Green electricity from wind and solar power can be abundant or scarce. Power-to-X technologies store this energy as electrochemically produced hydrogen, which is converted back into electricity in fuel cells. A modular solution with AC/DC converters supports various topologies for supplying electrolysis cells with direct current, simplifying maintenance and enhancing the availability and service life of electrolysis stacks.

The vision of an All Electric Society relies on affordable, renewable electricity. Wind and solar power are crucial but volatile, necessitating storage solutions. Future power grids will use pumped storage plants and battery storage systems to balance generation and consumption, though these aren’t suitable for long-term storage of large quantities of surplus electricity.

Power-to-X technologies can be used to store surplus electricity long-term by splitting water into hydrogen and oxygen via electrolysis. These can be converted into chemicals or fuels, or the hydrogen produced can be stored and later converted back into electricity in gas-fired power plants or fuel cells. Direct current through an electrolysis cell produces hydrogen at the cathode and oxygen at the anode, separated by a membrane to prevent reaction. The gases are vented off separately.

Modular concepts for electrolysis cells and power supply

Today’s electrolyzers are modular, with cells arranged in stacks, achieving powers from 10 kW to several MW. Larger plants, up to gigawatt scale, interconnect dozens or hundreds of electrolyzers. This modularity allows easy scalability and simplifies mass production. Designing a modular power supply for electrolyzers is ideal.

Scalable alternative to monolithic large-scale converters

All electrolyzers need direct current, so AC from the power grid must be converted by AC/DC converters. The cell voltage (1.6 to 2 V) must be maintained for the electrolytic process. Often, large monolithic converters are used, but a modular supply concept like the CHARX power system from Phoenix Contact offers an alternative. CHARX AC/DC converters convert AC to DC with the required voltage, ensuring high-quality electrical energy by reducing grid-side harmonics and the DC ripple is a maximum of just 1.5%. They also prevent short-term voltage dips and peaks.

Megawatt electrolyzer manufacturers impressed by modular supply concept

Phoenix Contact has implemented this concept in several electrolysis projects, equipping containerized units with modular rectifier units based on AC/DC converters. This modularized approach allows for standardized control cabinets that are adaptable to the power needs of each electrolysis module. Manufacturers were impressed by the technical details, such as integrated condition monitoring, long service life, easy maintenance, and high efficiency of the converters.

High-level efficiency and easy-to-integrate condition monitoring

Charx AC/DC converters, typically using IGBT technology with a 30 kW output, are highly efficient (up to 96%) and superior to monolithic converters. They offer a controllable DC output voltage range of 30 to 1,000 V, adaptable to various electrolysis stacks. Both voltage and current can be ramped up slowly. These converters provide internal electrical isolation between AC and DC grids, crucial for many electrolyzers. Charx converters with 20 kW output using SiC power semiconductors can achieve 97% efficiency, further reducing waste heat.

PLCnext Control devices from Phoenix Contact are ideal for control applications, offering library elements for simplified programming, flexible voltage and current control, and easy data integration for condition monitoring. Charx converters feature an openly accessible bus system. The modular power supply approach benefits electrolyzer manufacturers, allowing scalable green hydrogen production from pilot to megawatt plants.

Higher availability of converters and electrolyzer

Charx rectifiers optimize partial load operation by allowing parallel converters to be partially switched off, ensuring the remaining ones operate at optimal efficiency. This extends the service life by evenly reducing operating hours. Alternating the operation of converters also aids maintenance planning and prevents uneven loading

The concept benefits maintenance and servicing. Small-format modules can be easily kept as spares, and integrated condition monitoring alerts operators when replacements are needed. Modules can be replaced with standard tools while others continue to supply the electrolyzer, increasing system availability. Only during full-load operation is a slight reduction in supply noticeable when a module is replaced.

If a large monolithic converter fails, the entire electrolysis plant it supplies will stop. Replacement converters must be custom-made, causing the plant to be down for weeks and resulting in high yield losses.

Large megawatt converters supply multiple electrolysis stacks with the same voltage, but variations in stacks can cause issues. If one stack has a problem, it can affect the entire system. In contrast, using Charx modules allows individual stacks to be isolated and checked without shutting down the whole system, ensuring the remaining stacks continue to operate.

Using 19-inch modules may require more space and higher initial investment than large-scale converters. However, their advantages—higher availability, lower maintenance costs, and efficiency gains, especially in partial load operation—quickly offset these drawbacks.

Read more about AC/DC converters.

Single Pair Ethernet: Lean communication through to the field level of automation

Single Pair Ethernet (SPE) enables smarter, more sustainable connections, making it ideal for long-distance communication. Sensor manufacturer Jumo trusts SPE for its measurement technology, using connection solutions from Phoenix Contact, developed through close project collaboration.

“Single Pair Ethernet (SPE) enhances the use of intelligent sensors by transmitting more data, enabling profitable insights,” says Manfred Walter, product manager at Jumo. He highlights the seamless distribution of sensor information across system levels and the consistency it brings. SPE also saves cables by routing data and power via Power over Data Line (PoDL), allowing end-to-end communication from ERP to field level without media disruptions.

OEE as a basis for investment

Jumo and Phoenix Contact emphasize Ethernet’s consistency as crucial for sustainable production. It simplifies troubleshooting, facilitate condition-based maintenance, and improves Overall Equipment Effectiveness (OEE) by enhancing system availability. Additionally, it facilitates easier connections to cloud-based services.

Using SPE to combat media discontinuity in industrial communication could influence sensor-level connection technology choices. However, Manfred Walter notes that customer expectations in machine building and systems manufacturing are primarily price-driven, with limited budgets for measurement chains. The additional cost of SPE connections and the benefits of an end-to-end Ethernet architecture are difficult to present, especially in standardized tenders. Positive impacts on OEE are crucial for investment decisions and are best be argued directly.

Convergent networks are in demand

Martin Müller, a fieldbus expert at Phoenix Contact, views SPE as an important step towards convergent networks. TSN is designed for time-critical tasks like functional safety and motion control, while 5G is used for cellular communication needs. Similarly, WLAN 6 and 7 are used for license-free, wireless transmission.

“Single Pair Ethernet is ideal for communication at the field level,” says Martin Müller. The convergent Ethernet network is the common standard for industrial communication. If stakeholders in automation, electrical engineering, machine building, and systems manufacturing agree on this path, industry-specific fieldbus wars will end.

1,000 meters with 10 Mbit

The chances are favorable, supported by the transmission performance of standard consumer communication. SPE achieves a transmission rate of 10 Mbps over 1,000 meters, while I/O-Link delivers 230.4 kbps over 20 meters. Despite I/O-Link simplifying sensor connections, Manfred Walter believes its data rate won’t suffice for future tasks in coupled sectors.

Phoenix Contact and Jumo foresee a trend towards convergent Ethernet networks, particularly among younger specialists. “Digital natives are less tolerant of multiple systems in industrial automation,” says Martin Müller. The focus should be on maximizing sensor capabilities for efficient, resource-saving operations. “We see enormous potential for the future,” emphasizes Manfred Walter.

Hygienically clean IP67 connector solution

Install, connect, and you’re done: With SPE connectivity, installing a Jumo sensor is easy. The Ethernet layer eliminates the need for gateways or complex interface programming. Phoenix Contact’s M12 connector supports Single Pair Ethernet transmission up to 1,000 meters without limiting attenuation. “The M8 format wouldn’t fit a two-wire AWG 18 data cable for 1,000 meters,” explains Manfred Walter. The connection design ensures robustness and hygiene. Jumo’s “flowTRANS MAG H20” and “DELOS S02” sensors are popular in the pharmaceutical and food industries. High operational safety over long distances is achieved with connections that withstand demanding production processes or CiP cleaning. Phoenix Contact’s solution meets hygienic design standards and provides IP67 protection.

Read more about Sensor technology.

Safe and reliable operation with lower energy costs

A reliable power supply from renewable sources requires storing surpluses for times of low sunlight or wind. At the All Electric Society Park in Blomberg, Phoenix Contact demonstrates sector coupling for the electrification of society.

Climate change and geopolitical crises are accelerating the integration of wind and solar power into electrical power systems. However, these sources are intermittent. Battery energy storage systems (BESS) can store generated energy and supply it when needed. In Blomberg, a 1.2 MWh BESS ensures reliable operation and energy cost savings. Phoenix Contact uses its own electronic components to control the BESS, emphasizing quality, reliability, and safety. In addition, the company continues to expand its BESS portfolio, prioritizing these high standards.

Hybrid, battery-pole, and SPE connectors for a reliable connection

When creating battery storage systems, battery cells, and power electronics are usually prioritized. However, BESS systems are complex and require numerous technical components and electrical connections for power, signals, and data. Phoenix Contact offers a range of connection technology, including modular hybrid connectors that combine different connection types. These connectors can be customized to meet mechanical and electrical stability and safety requirements.

Often, people wire the systems discretely as an alternative to the hybrid approach. Battery-specific high-current connectors handle over 300 A and up to 1,500 V DC. Phoenix Contact’s battery-pole connectors, with UL 4128 approval, are widely available. For data communication, new solutions based on IEC 63171 Single Pair Ethernet standards are being established, offering robust, high-performance connectors with small sizes and high transmission capacities.

Certified hardware and software solution for feed-in control

The control cabinets, often divided into functional units, can be equipped using the Complete line range. This includes a comprehensive product portfolio for all control cabinet functions, such as uninterruptible power supplies, terminal blocks, and safety relays. The intuitive handling of these coordinated components saves time during planning, installation, startup, and maintenance, reducing operating costs.

In addition, the control systems of a BESS must communicate safely or be combined into one system. Managed switches like the FL Switch 2000 series provide necessary network functions. PLCnext Control controllers from the PLCnext Technology ecosystem integrate safety technology, eliminating the need for dedicated safety controllers. This allows for implementing standard and safety-related applications up to SIL 3 and PL e in the PLCnext Engineer environment. Using IEC 61131-3, high-level languages, and Matlab Simulink ensures faster and safer development of BESS control software.

The feed-in control system connects battery energy storage systems to the public power grid. Phoenix Contact offers a certified hardware and software system based on PLCnext Technology for users without their own solution. This system ensures low engineering effort, compliance with technical requirements, reliable operation, and easy grid connection. Intelligent automation solutions reduce operating costs, and preprogrammed software allows quick startup. Open interfaces enable customer-specific extensions.

360-degree security for protection against cyberattacks

Starting October 2024, the NIS 2 directive will tighten IT security rules for critical infrastructure operators (KRITIS). Neglecting IT security is considered negligent under this directive. Since prevention is more cost-effective than dealing with cyberattacks, Phoenix Contact offers TÜV-certified security products, services, and seminars. You can tailor these safety solutions to specific applications and requirements.

A challenge for battery energy storage systems is the international development and supply chains, with modules often developed and manufactured in distant locations. The complete solution is assembled at the user’s site, which can be anywhere globally. Manufacturers need internationally positioned partners with global expertise and production capacity. Components must meet all relevant international and local standards and have the necessary approvals.

Actively shaping the transformation to the All Electric Society

Phoenix Contact provides innovative products, solutions, and digitalization expertise for electrifying, networking, and automating economic and infrastructure sectors. Since its founding in 1923, optimizing energy flows has been a core expertise. The All Electric Society envisions abundant, affordable renewable energy. Achieving this requires comprehensive electrification, networking, and automation of all life and work areas. Phoenix Contact enables this transformation with numerous products, solutions, and services.

Read more about reliable components for battery storage systems.

Explosion protection and functional safety included

Power-to-X technologies are  becoming increasingly important for the All Electric Society. Compact Ex i signal conditioners with SIL 3 are vital for their safe use.

Technically, the All Electric Society offers a solution to the climate crisis and sustainable development. This vision involves using renewable electrical energy as the main, inexpensive, and abundant energy source. Achieving this requires comprehensive electrification, networking, and automation across all sectors—industry, mobility, infrastructure, buildings, and energy. Sector coupling integrates power generation, distribution, storage, and consumption into a holistic system, allowing energy exchange and optimal control through data evaluation.

Society’s energy needs will continue to rise, while fossil fuel use must be drastically reduced to cut carbon emissions. This presents challenges and opportunities, such as increasing renewable energy production. However, renewable sources depend on external factors like weather, making energy storage systems crucial. These systems buffer surplus electricity and convert it back when needed. Power-to-X technologies offer solutions for energy storage and further carbon emission reductions.

Use of green hydrogen in heavy industry is essential

Power-to-X technologies convert electrical energy into chemical energy sources, with “X” representing various chemical products from electrolysis or other processes. Green hydrogen production from renewable sources is the foundation for all power-to-X applications. Hydrogen is used to produce ammonia (mainly for fertilizer) and methanol (a raw material for the chemical industry).

Besides energy storage, power-to-X applications are crucial for heavy industry energy consumption. Green hydrogen is essential for industries like steel, chemicals, and refineries, which rely on fossil fuels. Since substantial electrification isn’t feasible, power-to-X is the only alternative to reduce carbon emissions.

Power-to-X applications require modularity due to the use of many small decentralized systems and control boxes. Explosion protection and functional safety are crucial because of the combustible gases generated. Phoenix Contact offers a comprehensive range of products and solutions for explosive areas, including the new Mini Analog Pro intrinsically safe signal conditioners.

High level of operating convenience, even in limited spaces

In modern process and power-to-X systems, intrinsically safe explosion protection and functional safety are crucial. Limited control cabinet space often reduces product handling convenience. Phoenix Contact’s Mini Analog Pro offers compact, user-friendly devices for intrinsically safe and safety-related measuring lines. The new signal conditioners and transducers include SIL 3 1oo1 functional safety for all signal types—analog, digital, control, and measuring signals—within a 6.2 mm width.

The Mini Analog Pro family allows easy conversion to digital protocols via modular communication modules without extra space. Compatible with Modbus RTU, Modbus TCP, Profinet, and Profibus, up to eight signal conditioners can form Mini Analog Pro gateways. This eliminates the I/O level and specific input cards, ensuring direct digital network connection, channel-specific electrical isolation, and precise signal transmission.

Broad product portfolio for power-to-X applications

To achieve a sustainable future, significant carbon emission reductions are essential. Power-to-X technologies are crucial in the energy transition, replacing fossil fuels where electrical alternatives are limited. These applications are efficient and scalable due to their modular and decentralized structure. Safety aspects like explosion protection and functional safety are vital, and the Mini Analog Pro signal conditioners meet these requirements. Phoenix Contact offers a wide range of products and solutions for power-to-X applications, making them a reliable partner for system extensions.

Read more about power-to-X