Urban Energy Systems - Challenges and Solutions for Zero Carbon Cities
• HFT Stuttgart University of Applied Sciences
On June 2nd, 2016, the German Center for Research and Innovation (GCRI) New York and the HFT Stuttgart University of Applied Sciences hosted a panel discussion on Urban Energy Systems: Challenges, and Solutions for Zero-Carbon Cities. The speakers discussed energy efficiency strategies and urban refurbishment scenarios, city-wide energy demand and consumption mapping, urban planning based on 3D models, optimization of building performance, and the integration of renewable energy sources in urban energy networks.
Prof. Charles Vörösmarty, Professor of the Department of Civil Engineering and Director of the CUNY Environmental CrossRoads Initiative City University of New York (CUNY), introduced CUNY’s environmental research facility, a focal point for interdisciplinary research on strategic large-scale environmental problems in the metro region of New York, the US, and in other countries. The initiative’s goal is to pave the way for zero-carbon cities. To achieve this, Prof. Vörösmarty and his team bring people from different fields and backgrounds together to get the best diagnosis of a particular problem and to ultimately create solutions. Vörösmarty explained that the initiative’s strategy is to generate and analyze large data sets and advance our understanding of the nature of the city by tracking the behavior of these environmental systems and the interactions with human systems. Vörösmarty’s team uses an interdisciplinary approach by creating a dialogue between various fields of science, including nanotechnology, structural biology, neurobiology, and photonics. Vörösmarty and his team aim to render an accurate environmental picture of New York City by using maps for visualization and analyzing the region and its potential energy sources. This may help to simulate and predict patterns of natural events, such as Hurricane Sandy in 2012.
The next speaker, Prof. Dr. Ursula Eicker, Professor at the Centre for Sustainable Energy Technology at HFT Stuttgart University of Applied Sciences, focused on energy systems and zero-carbon solutions from small European cities, which she hopes will be transferable to more densely populated environments, such as New York City (NYC). So far, her case study includes Vienna and Geneva. She teams up with Stuttgart PhD students, whose major focus area is how buildings dominate energy consumption. The consumption depends on the different types of climate, and whether heating or cooling is necessary in order to find optimal solutions for different challenges. One of the tools her research group relies on are 3D models of urban environments. According to Eicker, making a one hundred percent zero-carbon city is impossible. At present, a forty percent reduction in carbon emissions is more realistic. Eicker emphasized insulation as a possible strategy to reduce energy demand for heating and air-conditioning. In the case of Europe, she mentioned external insulation; for New York City, vacuum insulation would be more feasible. However, most of the time, refurbishing a building’s skin is too expensive. In any case, both the investment costs, as well as the accumulated heating costs should be taken into account. Eicker’s final example was a case study of a small village near Stuttgart that plans to be zero-carbon within the next five years. The village’s strategy is to use a variety of renewable energy sources, such as geothermal energy and photovoltaics for family homes and to install battery storage for accumulated energy. In closing, Eicker explained that larger urban areas, such as New York City, should try to reduce energy demand because renewables cannot cover the entire energy demand of a city’s population.
The next speaker, Michael Bobker, Director of the Building Performance Lab CUNY and Senior Fellow at the CUNY Institute for Urban Systems, presented a report by the NYC government called “Transforming New York City Buildings for a Low Carbon Future,” which analyzed different building sectors. Buildings that have predominantly been built between 1910 and 1950, for example, dominate the floor area of the city. Bobker cited from the report that the energy demand of NYC’s apartment buildings is dominated by heat and hot water. Most vintage apartment buildings use steam heating systems, which require high energy usage but are inefficient, and temperatures are hard to control. Thus, making steam heating more efficient is an important goal for Bobker’s team. These buildings, according to the report’s findings, are in need of lower temperature systems, high efficiency boilers, water heaters, and electrification via heat pumps. Furthermore, Bobker talked about recent findings on frequent leakages from gas distribution that in turn release greenhouse gases which trap heat in the earth’s atmosphere. Hence, Bobker argued that in NYC there is a need to electrify buildings. Bobker concluded by saying it’s up to utility engineers to build out the city’s grid and add renewable sources by using new strategies with the help of the framework he and his colleagues has provided.
Prof. Dr. Volker Coors from the Competence Centre Geodesy and Geoinformatics of the HFT Stuttgart University of Applied Sciences was the final speaker. In his research, Coors focused on building data models for 3D city models and sharing them with the public. First, he showed a 3D map of Stuttgart, which helps to determine the energy demand of each individual building. His research aims to contribute to the energy transition by building simulation tools in order to predict changes, simulate demand, and provide data sets that are fundamental in planning. Coors intends to make the results of his work available to citizens, not only to professionals. He then provided more details by explaining the CityGML, a model for data sets, made by airborne scanning, which is used for quality checks, analysis, and simulations of urban objects. Calculations are made for each building individually. Coors talked about the EU’s goal of having every member country publish its data. International standards for spatial data exchange are issued by the Open Geospatial Consortium (OGC). Concluding his talk, Coors said that 3D models, such as the ones he showed, can be useful to any city, especially large cities such as New York.
In the ensuing discussion, the audience members and the panelists covered issues such as growing urbanization and its effects on energy consumption, the role of solar energy for zero-carbon environments, the energy efficiency of elevators, and whether the height of a building determines its energy consumption.