PORTSMOUTH – Preliminary analyses by the town’s Sustainable Energy Subcommittee report that Portsmouth would not only save money in utility costs by installing a wind turbine at the middle or high school but wind energy would also generate revenue through the sale of excess power back to the utility company.
In public workshops last week, the committee estimated that one 600kW turbine would produce $30,000 per year in revenue after generating a school’s electricity and minus the cost of purchasing, installing and maintaining the turbine. Once the bond is paid off, the revenue a single turbine could generate, at 2007 energy prices, would rise to $150,000 per year or about $1.6 million over 20 years.
The committee is studying whether wind energy would be cost-effective for the town. Its focus is to determine whether to purchase two 600kW turbines, one each at the middle and high schools, or one 1.5MW turbine. The committee chose to study if wind energy could reduce the schools’ electric costs since, collectively, they consume 62 percent of municipal energy use.
“The nut we’re tackling here is an opportunity to reduce the schools’ electric bills and use that money on educational requirements,” said committee chair Gary Gump.
National Grid reports that the high school and middle school each use about 950,000kWh every year. A 600kW wind turbine, with a life expectancy of 20-plus years and height of 327 feet to the top of the blade, is projected to generate about 1,500,000kWh/yr.
Taking data from National Grid that averages the high school’s energy consumption over the last three years of Wednesdays and overlapping it against a projection of what a 600kW turbine would generate – based on wind speeds measured at Portsmouth Abbey, Newport Airport and Raytheon – indicates that there would only be a short period when the turbine would not produce enough of the school’s energy needs, generally during peak energy use when the wind is not blowing as hard. At that time, the school would buy electricity at retail rate from the utility. But during early evening, when winds can be active, and night, when school electric demand is low, the turbine would still produce power to sell back to the utility, at a lower rate.
A 1.5MW turbine is projected to generate about as much power as the town uses: 4,240,000kWh, which costs the town roughly $580,000 per year. The committee says a 1.5MW turbine has the potential to “zero out” municipal energy costs but only if proposed legislation passes adjusting the rate at which users are credited for selling excess power to utilities. Currently, the retail rate at which users purchase power from the utility is much higher than the rate credited for putting power into the grid.
Resident Joe Faryniarz asked how turbines are maintained and whether it could withstand hurricane-force winds.
Mr. Gump, using Portsmouth Abbey’s turbine as an example, said turbines have a computer system that links their operation to a central office and also notifies if a maintenance problem occurs. In hurricanes, Mr. Gump said the turbine reaches a maximum speed then automatically applies a brake that turns the blades to face into the wind until wind speed drops.
Asked if the committee explored other energy sources, Richard Talipsky said the committee was “not looking for science projects” but a power source that paid for itself and generated revenue, if possible, which they narrowed down to wind energy.
After the workshop, Mr. Faryniarz said he supports the town installing wind turbines. It’s a “source of energy (that) is free,” he said, and “the more a town can look at ways to cut overhead, the better.”
The committee contracted Applied Technology and Management to study the economic impact of turbines at the schools and the available wind resources. The study should be complete by the end of June, and then presented to the town council.
The town has been approved up to $2.6 million in clean renewable energy bonds by the IRS, which allows the town to borrow at zero-percent interest. Though borrowing for the wind turbine project does not require a bond referendum, the committee though it prudent to give residents final approval.
“Our goal is that when people go in that voting booth, they’re really well-informed,” said committee member Richard Talipsky.
If the project is approved, the committee said it would place an order for a wind turbine, which can take up to 12 months to deliver, and then hope to have it producing power by August 2008.
By Jill Rodrigues
21 June 2007