Information technology has been both a hindrance and help to the environment -- on the one hand, dematerializing commerce and increasing efficiencies; on the other, becoming a voracious consumer of energy. Indeed, today's biggest energy gluttons aren't necessarily steel mills and auto factories, but rather the Googles, Amazons,and eBays of the world. Their fast-proliferating data centers can use as much electricity as a small city. Energy use is both an economic and environmental liability for the IT industry and, to the extent its energy appetite is stressing electricity grids around the world, it may become a social liability,too. One study found that unless the IT industry starts taking advantage of power-saving features and build with an eye toward energy efficiency, the global impact of IT will eclipse the total emissions of the United Kingdom.

The greening of IT has become a huge business opportunity, as companies find ways to consolidate and optimize operations in ways that provide multiple benefits: lower energy use,equipment costs, real estate, and personnel -- all while maintaining or growing their data processing and storage capacity.

For example, Hewlett Packard last year completed an audacious revamp of its global IT platform, shaving total spending from about 4 percent of its annual revenue to below 2 percent -- a savings of about $1 billion a year. The savings come partly through consolidating its network of data centers dramatically -- going from about 85 facilities to just six and cutting energy consumption by 60 percent -- even while its overall computing capability more than doubles. And it's not just the big guys. A survey by IDC found that even the smallest businesses are undertaking green IT initiatives.

All of which is creating a boom market for energy-efficient computers, servers, printers, routers, and dozens of other products, not to mention software and services aimed at consolidating multiple machines -- "virtualization," in geek-speak.Eco-labels like EPEAT and Energy Star are helping buyers identify products that meet efficiency standards, and some companies are creating their own labels. Fujitsu announced its own certification, asserting that existing labels are not broad enough. Its label goes beyond energy to include whether products are made halogen-free and without brominated flame retardants and polyvinyl chloride,among other things. Verizon created itsown efficiency metricsto push equipment manufacturers to make products such as broadband, data center, network, and customer devices 20 percent more energy efficient.

This is one industry experiencing a "race to the top," in which companies are both cooperating and competing to create high standards of performance. The Green Grid, a global consortium of IT firms, proposed "miles-per-gallon" type standardized metrics that allow firms to compare the efficiency of competing servers, storage systems, and networking equipment. The European Commission issued a detailed set of efficiency benchmarks to guide IT managers as they build new data facilities or upgrade existing ones.

The potential is significant if the green IT industry gets this right: A McKinsey report says green IT can help eliminate 7.8 metric gigatons of greenhouse gas emissionsannually by 2020, equivalent to 15 percent of global emissions today.

Tomorrow: Building Energy Efficiency Rises Again