In fact, if retailers are smart enough, incorporating numerous green programs in their projects can get half an entire project paid for through tax incentives alone, said Scott Bearse, a director at Deloitte Consulting.

"The tax opportunities in the short term are unbelievable," he said.

Besides, the cost savings, retailers should be motivated by more scrutiny from government agencies in the future, once they identify how much of an impact retailers can have on the environment, Bearse said.

"We don't get too much attention yet from regulators," he observed. "In the future, we're going to play a very important role."

As it stands now, there is plenty of room for improvement to save money. Energy costs currently represent 1% to 2% of retailer sales, or $2 per square foot. For grocers, the cost is a bit higher, reaching $4 per square foot due to the need for bulk refrigeration.

Retailers haven't done themselves any favors in the past, building numerous buildings that might cost little to construct but waste plenty of energy, Bearse said.

"It's a constant invisible loss," he said. "We pay for that every day when we construct buildings that don't perform well."

J.C. Penney is one retailer that is upping its efforts to save energy in its stores, said James Thomas, vice president of corporate social responsibility at the Plano, TX-based company. It started implementing Energy Star guidelines and using related products in select stores in 2007. That number increased from four that year to 40 last year. The retailer's goal is to incorporate Energy Star in 200 of its 1,109 locations by 2011.

Thomas also said that the retailer opened its first LEED-certified unit, in Fairview, TX, in July, and currently operates nine solar-powered stores and one wind-turbine-pushed location, in Reno, NV.

Deliotte's Bearse stressed that there are many simple things that retailers can do to save energy, and in turn, save money. Forklift charges needn't be plugged in when they're not in use. Though it's more convenient to keep freezer doors open, it also wastes energy.

"It's not very hard to walk into a store and find enormous opportunity," he said.