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Writer's pictureDr Zeljko Warga, Slovenia

Speech Delivered at Workshop "Strategies for Emissions Reductions From the Indonesian Coal Fleet"

Updated: Jul 8


On behalf of the US Department of State (USDOS), the International Centre for Sustainable Carbon, ICSC (former Clean Coal Centre, click on image above leads to its website), London, UK held an event in Jakarta in July 2023. This 3-day event was supported by the Indonesian Ministry of the Environment and Forestry (MOEF), the Ministry of Minerals and Energy Resources (MEMR) and the Basel Convention Regional Centre-Asia (BCRC-Asia). Event included participation from relevant experts on emission reduction strategies. A Speech was delivered summarizing the past work done in this regards in Indonesia and introducing the cost-effective way to reduce emissions from coal fired power plants.


There is 2+ mil MW coal generating power capacity globally and growing even though being phased out in USA and EU. Each MWh takes nearly half of ton of coal to generate and each ton of burned standard coal releases around 1.8 t CO2. In total 4.5 billion tons of thermal coal is burned annually releasing more than 8 billion tons of CO2. Every year! That said every % less coal burned counts.


To know what goes on in a power boiler is to know how much heat is transferred in each boiler section, based on internal geometry, fuel consumption and operating parameters (pressure, feedwater and preheated air temperatures, O2 in flue gas etc.), and how a change in these affects boiler performance. Existing tools are complex and require a dedicated expert personnel to operate. The most inconvenient fact is these tools are not publicly available. That said plants don't use them unless urgent.


Plant Efficiency Toolbox constitute three items, a dedicated Boiler Heat Transfer Software, Boiler Operational Tuning and Boiler deposits removal technology.


A dedicated heat transfer software for boilers was developed with ease of use as main objection. It incorporates latest findings in heat transfer theory, fits requirements for daily use by engineers, handles all known power boiler designs and delivers accurate results quickly. Users can now assess an impact on boiler performance when operating paraments change (feedwater and preheated air temperatures due to clogging, coal change, coal blending, O2 in flue gas change, to name a most common issues plant operators deal with on regular basis). The convenient fact is that this tools is publicly available as and online application. It takes for an average boiler engineer with basic knowledge on heat transfer in boiler 1-2 hours to use it productively. Website: http://www.boilerdesignsoftwareonline.com/index.html


Innovative boiler operational tuning procedure was originally developed by ENEL, EU's largest Utility based in Italy. It was proven to deliver noticeable improvements in boiler operation resulting in reduced coal usage and consequently emissions and cost. It has been proven oved decades of use at multiple locations word-wide.


The software and boiler tuning procedure were demonstrated in 2016 on a 600MW unit boiler at Suralaya power station in Indonesia in framework of United Nations sponsored project. The plant is the largest in Indonesia with 4025MW (soon two 1000 MW units will be added), and is known as best operated in the country. This plant was chosen for a reason, namely if improvement was possible on a this well set and operated boiler, the potential for improvement exists everywhere. The data analysis showed there was indeed room for improvement. Heat transfer software was used to predict the tuning outcome based on identified combustion quality improvement potential, which it did with 90+% accuracy. It took a crew 24 hours to complete the job on-site.


Extrapolated to plant's 8 boilers, 4025MW in total a following operation improvement potential was revealed:

  • coal usage reduction: 0.225 mil t/y

  • CO2 emissions reduction: 0.43 mil t/y

  • SOx emissions reduction: 3070 t/y

  • further significant tuning potential was detected by the software

  • in EU with carbon tax in place at around $100/t of emitted carbon as of July 2023, carbon credits alone would fetch $12.7 mil/y

All that from 24h job.


Coal boilers are affected by deposits, which accumulate within hours. Heat transfer is consequently reduced. Predominant remedy is so called sootblowing, a blasting by steam, which wastes it. Consequently, more coal is burned to compensate for lost steam and reduced heat transfer. All mitigation techniques have something in common, namely there is room for improvement. That said there is a development, which addresses the issue as shown below in a self-explaining slides.







FS12 chemical injection animation.






Actual footage showing FS12 chemical effect on boiler tubes. Manufacturer: Therma-Chem International (https://therma-chem.com/)


Impact of wall deposits on coal usage and emissions remains unknown to the plants. So does effect of wall deposits removal techniques. A dedicated procedure is developed to address the issue. Plants can now assess the excessive coal usage and CO2 emissions as a consequence of wasted steam from soot blowing and reduced heat transfer due to wall deposits, and tract the effect of its removal on coal usage and CO2 emissions. The procedure for coal fired power boilers is available online for free: http://www.coalminder.co.uk/.



Wall deposition impact was assessed for Suralya power plant. Specific energy usage was calculated for 600MW unit boiler when it was new and clean, and for that boiler in operation. The difference was found to be 13% meaning this much more energy is needed to generate same amount of steam that reached turbine compared with when this boiler was new and clean. This is with wall deposits removal technique regularly applied. Boiler burns Indonesian coal, the best in the world. As high as 40%(!) was found at other sites using standard sub-bituminous coals. If 50% performance recovery is assumed the Suralaya power station would reduce its coal usage for nearly half a million tons a year, and CO2 emissions for around 0.9 million tons a year. That's on top of 0.225 million tons a year reduced coal coal usage and 0.43 million tons a year less CO2 emissions from the boiler tuning reported above. In EU carbon credits alone would fetch $27 million a year. All that with a solid boiler efficiency as calculated by standard method used by plants such as ASME PTC-4. This reveals why wall deposits' impact on coal usage and CO2 emissions remains unknown to plants. Now, this may no longer be the case.


Based on above the application of the presented expertise and technology to the existing around 37.000 MW coal power generating capacity in Indonesia as of summer 2023 could reduce country's thermal coal usage in excess of 8.3 million tons a year and CO2 emissions more than 15 million tons a year. Every year! As Indonesia as of 2023 has around 12.000 MW coal power under construction with some 14.500 MW planned there figures will increase accordingly.


The innovative so called PET, Plant Efficiency Toolbox, consisting of boiler heat transfer software for engineers, boiler tuning expertise and boiler anti-wall deposits technology is developed for coal power. Its application has a proven potential to significantly reduce plant's coal usage and CO2 emissions. It offers a solid and quick payback, there are no negative side effects, no boiler modification and shutdown are needed to implement and it's quick to implement to immediate and lasting effect. Financial gain from the reduced coal usage can assist in financing plant's emissions reduction strategies (Mercury, SOx and NOx). A way to reduce emissions and making investment money in process with immediate availability.



Dr Warga delivering the software-related Speech part.


Mr. Yunus of Kuala Lumpur, Malaysia delivering boiler deposits removal chemical-related Speech part.


Group photo.

Group photo.








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