycled--same answer.
- If the worker would have commuted by private car the footprint of the commute could be substantial, but would depend on the vehicle and the distance. (The average U.S. auto commuter travels about 15 miles to work, and so probably burns less than two gallons of gas per day commuting.)
- If a worker has to heat or cool his or her workspace when he or she does not come to the office (for instance if there would be no one home if the teleworker were not there and the heat or air conditioning needs to be used when the teleworker works from home) then there is probably a net increase in energy use for heating or cooling compared to when the worker is in the office. This has to be balanced against the carbon footprint of the worker's commute.
- A lot depends on where this telecommuting is taking place. In Boston in the winter heating an apartment for 10 hours might create significant emissions. In Oakland it might create virtually none. Air conditioning depends both on the climate and on the telecommuter's budget.
- If the telecommuter works from a coffee shop or other shared space, then there is no incremental heating or cooling emission, but there are some transportation emissions.
But if the teleworker avoided a 50-lbs-of-CO2 round trip commute (50 miles at 20 miles per gallon--see previous post) and doesn't have to additionally heat or cool his or her home while working there, the overall carbon (dioxide) footprint of the day's work might be reduced by 50 pounds. This could easily happen in the Bay Area. Or in Los Angeles if the worker didn't use air conditioning at home.
Elsewhere the net carbon footprint would be influenced by the time of year and local climate.
- In general the carbon cost of running a room air conditioner is several pounds of CO2 per day (1,000 Watt air conditioner running four hours = 4kWh, at about one pound CO2 per kWh--almost 2 lb in some places but only about 0.7 lb in California).
- The carbon cost of heating a home is higher. A home heated by natural gas could easily cause the emission of 20 or 30 pounds of CO2 per day during the heating season.
- Telecommuting in mild climates with long commutes reduces CO2 emissions.
- Telecommuting when it is hot or cold (and the worker lives in a home that is otherwise vacant during the day) with short commutes or public transportation increases emissions.
- Telecommuting when it is hot or cold with long commutes might result in little change in emissions.
1. The recent report The State of Telework in the U.S. (pdf here) says "The existing 2.9 million US telecommuters save 390 million gallons of gas and prevent the release of 3.6 million tons of greenhouse gases yearly." But it cites no source for this assertion and doesn't support it in any way. I have contacted the authors at Telework Research Network to see if they can clarify.
2. Considerations are different for the economy as a whole. If enough users of public transportation telecommute, for example, perhaps fewer trains would have to be run and savings could be significant.
This has been cross-posted to the SAP Community Network here.