Wärtsilä Corporation was awarded a major power plant contract for an 84.8 MWe replacement and extension of an existing diesel power plant at Manisa in western Turkey. It involved the first Wärtsilä 50DF generating sets for a power plant installation, while Wärtsilä 34SG sets were added in the extension. The new plant allowed a change of fuel from heavy fuel oil to natural gas.
In 1999, Wärtsilä supplied a 54.3 MW baseload plant to Manisa with three Wärtsilä 18V46 diesel generating sets. It met the heat and electricity demand of Manisa Organised Industrial District (MOSB), one of Turkey’s largest such business centres. MOSB houses some 115 companies from a range of industries, including paper, electronics, furniture, chemicals, textiles and food.
Under the new contract, the existing diesel generating sets were replaced by three Wärtsilä 18V50DF sets, each having an electrical output of 16,638 kWe. In addition, four Wärtsilä 20V34SG generating sets were installed, each giving 8730 kWe. The plant is being supplied under an engineering, procurement and construction (EPC) contract.
The plant is having a high overall efficiency and is very flexible in operation. High energy efficiency is given by the use of waste heat recovery to supply hot water and steam to the industrial park. The total steam production capacity is around 40 tonnes/h at a pressure of 14 bar. Hot water is fed into the district heating system of the industrial park, with the heating network having a pipeline length of 6 km.
The generators delivers electricity through 34.5 kV transformers to the local grid of the industrial park. Excess electricity is also sold to the public grid at a price determined by the Turkish electricity authority.
Flexibility is given by the use of two sizes of generating sets and the dual-fuel capability of the larger generating sets. Whereas the previous engines burned heavy fuel oil, the new engines are running on natural gas which is piped to the site. The Wärtsilä 50DF engines are dual-fuel engines which have a pilot injection of a small quantity of light fuel oil to ignite the gas fuel. They can also switch over to operate solely on fuel oil in the event of an interruption in gas supply. The Wärtsilä 34SG engines are pure gas engines with spark ignition of the gas fuel.
When the engines are running on natural gas, the plant is able to meet the environmental regulations without using the existing deSOx system that was installed with the original heavy fuel-burning engines for removing sulphur oxides from the exhaust gases. The dual-fuel engines bypass the deSOx system when they are burning natural gas. Then if the operator wants to switch the 50DF engines to heavy fuel oil the deSOx is put back into operation.
The installation of the plant required careful organisation. The previous generating sets were replaced within a time span of seven months. However, it was necessary to exchange the sets while keeping two sets running at all times. The Wärtsilä 18V50DF generating were delievred in September 2004 and the Wärtsilä 34SG sets were delivered in January 2005. The construction time of the power plant extension was eight months.
The deliveries of the Wärtsilä 34SG engine type alone has already exceeded the 1000 MW milestone, which proves the success of this engine type in gas power plant applications all over the world. To date (2005) Wärtsilä has delivered more than 3.6 GW of gas and dual-fuel engines.