Super Bowl for the Earth

The pigskin may be brown, but game day is going green.  When the stadium lights flick on in Miami Feb. 4 for Super Bowl XLI, the world's most ballyhooed kickoff will be carbon neutral. In the past, the NFL has sponsored tree plantings to offset the hundreds of tons of greenhouse gases emitted during the event--from stadium lights and other fuel burners, like the buses that shuttle spectators around town. This year the league is partnering with alternative-energy provider Sterling Planet to use renewable-energy certificates (RECs) to promote the use of nonpolluting power sources. Lowering emissions, rather than simply offsetting them, would be the next logical play.

HOW THE NFL'S RENEWABLE-ENERGY CERTIFICATE DEAL WORKS

1  Electricity is produced An alternative energy supplier, such as a solar plant, above, or wind farm, generates several dozen megawatts of electricity. Unlike power from fossil fuels, this type of energy produces little to no carbon.

2 Then sent to a utility The output is sold to a power company, where it is mixed with electricity from other sources. To keep track of it, a REC is issued for each megawatt of renewable energy a utility purchases.

3 Certificates are sold Consumers, such as the NFL, can then pay for the RECs--in addition to their electricity bill--as a way of investing in renewable energy, which is generally more expensive to produce than electricity derived from gas or coal.

4 And the lights go on When customers--here, the NFL--flip the switch, the electricity is delivered, as always, by a local utility. In buying RECs, however, they have helped offset carbon emissions by resupplying the grid with green power.