predictive emission monitoring systems

Predictive Emission Monitoring Systems (PEMS)

continuous emission monitoring systems
Marvin Oosterhof

Marvin Oosterhof

Marketing & Sales

We help energy companies with independent consulting services and software plant & IT solutions to improve the effiency.

Predictive Emission Monitoring Systems: PEMS

The industrial and energy sector is under immense pressure to reduce emissions and comply with environmental regulations. Governments and environmental organizations are taking serious measures to try to reduce emissions in several industries with regulations. In 2021, the EPA’s civil enforcement program assess 1,06 billion dollars in penalties and fines for non-compliance with environmental laws. Green policies have also forced major polluting industries, such as petrochemical, oil & gas, renewable energy, cement production, waste incineration, mining, and pharma to measure and monitor emissions more accurately and continuously by worldwide regulations such as US EPA part 60/75, EN 17255, KSA RCER, Swiss OAPC, Alberta CEMS code and Canadian 1/EPS/PG7.

From a plant owner’s perspective, it’s important that efficient and reliable tools for acquiring emission data are available to avoid costly penalties and plant shutdowns. There are a few ways to acquire emission data with CEMS and/or PEMS.

Predictive Emission Monitoring Systems, or PEMS, is typically used to predict emissions of NOx, SO2, O2, CO, CO2, and HC. PEMS will gather data from existing plant instrumentation and sensors as input to the calculation model of emissions. The parameters of this model are obtained by minimizing the difference between the predicted and measured emissions values. There are two methods that can be used for making PEMS models:

  • – First Principles Method (parametric system)
  • – Data-Driven Method (statistical hybrid method)

The most common challenges

Plant owners and operators face a number of challenges that affect the operations and the productivity of the facilities:

  • – Strict environmental regulations
  • – Limitations of emissions
  • – Reducing the plant workforce.

It becomes more and more important to find solutions to these challenges. There are two major solutions that can solve these challenges, like CEMS and PEMS. The difference between these two solutions is described in the next section.

Difference between CEMS and PEMS

Typical plant continuous emission monitoring systems (CEMS) are essentially hardware-based. In the field are several CEMS analyzers to sample and identify the compositions of released flue gas. These measurements will be sent to an IT infrastructure, AML-CEMS, to manage, monitor, and store the emission values. AML-CEMS is a software application that uses all the data from the CEMS analyzers and processes the data regarding EN 17255 (Data Acquisition)

The predictive emission monitoring system, or PEMS, is a software application that uses existing process data and statistical methods to predict discharges from a process. PEMS will collect data from the plant’s existing control systems, like the distributed control system (DCS), and uses mathematical algorithms and equations to predict the emissions.

The main differences between PEMS and CEMS are described in the next section. It is good to know that CEMS and PEMS often go hand in hand. With CEMS, the organization knows what the emissions are at a certain time, while PEMS gives an estimation of what the emissions will be in the future. Based, on this information the organization can adjust its strategy to avoid exceeding the limits.

Is PEMS approved by worldwide environmental regulations?

Predictive Emission Monitoring Systems – PEMS – are worldwide recognized as a method for emission monitoring, but it depends on local regulations. Currently, there is no global standard for monitoring emissions. Each country uses different standards, but the most common is the US-EPA and the European standard. In some countries, PEMS can only be used as a backup of CEMS analyzers, and in some countries, PEMS can use as a primary source. The following countries will allow PEMS as a method for monitoring emissions:

  • – US-EPA
  • – Europe
  • – UK
  • – Middle East


Benefits of PEMS

Predictive emission monitoring systems – PEMS – can provide significant advantages over traditional manual monitoring methods, including improved accuracy, increased efficiency, and reduced a lot of costs. Below are the key benefits:

Enhanced Accuracy

PEMS uses advanced data analysis methods to predict emissions data. This improved accuracy through the reliability of the data and in that way the organization can make better compliance decisions to avoid costly fines.

Better Performance

PEMS can automate many tasks associated with manual emissions monitoring, like information collection, analysis, and reporting. The benefit is to improve the overall efficiency of the emissions monitoring process.

Seamless Installation

PEMS doesn’t require any complex infrastructure to collect the sample at the stack and handle. It can connect to the plant control systems without the need for additional components (like shelters or field devices), no spare parts needed, and no shutdown required.

Lower Expenses

PEMS will reduce the costs associated with emissions monitoring by eliminating the need for manual data collection, analysis, and maintenance time. Also, PEMS can predict the emissions over a certain period of time, this can avoid high fines because the organization goes over the set emissions limits.

In the next paragraph, the difference between PEMS and CEMS becomes a lot clearer.

PEMS vs CEMS (advantages and disadvantages)


Both systems have their own pros and cons. PEMS can help organizations in achieving regulatory compliance applied:

  • – As a primary source without investing in CEMS hardware (this is only possible if the process has no changing fuel properties)
  • – As a cost-effective backup of existing CEMS, increasing the availability.

Most of the time PEMS will be used as a backup for CEMS analyzers. The benefit is to increase the availability of their CEMS. Through the adoption of PEMS as a backup, the uptime can be increased up to 99.5%. This means high reliability, less maintenance, reduction of costs, and reduction of unplanned downtime.

Steps to install PEMS (Develop, deploy & maintain)

  1. 1. Kick-off meeting (current situation and expected situation)
  2. 2. Data collection (existing data)
  3. 3. Data processing
  4. 4. Model building
  5. 5. Validation
  6. 6. Commissioning
  7. 7. Training
  8. 8. Certification

Predictive emission monitoring systems


With climate change European companies need to reduce their emissions by at least -55% by 2030. This can be very hard for many companies to meet this target. The role of technology in improving the predictability of violations and reducing the impact has a very important role in the coming years.

A predictive emission monitoring system (PEMS) is a good development in air pollution control. There are a lot of benefits of PEMS regarding traditional CEMS. Companies can predict the emissions, and it’s the ease of use, improve efficiency, reduction of operational costs, and avoid high fines in the future.

The combination between PEMS (AML-PEMS) and CEMS (AML-CEMS) would help companies to reduce emissions in an easy and efficient way. This allows managers and operators to make better decisions based on current and expected emission data.

We can help you upgrade your CEMS analyzers (hardware) with our AML-CEMS software to make reports or get started with PEMS today. Contact us to learn more or schedule a 30-minute call with our experts.  Schedule your free call here