FlexASU® Meeting today’s energy challenges with more flexible ASUs

The rising share of renewables in the world’s energy mix is certainly helping to resolve the carbon emissions dilemma. But it does present its own challenges when it comes to security of supply. By their very nature, renewable energy sources such as wind and sunlight are subject to strong fluctuations. This is creating volatility in the energy markets and, accordingly, in energy prices. Managing this volatility is a key challenge for today’s grid operators and market participants.

Focused on future power generation, the Kopernikus programme comprises four initiatives supported by Germany’s Federal Ministry of Education and Research. These projects bring together partners from science, business and civil society, allowing them to work together to develop technological and economic solutions aimed at transforming Germany’s energy system. Representing the largest research engagement behind Germany’s energy transition, these projects address the following four key areas:

• Harvesting renewable energy by converting surplus supplies to other forms of energy (P2X)
• Developing new network structures (ENSURE)
  
• Making industrial processes more flexible to accommodate fluctuating energy supplies (SynErgie)
  
• Improving interaction between all players in the energy ecosystem (ENavi)
  

When a large share of the energy mix comes from wind and solar power, balancing supply with demand becomes a real challenge. Storage technologies and flexible demand-side management (DSM) systems have a vital role to play here. 

Air separation units (ASUs) produce air gases that can be pressurised and supplied directly to customers (on-site market) or liquefied and distributed in bulk tanks or cylinders (merchant market). Liquid cryogenic gases have a particularly high energy density. Flexibility in liquid production is the key to demand side management.

However, ASUs were typically designed for continuous, steady-state production as, until now, there was no need to accommodate frequent load changes. Now this has changed with the new energy landscape.

To meet the growing demand for flexibility in air separation, Linde launched the FlexASU^® project in collaboration with the company MAN, RWTH Aachen University and the Technical University Munich, and with the support of Kopernikus SynErgie.

Thanks to highly flexible processes, process equipment and operation concepts, FlexASU^® is a robust, novel concept that gives operators the responsiveness they need to avoid peak energy prices by rapidly reducing liquid production when the grid is at its limits. This agility enables operators to adapt to changing market dynamics and capitalise on the rising costs involved in balancing power supply and demand, while also contributing to stabilisation of the energy grid. Ultimately the FlexASU^® concept supports the use of renewable energy and hence the pathway to a low-carbon or emissions-free society.

• Advanced process concepts that provide extended ranges for flexible, energy-efficient product and load management
• Advanced equipment design optimised specifically for frequent, fast load changes
• Next-generation advanced process control system enabling fully automated, fast yet smooth plant responses
• Cost-efficient operation thanks to minimal operator intervention

With project funding from the Kopernikus SynErgie initiative, Linde is currently building a test rig to develop a heat exchanger that responds flexibly to load changes. In the near future, the company aims to build a fully fledged FlexASU^® pilot in order to bring this future-proof, carbon-smart innovation to market as quickly as possible.