Abstract
The pulp and paper industry is an energy-intensive sector which the need for heat and electricity throughout the year makes an ideal user of cogeneration. This paper presents a survey of cogeneration plants installed in the Italian pulp and paper industry from 1986 to 2010 including the technologies installed and the size and the timeline of installations. The work, carried out in cooperation with ASSOCARTA (the trade organization of Italian pulp, paper and board manufacturers), examines 61 cogeneration plants, 14 of them in detail. The analysis involves 673.5 MWe of installed electrical power, accounting for 75.7% of the sector (890 MWe); the average plant size in the sample is 11.1 MWe, the Italian sector average being 18.2 MWe. Gas turbines coupled with heat recovery steam generators are the commonest technology in the low power range, with 35 plants found between 1 and 8 MWe. If combined cycles (commonly installed above 8 MWe) are considered, the cogeneration plants using gas turbines are 55/61. Our data show that from 1986 to 2010 nearly all plants worked with a positive PES (primary energy saving) index, using less primary energy compared to separate production of electrical and thermal energy. Only two plants had a slightly negative PES index, but the price of electricity and natural gas was such that they made a profit anyway.