Solar farm


Over the last several years, Grinnell College has made significant progress toward reducing the College’s greenhouse gas emissions. Grinnell now has seven solar installations, ranging from 3 kW to 4 MW, as well as one 50-kW wind turbine. One-third of the campus’ electricity consumption is from renewables on or connected to campus. In addition, Grinnell College is continuing its conversion to geothermal heating and cooling, reducing electric consumption and eventually eliminating the need for the natural gas–fueled boiler plant. Lastly, our newest building, the Humanities and Social Sciences Center (HSSC), is by far the greenest building on campus. It consumes less than 25% of the energy consumed by a building built to code.

What are the most important sources of energy on campus?

Renewable sources provide roughly a third of the campus’ electricity; Alliant Energy provides the remainder. Alliant has made significant progress on renewable energy as well. In 2012, 72% of the electricity the company generated was from coal, while renewables represented only 18%. By 2025, renewable energy will account for over 50% of Alliant's electric generation, and coal consumption will have dropped by 70%.

Grinnell's second largest source of energy is natural gas. Pipelines entering the state from Minnesota, Nebraska, and Missouri deliver this natural gas, most of which originates in Canada, Texas, and Oklahoma. The majority of the campus’ natural gas consumption is in the boiler plant, which burns natural gas to generate steam that is then distributed around campus to provide heat and hot water.

Although the boiler plant is currently the largest source of heat, Grinnell has begun to convert to heating through decentralized hot water boilers rather than centralized steam. Natural gas will still fuel these boilers, but much more efficiently. In addition, by converting from steam heat to hot water heat, Grinnell has laid the groundwork for the ultimate conversion to geothermal. Currently, five buildings on campus use geothermal (ground source heat pump): CERA’s Environmental Education Center, the HSSC, the Admission and Student Financial Services building, the Osgood Natatorium, and the Preschool Lab. Eventually, Grinnell plans to convert all campus buildings to heat pump technologies.

What are some of the efforts Grinnell College is undertaking to consume energy more efficiently?

Most important, when designing a new building, it is critical to hire architects who are champions of green building technologies. When sustainability goals are integral to the design of a building, success is almost guaranteed.

Read about our green buildings.

Retrofitting older buildings is also important. Residence hall renovations are ongoing. When renovating residence halls, the College replaces all lighting with LEDs; triple pane windows replace old windows; building automation is updated, etc.

Students living in residence halls now receive live electricity consumption data through submetering. This will allow for experimentation with behavior changes as well as competitions between the residence halls.

What are the renewable energy installations on campus?

Pioneer Solar LLC

The College has signed a 20-year contract to buy all of the power generated by a 4-MW solar project located along 16th Avenue. This installation is tied directly to campus electricity distribution. This project is estimated to generate 6.3 million kWh per year, which is roughly one-third of the campus’ electricity consumption. The project includes bifacial panels (power is generated from the top and bottom of the panels), a single-axis tracker that will rotate the panels to best use the sunlight, and a 500-kW battery that will allow for reducing the College’s peak demand.

CERA Environmental Education Center Solar

  • 131-kW solar
  • Average annual production is estimated at 171,648 kWh
  • Wind power currently provides 25% of the building’s electricity
  • This solar installation would provide the remaining 75%
Solar Panels

Facilities Management Warehouse Solar

  • 73.44 kW
  • Installed in 2018
  • Average annual production is 78,384 kWh
  • Provides 70% of the building’s electricity

Old Glove Factory Solar

  • 50.32 kW
  • Installed in 2018
  • Average annual production is 60,709 kWh
  • Provides 14% of the building’s electricity

Facilities Management Offices Solar

Charging station
  • 19.5 kW
  • Installed in 2014 to maximize an expiring Alliant rebate
  • Average annual production is 25,504 kWh
  • Provides 18% of the building’s electricity

GAME House and Electric Car-Charging Station Solar

  • 17.68 kW
  • Installed in 2018
  • Average annual production is 19,818 kWh
  • Provides 100% of the building’s electricity

Grinnell College Preschool Solar

  • 3-kW system
  • Installed during construction in 2012
  • Average annual production is 3,900 kWh
  • Provides roughly 6% of the building’s electricity

CERA Wind Turbine

  • 50-kW wind turbine
  • Installed in 2007
  • Average annual production is 50,000 kWh
  • Provides roughly 25% of the building’s electricity

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