How to deal with complexity while decarbonising your steam grid

Steam is a complex medium to analyse and optimise due to its two-phase nature. Its unique thermodynamic properties, such as phase changes with latent heat transfer and a high specific volume that increases with temperature, make it a complex yet indispensable medium in the process industry.

Optimisation questions such as “How can I lower my temperatures or pressure?” or “How can I avoid condensation for superheated steam while still guaranteeing the same quality of steam?” are far from straightforward based on the physics of steam. Effective steam flow management requires tackling issues such as turbulence, condensation and pressure drops.

This is just the tip of the complexity iceberg.

The complexity of steam

Individual unit changes profoundly affect the connected steam system and its overall steam balance. Networks are integrated, often composed of interdependent multi-pressure levels, and designed for steady-state operations.

Other challenges are that the historical documentation and data quality can be insufficient, which makes it challenging to precisely evaluate the steam balance or dynamical behavior within the network.

Since steam systems are often composed of multiple pressure levels, which are also not independent of each other, any applied changes have an impact elsewhere.

On top of that, business reasons such as contractual obligations within a chemical park can add to the complexity of any change. A Take or Pay contract with a contractual lower limit on the amount of steam to be taken can prevent companies from having any benefit as they are unable to truly reduce their steam consumption.

Hardware improvements for steam grids such as sensors or steam traps may require a partial or total site shutdown, which generates significant costs and risk.

“Steam is not a closed loop like an electricity network, steam will need to flow elsewhere if I reduce the flow here.”

Industry Advisor, Strategy Consulting Firm

Operators in industrial sites tend to focus on the output and supply security of the system, for example, having two boilers on standby to deliver heat when required. The approach has traditionally been to err on the side of caution when managing steam systems and establishing setpoints.

However, this has impeded the implementation of improvement initiatives at the steam process level.

By adding new, decentralised sources or renewables, these systems become increasingly complex and need to be operated differently and more dynamically than just in stationary conditions.

How can organisations deal with this complexity? Here are two best practices based on interviews with 35 leaders that make up our report Full steam ahead: The opportunity for industry in decarbonising its steam grids.

Best practice 1: Steam complexity calls for a portfolio approach where multiple decarbonisation options are continuously assessed with technology limitations, emissions, benefits and costs in mind

The most sophisticated sites approach their transformation as a portfolio, considering trade-offs involved in decarbonisation initiatives such as technology limitations, emissions and costs.

Such an approach requires an ongoing process of evaluating multiple options for decarbonisation. As options mature in such a process, it becomes clear how much CO₂ gets reduced against the cost applied, as well as what is feasible within current site constraints, such as available electricity or maintenance planning of shutdowns.

These options would often also include ones that might not be economically feasible at the moment but which you could rationally expect to be in the future due to, e.g., higher CO₂ and energy costs. Being aware of these helps with the planning.

Compare multiple options

The leaders we interviewed often pointed to the tactic of comparing multiple options – for instance, choosing to replace a boiler with a regular heat pump or one that uses waste heat from a condenser. This often entails working within the constraints available but also developing the ability to think forward.

A tangible example of this can be developing an Abatement Cost Curve for a site, including all the currently available options to decarbonise with a cost/tCO₂ e logic.

One example our interviewees mentioned is already switching to H₂-ready boilers when replacing the existing natural gas burners. Another one is more radical, switching to steam instead of electricity as the energy carrier between sites, driven by constraints on the electricity grid and potential buildout.

“My company made a clear division of responsibilities; the plants provide project ideas & resources and HQ provides money for investments.”

Technology Manager, Energy & Utilities Player

Leverage know-how across organisations

Decarbonisation opportunities often originate in both corporate teams and sites, considering the significant know-how at both ends.

Collaboration between these organisations plays a critical role in rolling out improvements to the steam grid efficiently. The interviewees who felt successful in an approach were often easily able to sketch out how responsibilities were divided across corporate and local teams.

Where such accountability was not defined, projects could get stuck on financial or resource constraints as both corporate and local teams would look at each other for solutions.

“We can always achieve short-term measures through their own initiatives on site – organisational measures, control philosophy optimisation, etc. – there is no link to CAPEX. For bigger projects that involve company targets and guidelines, we have a corporate department investigating improvement measurements. The team also analyses company-wide investments and projects. Huge investments are always tested for economic strength and ROI.”

Energy Business Developer, Petrochemical Company

Best practice 2: Digitalisation underpins a systems approach, improving the accuracy of sensors, their data and resulting insights

More and more organisations use modern IT solutions that provide a layer on top of Operational Technology (OT) systems such as DCS. Tooling such as online or offline models allow companies to move forward where limited data held them back.

These tools often work on the data available through the DCS system and complement this with modeling. Modern, cloud-based computing power has made this feasible, as these models require significant calculation power.

The new era of digital tooling

Since insight into systems is the ultimate goal, operators are reviewing means to realise this, ranging from adding sensors (often with a shutdown involved) to extending existing software to various software-based solutions.

Such tools allow organisations to simulate the downstream impact of changes and understand the implications of a change, for instance, answering questions such as the impact decision 1 in control room A has on a specific grid segment controlled by control room B.

“You also have to ask yourself to what extent you have to map everything completely or where is the sweet spot between the effort to create such a model and the effort and time to map all the restrictions we have and then actually the benefit from such an optimisation software, which then suggests actions or automates things?”

Energy Manager, Large P&P Mill

Wrap up

Decarbonising steam grids presents significant challenges due to their complexity and the intricate thermodynamic properties of steam. Effective management requires a comprehensive understanding of the system, implementing a portfolio approach to evaluate multiple decarbonisation options, and considering technology limitations.

Leveraging digital tools such as real-time Digital Twin platforms can enhance system insights, enabling operators to simulate and optimise steam network performance effectively.

Discover additional best practices for steam grid decarbonisation by reading our report Full steam ahead: The opportunity for industry in decarbonising its steam grids, featuring insights from 35 top leaders in European industry.