Asda is undertaking a raft of green measures as it moves towards the target set out by its parent Wal-Mart of becoming powered entirely by renewable energy.

This week, Asda moved a step closer to gaining planning permission for the first of six giant wind turbines at its Northampton depot.

Council officials voted 11 to one in favour of the development, which would stand 125m from ground to blade tip, a similar height to the Blackpool tower.

The two-megawatt turbine would produce sufficient electricity to power 1,100 homes and provide a significant amount of the power needs of the depot.

In January, Asda's application for a turbine at Falkirk was turned down on the grounds it would dominate the skyline and provide no tangible benefits to the community. But an Asda spokesman said the retailer had resubmitted its application for Falkirk and was awaiting decisions for Skelmersdale, Wakefield, Teesport, and Brackmills.

Meanwhile, Asda plans to roll out its scheme for reducing the use of carrier bags nationwide. It is currently half way through a 10-week trial at certain stores in the north, testing the effectiveness of keeping bags under the till and only making them available on request.

"It's not sustainable to keep throwing away billions of bags each year. That's why we want our customers to change the habit of a lifetime," said Claire Costello, Asda's anti-bags tsar.

Asda has also started saving fuel on its 800-strong fleet of home delivery vans with a new computer system. The Isotrak Active Transport System uses satellite tracking to calculate whether quicker routes can be taken and more efficient numbers of drops per shift can be carried out.

Asda's policy is to reduce energy requirements across the existing estate by 20% by 2012, and by 30% on new stores by 2010.