Building Operations Manager, Grinnell Mutual Reinsurance, Grinnell, Iowa

Utility and Customer as Green Energy Partners

At Grinnell Mutual Reinsurance in Grinnell, Iowa, BOC grad John Guthrie works as building operations manager for the company’s headquarters, an office with two accompanying buildings totaling about 165,000 square feet. He is currently working on a two-year project with utility provider Alliant Energy to convert the heating system in the main office building and the two associated buildings, which were using # 2 fuel oil and LP respectively, to natural gas. The project was quite extensive.

While the payback was on the long side, something had to be done with the old boilers since they had reached their operational lifespan. But with oil prices fluctuating wildly, issues managing deliveries, spending money about every three years to maintain the two 15,000 gallon fuel tanks and making sure the oil was up to standard during extended periods of little use, the decision involved more than just a simple payback assessment. Add to this the negative of fuel oil’s high sulphur emissions, and it seemed to be time for a change to natural gas.

Grinnell Mutual is a half-mile south of the Alliant natural gas service area so a pipeline had to be installed, which represented about one-third of the project costs. In the spring of 2008, Alliant installed over 5,000 feet of two-inch coated steel pipe and 156 feet of three-quarter inch steel pipe, as well as three separate meters, one per building.

Guthrie and his team then set about the task of removing the old boilers for replacement. They were replaced with steel vertical fire tube package boilers with a water-backed combustion chamber equipped with high-efficiency turbulators. The heating system is closed-loop hydronic and the boilers were set up for redundancy to accommodate building requirements. Five Triad 900s and five Triad 300, which have efficiency ratings of 82.9% and 84.3% respectively, were selected as replacement units “It was a real challenge to get the system up and running before the 2008 heating season,” said Guthrie. “After installation we were able to achieve as high as 85.9% on the 300s and 88.5% on the 900s on our efficiency test.” He is especially pleased with the new capability of the building energy automation system to control the boilers and stage them in a way to get peak efficiencies out of the system.

The old boilers in the main building had an efficiency rating of about 75%. For the improvement in boiler efficiency ratings, Grinnell Mutual received at rebate of $6,965 from Alliant for the first year of operation. The first heating season with the new boilers yielded a savings of 4,313 therms over the old fired boilers. Guthrie calculates the annual savings for the main building should be between $8,500 and $9,500, depending on weather conditions and natural gas prices. For the two other buildings, the savings will likely be between $500 and $1,000.

Payback is estimated at ten to fifteen years, but this doesn’t include the increased reliability of the system and the easier access offered by natural gas. Also not in those calculations is the hugely significant reduction in emissions. “We look to save money and create efficiencies,” says Guthrie, “but we are also concerned with doing the right thing in terms of the environment, so that factors into our payback equations.”

Grinnell Mutual also participates in Alliant’s electric interruptible program (sometimes referred to as demand or peak power programs). Guthrie explains, “We have a 1000-KW generator that can power the entire facility. Usually in the summertime when demand is highest, we receive a call from Alliant asking us to go to generator power. For this, we receive interruptible credit that varies anywhere from $25,000 to $35,000 per year. This generator is also use in emergency situations like storms or power outages. As everyone knows, loss of power is costly to a company.”

Since the company is constantly looking for ways to improve efficiency, working with utility provider Alliant Energy, Guthrie performed an energy audit on the three buildings. As it happened, Grinnell Mutual had already done quite a bit to achieve energy efficiency. Guthrie will be doing more as the budget permits. He is looking at possible lighting change outs. Going from 32-watt to 25-watt would save about $6 per fixture per year on a two bulb fixture with 4’ lamps, and changing out U-bent fixtures to 2’ F17T8 bulbs where feasible could save up to $12 a fixture. In the meantime, Guthrie will continue to help run the buildings as efficiently as possible and will keep and eye out for any new technologies coming out. He views Alliant Energy as an ally in this, and why not? He found out about the BOC program from his Alliant account representative.