Seventh Generation Energy Systems

Emerging technology

Dr. Fred Prehn knows an opportunity when he sees one. Nearly a decade ago, he took over a cranberry farm from one of his dentistry patients. The farm provides another source of income and satisfies Dr. Prehn’s sense of adventure. When his son suggested that he look into renewable energy, Prehn began to think about how to use the cranberry farm to include a second harvest - electricity.

After a site assessment, he began his research and found that the most promising turbine was manufactured in Canada. The Energie PGE had a long track record of steady reliable production. Because Oakdale Electric coop had net-metering limits of 40kW it was important to find a model with a nameplate capacity below the limit.

After applying for both USDA Rural Energy and the Focus on Energy grants, Dr. Prehn placed his order for a 35kW Energie PGE wind turbine on a 140’ lattice tower in the Fall of 2008. For good measure, he included a small roof-mounted solar array in the project to make electricity on the sunny days, when the wind is less forceful.

Best Laid Plans

Dr. Prehn’s Farm is host to the Wisconsin Cranberry Growers Association Annual meeting, and the plan was to have the renewable energy systems installed in good time to showcase at the annual event.

Shortly after the wind turbine was ordered, the manufacturer was sold to a U.S. company and the entire schedule was thrown into a tail-spin. The purchase order made to the Canadian company was the only one transferred in the sale. Dr. Prehn had the option to get out of the agreement and shop around for another system, or wait until the new owners, Endurance Wind Power, could deliver his turbine.

While the new manufacturers got a handle on their process, it became clear that the delay would push back the installation a few months past the expected delivery date. Prehn chose to stick with the freshly named Endurance Wind Power G-3120, recognizing the opportunity to install the first of its kind in the U.S. He also new that the cost would increase substantially when the system was commercially available to the U.S. market.

Patience Pays

As a relatively new turbine and tower design, the Endurance G-3120 was not without its challenges. Foundation designs were delayed along with the shipping of the equipment. Seventh Generation worked along with Dr. Prehn and the management of Endurance Wind Power to secure all of the pieces necessary to bring the project to fruition.

Fortunately, Endurance Wind Power was prepared for the start-up of a new model and installation day came on a blustery December afternoon. Because the system was originally designed for a shorter tilt-up tower, the blades needed to be secured to the rotor while the Seventh Generation crew worked beneath the nacelle suspended by a crane. The lift of the nacelle and rotor were secured in place and ready for production.

After some initial interconnection glitches were worked out, the wind turbine performed well and both customer and Seventh Generation were happy with the technology, the process and the manufacturer.

A second Wind

With his feet wet in the project process, Dr. Prehn took a leap and decided to go ahead and purchase a second system. The investment in renewable resources makes good sense for the long-term economic viability of the cranberry farm. Incentives from Focus on Energy coupled with the Treasury Grant provided nearly 50% of the system cost, narrowing the window of return on his investment.

This time around the wind turbine and tower was ordered and installed within a healthy sixmonth window. Small wind is a maturing market. Pioneers like Dr. Fred Prehn get us closer to an energy environment where wind and solar energy systems are commonplace.