An Eco-logical Mind

The Prius Effect

I recently heard a report on NPR about 25 high schoolers in San Francisco who were given cell phones as a way of reducing their environmental impact! You might ask yourself, “how can a cell phone reduce someone’s carbon footprint?” You would think all that talking, talking, would produce more carbon dioxide, not less, especially if you count the heavy breathing created by teenage sexting.

But these phones had something that most mobile communication devices don’t – a built in sensor that takes a reading of your movement speed every 30 seconds and determines how much time each day you spend immobile, walking, riding a bike or traveling by car. At the end of the day you can calculate how your transportation choices have affected the planet.

Brilliant! It’s the Prius Effect in a new application.

If you’re not familiar with the Prius Effect, a quick sidenote. I may or may not have coined the term - I haven’t heard anyone else use it – but I’m surely not the first to recognize it. When I got my Prius nearly two years ago I was only getting about 37 – 40 miles per gallon, which is less than advertised. I started watching the consumption gauge to figure out what was wrong and presto! My mileage improved to about 45 mpg. The constant feedback of how my driving was affecting my mileage changed my driving habits. It became a game and now I’m much better at it – if I’m paying attention I can get around 50 mpg.

This is what systems thinkers call “a negative regulating feedback loop,” which is a high leverage way to change a system, in this case the system being the car and its driver. A thermostat which keeps your house at a desired temperature is a simple example of a negative feedback loop. So is a hangover!

As Dana Meadows wrote in her seminal article “Places to Intervene in a System” (Whole Earth, Winter 1997) “The ‘strength’ of a negative feedback loop depends on the accuracy and rapidity of monitoring, the quickness and power of response and the directness and size of corrective flows.” In the case of the Prius, the monitoring is constant, while the power of response and the size of the corrective flow both depend on the driver’s ability to optimize fuel flows.

This year at Greenbuild (the world’s largest green design conference), there were literally dozens of examples of the Prius Effect being applied to buildings. Most of them were some variation on gauges that show energy consumption - for each room in a hotel, for example, or the overall building in an office lobby. The gauges tell building users how their habits are affecting energy use, just like the Prius consumption gauge. Lawmakers are currently discussing requiring energy labels on buildings, so that future tenants would have that information as part of their selection criteria.

Ankrom Moisan, where I work, uses Building Energy Modeling during the design of a building to measure how various design strategies will decrease the building’s energy consumption – another example of a regulating feedback loop.

At their best, negative regulating feedback loops positively change behavior. The more we recognize the Prius Effect, the more creatively we can apply it for the betterment of the planet. How about garbage cans that tell you the weight of your weekly refuse? Product labels that tell you how much energy was used in their production?

I’d love to hear from you, dear readers, about other possibilities.