Scarpa, Federico and Bianco, Vincenzo (2023) Circularity and Sustainability Roadmap for the urban context | Deliverable D2.1. Project Report. RES4CITY.

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Abstract

The present report analyses a set of renewable technologies, fuels, and strategies to enhance the uptake of renewable and sustainable solutions in cities. 33 items are preliminarily scrutinized along six dimensions, namely technical feasibility, economic feasibility, circularity, environmental impact, social acceptance, and gender issues. Out of the 33 items, 11 are analysed in detail in order to understand the potential to be readily applied in urban context. Solar PV Panels. PV panels can now be considered as a standard technology with a substantial deployment in urban contexts. It can be said that the main driver for further development is the regulatory context which can evolve to further support the installations. From the economic point of view, PV panels reached grid parity in many cases and the Capital Expenditure (CAPEX) sharply decreases. The main challenge is linked to the circularity and in the organization of the end-of-life phase for the recycling and reutilization of the materials and components. Solar Thermal Collectors. Low temperature solar thermal collectors can be considered a mature technology diffused in many EU cities, especially where the solar radiation conditions are convenient (e.g., South Europe). They are mainly used to produce domestic hot water, but new applications are also developed for industrial processes (e.g., food processing). From the economic point of view the feasibility depends on the alternative fossil fuel supply, but with the rising natural gas prices their convenience is quite easy to achieve. CAPEX considerably decreased thus large-scale deployments can be achievable. Green Walls/Roofs. Green Walls/Roofs are not a renewable energy solution, but they are an impactful solution for increasing sustainability in cities by mitigating, among others, the heat island effect. The concept is very easy and consists in integrating vegetation in buildings. Despite its simplicity, it is only implemented in a few buildings and infrastructures, most of which became iconic. From the economic point of view the feasibility of the solution depends on the cooling and heating cost since it can contribute to reduce them substantially. Heat Pumps. Heat pump is a pivotal technology for supporting the energy transition. It is the fundamental technology for enabling the electrification of heat generation. Its role in cities is relevant because it allows to switch the building heating demand from the fossil fuels to the power market, thus it permits to exploit the increasing renewable power generation. Different options are available on the market and they are also cost-competitive. The main issue is linked to the environmental sustainability of the refrigerants. However, the environmental impact is only ascribed to refrigerant leakage, while there are no issues during the normal operation. More and more sustainable refrigerants are object of research worldwide. Thermal Energy Storage Technologies. Thermal storages serve to decouple the thermal energy consumption from its generation to ensure the continuity of supply. The scale of thermal storage systems can be different depending on the application. Large scale high temperature solar plants need large storages whereas individual thermal storage systems for domestic applications can be simple and very small (e.g., water-based storage in well insulated tanks). Small thermal storage systems are already feasible from the economic point of view. New systems with increased performances (e.g., in terms of improved insulation for longer storage) are continuously delivered to the market in combination with low temperature solar collectors, in order to provide plug and play solutions. Furthermore, the environmental impact of the domestic solutions is very limited because only standard materials are used. If they are properly recycled and reused (e.g., circulation pumps), a virtuous circle can be activated. Biofuels. Biofuels gained a relevant importance in the last years because they can be easily integrated with the distribution of traditional fossil fuels (e.g., petrol, gasoil, fuel oil, etc.). In fact, blended fuels appeared on the market. 100% biofuel products are also available. On the other hand, biofuel posed a relevant environmental issue in terms of reduction of biodiversity and reduction of land devoted to the production of food products. The most interesting aspect of biofuels is their production starting from waste treatment, in particular organic wastes, such as exhausted vegetables oils. In such a case, a good example of circularity and industrial symbiosis (e.g., food industry and energy industry) would be implemented. E-fuels. Electrofuels gained their popularity recently as possible substitute for conventional fossil fuels. They are produced by exploiting electricity from renewable sources in order to activate chemical reaction and make synthetic fuels (e.g., e-methanol, e-methane, e-ammonia, etc.). On the other hand, the combustion of such fuels determines the emissions of CO2, thus its success depends on the carbon capture storage to implement. Economic aspects are still uncertain since the technology is under development. However, there are economic advantages in the distribution of these fuels because the existing network can be largely exploited. Hydrogen. Hydrogen can be also considered an e-fuel, because through the electrolysis process it can be generated starting from water and electricity. The main advantage of the hydrogen is that a clean combustion can be achieved without pollutant and greenhouse gas emissions. Hydrogen would be a game changer in the transport sector, especially for heavy duty vehicles which have a relevant impact on city (e.g., in cities hosting large harbours for example or in large cities in general). On the other hand, there are still a lot of uncertainties on both technical (e.g., safety concerns, distribution network, storage, etc.) and economic side since the production cost via electrolysis is not yet competitive. Green Financing. To support the energy transition and decarbonization, financial resources are necessary, but public finance is not enough, thus it is necessary to attract private capital for these investments. To this aim innovative forms of financing are to be introduced on the market. On-bill mechanisms are innovative source of financing through the energy bill. The energy utility provides the upfront capital for making sustainable investment and then the users repay the investment on the bill in a number of years. On-tax financing is a mechanism of energy efficiency financing linked to local taxes (e.g., PACE mechanism). Local administrations, e.g., municipalities, provide upfront cost for energy/environmental retrofitting. Users repay the investment cost through local taxes in a fixed number of instalments as given by the specific mechanism. Both on-bill and on-tax mechanisms can be also transferred to next users (e.g., next owner or tenant). Finally, green mortgages are mortgages with lower interest rates with respect to standard ones because they are conditioned to investments in sustainable buildings. Sources of financing for green mortgages are available for commercial banks on the secondary markets and made available by financial institutions such as World Bank, European Investment Bank, etc. Roadmap for the Decarbonisation of Cities. Based on the analysed technologies, renewable fuels, and strategies a roadmap is defined. Main elements and motivation of the roadmap are highlighted, and it is concluded that buildings, transportation sector, and energy system integration are the main aspects to consider for cities decarbonisation.

Item Type:	Monograph (Project Report)
Keywords:	Circularity and Sustainability Roadmap; urban context; RES4CITY; Renewable Energies System for Cities;
Academic Unit:	Faculty of Social Sciences > School of Business
Item ID:	17817
Depositing User:	IR Editor
Date Deposited:	13 Nov 2023 11:53
Publisher:	RES4CITY
Funders:	HORIZON-CSA
URI:	Organisation
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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