Waste management company Energnist operates two waste incineration plants in the towns of Esbjerg and Kolding in Denmark. The plants together produce 805,000 MWh of district heating and 195,000 MWh of electricity annually.
The Esbjerg site is the larger of the two and was built in 2003. After it was opened problems began to appear with its original generator, which was not supplied by ABB. An internal inspection showed that the corona protection was burned in a number of places.
In 2013 Energnist commissioned ABB to perform an ABB Life Expectancy Analysis Program (ABB LEAP) assessment of the non-ABB generator. This showed it was highly likely that the generator would break down after only one or two more years of operation.
A sudden generator failure would be extremely expensive for Energnist, as the time needed to order, deliver and install a new unit would mean a long production stop. The company therefore ordered a replacement generator from ABB. This was delivered in mid-2014 but installation had to wait until a normal maintenance stop – and stops are only arranged once every 18 months.
The 30-day maintenance stop saw a lot of activity at the plant, with installation of a new gearbox and control system as well as the new generator. Up to seven suppliers had to work in a very restricted space in the turbine hall, and so it was vital that everyone worked to tight schedules.
ABB had only three weeks to install the 45-ton generator, which meant that every step had to be carefully planned. It was difficult to get the old generator out and the new ABB generator in to the building, so they had to be lifted using a big crane.
The new generator was successfully commissioned on time. It has a 25% higher output (25 MW versus 20 MW) and a higher quality corona protection system than the previous unit. It is a proven, quality product based on ABB’s long track record of providing generators for the energy industry. In Denmark alone, ABB has supplied generators to around 10 different energy plants.