Cleaning up in Kosovo

Above: The Kosovo B power plant

Kosovo B, a 2 x 339 MWe lignite-fired power plant, built by the power division of Alstom (now GE) in the early 1980s, is located 10 km to the north west of Pristina, Kosovo. The boilers were supplied by Stein Industrie, a subsidiary of Alstom. Unit 1 began generating commercially in 1983, followed by unit 2 in 1984. The power station is located some 6.5 km from a large open-cast lignite mine at Sibovac and the fuel is delivered to the plant via a series of conveyor belts.

Today, the Kosovo power plant is regarded as one of the most heavily-polluting in Europe, with NOx emissions currently running at 700-800mg/ Nm³ at 6% O2 and dust emissions fluctuating between 300 and 700 mg/Nm³.

With Kosovo having firm ambitions to join the European Union, a €74 million air quality improvement programme has been put in place, funded by the EU’s Instrument for Pre-Accession Assistance (IPA), to significantly reduce emissions of NOx to less than 200mg/Nm³ by implementing a firing system upgrade and installation of a selective non-catalytic reduction (SNCR) system. In addition, a new electrostatic precipitator (ESP) will bring dust down to 20 mg/Nm³.

These emission values for dust and NOx are required by the EU Industrial Emissions Directive (IED 2010/75EU) that Kosovo Energy Corporation (KEK) should fulfil by 1 January 2023 at the latest.

The clean-up project, financed by the European Union in Kosovo, was awarded to a consortium consisting of three companies.

Engineering Dobersek GmbH, from Germany, is the lead partner, with responsibility for overall project management, the pneumatic ash handling system and associated air supply. Hamon Thermal Europe SA, from France, will design and supply the ESP system, configured to have a collection efficiency of 99%. UK-based RJM International is designing and engineering the NOx reduction system, using its advance capabilities to achieve the 75% reduction in NOx emissions mandated by the EU.

Legacy issues

An additional challenge for the consortium on this project, is having to work with a plant that has some major legacy operational issues. For a typical European plant of a similar age, these would have been attended to as a matter of course, as part of the ongoing programme of planned maintenance. Needless to say, with a power station that was built during the regime of the Socialist Federal Republic of Yugoslavia, it did not have access to proper funding, or adequate technical skills, nor could it provide a safe working environment for maintenance crews.

Fast forward 40 years and we have a plant that is not just highly polluting, but because of the compromised operation due to historical reasons, cannot currently deliver original design capacity MWe into the grid.

The knock-on effect of these factors is that the consortium is having to work especially closely with the operator KEK, to investigate the critical elements of plant performance and to work collaboratively to understand plant shortfalls in performance which must be addressed to bring the plant capacity up to its original design while complying with the emission limits required by the project.

This is a complex process and the detailed design procedures and experience employed by RJM and its consortium partners in challenging retrofit projects of this nature are an essential element of the process to ensure project success.

The two units in Kosovo are both tangential fired and RJM has considerable experience of resolving complex emissions challenges with this configuration. For example, in 2011, it refurbished the 690 MWe AES Maritza plant in Bulgaria, which is also a tangential lignite fired plant.

Outage rescheduled

In Kosovo, the consortium was under a very tight 16-month timetable for conversion of the first unit, so various work streams were running simultaneously. Now with the global Covid-19 pandemic, the consortium, following discussions with the customer, has rescheduled the programme of work, so that the outage

for unit B1 will begin in March 2021 and the outage for unit B2 in March 2022. This means that during the winter months when demand for power is at its highest, the plant will still be generating.

Author information: Christopher Biggs, RJM International