Retailers have focused on using resources more efficiently, as this is a way to be more sustainable and to cut costs. In the article from Financial Times, Charles Zimmerman, vice-president of international design and construction at Walmart, the US retailer says: “Long before any of us anywhere in the world knew what sustainability meant, we were very focused at Walmart on energy efficiency. Just simply from the fact it’s our number two or number three operating expense in every market where we are in the world.”