Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - ECo (Efficient Co-Electrolyser for Efficient Renewable Energy Storage - ECo)

Teaser

Europe’s ambitious goals to counteract global warming require a continuous increase of energy production from renewable sources. Wind and solar technologies deliver fluctuating electricity, which does not correspond to the consumption patterns of our society. At the same...

Summary

Europe’s ambitious goals to counteract global warming require a continuous increase of energy production from renewable sources. Wind and solar technologies deliver fluctuating electricity, which does not correspond to the consumption patterns of our society. At the same time, society requires solutions that allow for decarbonization of the transportation sector where electrification is difficult to impossible.
High temperature electrolysis provides a solution to these challenges. It promises an efficient method of storing energy, short and long term alike, as well as a way of creating truck diesel or jet fuel with limited environmental impact. Solid oxide electrolysis cells (SOEC) can convert steam and CO2 directly (co-SOE), using renewable electricity, to synthesis gas (hydrogen and carbon monoxide). The synthesis gas can be converted to methane, for easy storage and distribution in the extensive European natural gas infrastructure, or to various types of fuel for transportation, by known industrial processes. The efficiencies of the electrolysis exceed 90%. Industrial processes that emit CO2 or biomass treatment plants can supply the gas for the co-SOE process; in the future, it may be captured directly from the atmosphere, creating a closed carbon loop.
Challenges of the SOE technology towards commercialization are degree of matureness, costs, and lifetime, which the ECo project put into focus. The overall goal of the ECo project was to develop a highly efficient process for conversion of excess renewable electricity into distributable and storable hydrocarbons via co-SOE.
More specifically, the ECo project aimed at:
Reducing costs by improving state of the art (SoA) electrolysis cells
Increasing lifetime by identifying safe operating windows and understanding durability under realistic conditions at cell & stack level
Maturing the technology by validating the concept at system level
Facilitating commercialization by design of a plant integrating co-SOE with fluctuating electricity input and methane production for analysis of optimal operating parameters
Identifying techno-economic and environmental benefits of using the plant in existing scenarios, including a life cycle assessment (LCA).

Work performed

ECo delivered four improved cell versions and verified them at cell & stack level. They take advantage of existing materials and manufacturing paths, which facilitates implementation into large-scale production. ECo results paved the way for further improvements not only by developing better cells but also by increasing the understanding of the detailed durability behavior of cells & stacks under relevant conditions. The project showed that operating windows exist that allow for low degradation rates of less than 1% per 1000 h on cell/stack level, and in some cases rates of zero. The ECo project demonstrated that going from ideal laboratory to more realistic operating modes does not increase degradation. A system test integrating improved ECo cells reached an exceptional high efficiency of 94% (based on higher heating value).
A Power-to-Methane plant design allows identifying SOE system parameters to achieve a given output like gas production or efficiency. Three types of industrial plants were identified for integration with the modelled Power-to-Methane process (“ECo concept”) with the aid of main players in the respective sectors:
- Cement plant with oxy combustion CO2 capture:
The ECo concept supplies the needed oxygen. Methane formed through the ECo concept substitutes part of the fossil fuel needed for cement production. The benefits are thus reduction of fossil fuel use and of CO2 emissions.
- Biomass gasification plant:
The ECo concept boosts the methane production of this plant through using the CO2 bi-product.
- Biogas plant for methane production:
The methane output is doubled by using the ECo concept because the inherent CO2 in the biogas mixture is converted into methane. CO2 is thus valorized and emission avoided.
A techno-economic assessment used these three specific cases. Access to cheap and CO2-lean electricity is crucial for the economic viability. Some European countries already have a high share of renewable electricity in the grid and an integration with the ECo concept is thus attractive. Moving – as planned - to fossil-free electricity production will enhance the economic advantages.
The LCA compared the three cases mentioned above with the base case (the plants without the ECo system). The ECo concept yields benefits in all three cases, granted the right local context. The highest benefits arise in the cement plant case study with savings of up to 240.000 tons CO2-eqivalent annually. These savings will only increase with the increasing decarbonization of the electricity grid.
The ECo concept and results were lively disseminated to a broad community, including the public, the industry, and the scientific community (19 conference contributions, 13 peer-review articles), as well as the policy makers (popular articles). The used media involved public events, the Hannover Fair, visits, posters and oral presentations, website, brochure, social media, workshops, video and more. In that way, the communication has reached a large variety of audience at different knowledge and influential levels.
Exploitation of the results is within reach for a number of SOE players. In particular, a workshop jointly organized by EU ECo and the EU GrInHy projects illustrates the immense attention by attracting 40 experts from 8 European countries, from 9 research and 8 industrial players, who exchanged views on status, progress, and critical issues on the path of SOE towards the market.

Final results

Over the project period the technology readiness level (TRL) increased from 3 (Applied Research) to 5 (Large Scale Prototype).
The improvement of the electrolysis cells allows for 100 oC lower operating temperature with the same gas output as compared to SoA. This achievement directly translates into reduced costs. Each of the cells contains parts from at least two project partners, demonstrating the obtainable synergies of a close collaboration throughout Europe.
Durability of cells and stacks in co-SOE operation reached a value threshold needed for commercialization (degradation rates <1% /1000 h) including realistic operation conditions such as “wind-profile” electricity and high-pressure operation. A system with improved ECo cells reached high electrolysis efficiencies of 94%. These results demonstrate impressively that SOE is an efficient technology solution for utilizing intermittent electricity for energy storage – the main objective of the ECo project.
The ECo project delivered, for the first time, a co-SOE plant design including renewable electricity input and methane output. This model allows for definition of optimum parameters to achieve high efficiencies, gas output, etc.
Putting this technology into specific scenarios made it possible to assess economic and environmental impacts and the related local / political conditions and to perform LCAs. This allows potential users to carry out substantiated evaluations based on facts & numbers. Favorable conditions exist already now. Furthermore, Europe’s goals of reducing the use of fossil fuels for electricity productions favor the presented ECo concept even more.

Website & more info

More info: http://www.eco-soec-project.eu/.