More than 53% of executives at the UK's top 5,000 firms have admitted to being unaware of the mandatory CRC Energy Efficiency Scheme, which leaves the companies open to hefty penalties if they do not register the firms by September 30, 2010 and put a monitoring plan in place, according to a report by green IT consultancy Externus.

The CRC Energy Efficiency Scheme is a mandatory carbon cap-and-trade scheme targeting energy-intensive organisations not covered by the EU carbon emissions trading