Energy Saving Strategies for the Acton Home Owner
By Karl Coumou
December 7, 2007

All of us are have a vital interest in reducing the use of carbon-based fossil fuel for home heating and electric power generation. To this end, our neighbor to the east, the Town of Concord, has established a Sustainable Energy Committee to promote the use of energy efficient technologies in their town. It is time for Acton to establish a similar committee at a formal level. The purpose of this article is to make a few suggestions on energy saving strategies from which any homeowner can benefit. In the order in which various options should be implemented they are:

1. Conserve energy by changing habits (install a setback thermostat, buy fluorescent light bulbs, turn off unnecessary lights)
2. Conserve energy by changing the “efficiency” of the dwelling (add insulation, replace windows, install a high efficiency furnace, buy energy star appliances)
3. Apply alternative energy technologies (solar, wind, geothermal, biomass, micro-CHP)

This article focuses on alternative home energy options, the third and most complex of the strategies listed above. Although much talked about in the press, alternative energy options that are not available now or within the next ten years include: hydrogen fuel, fuel cells, electric storage, or hydro power (unless you’ve got a river on your property). So, what is available today or in the near future?

• Solar photovoltaic, or electricity directly from sunlight. Grid connected. About 4 kW rated capacity is required to supply 50% of the annual electric need of an Acton household. The installed cost ranges from $30k to $40k. Benefits are: no fuel cost, zero carbon emissions, incentives available to reduce cost by up to 50%. Challenges are: siting, aesthetics, long payback of investment, and it works only when the sun shines. At the moment there are about 20,000 systems in the US, mostly grid connected.
• Solar thermal heating. In our area it is used mostly for heating of domestic hot water, not for space heating. Installed cost ranges from $7k to $9k. Typical savings $200 to $300 per year. Benefits are: no fuel cost, zero carbon emissions, good incentives in place. Challenges include siting, long payback, aesthetics, small overall impact on energy use.
• Wind power. Grid connected. According to the Dept. of Energy, a typical US home that consumes about 720 kWh per month (i.e. an average of 1 kW for 720 hours, as many in Acton do) would need a turbine rated in the range 5 to 15 kW depending on average wind speed in order to make a significant contribution to the demand. A 10 kW turbine costs $32k. Wind power would appear to be impractical for all but a few suburban homeowners because of siting, aesthetics, and zoning regulations.
• Geothermal heating. In a New England home only the most efficient geothermal heat pump systems will make a difference in primary energy use and operating cost unless combined with on-site solar panels. This is because the fuel energy needed by the utility to produce the electricity to run the system amounts to 60% to 80% of the thermal energy taken from the ground. The impact on the carbon footprint depends on how the electricity is generated. Estimated cost is $20k so the payback is relatively long.
• Wood pellets. This renewable energy source for home heating reduces our dependence on imported oil. Burning wood pellets is carbon neutral in that these forest products would otherwise decay thereby producing the same amount of CO2. Modern, fully automated pellet home heating systems will become available in the US over the next five years. The technology developed in European countries like Austria is ahead of the US. The expected system cost is 2 to 3 times that of a conventional boiler or furnace.
• Micro-combined heat and power, also called small-scale cogeneration. This is the production of home heat and on-site electricity from the original fuel source. Micro-CHP systems are rated to produce from 1 to 5 kW electric power. They are normally grid connected but are designed also to produce power during outages thereby keeping the heat on. Depending on the technology used, a Micro-CHP system can run on natural gas or other fuel. One such system has recently come on the market in Massachusetts and uses a Honda natural gas fired internal combustion engine to generate the electricity. The installed cost is $8k above that of a conventional heating system. Benefits are: approximately 50% annual electricity savings, 60% lower carbon emissions per generated kW than at the power plant, incentives available from the local gas utility Keyspan. Challenges are: 5-10 year payback of investment.

If you wish to know more about any of the above technologies, please contact Karl at kcoumou@verizon.net.