Those claiming that relatively large scale wind turbines can prove viable in urban and industrial locations saw their argument strengthened this week as plans emerged for two high-profile urban projects.

Car manufacturer Nissan has confirmed that it is to add two more turbines at its plant in Sunderland, bringing the number operating at the site to eight.

The company said that the new turbines, which are expected to be fully operational next January, will ensure that its onsite wind farm provides up to six per cent of the plant's electricity.

"The six current wind turbines are performing really well in terms of cost reduction," said a spokeswoman for the company. "Since they were installed in 2005 they have generated 12,450MW, delivered £1m in cost avoidance and cut our carbon emissions by 5,500 tonnes."

She added that the company would continue to monitor the situation and would investigate the possibility of adding further wind turbines to the site.

The announcement comes as reports reveal the MPs are considering plans to install a 35m-high, 1.65MW wind turbine outside the Houses of Parliament. The feasibility report, which was seen by The Guardian newspaper following a Freedom of Information request, argues that despite the central London location and average wind speeds of just eight metres a second, the turbine could still cut the Palace of Westminster's carbon footprint by over seven per cent.

Critics of urban wind turbines have argued that they are little more than marketing gimmicks because disruption to the wind caused by buildings means they generate very little energy.

However, Alex Murley, small systems manager for the British Wind Energy Association, said that although it was harder to make the case for wind turbines in urban environments, they could still prove extremely effective.

"The fact is you can't generalise, there can be urban sites that are very good" Murley said. "Generally, you'd expect an urban location not to be as good as a wind farm on a gently sloping hill, but if you can get the turbine high enough you can tap into good wind speeds that will deliver impressive energy yields."

Murley added that companies should not immediately discount urban environments as possible locations for wind turbines, advising that they should assess the site using wind measuring equipment before making any decision. "If you can get an average speed over five to six metres per second, then micro turbines can deliver a good energy yield," he said.

Dale Vince, chief executive of green energy provider Ecotricity, agreed that urban locations should not be ignored as potential sites for turbines. The company has recently been involved in projects to install turbines at Ford's plant in Dagenham, east London, and the City of Manchester Stadium, and Vince has pledged to "push the limits" of where wind turbines can be effectively deployed.

Vince added that there was growing evidence that such turbines were also delivering cost savings to firms that install them. "Having or hosting a turbine makes sense for business on two fronts," he said. "One, it secures a long-term source of green energy; and two, it should cost less than they currently pay for energy."