Now, something quite like this can be made to happen with your well water, only it's heat, not cold, that you are trying to produce. No matter what is going on with the weather aboveground—never mind the nor'easter blizzard—the ground just 4 feet beneath your lawn's frozen surface will remain at a constant temperature, roughly equal to the yearly average air temperature in your area. In New Hampshire, this is about 50 degrees Fahrenheit, and the temperature will be constant hundreds of feet down. The water in any New Hampshire well, therefore, will be pumped out of the ground at about 50 degrees, winter or summer. Any liquid pumped into the ground will warm or cool to 50 degrees.
And here is where your refrigerator's heat-exchange technology comes in. Imagine you could pump out your 50-degree well water and run it through coils filled with compressed refrigerant, which, when decompressing through its outlet valve, cools the water to, say, 40 degrees, much the way your refrigerator cools milk. Imagine, then, that the warmed refrigerant, storing the captured 10 degrees in a (more or less) gaseous state, is recompressed into outlet coils, where it returns to its liquid state, and is thus forced to surrender its concentrated heat—which is blown out by a fan. If you use enough water, and wed it to a big enough compressor, heat-exchanging coils, fan, etc., you can generate as much as 120 degrees in the outlet coils—and can warm an average-size, well-insulated home to 68 or more degrees in the coldest of winter. Return the 40-degree water to the ground, and it will soon be warmed back up to 50 degrees.
Run the process over and over, and the whole, integrated apparatus gives you central heating. Reverse the process and the same apparatus gives you central air conditioning. The only cost is the electricity that runs the water-circulating pump and the refrigerant's compressor. The more your electric utility moves to renewable energy, the closer your home comes to being a zero-emissions building.
Capital Well specializes in open-loop systems, which draw water from the well and return the water to the ground. The advantage is in leveraging the hole that customers would drill anyway. Closed-loop systems—more like the systems you find in refrigerators—are also increasingly popular. They can be laid horizontally in a big yard, or vertically in a smaller yard, or sunk in a half-acre pond. And because the system is one continuous loop, the fluid can be some kind of refrigerant, like the antifreeze you find in car radiators, that cools more than water and eliminates the need for a well pump, thus increasing the system's life span and reducing maintenance.
With either system, for every one unit of energy expended to pump and compress, three to four units are extracted out of the ground. The Environmental Protection Agency has estimated that geothermal heat pumps can reduce energy consumption—and corresponding emissions—up to 44 percent compared with air-source heat pumps and up to 72 percent compared with electric resistance heating with standard air-conditioning equipment, making geothermal the cleanest and most cost-effective space conditioning system available.
Clearly, this technology promises to be a gain for the environment, but for Capital Well's customers, that is a secondary benefit. New Hampshire homeowners, typically heating 3,000 square feet, are a conservative, hard-edged bunch, and they endure the long winter any frugal way they can. They have to believe that the all-in cost of geothermal is attractive and the maintenance is painless. Otherwise, forget it.
The point is, geothermal's payback is (as they say in neighboring Massachusetts) a no-brainer. On average, the payback in the U.S. is about 12 years if the alternative is gas, five years if oil, and four if electricity. But for 3,000 square feet of new construction in New Hampshire, the payback is about three years for a gas or oil alternative, two years for electricity. Thereafter, the maintenance cost for heating and cooling is about $100 a month.
Last October, I visited the home of a Capital Well customer, Robert Wyatt, who lives just outside of Concord. The installation was under way; the home was being retrofitted after years with gas. Wyatt is in many ways the poster child for the kind of informed buyer Capital Well is counting on. He is a utility analyst for the New Hampshire Public Utilities Commission and has been following (and regulating) the gas industry for years.
"Five years ago, I was paying about $2,800 a year to heat my house with propane," he told me. "Today, this would cost $4,500, and the cost will rise with demand from emerging economies like India. Conservatively, I figure I'll be saving $2,250 a year with the new system. This means a seven-year payback. "
However quickly Capital Well moves from early adopters to mainstream customers like Wyatt, the company provides an unusually vivid case from which to draw some larger conclusions about the pace of diffusion of green technologies. The planet desperately needs them. But for any innovative product to spread quickly through an economy, it has to deliver a clear value proposition that both nests in an established technology and leverages the incentives in an established commercial ecosystem. Everybody would drive a hydrogen fuel cell vehicle if the fuel were a quarter the cost of gas, the car were only a couple thousand dollars more, and there were a hydrogen pump at every service station. But where are the incentives to build the car or produce the hydrogen if the local stations have no incentive to invest in distribution? Where is the incentive for service stations if no cars are on the road?
