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.
