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EU decarbonization goals require greenhouse gas emission reductions by more than 55% before 2030, and emission neutral goals for 2050, to feasibly reach these goals, green hydrogen can make a huge impact on emissions from hard to abate sectors, where emissions impact can be reduced or eliminated through “Power-to-X” value chains enabled by green renewable hydrogen. Hydrogen production in general is currently predominantly fossil fuel based, therefore low carbon or green hydrogen from water electrolysis coupled with wind and solar power can replace non-renewable based hydrogen for synthesis of carbon neutral methanol fuels for heavy transport, trucks, ships, airplanes. In addition, the value chain utilizing hydrogen as a molecule extend to ammonia which can used for alternative fuel and synthetic fertilizer. Hydrogen as a raw feedstock can be used in Hydrogen Direct Reduction (HDR) for green steel production.

For this to be viable, the investment in a green hydrogen value chains needs to be cost competitive with fossil alternatives, i.e. if the resulting levelized cost of production of hydrogen (LCOH) derivatives does not match polluting alternatives, there won’t be a market for it. Despite advances in electrolysis technology and manufacturing technology green hydrogen still isn’t cost competitive due to high operational expenses from direct electricity consumption.

The foremost cost, capital expenditure of building a hydrogen plant can be reduced through learning driven forces theorised to be like the historic reduction of cost of photovoltaics (PV) and wind turbines as those markets have matured and manufacturing has become efficient since the 1970’s, through scale up of production, and standardization. And, with a potential increased market demand to support the innovation and supply chain development along with the existing renewables infrastructure from wind and PV. This sector coupling contributes much lower electricity prices, from cheaper and more efficient investments in existing renewable energy sources, or the additional investment outlook of a combination of wind and PV together with electrolysis to generate multiple possible revenue streams for a project, selling electricity when the price is high and producing hydrogen when the price is low.

This is the crucial next step for green hydrogen to become a viable solution, operational expenditure (OPEX) consists primarily of the power consumption & the market price of electricity, which, thanks to renewables, has become incredibly cheap to produce in many places. In Denmark there are low consumption periods with high wind and solar output resulting in negative electricity price periods. Ignoring tariffs, tolls, transportation on the power grid etc. this creates the foundation for the Power-to-X idea, to utilize free or cheap power to store in molecules for later consumption in fuels, heat, feedstock for other industries, or even back into electricity in high power cost periods.

 

Apart from the capital expenditure (CAPEX) and the power costs which are the dominant costs of LCOH, primarily affected by market forces and local energy infrastructure, the operations and maintenance (O&M) costs are directly related to the strategy and knowledge of the owner/-operator. These costs can also be compared to different energy storage systems for largescale technoeconomic analysis. For a green hydrogen electrolysis plant there is a need for maintenance of electrical systems, as well as mechanical systems such as pumps, electrodes/stack plates, and pressure vessels. The degradation and subsequent maintenance and operation of these parts is the focus of this project, simulating how to optimally operate the plant in a cost-effective manner to reduce the O&M contribution to the total LCOH, while balancing overall effectiveness and performance indicators.

Together with industrial partners, simulation models for a modular plant will help determine the maintenance requirements, activities, and resulting costs, based on technical information available from the current design and failure rates from actual test sites or databased from comparable industries. This simulation will then be used as input for a process simulation model of a larger plant to optimize the effect of maintenance scheduling around a fluctuating power price market. The future research goals are creation of a digital twin maintenance and operations model of the hydrogen plant concept, to optimize cost, plan maintenance and spare parts strategy, schedule safe maintenance and ensuring long term plant efficiency, minimizing LCOH and maximizing return on investment.