Calculate, don’t measure

Off the northeast coast of Scotland, the Bruce platform endures the harsh conditions of the North Sea—icy winds, salt water, towering waves. For Serica Energy, the Bruce asset is a key component of their portfolio, supplying gas to support the UK’s energy needs. However, today, production alone isn’t sufficient. Monitoring emissions has become essential, as pressure on the oil and gas industry to improve its environmental impact continues to grow.

It's a challenge faced by offshore platform operators worldwide. Knowing one’s emissions is crucial for several purposes, including regulatory compliance, proactively achieving a company’s decarbonization goals, managing facilities that are difficult to adapt, corporate sustainability reporting, performance diagnostics, or maintaining a license-to-operate credibility.

Continuous Emissions Monitoring and its headaches

Yet, here’s the challenge: accurately measuring carbon and other emissions offshore without adding complicated, expensive, and maintenance-heavy equipment. Traditional Continuous Emissions Monitoring Systems (CEMS) pose logistical headaches: specialized hardware, calibration, and technician visits—cumbersome to maintain offshore, costly to run, and increasingly unreliable over time.

This also explains why many offshore gas turbines lack continuous emissions monitoring systems. The industry clearly needs an alternative that reduces hardware requirements while enhancing visibility and trust in the data.

Predictive Emissions Monitoring System – 50-80% lower lifecycle cost

Enter PEMS—Siemens Energy’s new Predictive Emissions Monitoring System. Its main feature is to calculate rather than directly measure exhaust emissions, utilizing unique algorithms that rely solely on an engine’s known parameters, such as turbine temperatures, pressures, or power output. It is also OEM-agnostic, requiring no additional hardware, and offers lifecycle costs that are 50-80% lower than those of CEMS. Overall, it provides a much simpler path to achieving emissions compliance in offshore environments. Siemens Energy started developing PEMS in 2020 using its extensive gas turbine expertise and existing data wealth (the company has over 7.400 gas turbines installed worldwide), harmonizing algorithms across different turbine sizes and types. The company is also closely working with Environmental Agencies in the EU and US to ensure easy certification.

Combining algorithms with physics

By mid-2024, Serica Energy and Siemens Energy had partnered to pilot PEMS on the Bruce platform. Mainly due to its cost, Serica Energy did not have a CEMS installed on the Bruce platform. “With PEMS, we had a solution to meet environmental regulatory commitments, better understand our emissions to meet our environmental goals,” says Andrew Wood, Rotating Equipment Engineer at Serica Energy. “And the implementation was straightforward; the in-person discussions made that particularly easy.” Currently, PEMS is installed at 25 sites by different oil and gas companies, with a commercial launch scheduled for September 2025.

PEMS draws on decades of OEM turbine experience, utilizing AI and physics-based engineering models to estimate emissions such as carbon dioxide, nitrogen oxides, oxygen, hydrogen sulfides, or unburned hydrocarbons. It is highly robust, working in all kinds of environments.

Making informed decisions

Alongside its affordability, PEMS's regulatory preparedness is a critical value driver. “PEMS was built with certification in mind,” says Martin Piesker, Head of Digital Products and Solutions at Siemens Energy. “And that’s helped by the fact that it can be applied to both Siemens Energy and non-Siemens Energy turbines, which is ideal for operators with mixed fleets.”

But that’s not all: the system enables fault detection through data analysis. Since it’s data-driven, it also enables predictions under various operating conditions. This supports proactive performance optimization, which helps operators make informed decisions about plant operations and adjust operating profiles to reduce emissions, fuel consumption, and maintenance costs.

Different types of deployment to meet oil and gas customer needs

There are three ways to implement PEMS: Generic PEMS is trained on Siemens Energy’s vast trove of test-bed turbine data. It can serve as a backup system for CEMS or as an initial step toward a certified PEMS. The site-specific PEMS is validated with site data, using one algorithm for each emission type, resulting in overall higher accuracy. This system can replace CEMS. Lastly, there is a certified PEMS, which undergoes annual validation by an independent third party according to US EPA or EU TS standards.

Additionally, since many countries restrict cross-border data transfers, Siemens Energy ensures that each PEMS system complies with the client's local regulations and is tailored to their individual setup. Also, all solutions comply with international cybersecurity standards to safeguard operational data. And PEMS is also validated before deployment; if desired, it can even be validated with CEMS data during implementation or periodically during operation.

PEMS: A future standard for gas turbines

Serica Energy’s successful pilot of Cloud PEMS shows that emissions monitoring can be done differently—and more effectively. By using software instead of emission sensors, Siemens Energy has developed a lean, scalable, and future-oriented solution. In the near future, Siemens Energy envisions all new gas turbines potentially being equipped with PEMS as standard, similar to how hydrogen readiness has become part of Siemens Energy’s roadmap for gas turbines.

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