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Key Objective: 3.1 Explore Options for 100 Percent Clean Campus Energy
The 2015 iCAP, chapter 3, objective 1 is "The Energy Generation, Purchasing, and Distribution SWATeam, in collaboration with Facilities & Services and topical Consultation Groups, will lead an exploration of options for 100% clean campus energy during FY16 and submit recommendations through the formal sustainability process."
The campus community has considerable intellectual resources that can be brought to bear on the future of energy generation, purchasing, and distribution. The Energy Generation, Purchasing, and Distribution SWATeam has formed consultation groups consisting of faculty, staff, students, and other interested individuals, centered around each of the most promising clean energy technologies. Over the next year, input from these consultation groups, together with the Utilities Master Plan, can inform the development of recommendations for moving to 100% clean campus energy.
Below we list the most promising technologies for use on our campus, around which the consultation groups have been formed. Because wind and nuclear energy will be more effectively purchased from off campus, these technologies are not included in this section.
Geothermal heating and cooling
As it appears that it would be difficult to directly and entirely replace our existing steam production system with a carbon-free equivalent, we must examine the electrification of our thermal energy production system. One very promising technology for this involves the use of geothermal heat pumps.
As an example of what can be accomplished with current technology, we consider Ball State University, which commissioned a large-scale district geothermal heating and cooling system in 2012. It uses large heat pump chillers to simultaneously produce chilled and hot water. The system has a design coefficient of performance of 3.8 for heating and 2.9 for cooling, meaning that for each unit of electric energy consumed 6.7 units of heat are moved. Ball State University is at almost the same latitude as our university, so similar systems could be evaluated for use on this campus. A district geothermal system would reduce the use of fossil fuels on campus, but would increase the campus average demand for electricity by about 18 MW over our current average demand of about 52 MW. The amount of GHG emissions associated with heating and cooling would then depend on the source of the electricity to run the geothermal system. By generating renewable electricity on campus or purchasing renewable energy from off campus, we could greatly reduce our GHG emissions both in the short and the long term.
An additional attraction of geothermal is the use of a hot water distribution system. A study of the benefits of a possible transition from steam to hot water thermal distribution was recommended by the 2010 iCAP, which suggested that this transition, either central or distributed, can yield considerable energy savings.
Air-source heat pumps
About ten percent of campus buildings are heated by steam but cooled by window air conditioners. If these were replaced by air-source heat pumps, each room could be both heated and cooled by the same unit. The required capacity of the heat pumps could be reduced by a deep retrofit of the building, including replacing the windows with high quality double pane windows, reducing the size of oversized windows, and adding insulation to the interior or exterior of poorly insulated walls. Rooms could be conditioned only when occupied, producing further energy savings. There would be no need for ductwork to distribute the cooled air which can lead to cost savings. As with geothermal technology, the amount of GHG emissions associated with heating and cooling these buildings could be reduced by generating or purchasing renewable electricity.
Biomass can replace coal for direct combustion, or replace natural gas if it is first used to create syngas through gasification or biogas through anaerobic digestion. In 2013, the University of Missouri commissioned a 100% biomass-fueled boiler in their combined cooling, heat, and power plant, initially utilizing waste wood as the primary feedstock. Eastern Illinois University installed a gasifier in 2011, but it is not yet working reliably. These example projects highlight two necessary conditions for the success of biomass: establishing a sustainable supply chain and utilizing a reliable technology.
Due to the large acreage required to grow enough biomass to meet campus energy demands, some fraction of the biomass would likely need to come from off campus. This could be in the form of dedicated energy crops or agricultural waste. One must take into consideration the energy cost of growing, harvesting, processing, and transporting the biomass. While burning the biomass is carbon neutral if it is regrown, the growing, harvesting, processing, and transporting steps release greenhouse gases if they involve fossil fuels or certain fertilizers. On the other hand, the growth of perennial biomass crops such as miscanthus leads to an increase in the amount of carbon stored in the soil; this sequestration of carbon in the soil may more than offset the emissions from biomass processing. As a result, the entire life cycle of biomass growth, harvesting, processing, and combustion may result in a net removal of carbon dioxide from the atmosphere.
Solar Photovoltaics and Solar Thermal
Solar energy is a proven technology that has become more cost-effective in recent years. There are some existing installations of solar photovoltaics and solar thermal on campus now, and some installations currently in the implementation process. A consultation group is working to identify the best locations for installation of additional photovoltaics on campus, and to help expedite those installations. Solar thermal is also being considered where appropriate.