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ZERO means so much

Last week, and only four days apart, two major league baseball pitchers performed the rare feat of throwing a zero hitter. Their performances – and the publicity they generated – proves the power of zero to capture the public’s imagination (as well as a certain victory).

Getting to zero is the elusive –  yet achievable –  holy grail in many arenas. Sometimes it is achieved – like last winter when Nissan rolled out its zero-emissions, all-electric car, the Leaf. Sometimes it is an ideal, tempered by political or technical limitations, against which to measure progress (or lack thereof)– zero nuclear weapons, zero destruction of rainforests, zero national debt.

Against this backdrop of zero achievement, I introduce you to the Zero Net Energy (ZNE) house – as rare today as a no-hitter, but much more readily achieved by most Americans. The ZNE building is to global warming what a no-hitter is to the winning team – an effective but also highly symbolic accomplishment that builds momentum towards the larger goal, but ultimately is meaningless unless the entire team performs consistently.

A ZNE house extracts its energy needs from the power grid like yours does. But then it “pays back” the grid with energy deposits from renewable sources generated on the premises. By year’s end, it has thus produced as much energy as it has consumed.

Half our nation’s energy is gobbled up by buildings each year. ZNE is one path to greater energy independence and reducing carbon emissions. And if some buildings generate more than they need, they can sell their excess (via the grid) to the underachievers. As ZNE capacity increases, coal-fired power plants can be retired.

 

"By year’s end, it has thus produced as much energy as it has consumed."

 

"[...] its larger goal is to demonstrate the kind of smart stewardship we will need to practice to achieve that much larger, more elusive goal – the Zero Net Energy Nation."

Going ZNE requires you to take the long view, because the investments are substantial. But you can take them one step at a time, adding the most expensive component last. If you never get to that step, you’ve still vastly reduced your energy bills and carbon footprint. Here is how to throw the energy equivalent of Verlander or Liriano’s “zero-hitter”:

STEP ONE – PLUG THE LEAKS. You could keep your drafty, inefficient house heated by expensive electricity and still be a “zero net energy” home, if your solar photovoltaic array is big enough! But that would be a lazy and expensive approach that doesn’t address the underlying problem. There’s only one effective way to plug the leaks if you’re considering a retrofit – create an airtight, highly insulated thermal envelope around your conditioned, ventilated living space. Add high-performing windows or insulated interior shutters, and airlocked vestibules to limit heat loss. And finally, when it comes to energy savings, it’s not enough to just walk the walk. You’ve also got to caulk the caulk, with or without a federal “Cash for Caulkers” program.

STEP TWO – REDUCE USE. Once you’ve plugged the leaks, reducing demand for energy comes down to two words – Take Charge. Insulated shutters don’t work if you don’t open and close them. Lowering the thermostat doesn’t work if you won’t put on a sweater. And you can choose a solar clothes dryer (a rack and a line), or not. You can design (or redesign) your living space to close off seldom used rooms in the winter, and you can “zone” bedrooms separately so they’re not conditioned for the time you’re not in them. Finally, you can be an informed consumer and research each appliance. If your water is heated by the sun, there’s no guilt in the 15-minute shower.

STEP THREE: SIP, DON’T GULP. In choosing the equipment you require to generate the little heat you still need, you’ll find that performance varies greatly. Heat pumps bank on the earth’s insulative powers (“ground-source”) or extract heat from the air (“air source”). Both are very efficient, have reasonable payback periods and are now suitable for our climate. They work well with a ZNE approach since their electric pump can ultimately be fed with renewables. Solar thermal panels on the roof preheat large quantities of water. That will reduce your reliance on fossil fuels for hot showers or for hydronic heating.

STEP FOUR: GENERATE YOUR OWN. After you’ve plugged the leaks, reduced your demand, and established low-energy means of meeting that demand, you can produce that energy from a renewable source such as solar photovoltaic (PV) panels or a small wind installation. On a sunny (or windy) day, your proverbial meter spins backwards as the National Grid stores the surplus for you. You then get it back when your demand exceeds your on-site generating capacity.

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ZNE’s immediate impact is zero utility bills for you and zero carbon footprint from your energy habits. But its larger goal is to demonstrate the kind of smart stewardship we will need to practice to achieve that much larger, more elusive goal – the Zero Net Energy Nation.

Rick Hauser