Electrostatic Precipitator Power Supplies - True Cost Investigation


Discussions about precipitator power supplies at Power-Gen will take place at various stands as well as in pre-arranged and impromptu discussions on the exhibit floor and conference area. Paul Leanza and Dan Holt of KraftPowercon have volunteered to help maximize the discussion value and activity. A recorded interview with them can be the foundation of some of the discussions.


Sessions: None of the sessions will directly address the precipitator upgrade question but Babcock Power has one speech which is tangentially relevant.


ExhibitorsCECO - AVC supplies precipitator controls. Doosan provides precipitator control systems. Hamon provides precipitators and control systems. R&R Beth provides precipitators and control systems. Southern Environmental provides precipitators and control systems.  Wood acquired Wheelabrator which supplies precipitators and controls.


Here are contacts who are volunteering to discuss  power supplies. They are  at the stands or walking the floor


Company Name

Last Name

First Name











Hamon RC





Hamon RC





Southern Environmental





Southern Environmental








KraftPowercon presented their line of precipitator control, power, and safety products in a recorded interview. It is accessed at  https://youtu.be/d_pVvdIYJHc.  The slides accompanying the presentation are shown at



Paul Leanza and Dan Holt discussed their product capabilities and how they have seen them applied effectively. The discussion of each new item and its technical merits continues to circle back to how to apply each effectively at best cost. This 52-minute interview provides good coverage of the options of supplies and controls which are available. It can be addressed by other suppliers as a reference point for hearing all sides of the issues.


Dan is a former pulp mill engineer. Paul owned a precipitator consulting company, which merged with KraftPowercon. Both demonstrated the process knowledge, which allows the company to provide solutions and not just products.


KraftPowercon offers all variations of power supply.  Dan and Paul explained that single phase TR sets are reliable and modest in cost. But they do not deliver the high efficiency needed in many applications.

Single-phase TR unit

      120 Hz current ripple

      Results in ≈ 35-45 % ripple voltage on an ESP load

      Voltage peaks limits the current into the ESP


The 3 phase TR set is more efficient but also more costly

3-phase TR unit

       360 Hz current ripple

       Results in ≈ 0.5-1.5 % ripple voltage on an ESP load

       30–40% higher current into the ESP compared to single-phase TR

Switch Mode Power supplies are efficient with low installation cost. Maintenance has been an issue with this technology being applied to ESPs.


High frequency SMPS

       24kHz current ripple

       Results in < 1 % ripple voltage on an ESP load

      30–40 % higher current into the ESP compared to single-phase TR


To rectify the problems with SMPS KraftPowercon introduced a version with features to make it more reliable.



SmartKraft DC


Oil Cooled

Air Cooled

12 IGBTs

4-6 IGBTs

Aluminum Tank

Steel Tank

Amplitude Control

Frequency Control


KraftPowercon also points to improvements in controls.



NWL is a major supplier of power supplies around the world. NWL states that its unique integrated design, places the power supply and control system on a common assembly. The NWL PowerPlus™ has been installed on precipitators in many different industries and applications throughout the world. This product is claimed to  provide the following benefits to its users:

  • Increased collection efficiency
  • Decreased kVA for the same amount of power applied to the field
  • Faster spark response with less wasted spark current
  • Higher Reliability
  • Significantly higher power factor when compared to a conventional TR
  • Lower initial installation cost
  • Reduced space requirement with integrated design
  • Able to facilitate buss and guard or cable for HV connection


B&W has supplied thousands of precipitators. The most common way to improve the performance of an ESP, wherever it is located says B&W is to boost its corona power. The relationship between specific corona power (watts/1,000 acfm of gas flow) and collection efficiency is well understood and is a common upgrade. Other ESP efficiency improvements are possible, such as reconfiguring compartment geometry, increasing plate area, or adding additional fields, although each upgrade usually requires replacing or upgrading existing power supplies. The best option is to select a power supply that can efficiently boost corona power output and maintain high operating reliability.

The single-phase power supply design has limited upgrade potential to meet MATS, so Babcock & Wilcox (B&W) began the process of identifying better power supply options. 

The increase in corona power from a low ripple power supply can be achieved with several different technologies (HFPS, TPPS, MFPS).

Integrating all components into one package (HFPS) has the advantage of the most compact configuration. This can have the disadvantage of placing the control section for the power supply in a harsh environment which affects service life and maintenance.

Providing a separate transformer and control cabinet (MFPS, TPPS) has the advantage of placing the electronic controls in a controlled environment and allows for duplicate sources of supply. This has the disadvantage of the need for a remote-control cabinet and larger size and weight.

MFPS and TPPS use passive cooling while HFPS designs require active cooling. The increase in components and complexity for active cooling increase cost and maintenance. HFPS designs provide low ripple at higher cost, lower reliability, but in a smaller, lighter integrated package.  MFPS and TPPS provide low ripple at lower average cost, higher reliability, but in a larger, heavier package with a separate control cabinet.

The HFPS, MFPS, and TPPS provide the lowest ripple voltage on an ESP load. A field test showed the TPPS produced an average 50% higher power in the ESP compared to the single-phase precipitator power supply. This suggests that like other low ripple power supplies, the TPPS can produce higher ESP collection efficiencies. More than 900 installations of TPPS have demonstrated reliability. The availability of all sections of an ESP allows plant owners to achieve maximum PM reduction

Capital cost is also a significant consideration in the selection process of ESP power supplies, and the differences are significant. For example, if the single-phase power supply cost is 1.0, then the relative cost for a like-sized high-frequency SMPS ranges from 1.49 to 2.31. A like-size low-frequency three-phase power supply’s relative cost is only 1.12 to 1.17.

The predicted reliability of a power supply is difficult to quantify. The reliability track record of the single-phase ESP power supply is excellent, and many installations have been in service for over 40 years. This is a reliability benchmark that low-ripple power supply designs must match. Anecdotal evidence finds that high-frequency power supplies have experienced a poor reliability record; although it has improved in recent years, it remains lower than for single-phase designs.

Field test results at Duke Power confirmed that the three-phase power supply typically produced 50% more corona power delivered to the ESP than from a conventional power supply (average three-phase power/average single-phase power) with low total harmonic distortion. The installation costs were on par with a standard single-phase power supply. There were no failures of the three-phase power supply during the six-month test run.


and   https://www.babcock.com/-/media/documents/resources/gated-content/br-1941.ashx?la=en&hash=ABB2C7B1FFAF56483BB8CDF68D2E29CEF3DD6A07


CECO is an exhibitor and will be displaying systems, dampers and precipitator controls. AVC Specialists brand Powercon™ 900 Automatic Voltage Controller is the latest of its precipitator Automatic Voltage Controller systems. It is designed to be a simple upgrade for  older models, as well as a replacement for most older competitor’s models.

With color touch screen display, and easy-to-use operator HMI, all functions can be controlled, edited, and troubleshot, without ever having to open the door, which can be a time-consuming problem at most facilities. the operator interface offers easy access to status, parameter settings, fault history, and tuning screen, including a built-in oscilloscope.


Hamon is an exhibitor and  arguably the world’s first supplier (Research Cottrell Precip for a cement plant 100 years ago) HR-C works with selected suppliers to provide advanced microprocessor controls and the latest in transformer/rectifiers and switch mode power supplies to maximize performance. So, they can offer third party analysis of the options.


Doosan is an exhibitor. Doosan Lentjes can rely on the experience accumulated in one of the largest precipitator databases throughout the world due to the fact that over 6,000 electrostatic precipitators (ESP) have been built to date.


R&R Beth

The company is an exhibitor and has supplied precipitators for many different industries in many locations of the world. It uses high voltage power supplies and its views on the options will be sought.

Southern Environmental

It is an exhibitor and part of  the SEI-Group comprised of three operating units:  Southern Environmental, Inc. Southern Erectors, Inc. and Thermal Systems Group. Internationally, SEI-Group has performed projects in Antarctica, Argentina, Bolivia, Brazil, Canada, China, India, Mexico, Qatar, Russia, Singapore, South Korea, Sweden, Taiwan and Thailand.  SEI started as a specialist in maintenance and repair of precipitators but started designing and building new precipitators some years ago. Its perspective on controls will be a valued addition.


Wood acquired Wheelabrator from Foster Wheeler. It is an exhibitor and also exhibited at  POWER-GEN Asia in September in Kuala Lumpur, Malaysia. It has been supplying air pollution control equipment for more than 50 years. Precipitator  projects have ranged up to 5 million cfm. Its views on power plant supplies will be welcomed due to its extensive experience.


True Cost Data from the Precip Knowledge Network - GE Example

The Electrostatic Precipitator Knowledge Network has lots of valuable information about precipitator supplies. Here is an example using GE as the subject. GE has a long history with electrostatic precipitators due to the acquisition of Flakt.  This European based company made improvements to precipitator reliability which were significant enough to change the market domination of Research Cottrell, Mitsubishi Lodge Cottrell and Lurgi.  The company introduced SMPS decades ago and has installed thousands of units.

There are a number of true cost factors for which GE has input.

One is the full scope responsibility for the precipitator design and even remote optimization. This can result in a 95% reduction in electricity consumption for particulate control along with reduction of particulate to 10 mg/Nm3.

Another aspect is capability in different geographical markets.  GE purchased Combustion Engineering (indirectly) and therefore is the supplier of many of the coal fired power plants in the U.S. and elsewhere. It has recent contracts in India and should be well situated to address the need to upgrade the 100,000 MW of precips which must meet new standards.

It has experience with various fuels including lignite. It has experience supplying SIR units for wet precipitators removing sulfuric acid mist. It also has experience with SIR in cement plants and pulp mills.

The ongoing true cost investigation analyses in each niche are supported by articles in the Precip Newsletter and articles in magazines such as Power Engineering.  Here are articles about SIR from previous Precip newsletters. Subscribers to the Precipitator Knowledge Network or Coal Fired  Power Plant Decisions can retrieve the full articles.

1. Advantages Abound with SMPS

... the mid-1990s, Alstom has supplied SMPS for ESP use under the trade name "SIR," which stands for Switched Integrated Rectifier. Note that some technical features that ...

Terms matched: 1  -  Score: 243  -  16 Oct 2007  -  URL: While the initial cost for a SIR unit is higher than for a conventional TR, roughly estimated at about €25,000 for a SIR compared to €10,000 for the TR, many of the installation costs for the SIR are lower. SIR is an all-in-one-box unit, including outputs for HVDC and rapper motors. This reduces design and engineering cost to near nil, and installation and commissioning costs are very low. Note that an Alstom thyristor controller for TR and rapper has a total of no less than 72 cable connection points and other vendors have similar designs. Although seldom are all connection points used, a large amount of cable connections need to be run, increasing costs for the TR versus the SIR.

Consider this example. If a greenfield SIR investment of €25,000 and the “advantage-SIR” profit is subtracted, the first year cost for a SIR will be about €8700. With an estimated profit of €2000 per year, a SIR will then have entirely paid for itself within about 4-5 years. Note that this comparison does not consider the cost for the conventional TR itself. The conclusion must therefore be that a SIR often pays for itself within the first year in a greenfield installation, and within several years for an upgrade.


2. Meeting Emission Reduction Challenges with Industrial ESPs

... use of high frequency power supplies — Alstom's trade name is Switched Integrated Rectifier (SIR) — is becoming a common method of improving the efficiency of older ESPs in ...

Terms matched: 1  -  Score: 237  -  20 Jan 2010  -  URL: http://www.mcilvainecompany.com/precip/subscriber/precipnl408/Meeting%20Emission%20Reduction%20Challenges%20with%20Industrial%20ESPs.htm

Consider the ESP collection efficiency improvements for two different industrial applications:


(1)   An integrated cement plant in the state of Victoria, Australia; and
 (2)   A pulp and paper plant in Kawreau, New Zealand.

 The cement plant in Victoria has a production capacity of 325,000 Mtpa. It is equipped with a rotary kiln with two ESP casings. A portion of the gas is treated through an alkali bypass ESP. There is also a clinker cooler with a capacity of 2100 tpd, which is also equipped with an ESP. This example focuses on the cement kiln ESP. It has two ESP casings, each with three fields. Each field is 2.5 m long x 7.25 m wide x 5.5 m high. The collecting electrode spacing is 250 mm and the total collecting area per casing is 1986 m2, recalculated to 300-mm spacing. One casing is equipped with conventional transformer rectifier (TR) sets rated 55 kV, 600 mA, while the other is equipped with SIRs rated 70 kV, 800 mA.



5. ESP Power Supply Upgrades Reduce SO2 Emissions Substantially

... HFPS), ESP controls and supervisory control systems. Alstom's Switched Integrated Rectifier (SIR) high frequency power supplies were installed. The SIR contains all the equipment necessary ...

Terms matched: 1  -  Score: 83  -  9 Jun 2009  -  URL: http://www.mcilvainecompany.com/precip/subscriber/precipnl401/ESP%20Power%20Supply%20Upgrades%20Reduce%20SO2%20Emissions%20Substantially.htm

Boilers 7 to 10 are 150 MW nominal. Boilers 7 and 8 are each followed by a two-chamber AAF/Fläkt (Alstom-modified) ESP. These ESPs have six mechanical fields and eight dual output T/Rs. The collecting electrode spacing is 12 inches, collector height is 35 feet, and the total treatment length is 55.7 feet, resulting in a total collecting area of 171,494 square feet per ESP.

Boilers 9 and 10 have a single two-chamber Fläkt ESP per unit. Each ESP has six mechanical fields, 12 dual-output T/Rs, and 24 electrical bus sections. The collecting electrode spacing is 12 inches, collector height is 35 feet and the total treatment length is 59.0 feet. The total collecting area is 181,843 square feet.

The scope for the Johnsonville unit 1 to 6 upgrade included high frequency power supplies (HFPS), ESP controls and supervisory control systems. Alstom’s Switched Integrated Rectifier (SIR) high frequency power supplies were installed. The SIR contains all the equipment necessary to support a single bus section with high voltage, and all the forms of regulators associated with this supply. The SIR comprises a compact T/R which weighs less than 230 kg in comparison to a traditional T/R weighing over 1200 kg. In addition to supplying high voltage, the SIR has integral rapper controls and rapper motor contactors. The modular design and low weight greatly simplifies installation.

The switching technology used in the SIR increases the power conversion efficiency. The total conversion loss for a SIR rated at 60 kW is always less than 3 kW, and therefore results in a shorter payback period. Because the SIR is symmetrically powered by all three phases of the mains, there are almost no mains disturbances. The Electrostatic Precipitator Optimization of Q (EPOQ) and Power Control Rapping (PCR) algorithm were also included in the SIRs specified for Johnsonville. EPOQ maximizes ESP efficiency by allowing for continuous optimization of each individual bus section. PCR reduces the ash holding forces during rapping by intelligently limiting T/R charging. On units 1 to 6, the total number of power supplies per ESP was increased from 6 to 8. The increased sectionalization provides reliability and optimizatio


6. Alstom Opens New Switched Integrated Rectifier Manufacturing Site in Beijing

... in Beijing Alstom' Thermal Services business has recently inaugurated its Switched Integrated Rectifier (SIR) manufacturing site in Beijing. With this facility Alstom aims to support Chinese power ...

Terms matched: 1  -  Score: 81  -  9 May 2013  -  URL: http://www.mcilvainecompany.com/precip/subscriber/2013 PRECIP/precipnl448/Alstom%20Opens%20New%20Switched%20Integrated%20Rectifier%20Manufacturing%20Site%20in%20Beijing.htm

8. Maximize ESP Dust Collection at Minimum Cost

... the ESP operation in a better way. With their switch mode power supplies (SIRs) added, the emission reduction usually begins around 50 percent. Some of the ...

Terms matched: 1  -  Score: 51  -  22 Jun 2010  -  URL: http://www.mcilvainecompany.com/precip/subscriber/precipnl413/Maximize%20ESP%20Dust%20Collection%20at%20Minimum%20Cost.htm

11. Advanced ESP Upgrades

... (T /R ) control, high voltage power supply Switched Integrated Rectifiers (SIR), flue gas conditioning, more efficient ESP design and field extensions. The ...

Terms matched: 1  -  Score: 45  -  19 Dec 2009  -  URL: http://www.mcilvainecompany.com/precip/subscriber/precipnl407/Advanced%20ESP%20Upgrades.htm

13. WESP Reduces Opacity Below 10 Percent at DGC

... Pilot testing demonstrated that a new high frequency power supply, Switched Integrated Rectifiers (SIRs™), provided enhanced WESP performance. Therefore, each bus section is energized ...

Terms matched: 1  -  Score: 35  -  4 Sep 2007  -  URL: http://www.mcilvainecompany.com/precip/subscriber/precipnl326/WESP%20Reduces%20Opacity%20Below%2010%20Percent%20at%20DGC.htm


Dakota Gasification Company (DGC) has completed installation and performance testing of a full-scale (1,200,000 ACFM, 400 net MW equivalent) wet electrostatic precipitator (WESP). It is located downstream of an existing ammonium sulfate (ASFO) flue gas desulfurization system. The WESP was installed to remedy high stack opacity that appeared to be the result of submicron particulate emissions and condensed acid mist droplets. The project was described by Michael W. Pontbriand, DGC, Robert J. Keeth and Richard S. Blagg, Washington Group International. The potential for usage of WESPs is increasing because they can efficiently remove submicron particles (PM2.5), aerosols and fumes downstream of wet flue gas desulfurization scrubbers


18. Alstom Wins ESP Upgrade Contract in China

... of the ESP upgrade. The contract also includes supply of Switched Integrated Rectifiers (SIR), Alstom's high-frequency power supply, which optimizes the energization and performance of the ...

Terms matched: 1  -  Score: 14  -  5 Jan 2011  -  URL: http://www.mcilvainecompany.com/precip/subscriber/precipnl420/Alstom%20Wins%20ESP%20Upgrade%20Contract%20in%20China.htm

Alstom was recently awarded a contract from Baoshan Iron & Steel Co. Ltd. (BaoSteel) in Shanghai to upgrade the electrostatic precipitators of units 1 and 2 of the captive power plant. The ESPs at BaoSteel were originally supplied by MHI Lurgi and have been in service since 1980. The upgrade will reduce particulate emissions, currently greater than 400 mg/Nm3, down to a level of 100 mg/Nm3, thus allowing BaoSteel to conform to China’s environmental requirements. The contract scope includes design, supply of materials and equipment as well as technical advisory services during installation and commissioning of the ESP upgrade. The contract also includes supply of Switched Integrated Rectifiers (SIR), Alstom’s high-frequency power supply, which optimizes the energization and performance of the ESPs.


20. Lignite-Fired Power Plant for Bulgaria

... conditions in the ESP and address difficult operational conditions. The Switched Integrated Rectifier (SIR) uses high frequency electronic power processing techniques and can deliver more power in a ...

Terms matched: 1  -  Score: 13  -  13 Oct 2009  -  UR

21. Advanced Hybrid Particulate Collector

... , which resulted in significant arcing. The arcing and high spark rate required the SIR controller to decrease the ESP current level. Due to the low power, greater ...

Terms matched: 1  -  Score: 13  -  4 Sep 2007  -  URL: http://www.mcilvainecompany.com/precip/subscriber/precipnl299/Advanced%20Hybrid%20Particulate%20Collector.htm

23. WET's FGC Licensed

... with ABB's advanced control system, EPIC II, and new high frequency transformer-rectifier, SIR, constitutes a unique platform to create and deliver value to ABB's customers. Back ...

Terms matched: 1  -  Score: 13  -  4 Sep 2007  -  URL: http://www.mcilvainecompany.com/precip/subscriber/precipnl280/WET's%20FGC%20Licensed.htm

24. WESPs Benefit Many Applications

... This capability allows a more compact and more cost-effective layout. Switched Integrated Rectifiers (SIRs™) will be used. For many years the allowable emissions from fiberglass production ...

Terms matched: 1  -  Score: 13  -  4 Sep 2007  -  URL: http://www.mcilvainecompany.com/precip/subscriber/precipnl306/WESPs%20Benefit%20Many%20Applications.htm