Hydrogen Technology in Buildings and Industry - Electrolysis

 

 

 

 

 

 

What is electrolysis?

Electrolysis is simply a process in which direct electric current is used to dissociate a water molecule into its components: oxygen and hydrogen. When using renewable electricity (solar, wind, etc.), it is considered clean 100% renewable hydrogen H2. It is a modular and scalable solution. The process of hydrogen production does not involve combustion or gas emissions.

Electrolysis using PEM (Proton Exchange Membrane) membranes - Advantages 

• High current density
• High efficiency
• Good efficiency under partial load
• Fast system response
• Compact
• High gas purity
• Easy maintenance
• No hazardous substances

1MW Electrolyzer Size Scale

Technology - PEM Electrolysis - Process Diagram 

• General electrical installation: to power all instruments and equipment, includes an uninterruptible power supply (UPS) to provide energy in the event of a power failure.
• Control system: Fully automated PLC controller to monitor and control the electrolyzer to ensure the entire process operates correctly.
• Rectifier (AC/DC converter): The required electricity, which can be sourced from renewable energy, is adjusted before powering the stack.
• Stack: Electricity and water enter the system, splitting water into hydrogen and oxygen molecules.
• Oxygen separator: The produced oxygen is a two-phase stream (O2 + H2O) where gaseous oxygen, steam, trace amounts of hydrogen, and large amounts of liquid water coexist. This device recovers liquid water and releases oxygen into the atmosphere. Recovered water is recirculated to the stack in a closed loop (minimizing water consumption).
• Pumps: The electrolyzer contains two pumps, one to support deionized water supplied to the stack and the other to balance with deionization resins.
• Gas cooling system (chiller): To cool the hydrogen stream, improving the overall system efficiency.
• Hydrogen separator: The produced hydrogen is also a two-phase stream (H2 + H2O), where water vapor, hydrogen, and trace amounts of oxygen (in the gas phase) and liquid water coexist. For hydrogen purity required in further applications, this device separates water from hydrogen.
• Water treatment plant (WTP): Converts ordinary water into pure water, required when deionized water (conductivity <0.1 µS/cm, TOC <30 ppb) is not available.
• Purification system: Installed at the hydrogen separator outlet, consisting of a dryer (to retain moisture) and deoxo (a catalytic recombiner to collect oxygen) in line with the cathode outlet from the stack - used when hydrogen purity above 99.9% is required.

There are four technological aspects of electrolyzer development for hydrogen production

• Stack technology (stacking or stacking membranes in which electrolysis occurs) - Investment and technology agreement with Giner ELX.
• Balance of Plant (BoP) - Based on stack requirements, Eco-Prius designs and develops auxiliary devices and systems that allow the stack to operate, optimizing overall system efficiency.
• Integration technology (of the stack with BoP, the electrolyzer with other plant components, such as storage and compression, and the plant with renewable energy-utilizing devices).
• O&M related expertise

Small Scale Electrolyzers

• Small electrolyzers can produce hydrogen from 0.5 to 5 Nm3/h.
• They are optimal for small consumers: laboratories, residential buildings, small fleets, etc.
• These systems are simply integrated into a cabinet.
• Electrolyzers are certified and developed according to European or American (depending on the customer’s location) codes and standards.
• Eco-Prius provides electrolyzers with CE marking and, if necessary, ETL stamp (priced separately), as well as required safety studies (by default HAZOP).

Small Scale Electrolyzer Production Capacities:

• 0.5N - 0.50 Nm3 H2/h - 1.08 kg H2/day
• 1N - 1.0 Nm3 H2/h - 2.15 kg H2/day
• 2N - 2.0 Nm3 H2/h - 4.31 kg H2/day
• 3N - 3.0 Nm3 H2/h - 6.41 kg H2/day
• 5N - 5.20 Nm3 H2/h - 11.22 kg H2/day

Medium Scale Electrolyzers

• Medium scale electrolyzers can supply hydrogen from 10 to 105 Nm3/h
• These systems are integrated into a container

Medium Scale Electrolyzer Production Capacities:

• 10N - 10.5 Nm3 H2/h - 21.68 kg H2/day
• 30N - 31.70 Nm3 H2/h - 68.40 kg H2/day
• 60N - 63.30 Nm3 H2/h - 136.58 kg H2/day
• 100N - 105.50 Nm3 H2/h - 227.60 kg H2/day

Large Scale Electrolyzers

• The largest electrolyzers can supply hydrogen from 200 to 400 Nm3/h.
• These systems are integrated into a 40-foot container.

Large Scale Electrolyzer Production Capacities:

• 200N - 207 Nm3 H2/h - 446 kg H2/day
• 400N - 414 Nm3 H2/h - 893 kg H2/day

Portable Hydrogen Refueling Stations

• 20 - 40 foot container
• On-site production
• 520 Nm3/h
• 248 cars/day (expandable)
• H35 (350 bar) and H70T40 (700 bar)
• Light and heavy vehicles

Stationary Hydrogen Refueling Stations

• Size on demand
• Fully automated and integrated with the refueling station
• 200 kg/day: 10 buses
• 1000 kg/day: 8 long-haul tractors

Hydrogen Production Plant H2 - Modular Concept for Markets

• 10s - 100 MW
• Feedwater treatment plant
• Ultra-pure hydrogen
• 40 bar supply
• Fully automated

Fuel Cells

We are convinced that hydrogen will be the foundation of the future global energy system. The growth of renewable energy provides an abundance of excess hydrogen, making it a widely available commodity in the future.

There is increasing demand for electrifying such green hydrogen in both stationary and mobile applications. As the hydrogen economy matures, a market for reliable and durable solutions will emerge.

Hydrogen will strengthen the energy transition, and we are strongly committed to working with a fuel cell manufacturer who invests in the development and industrialization of PEM technology and products.

PEM Fuel Cells

Proton exchange membrane or PEM fuel cells are considered the most versatile type of fuel cell currently produced. They generate the most power for the given mass or volume of the fuel cell. Since they are lightweight, have such high power density, and the ability to start cold, they qualify for many applications, such as stationary combined heat and power, transport, portable power, and even space applications. The PEM manufacturer is a supplier of stacks for integrators aiming to create high-power applications based on designs and meeting high longevity and performance requirements.

Buildings and Built Environment

The supply of renewable energy and the demand for heat and power in the built environment are not balanced. While the sun shines brightest at noon, we primarily consume heat and power during morning and evening peaks. Hydrogen is the ultimate buffer to balance such asymmetries in our energy system, and we know how to do it best and at the right scale. Our built environment applications team is well-trained to help you define the best District PEM-CHP solution for your needs.

Our CHP solutions are key to providing emission-free districts

Local PEM CHP Plant Capabilities

We have developed a versatile and comprehensive PEM-CHP plant concept for the built environment, enabling the alignment of energy system sets. Application possibilities are widespread and include:

• Residential areas with heating networks
• Holiday parks
• Hotels and conference centers
• University campuses
• Industrial parks
• Apartment blocks
• Hospitals
• Shopping centers
• Other buildings and districts requiring heat and energy

Energy-yard H2

Uses hydrogen as a balancing mechanism between the supply of green heat and energy, and the demand for heat and energy at the district level.
We urgently need new ways to heat and power our built environments, and most importantly, we need smarter ways. In pursuit of such solutions, we must open ourselves to the broader context of the energy transition. We need a structure that integrates the monodisciplines of electricity, heat, and gas into a holistic concept that optimizes our energy system and accounts for all the flows and transformations created by these holistic frameworks.
We have built Our framework and labeled it as the H2 energy yard, a local CHP solution that integrates the hydrogen production function, hydrogen and heat buffering, hydrogen conversion to CHP, and a heat pump booster. The Energy-yard H2 concept is about proper power-to-power use. Instead of only optimizing electric power in a power-to-power configuration, we collect and mobilize heat at all appropriate stages and allow flexibility between the mission of maximum electrical efficiency, maximum heat utilization, and interaction between them.

Our proposal:

• Hydrogen not as a monopolized energy carrier, but only as a buffer balancing supply and demand
• Hydrogen storage and distribution limited to the H2 Energy-yard (no H2 in buildings), allowing for a centralized safety concept and easy control and maintenance
• Dual buffer strategy (heat and hydrogen) to achieve maximum efficiency of the entire installation
• Indoor installations (heat exchanger and standard two-way electrical connection) are small, simple, and widely available
• Distribution of heat and energy from the grid via standard networks
• Energy and heat without emissions (also without NOx emissions);

H2 Project Support and Directive Compliance

Our project support team adheres to relevant directives, standards, and regulations. Although EU standards (specifically IEC 62282-3) and relevant EU directives (specifically 2006/42 / EC, 2006/95 / EC) provide a strong compliance base, in the context of the built environment, this always matters.
We support you throughout the process of obtaining the necessary permits, conducting safety assessments (HAZID), discussions with bureaucrats, and further safety and compliance planning.
Our project service package for the built environment is always tailored and includes a set of engineering services required to ensure the success of your project.

Our services include

• Feasibility assessments of hydrogen power plants
• Modeling of mass, energy, and heat balances
• Installation sizing studies and connection solution recommendations
• Thermodynamic modeling
• Participation in safety studies;
• On-site measurements
  

Application of Hydrogen in Multi-Family Buildings

Key Values of PEM Fuel Cells

• Zero particle and NOx emissions;
• Zero CO and CO2 emissions during operation - clean hydrogen;
• Long service life (> 20,000 hours) to overhaul;
• High power density;
• Low temperature, hence versatile operation;
• Proven technology with extensive experience in many different applications;
• Best-fitting fuel cell type or 4th generation thermal grid;
• CAPEX winner.

Cascaded Fuel Cells

Fuel Cell Power

7-XXL PEM FUEL CELL STACK

10-XXLPEM FUEL CELL STACK

13-XXL PEM FUEL CELL STACK

Large PEM Power Plants

PEM GEN CHP-FCP-1000 is a PEM fuel cell power system designed for industrial applications, Power-2-Power purposes for solar and wind farms, and cogeneration applications in the built environment. The CHP-FCP-1000 is optimized for seamless integration with local or collective power networks through the ability to use all types of commercial, ready-to-use power electronics. The PemGen fuel cell power systems offer is available in custom configurations.

PEM CHP Track Record

Fuel Cell Types (PEMFC Winner)

Principle of Operation of Proton Exchange Membrane Fuel Cells

In a PEM fuel cell, hydrogen and oxygen react in an electrochemical matter, producing electricity, pure water, and heat. The structure of a single fuel cell is explained below:

Fuel Cell Structure

The thin dark blue layers represent gas diffusion layers (GDL). The gray layers are electrodes made of conductive carbon and ionomer, carrying the catalyst, platinum. Between these layers, shown in light blue, is the proton-conducting electrolyte, known as the proton exchange membrane (PEM).

PEM Operation Principle

The PEM membrane is a thin layer made of PFSA (Per Fluor Sulfonic Acid). The ionomer in the electrodes also consists of PFSA. PFSA has a PTFE polymer backbone with side chains attached to sulfonic acid (SO3H). The membrane allows protons to pass through but is impermeable to electrons. The membrane must be saturated with water to act as a proton carrier. The combination of water and sulfonic acid allows H+ ions to pass through the membrane, so membrane hydration is essential. The membrane is also slightly permeable to gases like hydrogen, oxygen, and nitrogen. During operation, the main component of air diffusing from the cathode (oxygen side) to the anode (hydrogen side) is nitrogen, as oxygen will react with protons.

The combined layers of membrane, electrodes, and gas diffusion (GDL) form the membrane electrode assembly (MEA). When hydrogen and oxygen from air are present, a potential difference of about 1V (maximum 1.23V) is created on the membrane. The potential difference is lower when current flows through the membrane. For a fuel cell current of 120A, commonly used in PEM power plants, the voltage drops to 0.7V at the beginning of the service life (BOL). This corresponds to an energy conversion efficiency of hydrogen to electrical energy at 56%. Note: the lower heating value (LHV) of hydrogen was used for this number. The remaining 44% of hydrogen energy is carried away by cooling water. The thermal energy of warm water can be used for useful purposes. During the fuel cell's service life, electrical efficiency will decrease, and thermal efficiency will increase to maintain a consistently high efficiency of the combined system.

• The total reaction 2 H2 + O2 → 2 H2O is divided into the main reactions:
• At the anode (hydrogen side): 2 H2 → 4 H + + 4 e¬-
• At the cathode (air side): O2 + 4 H + + 4 e-- → 2 H2O

From Cell to Stack

In a fuel cell stack, fuel cells are connected in series to achieve a useful voltage and form a stack. Such PEM stacks are the building blocks of larger fuel cell systems.

Stack Concept: The stack consists of cells connected in series

IV Curve

The graph below shows the change in voltage with current for a typical PEM stack. A fuel cell always follows the applied load. To follow this load, sufficient hydrogen and oxygen must be present. If reactants are lacking, the fuel cell consumes electrode materials such as carbon and damages itself. Therefore, hydrogen and air availability must be ensured before load is applied. Cell voltage monitoring is installed to prevent damage when load settings are too high. A stack group will automatically shut down when the cell voltage in any stack in that group falls below the threshold T.

Heat Recovery and Water Production

PEM fuel cell stacks manufactured in the EU operate at temperatures of around 65°C. The excess heat generated during energy production is transferred by the coolant. This is pure water with electrical conductivity below 5 µS/cm. The water must maintain low conductivity to prevent short-circuit currents between individual cells. Deionized water efficiently transfers the generated heat.

The cathode reaction O2 + 4 H + + 4 e- → 2 H2O generates water on the side of the fuel cell where air is present. Oxygen reacts at the cathode, while nitrogen acts inertly, preventing easy access of oxygen to the catalyst. The water generated in the reaction tends to form droplets, hindering airflow to the cathode. For a stack current of 120A, i.e., the air flow must contain twice as much oxygen as the amount consumed. The produced water is collected using a condenser. This pure water is available for humidifying hydrogen and air or may also be used for other purposes or drained when no useful purposes are available.

The anode reaction 2 H2 → 4 H + + 4 e- is simple and attracts hydrogen to the fuel cells. Before entering the stacks, hydrogen is humidified. At the chimney outlets, the concentration of water vapor is higher than at the inlet due to the consumption of hydrogen inside the chimneys. The increased water concentration causes droplet formation. An excess of hydrogen compared to stoichiometry is required to remove these droplets. The PEM manufacturer uses a minimum excess of 25%. The excess hydrogen is recirculated.

Hydrogen Power Plant - Process Flow Diagram

Hydrogen Power Plant - System Components 

Main Advantages of Hydrogen Power Plants - Hydrogen Power Plant H2:

• Offers a solution to the asymmetry between renewable production and demand.
• It is not a monopoly on the supply of heat, cooling, and electricity but complements solutions like heat pumps.
• Allows for zero-emission energy supply.
• Focuses on heat, cooling, and electricity.
• Supports projects such as solar panels, wind energy, and electrification of the built environment.
• Offers support for electrical grids.

The Role of Hydrogen

Energy Backup - Time

1. Days - Stored hydrogen energy
2. Hours - Batteries, stored hydrogen energy, high-energy supercapacitors, pumped hydroelectric storage, compressed air energy storage CAES
3. Minutes - Kinetic energy from long-distance rotating wheels, batteries, molten salt, stored compressed air energy CAES
4. Seconds - High-power supercapacitors, kinetic energy from high-power rotating wheels, high-power supercapacitors, superconducting magnetic energy storage SMES