Had the proto-green architect Frank Lloyd Wright lived in the 21st century, he might have built something like the Natural Resources Defense Council (NRDC) offices in Santa Monica, Calif. Although framed by a century-old structure, the retrofitted downtown site now includes the latest and best eco-friendly features. Reflective roofing and hanging plants cool its surface. Light wells suffuse the interior. Sensors allow artificial illumination only when rooms have occupants. A smart air conditioning system ignores areas that are already cool. Solar panels generate a fifth of the building’s energy, and wind farms provide the rest. As a result, the building’s total energy costs are 44 percent lower than those of a comparable 15,000-square-foot office space. As befits the NRDC’s mission to protect the planet, its headquarters’ materials are also of the greenest caliber. Named the Robert Redford Building, its wood comes from forestry operations that meet the highest sustainability standards. Its paint and other materials emit almost no toxins. And its renovators recycled all but 2 percent of the waste they generated during construction. For these many environmentally friendly specs, the nrdc headquarters received a platinum rating—the highest possible—by the Leadership in Energy and Environmental Design (LEED) program. Created by…