
71Introduction to Sustainable Energy
© 2008 Taylor & Francis Group, LLC
Problems
1.1 The hallways of a three-story building in Denver, Colorado, use 600 lights per oor,
and each light is an incandescent bulb rated at 60 W.
a. Estimate the amount of energy that could be saved in August by turning the
lights on when the sun sets and turning them off when it becomes light.
b. Assuming that the power for the lights comes from a 30% efcient coal-red
power plant, estimate the amount of CO
2
that would be saved with this con-
servation measure. Assume that the chemical composition of the coal is CH
0.8
and that coal has a heating value of 29 MJ