B1505. Hybrid Plant Aarmatt a novel renewable energy concept applying PEM electrolysis

Transcription

1 B1505 Hybrid Plant Aarmatt a novel renewable energy concept applying PEM electrolysis Marcel Rindlisbacher Hans J. Vock Regio Energie Solothurn Diamond Lite S.A. Rötistrasse 17 Rheineckerstr. 12 CH-4502 Solothurn CH-9425 Thal Tel.: Tel.: marcel.rindlisbacher@regioenergie.ch hans.vock@diamondlite.com Abstract Regio Energie Solothurn has built a plant based on a novel energy concept combining distributed heat, electricity and gas grid to a convergent system, often referred to as Power-to-Gas. Hydrogen from electrolysis is a promising technology providing linkages between other infrastructures such as transportation to provide flexibility in the overall solution. Hydrogen has the capability to store massive amounts of energy in a relatively small volume, with no carbon footprint when generated from electrolysis of water and renewable energy. To be able to use excess / stranded power from their regional PV grid, Regio Energie decided to install 2 PEM electrolyzers of 350 kw input, to generate hydrogen, which will serve as an energy carrier. Hydrogen can be seasonally stored and / or used in various grids if and when needed. The two PEM electrolyzers serve as the core of the system. These units are well suited to handle the fluctuating power available from 0 to 100%. Fast changes can be handled without deterioration of the units as has been evaluated by NREL. Regio Energie selected the PEM electrolyzer of Proton OnSite due to the long-term experience of these units, which are used in industrial applications since 18 years. The need for grid control (e.g., load shifting and frequency regulation) is also an important reason why such electrolyzers are applied. For this purpose, they can be remotely started and stopped based on the grid demand. The paper will report about the practical experience with this concept and the role it can play managing sustainable energies in light of the Energy turnaround goals. It will also inform about the fine-tuning of the operating regimes of this Hybrid plant and the resulting next steps. B1505 / Page 1-6

2 Introduction The Swiss public utility Regio Energie Solothurn ( RES ) has setup a hybrid power plant based on renewable energy, which is unique in Europe. It serves as a lighthouse project for the Energy turnaround as designated by the Swiss Federal Department of Energy. Why is this system unique? It s because of the way the energy storage question has been addressed. When the project started, the need for a backup boiler to the heating power plant for the district heating system was in the center place. The estimated cost was up to 5 million Swiss Francs. Fig. 1. Fig. 1 Starting point However it seemed not meaningful to invest in such a system for a backup situation only. So in light of the energy policy of the Swiss Federal government the Energy Strategy 2050 all turned into an ambitious project: At the Aarmatt site near Solothurn, a facility should be set up which connects the energy carriers - heat - electricity and - natural gas depending on needs. The scenario 2035 served RES as orientation for already completed or envisioned ideas. The challenge of future energy storage was in the forefront: In summer of 2035, RES calculates with electricity overcapacity from photovoltaic plants. Fig. 2. Fig. 2. Estimated Storage requirement for PV overcapacity in Switzerland in 2035 B1505 / Page 2-6

3 1. Concept of the Hybrid Approach In Solothurn alone, production from PV is estimated at 3,8 Gigawatt hours. The question is how to use it. Unlike the question how pumped hydro power storage plants could help solve such future problems, the hybrid plant at Aarmatt in Zuchwil is based on a different concept. It functions as follows: To cut peaks from overcapacity, the «Aarmatt» plant transforms electrical power into hydrogen gas by means of PEM electrolysis according to the so called «Power-to-Gas» concept. This concept also allows to shift electricity produced in summertime into wintertime. On one hand, electrolyzers, Fig. 5, will convert excess electricity into hydrogen. Hydrogen will then be injected into the gas grid. Fig. 3 Overall concept and principle schematics On the other hand and in the midterm, a methanisation plant is foreseen, which also uses hydrogen and synthesizes it together with CO2 into methane. Methane is the major portion of natural gas. Hydrogen can be injected in small amounts into the natural gas storage or grid. When increased electricity demand occurs, natural gas can be retrieved from the existing natural gas storage. Fig. 4 and reconverted into electricity via a combined heat and power plant. The resulting rejected heat will be recovered via heat pumps and fed into the district heating system. This is the basic principle of the hybrid plant at a total investment of approx. 10 million Swiss francs. B1505 / Page 3-6

4 Fig. 4 Existing natural gas storage Fig. 5 Electrolyzer data B1505 / Page 4-6

5 2. Planned further steps and investments Further to the described plant concept and the methanisation, RES is envisioning a number of further process steps. Fig. 6. Among them are: - compressed air storage - battery storage - wood gasification - a geothermal system The RES hybrid plant is a full scale lab of accomplishments. It will stay a construction site for quite some time and this on purpose. It will be a learning site, a research and thinking place which already today serves students for thesis work. And last but not least, it will allow RES to determine further optimization steps. Fig. 6. Current and future process diagram. B1505 / Page 5-6

6 3. Results As of today, all equipment is installed and all functional tests have been completed. The official inauguration took place on June 30, Full production and optimization are in process. The view of the site is shown in Fig. 7 Fig. 7 View of Hybrid plant Aarmatt B1505 / Page 6-6