Clean Energy
Success Stories
CERTs-Southeast: Clean Energy Resource Teams of SE Minnesota
Earthen Path Organic Farm is Powered by Wind, Sun & Horses
In 1976, Steven Schwen purchased a general store in the tiny village of Oak Center, MN in Goodhue County. The 1913 building had stood empty for 5 years. Schwen set up his woodshop and got busy bringing the store back to life. He purchased 13 adjacent acres of pasture and planted trees and market vegetables on them. He dreamed of a totally self-sufficient farm.
Now, 31 years later, the Oak Center General Store has become a hub of community and cultural activities. It is renowned for bringing nationally-recognized musicians to its winter folk music series in the upstairs concert hall and for hosting community forums on a wide range of topics. Farm produce and global handcrafted items are sold in the store. The successful farming operation, Earthen Path Organic Farm, operates a CSA and is an anchor at the Rochester Downtown Farmers Market. The farm raises vegetables, herbs, fruits, eggs, chickens, lambs and bedding plants.
Earthen Path has 5 acres of vegetables and 120 fruit trees on two acres. Everything is grown organically and sustainably, using primarily renewable energy sources - wind, sun, wood, and horsepower (draft horses, that is.) From the very beginning, Schwen has been investing in and improving upon a variety of renewable energy technologies:
A wood boiler heats water for all domestic hot water use. The fuel for the boiler is waste wood from a nearby sawmill and dead trees removed for neighbors.
Taking advantage of solar tax credits in the late 1970's, a solar space heater was installed to heat the 2nd floor of the store, which is used as a concert hall. There are three 4' x 8' panels, each with two layers of fiberglass glazing and a metal panel painted with flat black paint. Air in a plenum behind the panel is heated and a thermostat embedded in the plenum initiates a fan, which blows the warm air into the concert hall. This system was sufficient to heat the large concert hall space to 70 degrees, even on a very cold (-20oF to -30oF) sunny, winter day! The system performed efficiently for 15 years. It is still operational 30 years later, but the fiberglass has clouded from years of UV exposure and must be replaced.
Schwen's first endeavor with wind was a small, direct current 32-volt "Wincharger" turbine, mounted on a telephone pole. Power was battery-banked in 6-volt golf-cart batteries. This system powered the lights in the barnyard.
During the first Gulf War, Schwen installed a larger wind machine - a 12.5 Kw Jacobs alternating current turbine with a grid tie-in. The turbine generates an average of 500Kw per month but has generated as much1000Kwh, providing electricity for the farm operations and the coolers.
In 1991, Earthen Path Organic Farm constructed an off-the-grid greenhouse. The greenhouse enables the farm to start plants early for retail, to grow things throughout the winter, and it houses a repair shop. The building is 45 ft x 60 ft, including the 30 ft x 60 ft greenhouse. Direct current from six photovoltaic panels charge batteries using an Outback Power System and it is converted to alternating current by a Trace inverter. The batteries provide all the electricity for the building and its operations, including lights, an electric roto-tiller, and a table saw in the repair shop. Total cost for the photovoltaic system, batteries and inverter was $11,000. In addition, the greenhouse was further enhanced by capturing the heat that rises to the roof of the greenhouse . Fans pull the heat through pipes to gravel beds in the floor beneath the plants. The heat is captured by the gravel, then released through the night, maintaining constant warmth for the plants. The solar installations were made possible by grants from SARE, Sustainable Agriculture Research in Education and from the Experiment in Rural Cooperation.
For the past 25 years, Steven has farmed with a team of draft horses, two Percherons he acquired as colts. The three of them worked together until last year, when one horse succumbed to old age. He has resorted to using a tractor this summer, but plans to start a new team next year. Schwen says horses are more economical than tractors and he likes that they are a holistic system--horses can produce their own food and they produce valuable fertilizer.
Schwen's dream is to eventually have the farm produce all its energy needs and potentially be a net provider of energy. For now, refrigeration and transportation are the greatest obstacles to achieving that goal. Vegetables must be cooled immediately upon harvest and must be stored in coolers and everything must be transported significant distances to market. In order to tackle the refrigeration challenge, Schwen's next project is to build a super-insulated root cellar and ice house. Ice would bemade by freezing water in wood forms during the winter.
Then, if they could just develop vehicles that run on methane...
Earthen Path Organic Farm & Oak Center General Store Route 1, Box 52BB Lake City, MN 55041 (507) 753-2080