One important requirement for the development of a CO2 neutral energy system that forms a base for achieving the climate protection goals is the integration of the electricity, heat and mobility sectors on an urban level. With a large share of the total energy demand and a high density of energy-related infrastructures and actors, cities are key to a successful energy transition. Due to the growing understanding that there is a need for a more sustainable handling of resources, but also due to the increasing decentralization of the energy system, new opportunities and possibilities arise for using technologies and development processes that better exploit existing potentials. The neighborhood level is the ideal platform for implementing these processes, as it can bundle supply services for heating, cooling, electricity and mobility and can offer various system services by increasing the flexibility of electrical and thermal consumers and producers. 

The German Energy Agency (dena) has supported the State Grid Corporation of China (SGCC) with the development of a comprehensive concept for the innovative lighthouse project “Tongli New Energy Town” – a state-of-the-art showcase for an integrated urban energy system using smart and climate friendly technologies. Together with the E.ON Energy Research Center at RWTH Aachen University, dena has developed a simulation approach for calculating an optimized and integrated energy system. In addition, dena has created a holistic assessment system to monitor achievements throughout the planning, implementation and operation phase of the project. Qualitative objectives are translated into measurable assessment categories and indicators and the basis is a set of guidelines for the development of specific plans, policies and processes. These include an integrated energy plan, a building plan, a mobility plan, a land-use plan, as well as a participation plan or communication plan, with the purpose of effectively addressing all objectives.

For dena the project has also proven that there are tremendous benefits within the integrated approaches for the following three reasons:

Integrated urban energy systems promote system efficiency 

Using digitalization technologies, sensors, prediction models and optimization methods, the entire energy production and consumption of the urban area across the sector can be controlled and optimized according to predetermined parameters such as costs, CO2 reduction or utilization of renewable energies. By considering all producers and consumers, the overall efficiency will be increased. Process optimization is further achieved through the application of flexibility options such as demand shift, energy storage, crosssectoral optimization buffering and by avoiding peak loads or shortages. The optimization process is carried out across sectors and all energy infrastructures, including the power grid, the natural gas network, heating and cooling pipes and mobility infrastructures such as electric chargers. Consequently, integrated energy systems do not only optimize energy consumption within the boundaries but also promote total system efficiency.

Integrated urban energy systems use economies of scale 

The increased interaction between buildings through the installation of heating networks and decentralized supply stations at neighborhood level has both economic and ecological advantages. The economic advantages arise both in relation to the investment in and the operation of the heating and cooling supply. On the one hand, specific smaller capacities can be installed per subscriber, since the presence of several energy consumers reduces the simultaneity of use. On the other hand, higher capacities can be installed in the few large generation units, which leads to higher efficiency or, as for CHP plants, to more profitable operation. Furthermore, there are advantages in digital control as it is less complex compared to many small decentralized building systems and can be better operated and updated, which saves costs. These economies of scale are easier to use in new quarters, as decentralized systems can be more successfully implemented at quarter level. Additional challenges are posed in existing buildings, as the interests within the possible heterogeneous ownership structure do not always reflect the technical, economic and social needs. Therefore, the various interests must first be discussed in the portfolio and then, if necessary, optimal systems must be developed in smaller units (cellular approach). Under the best case scenario and depending on whether or not interests change, these could then also be merged in the long run.

Integrated urban energy systems enable optimal use of climate-friendly energy sources in urban areas 

Urban space offers both a variety of climate-friendly energy sources (e.g. waste heat, climate-neutral heat, renewable energies) and a high number of usable areas (facades, roofs, sewage systems, watercourses etc.) for the production of climate-friendly energy. In addition, urban space provides short transport routes for energy and other resources and the possibility of simultaneous use of renewable energies or energy mixes by multiple users. This potential remains largely untapped. Integrated urban energy systems promote the optimal exploitation of sources through efficient land use, networked supply infrastructures and energy storage. In order to ensure efficient use, existing energy infrastructures must be taken into account. Aspects such as public acceptance also play a major role. This includes a sensitive handling of the cityscape (e.g. monument protection), as well as environmental compatibility of the applications. Thus, both new and existing neighborhoods face challenges with regard to the use of climate-friendly energy sources and urban areas, which must be met by an integrated planning and implementation process and the involvement of all actors. 

 However, besides using all advantages of an interconnected urban system, energy efficiency is still the core of the urban energy transition, also on neighborhood level.

Real labs of integrated urban energy systems in Germany and in China 

In Germany, together with over 30 regional key stakeholders of urban energy systems, dena is currently working on the integrated urban energy transition. The goal of this project is to analyze the challenges and requirements for the design and implementation of integrated solutions in an urban context, and to improve the political and economic framework, which would support the development of these practices from real labs to widespread application. In the meantime, dena has also taken the first step towards implementing the same solutions in China. Combining the knowledge gained through the study with German partners with the determination of special requirements for urban development in China, dena will develop the basic structure and key elements of a prototype of an “Integrated Energy Transition Quarter” (IEQ) and intends to initiate the first real-lab pilot projects in 2019.

Article Resource: Econet Monitor Special Green Building