Combatting climate change will likely require a multi-pronged approach to renewable energy generation. After all, it's not sunny or windy everywhere all the time. Geothermal energy, which harnesses the natural heat generated by the earth, can significantly shrink the carbon footprint of heating and cooling buildings. Those systems are currently just a small part of the HVAC market. But the Department of Energy wants to accelerate production by 10% a year. Rae Solomon at KUNC in Northern Colorado reports on how one geothermal project in the municipality of Hayden is progressing.