Pressurised large scale hydrogen production by alkaline water electrolysis

Big industry companies are mainly using hydrogen produced directly from hydrocarbons. This process releases huge amounts of CO2. These companies are starting to investigate water electrolysis as an opportunity to reduce CO2 emissions. Electrolysis will produce hydrogen without CO2 emissions if the power used is renewable. The fossil sources is/have been the most economical production method. We are seeing two things happening that can change that. The first is that renewable energy production from solar and wind are starting to get a global foothold. Multiple places the energy from these sources are cheaper compared to fossil sources. The second is the coming economical expense to emit CO2. One of the main key performance indicators (KPI) for water electrolysis at the system level is the capital expenditure (CAPEX). Here, alkaline water electrolysis technology has an advantage compared to other water electrolysis technologies, mainly due to the possibility to use lower cost materials such as KOH, nickel and steel. The cost of hydrogen is also highly influenced by the cost of the electricity required for the process and other operational expenditures (OPEX) and an improvement in the efficiency of the electrolysis process is of high importance. This project targets to significantly reduce the cost of hydrogen produced from water. This project deals with the development of an alkaline pressurized electrolyser for large scale hydrogen production. The main goal of the project is to design, build and test a large scale pressurized electrolyser based on a smaller design currently being tested. At the end of the project, we expect to have a complete demonstrator for an electrolyser capable of producing pressurized hydrogen and able to provide hydrogen to the large hydrogen consumers. The complete demonstrator was not finished at the end of this project. The work will be continued in a follow up project, though. The main challenges were to secure stability of the electrode system and this work required more resources and work. At the end of the project the stability was inside of the requirements. This project has built knowledge about metals and polymers exposed to KOH at high temperatures and pressures. Together with KOH the materials have been exposed to hydrogen or oxygen. The two different gases affect the materials differently. The oxygen affects polymers to a bigger degree. There is a huge selection of polymers available. Chemical compatibility, mechanical properties and cost are the main selection criteria and needs to be balanced. The chemical compatibility with the exact environment inside the electrolysers has not been available and a key topic to investigate in this project. When metals are exposed to oxygen, an oxide layer is created on the surface. This oxide layer is in many instances a protective layer for further oxidation. The thickness and protection of this layer changes with the alloy and environment. This has been investigated. Oxide layers on metals exposed to hydrogen or in a reducing environment can decrease in thickness and make the metal susceptible to repeated oxidation. Flow simulations and flow tests have been conducted to ensure correct internal two-phase flow. This process has now resulted in an optimal design. In the project activation of electrodes is a key work package. Screening of catalysts manufactured at different manufacturing parameters has been done. The best candidates have been better analyzed with equipment located in The Norwegian Fuel Cell and Hydrogen Centre. The tests have given valuable characterization that will go into the choice of electrodes to be implemented in the stack to be built in the project. In parallel internal electrode testing to measure absolute cell voltage and degeneration over time are being done. Testing protocols have been developed and the stability of the electrodes under repeated startups and shutdowns was of special interest. The stack is the core of the electrolyser. The Balance of plant (BOP) is the system around the stack that make the machine work. We are now going through all the parts of the BOP to ensure that intermittent renewable sources can be used. Historically electrolysers has been designed and run on stable sources.

En virkning av prosjektet har vært signifikant kompetansehevning innad i bedriften. Kontakten med prosjektpartnerene SINTEF og IFE har gitt innsikt i disse instituttenes vitenskapelige metoder og ressurspersoner har vært til inspirasjon for adferd og praksis innen R&D. En effekt av prosjektet er at det ble søkt om et nytt prosjekt med de samme forskningsinstitusjonene. Dette for å beholde forskningssamarbeidet og fortsette kompetansehevingen. Forskningsresultatene fra dette prosjektet inngår allerede i bedriftens strategi for fremtidig markeds- og produktutvikling.

The global energy market is growing very fast with the main strategic focus on renewable energy sources, mainly solar and wind. The transition to an energy system based on a large degree of intermittent renewable energy will result in a power generating scenario subjected to both seasonal as well as hourly variability, with significant amount of excess renewable energy (on the order of TWh) emerging in countries across the EU and around the world. Thus, energy storage, in particular Power-to-Gas technologies, e. g. water electrolysis, are expected to play a major role in future energy systems. One of the main key performance indicators (KPI) for water electrolysis at system level is the capital expenditure (CAPEX). Here the alkaline water electrolysis technology has a clear advantage compared to other emerging water electrolysis technologies, mainly due to the possibility to use lower cost materials such as KOH, nickel and steel. On the other hand, hydrogen production cost specifies all cost to bring out one unit of hydrogen (volume or mass) at the installation site. Probably this is the most important KPI for an end user as it allows an economical evaluation. Electricity cost and other remaining operational expenditure (OPEX) to run the electrolysis process as main part of the variable costs. This project targets to significantly reduce the cost of hydrogen produced by water electrolysis and stimulate on-site hydrogen generation from renewables to be used in the industry and transport sector. The PE1000 project deals with the development of an alkaline pressurized electrolyser for large scale hydrogen production. The main goal of the project is to design, build and test a large pressurised electrolyser. However, to do this, some of the electrolyser components and design features are in need of further R&D. In addition, the electrolyser have to undergo extensive testing in order to establish good efficiency and functionality over time.