I just watched a webinar about Oberlin College's efforts to get to zero carbon heating and cooling for all of their buildings by 2025. They've installed a large solar array to provide electric power for heat pumps. They are installing 846 bore holes for a large array of geothermal heat for use with heat pumps in a "district" system. They are also installing resiliency features such as multiple points of control, so they can isolate parts of the system for future construction or if a building is damaged by a storm, etc.