By walterbays on Aug 15, 2007
Today is another "curtailment day" here in San Diego. When SDG&E forecasts that peak demand will come too close to available electricity supply, they notify commercial customers who participate in their voluntary curtailment program. At Sun that means that more lights are turned off, and the air conditioning is turned down especially as we approach the peak energy usage time of day in mid-afternoon. Cal-ISO publishes near real-time charts of current and forecast energy demand.
For employees, and email notice of impending curtailment means it's a good time to come to work in shorts and sandals, aka "San Diego business casual." (It reminds me when I lived in Houston, Texas, there was a campaign to persuade businessmen downtown to stop wearing neckties. Open collar, higher temps, lower A/C, big energy savings.)
Another thing a San Diego curtailment day does is persuade more people than usual to work from home. That certainly saves energy for Sun, with more computers and lights powered off, and less human heat load on the A/C. For the city as a whole it could save electrical energy, not to mention the gasoline saved by the car trips avoided. For instance when I go home to work I don't need air conditioning (I don't even have an air conditioner) because I can just open windows to get a comfortable cooling breeze, whereas this office building has the usual sealed windows and needs air conditioning even on the most pleasant days. The Sun office and my home are both located near enough to the coast to get shore breezes.
But in certain cases might telecommuting cost energy city-wide? Consider a person who usually works in his Sun office cooled by a high efficiency air conditioner using a 4W Sunray. What if he works from home in the East county where temperatures are much higher, using a lower efficiency home air conditioner and using a 300W home PC? Sunray at home looks better and better.