The initiative encourages operators or tenants of high rise office buildings to save energy, increase recycling and water efficiency and reduce paper.
The mayor recalled a time when green initiatives were regarded as something of a nuisance. Now he says they are in vogue.
"The businesses want it, the customers want it, the employees want it. Everybody really believes this is a win situation economically for everyone. We believe in a green technology philosophy that it's good for government and business and good for society as a whole," said Daley.
For the second year, Chicago will be a flagship city for 'Earth Hour' and join hundreds of cities worldwide by turning off the lights for one hour.
The city will turn off or dim lights at sites like navy pier and the sears tower on March 28.