BENTONVILLE, United States — Wal-Mart wants to make its most energy intensive products 25 percent more efficient in the next three years.

CEO Lee Scott outlined additional steps the world's largest retailer wants to take to improve its environmental footprint in a speech Wednesday. That includes strengthening environmental, social and ethical standards for its suppliers, some of whom could be paid more if they meet Wal-Mart's wishes.

"Our customers want products that make them feel good about their purchases," Scott said. "They want to walk into our stores and be confident that the products on our shelves are safe and durable. They also want products that are made in a way that is consistent with their own personal values."

The speech was designed to build upon the goals Scott described in 2005: using 100 percent renewable energy, achieve zero waste, and selling eco-friendly products. Among other announcements since then, the retailer has committed to only selling eco-friendly, high-concentrated laundry detergent and compact fluorescent lightbulbs, as well as measure the carbon footprint of seven product categories.

Scott said the company also would begin communicating the amount of energy required to make and use some of its energy-intensive products.

"Taking waste and non-renewable energy out of our supply chain reduces the amount of pollution and greenhouse gases our suppliers send into the atmosphere," Scott said. "And helping our customers buy more sustainable products and be better stewards of the environment reduces their own carbon footprint.

In his speech, Johnson also said Wal-Mart wanted to contribute to making health care more affordable by focusing on e-prescribing, electronic health records and helping managers manage pharmacy benefit programs.