Apr 30, 2009

A Winter’s Tale: My First Season With Micro-Combined Heat and Power

Boston’s home heating season came to an abrupt close in April and with it my experiment with a technology known as micro-combined heat and power, or MCHP.

The idea behind this and other so-called co-generation systems is to minimize wasted energy by generating two forms of it — electricity and heat — from a single source.

My system — called the freewatt — burns natural gas to create 1.2 kilowatts of electricity from an electrical generator. The heat from that combustion also warms the water in my home’s cast iron radiators and, incidentally, the hot water heater. (Larger, industrial sized co-generation systems can even harness heat to reduce cooling costs, using evaporation technology known as desiccant cooling — though the co-generation cooling systems are not yet scalable to residential use.)

Using the system from November through March, I saved $2,000 in energy costs over the same period last year. Much of that, of course, can be attributed to switching from oil heat to natural gas, but the MCHP unit also saved me $500 by generating electricity (power that I don’t have to buy from the grid) — and it produced fewer carbon-dioxide emissions.

By all means, residential co-generation is technology still in development. A 2008 report from IDC, the market research firm, noted that while the market for residential systems of this kind was “fast expanding” in Europe and Japan, in the United States, where MCHP (also known as micro-CHP) is still in its infancy, growth is slow moving.

Still, in the report summary, Nick Lenssen, the director of energy insights for IDC, said, “We expect to see micro-CHP systems gaining ground in the United States over the next five years, especially in the Northeastern part of the country, which manufacturers are targeting due to that area’s cold climate and more favorable regulatory policies.”

Marathon Engine Systems of East Troy, Wis., and Whisper Tech, a subsidiary of Meridian Energy of New Zealand, are among the very few manufacturers with MCHP systems in the American market.

ECR International, a heating, ventilation and air conditioning manufacturer in Utica, N.Y., is a third — and the one distributing the freewatt. ECR says it has “a couple hundred” MCHP systems operating in New England — including about 40 purchased by the Low-Income Energy Affordability Network of Massachusetts, which is funded by the commonwealth’s Renewable Energy Trust fund.

“I feel pretty positive about the systems,” says Bruce Ledgerwood, manager of the Network’s alternative energy program, which has also installed co-generation systems that use photovoltaic, geothermal and wind power.

Still, there are downsides. MCHP isn’t exactly cheap. The cost for my system, including installation, came to $24,880. Rebates from the local utility and other incentives brought my out-of-pocket expense down to about $20,000, but even so, any payback in terms of annual savings on my utility bills will take several years to realize.

Another caveat to the system: it only produces electricity when it is also producing heat. In the warmer months, or any time heat is not needed, electric power must be drawn from the grid.

Harvey Sachs, senior fellow at the American Council for an Energy-Efficient Economy, a Washington nonprofit organization funded by environmental groups, energy utilities and others, suggested that this was why MCHP is not for everyone.

“MCHP systems, in general, are a misapplication for most residences,” he said, though he added: “There are some exceptions. For example, if you have an old Victorian that’s hard to heat.”

That’s precisely what I have, and even after buttoning up the house with new storm windows and attic insulation, my old oil system — and New England’s chilly winters — combined for pricey utility bills. So far, that has made my MCHP experiment seem well worth the expense.

By Kevin Ferguson

April 29, 2009, 9:18 am


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