From our experience working with cities with energy systems models, we identified particular challenges both when developing the model, i.e., in meeting the modeling requirements, and when developing scenarios.
3.1 Identifying Challenges in Meeting Model Requirements
We have realized some patterns that were challenging when developing the model. Sometimes, it concerned the data collection, and sometimes it was about the communication with the stakeholders (municipality officials). We categorized the challenges in meeting the modeling requirements as the following: data availability and quality, communication, knowledge and background.
Data availability and quality: The existing data at the city level are mostly financial, while it is energy data that is needed for the model. For example, municipalities know how much they paid for fuel in a year for city-owned vehicles, but they do not necessarily know how much fuel they consumed. In another example, total electricity consumption in buildings was known, but the purchase distribution per building type was only documented in the economic system. Thus, the available unit of data is not in energy units. Data quality is crucial for base-year calibration, and good data quality is challenging to attain when demand and supply data do not match. This is especially the case when converting financial data to energy units. In the cases when collection is required by law and regulations, data is available. It has been straightforward to collect information on energy-related entities (e.g., district heating plants), even if the companies are privately owned, when their profession is energy. On the other hand, data on non-energy-related entities (e.g., schools), was more difficult to find. Final energy consumption can be directly measured in municipality-owned entities, but it is often not done. In these cases, when only aggregated energy statistics were available, these needed to be disaggregated in order to calibrate the model for the base-year.
Communication: It is crucial that cities understand their energy systems, the model and how they can benefit from it in order for these models to become useful. However, conveying this information is a complex task, since municipalities usually lack energy systems expertise and modelers generally do not have municipal insights. Thus, clear and continuous communication is required between the researcher and the city officials. Moreover, several models and data files are shared during model development. Therefore, finding ways to communicate the model and to share the files are important to have a smooth model development process.
Another challenge is the terminology used in the model and by the researcher, which can make it difficult for the civil servants to understand which data to collect unless there is a common language to communicate about the model. Misunderstanding the required data slows down the data collection and base-year calibration processes. For example, in energy system models, the difference between the final energy demand and the final energy consumption is important, but a civil servant who has not been working on ESOMs might not pay attention to this detail. Therefore, when the data required is not understood, the data collection process takes longer. Communication is crucial, and there is a need, in the beginning, to define how to communicate the project. Multiple ways of communication are needed for different purposes, e.g., file sharing, model explanation, clarification of required data, etc.
Knowledge and background: Civil servants have different backgrounds that may not be related to the field of energy. Even in the case when they have an energy-related background, our experience was that they rarely have energy system modeling expertise. Therefore, one of the main challenges to the collection of adequate information was that the civil servants providing the information had difficulties interpreting the energy system concepts because they lacked the relevant terminology. This sometimes meant that we retrieved the wrong kind of data and sometimes no data at all. This slowed down the process of data collection significantly.
3.2 Identifying Challenges in Working with Scenario Development
In ESOMs, scenarios let us explore future pathways for, e.g., meeting specific climate targets under different conditions. Scenarios typically include coherent assumptions about the main drivers of the energy system and available energy resources, policy options and technologies, which should be internally consistent (Loulou et al.
2016: 10). In the scenario generator, the cities can define scenarios by combining assumptions about the various parameters. However, the scenario generator cannot serve its purpose if the parameters are not clearly understood by the civil servants. We wanted the civil servants to define their scenarios, but many times we saw that they had difficulty understanding how to select parameter combinations. The reason was due to the complexity of the model (capturing the comprehensive energy system, including both energy supply and demand sectors) and that they often wanted to see the impact from using a certain technology and/or energy source (while technologies and energy commodities are chosen by the model in this kind of scenario analysis). Consequently, the challenges are both in the parameter selection and in the complexity topics, and we elaborate them subsequently.
Parameter selection: The scenario generator includes several assumptions like change in demand, CO2-mitigation levels, policy options for the transportation sector, energy savings in the building sector, fuel prices, targets for renewable technology implementations and so on. These assumptions can be divided into two sub-groups: externalities that may impact city energy systems and assumptions that cities can directly impact. Examples of external parameters are: population evolution (impacting the living area, thus impacting the future demand for space heating and hot water), GDP (impacting purchase of goods, therefore impacting the demand on freight transportation) and fuel prices (a key assumption in the model). Examples of scenario parameters that the city can impact and may vary are: targets (e.g., renewable energy target for the purchased electricity; emission reduction target in transportation sector within city borders); and infrastructure (e.g., expansion of cycling infrastructure may impact the share of people who choose cycling instead of driving the car). Among all the various assumptions, selecting consistent parameters to define a scenario and collecting relevant data is challenging because it requires knowledge of national and local targets and conditions.
Complexity: How the parameters defined in the scenario generator may affect the overall energy system is not clear when the civil servants does not have experience of using ESOMs, which might lead to misunderstanding of the assumptions and the scenarios. Understanding the energy system and how various inputs affect the system is not easy, and it is not straightforward to explain. Interactions between the multiple parts of the system produce a complexity that is difficult to understand if you are not an expert.