The Cave Tour Power Chain

Power at Cedar Hollow Cave

1Cedar Hollow Cave offers guided tours. Electric lights help visitors see the cave walls, and electric fans move air through the tour path. The tour team wanted to learn where this energy comes from and what happens when the team uses more of it.

2The cave's utility electricity is made at a power plant that burns natural gas. Natural gas formed from ancient living material buried deep underground, so it is a nonrenewable resource. At the plant, burning the gas heats water. The moving steam turns equipment that makes electricity. Burning natural gas releases carbon dioxide and other air pollutants.

3Sunlight is another natural resource used at the cave. Solar panels on the visitor center roof change sunlight into electricity while they operate. The roof is already covered with pavement and buildings. A proposed hillside solar site would require clearing 0.5 acre of shrub habitat. Getting natural gas from underground wells and building pipelines can also disturb land.

4The team recorded two tours with the same lights and fans. A 2-hour tour used 8 kilowatt-hours (kWh): 6 kWh from natural-gas electricity and 2 kWh from the roof panels. A 4-hour tour used 16 kWh: 12 kWh from natural-gas electricity and 4 kWh from the roof panels. The longer tour kept the equipment running for twice as long.

5For a 4-hour tour, the team compared three plans. The current plan used 12 kWh from natural-gas electricity and 4 kWh from roof solar. Plan Roof would use 8 kWh from natural-gas electricity and 8 kWh from larger panels on the paved roof. Plan Hill would use 6 kWh from natural-gas electricity and 10 kWh from panels on the hillside.