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Finally-A Really Green Sensor!

January 16, 2009 By: Ed Ramsden


Ed Ramsden

Living near Portland Oregon, the new self-proclaimed Green Capital of America, one hears a lot about how the new environmentalism is going to save the planet, the economy, and our immortal souls—all at the same time. Our homes will be powered by clean renewable energy, we will all be driving electric or bio-fueled cars, and everything we buy will be made from recycled, eco-friendly materials. The only thing standing between our evil unsustainable present and this future eco-topia are a few minor technological breakthroughs. And more studies, followed by punitive laws, and barrels of pork from the public coffers to make it all to happen.

Similarly, portions of the sensors industry have also begun to catch the 'green bug', with a recent flurry of activity in new energy harvesting research and product introductions. Anyone, however, who has walked into the paint department of a Home Depot knows that green comes in many shades. For much of the recent green movement, I suspect that the predominant shade of interest is the one coming out of the U.S. Treasury Dept. Like many recent booms (dot-com, fiber-optic communications, and now housing), much green development going on today will serve mainly to transfer money from the pockets of investors and the government to the pockets of various hucksters and snake-oil salesmen.

Still, there are growing opportunities for sensors to make genuine and substantial contributions to conservation and the environment. As an example, consider the lowly thermostat used in your home's heating system (a temperature sensor). Simply upgrading from a bimetallic strip thermostat (the dumb sensor version) commonly used in this application to an automatic setback thermostat (the smart sensor version) can have profound effects.

The U.S. Department of Energy estimates that it is possible to save between 5% and 15% on one's heating bill by installing a set-back thermostat, and dropping your home temperature by 10°F–15°F for only 8 hours a day (presumably during heating season). Saving perhaps 10% on your heating bill is nothing to sneeze at; in northern climes, this would typically result in a payback period for your new thermostat on the order of weeks. When one considers what would happen if everyone made this change, the results could be staggering. In 2001, U.S. household energy consumption for space heating (natural gas, electric, oil, and LPG) was estimated to be equivalent to approximately 4.6 quadrillion BTUs. If one out of every four residential customers put in a set-back thermostat, and programmed it appropriately, this could result in a potential energy savings of 2.5%, or 115 trillion BTUs. Numbers with a lot of zeroes can be hard to wrap one's head around, especially in abstract units. Another way to think of 115 trillion BTUs is as 33.7 billion kWH of electrical power. Still too abstract a number? Well visualize this as either:

  1. 8 new 500,000 kW power-plants running at full capacity, 24/7
  2. 1500 new 2.5MW wind turbines (the really gigantic kind) running at full capacity, 24/7

This represents tangible and substantial benefits, without waiting for some new super technology that is always 5 years and billions of dollars in the future. What's not to like? The challenge isn't the technology, it's getting people to actually upgrade.

A similar challenge (in a different arena) occurred over the past year. With the switch to digital television broadcasting (DTV), it has become necessary to either run out and buy a new TV set, or buy a DTV converter box if you should wish to continue to receive over-the-air television. The federal government decided that forcing people to shell out fifty or sixty dollars by February 2009 was not in the public interest and instead implemented a coupon program. Upon request, the feds would send you a coupon worth $40 to buy a converter box allowing you to continue to use your old TV set. Perhaps a similar program, subsidizing part of the cost of upgrading to an automatic setback thermostat would make sense. Such a program would have numerous benefits:

  1. Reduce people's heating bills
  2. Reduce U.S. dependence on imported energy
  3. Help improve the environment by reducing carbon emissions
  4. Make us all feel warm, fuzzy, and ecologically-correct

And perhaps the number one benefit is that if the political will existed to drive a program like this, all of the substantial above-mentioned benefits could be realized in the next two or three years, for modest levels of public and individual investment as opposed to many current eco-topian fantasy programs where many studies will be made, and much money will be spent, but the promised green nirvana will always remain sometime out in the future.






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