Energy systems impacts

Energy systems describe the techno-socio-economic interactions and relationships between the production, consumption, storage, transformation and distribution of energy in the different forms of electricity, heat and fuels. In this research area we focus on better understanding these energy systems. In particular, we investigate the impacts and interplay of different technologies (e.g. solar PV, electricity based mobility, hydrogen storage, etc.) with current and future energy systems and vice versa. Due to the different scales (buildings, districts, cities, regions, countries) of energy systems, we apply both top-down and bottom-up approaches. With a bottom-up approach we utilize our group’s expertise of district and building energy systems modelling, while for top-down approaches we rely on a large variety of data and models from other domains (meteorology, hydrology, economy, ecology, geography, sociology, etc.). Due to the high spatial and temporal complexity of the challenges in the energy systems, we apply tools from geographical information systems (GIS) along with data-driven (statistical & machine learning) and physical models.
Figure 1: Schema visualizing how the Energy Systems Impact Research is linked to other areas of the Urban Energy Systems Laboratory.

ongoing projects

  • EBM - Electricity Based Mobility
  • H2E - Study on H2 production at a run-of-river power plant in Aarau
  • JAPtX White Paper

Finished projects

  • BAFU-PtG - Potential analysis of Power-to-Gas in Switzerland

Electricity based mobility

Mobility is currently the largest consumer of fossil energy in Switzerland and causes about one third of Switzerland‘s CO2 emissions. Therefore, substituting fossil energy carriers in the mobility sector by renewable ones is essential to meet the CO2 reduction goals of Switzerland. Three technologies, namely Battery Electric Vehicles (BEV), Fuel Cell Vehicles (FCV) and Synthetic Natural Gas Vehicles (SNGV) have the potential to replace gasoline/diesel-fueled internal combustion vehicles (ICE). All of these technologies use electricity as their primary energy source: BEV directly in the battery and electric engine; FCV and SNGV indirectly as hydrogen (H2) and synthetic natural gas (SNG) produced from electricity via Power-to-Gas (PtG) technologies [Ref]. However, their overall CO2 footprint depends on the CO2 intensity of the used electricity with high values in winter and low values in summer. High winter values are generally caused by importing CO2 intensive electricity from abroad, while low summer values are due to the abundance of renewable electricity (in particular from hydro) in this season.

In this project, commissioned by the Competence Center Energy and Mobility (CCEM), the actual CO2 content of a future electricity based mobility (EBM) is assessed in terms of CO2 emission per km driven. To this end, a Life Cycle Analysis (LCA) with respect to CO2 emissions is conducted on both vehicles and fuels. The CO2 intensity of the used electricity is based on different future passenger car fleet compositions, mobility demand and charging/fueling patterns. Moreover, strategies, such as time-delayed fuel production / electricity supply, are derived to minimize these grid-related CO2 emissions of EBM. A schematic project overview with the different tasks and outcomes is depicted in Fig. 1.

Figure 2: Schematic overview of the different tasks and outcomes in the electricity based mobility project.

H2 energy

As part of an R&D project funded by the Federal Office of Energy (FOE) on the hydrogen (H2) production at a run-of-river power plant, this accompanying study investigates in particular the arrangement.

Based on the pilot operation at the IBAarau hydropower plant, it is analyzed how the production of H2 by means of electrolysis for a logistics fleet of 200 fuel cell trucks can be integrated into the local and national electricity supply. The complex relationships between regional electricity production and consumption, the design of hydrogen production and filling stations, and the needs of fleet operation are analyzed for a past year and an operating strategy for the H2 production is made. Estimated changes in the production of electricity according to the federal “Energy Strategy 2050” with a phase-out of nuclear power and a massive expansion of renewables are also considered. Moreover, the size and design of the H2 storage is analyzed based on real measurements of the H2 consumption at the filling station as well as on a current and future electricity production patterns.

Figure 3: Left: PEM electrolyzer from Proton Onsite C30 at the IBAarau run-of-river pow-er plant. Middle: Fuel pump with a 350 bar dispenser (left) and a 700 bar dispenser (right). In the background is the H2 trailer from H2 Energy, which supplies the filling station with sustainably generated fuel. Right: First 35-ton fuel cell truck with a 100 kW fuel cell.

Potential analysis of Power-to-Gas in Switzerland - Focus on technologies, CO2, locations, electricity, economics and deployment in mobility

Power-to-Gas (PtG) is a process for the conversion of renewable surplus electricity (e.g., from wind and solar PV) into storable chemical energy carriers such as hydrogen, synthetic natural gas (SNG) and liquid hydrocarbon (e.g. methanol). In this study commissioned by the Federal Office for the Environment (FOEN), the technical, geographical and economic potentials of PtG in Switzerland are assessed.

Using high resolution temporal and spatial data, it is analyzed how PtG can contribute to the reduction of fossil CO2 emissions in the mobility sector and how PtG can be integrated into the energy system. Predictions on the available surplus electricity in the current and future Swiss electricity system with a phase-out of nuclear power and a substantial expansion of solar PV are made. As a result, large amounts of surplus electricity are generated from PV in summer, while in winter there is a shortage of (domestic) electricity production and CO2 intensive imports are needed. The high flexibility and seasonal storability of PtG products make them a promising option to still promote the planned expansion of PV, while reducing CO2 emissions in other sectors (such as mobility). As a prerequisite various boundary conditions and dependencies have to be met. A geographical boundary condition is for example the spatial and temporal availability of CO2 sources (cement plants, KVA, ARA), hydropower plants, and natural gas grid feed-in points. These geographical dependencies are evaluated and quantified by means of a GIS analysis (see Fig. 3). Moreover, a business case model is used to show how the competitiveness of PtG products, in particular, depends on low electricity prices and grid fees (see Fig. 4).

Figure 4: Potentials expressed in (1000 t CO2) for a) electricity production from hydropow-er plants b) total available CO2 from cement plants, KVA and ARA, c) effective PtG poten-tial at hydropower plant sites with CO2 transportation of maximum 10 km d) unused poten-tial due to limitations in the available CO2 or hydropower electricity. Source: FSO, The-maKart, 2017, reproduced with swisstopo approval JA160150). (in final version: interactive, zoomable Leaflet plots in 4 tabs)
Figure 5: Composition of the absolute SNG selling price according to production costs (CAPEX and OPEX) and EK yield for four scenarios with diff different boundary conditions regarding PV surplus electricity, CO2 separation, CO2 transportation, and natural gas grid feed-in. Additionally, a subdivided according to the installed power of the PtG plant (in MW_el) and grid fees (in Rp./\kWh_el) is made. CAPEX: colored bars, OPEX: gray bars