AN energy firm has admitted it doesn’t know when construction of a dormant Teesside factory - which left 700 contractors out of work - will restart.

Air Products’ waste-to-energy plant at Billingham, near Stockton, will remain idle as the company focuses on a neighbouring sister site.

Work was halted on the factory, known as Tees Valley 2 (TV2), in November, when bosses cited a need to remedy technical issues on its adjacent development.

They added TV2’s standstill will allow the business to make sweeping changes, rather than “piecemeal” improvements, which could cause further delays.

A spokeswoman told The Northern Echo work is progressing well on Tees Valley 1 (TV1), which is providing jobs for hundreds of construction workers, and allayed fears TV2 may never being finished.

The first factory, based on Tees Valley enterprise zone land near the North Tees Chemical Complex, is expected to be completed this year.

Officials previously said the two sites would create 100 permanent jobs and generate energy for about 100,000 North-East homes every year, by burning thousands of tonnes of domestic and commercial waste destined for landfill.

The spokeswoman said: “The commissioning and start-up work on TV1 continues to progress.

“We have not yet set a timeframe for work on TV2 to recommence as all of our efforts are directed towards achieving full TV1 operation and we are aiming to have TV1 completed this year.”

She also dismissed fears TV2 may never be completed, adding none of the 700 workers, who accepted severance pay in the days after the suspension, were transferred to TV1, as the work was overseen by a sub-contractor.

She said: “Our plans are about getting the two up and running.

“It makes more sense to work on TV1 (and complete it), rather than make piecemeal improvements to TV2.”

US firm Air Products previously told The Northern Echo the North-East plants were crucial for its future.

Speaking in 2014, David Taylor, its energy business vice-president, said: “We know the North-East; it's not a new area for us and we like being here.

“As a company, we've been in the UK for more than 50 years and know this region from our chemical operations on the old ICI site.

“This is a business we intend to be in for the long-term and this is a massive project and one of the largest investments we've made.”