Project Description
Goals and Approach
In order to find the best portfolio of technologies, given the complexity of the system, several aspects must be tackled at the same time. Therefore, different key areas were identified and investigated within the IMES project, under the coordination of the joint umbrella project:
- the time-resolved future building energy demand and integration of technologies into buildings (using the energy-hub concept),
- the technology performance prediction and integration,
- the economic and market analysis,
- the overall energy-hub system control,
- the social evaluation.
The IMES approach to tackle the issues is shown in the following figure.
Starting from the data input for different selected test cases, the project provided as main outcome the optimized multi-energy hub solution in terms of technology portfolio, hub layout and operation and control approach. The optimization methodology required an iterative information exchange among IMES-TEC, IMES-BP, IMES-SC and IMES-ECO while applying the social constraints given by IMES-SE.
Accordingly, IMES-TEC provided the technical assessment and the simulation tools required by IMES-BP to build and evaluate the most promising hub layouts for a given neighbourhood area; IMES-SC then established the operation and control strategy taking into account the technology limitations and the interactions with the electric and gas grids. The economic evaluation was performed by IMES-ECO. IMES-SE defined the social acceptance boundaries for different hub-solutions (in terms of technology, cost and control requirements).
Furthermore, in order to assess the future potentialities of decentralized multi-energy hub systems, IMES evaluated the deployment of the optimized configurations in 2050: the interaction of the decentralized hub-systems with other power generation systems (e.g. geothermal, hydropower, stand-alone PV) were assessed defining different scenarios for energy supply mix. Accordingly, the optimized hub configuration was updated performing a sensitivity analysis on possible technology improvements, technology learning curves, new building requirements and grid operating conditions. Given the high interdependence of the above mentioned analyses, a continuous information exchange was established during the project, which was guaranteed and coordinated by the umbrella project.
Bringing together all the required expertise, from the thermodynamic to the economic and social point of view, IMES enabled a clear assessment of the potential role of decentralized multi-energy sys- tems.
In Switzerland (and many other countries) a major part of the final energy demand is due to buildings. Both energy demand reduction measures by increasing the building energy efficiency and active energy generation will be required in the future. This can be achieved with local integration of renewable energy systems and connecting buildings with local energy grids and decentralized energy production facilities. To overcome periods where energy from renewables is not available, micro cogeneration systems (e.g. internal combustion engines, micro gas turbines, and fuel cells) and energy storage (power to gas, batteries, etc.) are required.
The goal of this sub-project IMES-BP was to develop models and methods to determine, for given cases, the best combination of technologies and to provide a comprehensive analysis of the decentralized energy production at neighbourhood scale. This included i) a method to assess future buildings' energy consumption, ii) methods to assess the potential of integrating renewable energy carriers at both building and neighbourhood level, iii) the development of an optimization tool, which is based on the energy hub concept, to assess the performance of a combination of conversion and storage technologies to manage energy flows at building and neighbourhood level iv) and finally, the development, assessment and parametric analysis of future decentralized energy system layouts for different neighbourhood configurations, leading to the identification of the best solutions for the future.
Principal investigators: Dr. Kristina Orehounig, Prof. Dr. Jan Carmeliet
The objective of IMES-ECO was to assess the economic feasibility of the energy hub systems considered in IMES. Besides technology and energy costs, the interaction of the different energy supply and storage technologies, the energy demand patterns and dynamic technological learning were investigated.
The project was structured on four main activities:
- Model development: The existing, Single-Building-PV-Battery, techno-economic model was extended into a District-Multi-Energy-Multi-Storage model. In order to assess future scenarios, the new model included a technology learning module. As a novel approach and methodological contribution to literature, non-market policies were introduced into the model, besides the carbon tax, such as market niche-policies helping to trigger cost reduction via learning-by-doing.
- Data collection: Capital costs for "first of its kind" and “n- of its kind” were assessed for the key technologies of the energy hubs. This formed the basis for the technological learning module.
- Economic assessment: The economic assessment aimed at deriving key performance indicators for energy-hubs, which included the Net Present Value (NPV), Internal Rate of Return (IRR) and life-cycle greenhouse gas emissions. Depending on the details of the decision situation, a Monte Carlo Simulation was conducted in order to evaluate the uncertainties immanent in the technical and context factors.
- Deployment pathways: To effectively support widespread adoption of sustainable multi-energy-hubs, besides a static perspective on single sites, a dynamic perspective on the possible evolution of the technology was required. Therefore, potential early markets for the multi-energy-hub systems were identified through structured interviews with the industry and research partners as well as through the evaluation of past development of similar technologies.
Principal investigator: Prof. Dr. Volker Hoffmann
Increasing energy efficiency at the unit and neighbourhood level for residential, commercial and industrial through innovative approaches is crucial for achieving Switzerland’s strategic objectives in the energy domain. In order to pursue this aim it is necessary to develop more advanced control algorithms to appropriately schedule energy utilisation by fully exploiting the novel conversion, storage and allocation possibilities offered by integrated energy hub systems. IMES-SC objective is to develop and implement a viable control scheme for the operation of such entities. The proposed scheme must be capable of appropriately controlling the relevant generation, conversion and storage technologies in order to meet the required electric and heat demand while ensuring performance optimization regarding, e.g., economic costs, losses, or CO2 emissions and by also taking the interdependency of the different energy carriers inherently into account.
A promising approach for addressing such multivariable and multiobjective problems is the use of model predictive control (MPC) methods, as such methods are capable of controlling complex systems with both operational constraints and time-varying objectives. MPC is suited for control of multi-carrier systems, since it can adequately take into account the dynamics of the energy storage devices and the characteristics of the electricity and natural gas networks. By using MPC, actions can be determined that anticipate future events, such as increasing or decreasing energy prices or changes within the load profiles. Operation costs are reduced by exploiting forecasts about future loads, weather, and energy availability, to plan an optimal energy use scenario for a medium term (several days) horizon. The strategy is recalculated typically every 15 minutes to compensate for changing operating conditions. This allows predictive action, such as storing energy before peak times, changing the settings of a power plant with sufficient lead-time, or starting up an additional power plant as required.
Principal investigators: Dr. Turhan Demiray, Prof. Dr. Roy Smith
IMES-TEC addressed the development of the thermodynamic models of the different technologies considered in IMES. Especially, micro-cogeneration systems based on natural gas and hydrogen and power-to-gas energy storage were investigated.
The main objectives of this project, in tight connection with the umbrella project, were:
- To provide reliable and detailed thermodynamic simulations of all the natural-gas/biogas/hydrogen based technologies considered in the project, i.e. micro-gas turbine, fuel cells and internal combustion engine.
- To provide reliable and detailed thermodynamic simulations of the technologies adopted for power-to-gas energy storage, e.g. hydrolyser.
- To define the level of simplification (i.e. reduced order model) required for the simulation of the integrated multi-energy hub and its optimization.
- To define the technology barriers for both energy production and storage when connected to the grids (electric grid, natural gas grid and heat grid) and to assess their influence on the system optimization.
Principal investigators: Prof. Dr. Marco Mazzotti, Dr. Ndaona Chokani
A promising way to promote renewable energy production are decentralised (i.e. neighbourhood-scale) "multi-energy hubs". These systems (hereafter referred to as energy hubs) integrate renewable sources, small-scale natural-gas-based combined heat and power production, various methods for energy storage, and active demand side management.
However, the implementation of a decentralized energy system at neighbourhood scale presents a variety of challenges, ranging from selecting an optimal set of technological components to potential conflicts between different involved actors. The latter is especially important for the case of Switzerland because of the lack of available land for greenfield projects and the relatively high population density. Moreover, there is a lack of understanding of the societal implications of energy hubs. IMES-SE project addressed the guiding question "What are societal challenges and opportunities for the realisation of energy hubs in Switzerland?" based on the following activities:
- Identification of societal challenges and opportunities for the realisation of energy hubs (literature study and expert interviews)
- Profiles of energy hub actor groups: characterisation of the different types of actors involved in energy hub projects (survey among the population)
- Analysis of the implementation potential of actual energy hubs (focus groups and experimental survey)
- Assessment of opportunities and risks in realising energy hubs from a larger community perspective (expert workshop that includes community representatives).
This sub-project provided decision-makers and investors with guidelines on what locations have a high societal potential to host energy hubs and how to organise the respective siting and communication process.
Principal investigator: Dr. Roman Seidl