Optimizing Renewable Electric Energy Generation on Minnesota Dairy Farms

Mike Reese, Renewable Energy Director

In September 2015, researchers in the renewable energy and dairy programs at the West Central Research and Outreach Center (WCROC) began working on a $982,408 project funded by the Xcel Renewable Development Fund.  The three-year project titled “Optimizing Renewable Electric Energy Generation on Minnesota Dairy Farms” builds off previous research in which energy efficiency improvements and clean energy systems have and are being installed within the WCROC dairy.  Past research has been geared towards auditing energy consumption, installing and testing energy efficient milking systems, and developing thermal energy production and storage.  This new project seeks to increase renewable electric energy generation on Minnesota dairy farms by establishing a model “net-zero” energy dairy parlor where the same amount of energy consumed is also produced on-site.

The project team will research effective methods to integrate on-site small wind and solar photovoltaic generation, conduct economic feasibility and life cycle analysis, and then disseminate the results through the web, regional meetings, and a hands-on statewide workshop and tour.  The team will design, install, and performance test an integrated, on-site generation system with 20 kW of small wind and up to 54 kW of solar PV nameplate capacity.  Through a leveraged project from the University of Minnesota, energy efficiency upgrades, control hardware, and conversion of thermal loads from gas to electric have been previously funded.   In addition, an innovative thermal storage tank combined with a heat pump has also been previously funded which will allow for time shifting of the proposed on-site wind and solar PV generation into periods of peak loads for the dairy and connecting utility.  Since wind generation occurs predominately at night during periods of low demand for utilities, the ability to use the electricity by operating heat pumps and storing the resulting thermal energy for later use (time shifting energy) will greatly improve the overall efficiency of the system for farmers and utilities.  In addition, Minnesota manufacturers will be supported through field testing and demonstrating their small wind, solar PV, and control systems.  

Assembled foundation

Over the next six months, the team anticipates the installation of two 10 kW wind turbines which will be mounted on innovative, self-raising monopoles. The wind turbine towers will use an assembled foundation that can be installed in one day without a poured concrete foundation (pictured right).  The tower can also be easily folded down for turbine maintenance.  This support structure has the potential to markedly reduce the cost of electricity produced by small wind turbines by simplifying the tower raising process and eliminating the use and cost of a poured concrete foundation.  The combination of integrated and optimized generation systems, innovative mounting system, and efficient storage of on-site electrical generation is anticipated to dramatically lower the cost compared with current stand-alone on-site renewable energy systems.

Finally, life cycle analysis will be performed on the conventional and new generation systems within the dairy as processors, retailers, and consumers are increasingly demanding “green”, low-carbon footprint products.  Ultimately, this project will provide dairy producers with critical performance information, best management practices, and tools to meet increasing demands for carbon-neutral products. 

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