Box 1. Look, no carbon!

Two US labs have gone further than just using efficient energy, and have become 'carbon neutral'. The National Renewable Energy Laboratory (NREL) in Golden, Colorado (see below), and the Robert Kerr Environmental Research Centre in Ada, Oklahoma, think that they are the only labs in the world to have reduced and offset their carbon emissions to zero — blazing a trail for others to follow.

NREL, which researches everything from photovoltaics to biomass energy, has just completed its first carbon-neutral year by balancing its power use and emissions generated from staff flying to conferences and commuting to work with various energy-saving initiatives and offsets.

The lab uses ethanol-fuelled vehicles and has designed or refitted its buildings to Labs21 principles (see main story). It also uses energy generated from its experiments to power the facility, although this accounts for only about 5% of the lab's needs. "If we can capture power — like on our wind experimental site — then we will use it," says Robert Westby, who oversees sustainability at the facility. But the experiments are experiments first, practical generators second.

Burning tree thinnings from the nearby forest, NREL should be able to generate as much as 20% of its own energy this year, Westby estimates, thanks to a plant being paid for, designed, installed and operated by a private company. "The private sector sees that it can make money doing this," explains Westby, "so the lab doesn't have to make the investment."

The Robert Kerr lab, which does mostly groundwater research, decided to go 'zero emission' in April 2005. Like NREL, the lab supplements energy-efficiency measures and renewable-energy sources with the purchase of green-energy certificates — though travel is not offset. The 1960s lab has replaced its former natural-gas use with a 'ground-source heat pump'. A series of wells (also run as a public–private partnership) tap into the ground's constant temperature, cooling the lab in summer and warming it in winter. A variable air-volume system also reduces the amount of air and electricity required.

 P. CORKERY/NREL/DOE

Zoë Corbyn