scholarly journals Towards Fossil Free Cities—A Supermarket, Greenhouse & Dwelling Integrated Energy System as an Alternative to District Heating: Amsterdam Case Study

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 347
Author(s):  
Nick ten Caat ◽  
Luuk Graamans ◽  
Martin Tenpierik ◽  
Andy van den Dobbelsteen

The municipality of Amsterdam has set stringent carbon emission reduction targets: 55% by 2030 and 95% by 2050 for the entire metropolitan area. One of the key strategies to achieve these goals entails a disconnection of all households from the natural gas supply by 2040 and connecting them to the existing city-wide heat grid. This paper aims to demonstrate the value of considering local energy potentials at the city block level by exploring the potential of a rooftop greenhouse solar collector as a renewable alternative to centralized district heating. An existing supermarket and an ATES component complete this local energy synergy. The thermal energy balance of the three urban functions were determined and integrated into hourly energy profiles to locate and quantify the simultaneous and mismatched discrepancies between energy excess and demand. The excess thermal energy extracted from one 850 m2 greenhouse can sustain up to 47 dwellings, provided it is kept under specific interior climate set points. Carbon accounting was applied to evaluate the system performance of the business-as-usual situation, the district heating option and the local system. The avoided emissions due to the substitution of natural gas by solar thermal energy do not outweigh the additional emissions consequential to the fossil-based electricity consumption of the greenhouse’s crop growing lights, but when the daily photoperiod is reduced from 16 h to 12 h, the system performs equally to the business-as-usual situation. Deactivating growth lighting completely does make this local energy solution carbon competitive with district heating. This study points out that rooftop greenhouses applied as solar collectors can be a suitable alternative energy solution to conventional district heating, but the absence of growing lights will lead to diminished agricultural yields.

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4292
Author(s):  
Lidia Lombardi ◽  
Barbara Mendecka ◽  
Simone Fabrizi

Industrial anaerobic digestion requires low temperature thermal energy to heat the feedstock and maintain temperature conditions inside the reactor. In some cases, the thermal requirements are satisfied by burning part of the produced biogas in devoted boilers. However, part of the biogas can be saved by integrating thermal solar energy into the anaerobic digestion plant. We study the possibility of integrating solar thermal energy in biowaste mesophilic/thermophilic anaerobic digestion, with the aim of reducing the amount of biogas burnt for internal heating and increasing the amount of biogas, further upgraded to biomethane and injected into the natural gas grid. With respect to previously available studies that evaluated the possibility of integrating solar thermal energy in anaerobic digestion, we introduce the topic of economic sustainability by performing a preliminary and simplified economic analysis of the solar system, based only on the additional costs/revenues. The case of Italian economic incentives for biomethane injection into the natural gas grid—that are particularly favourable—is considered as reference case. The amount of saved biogas/biomethane, on an annual basis, is about 4–55% of the heat required by the gas boiler in the base case, without solar integration, depending on the different considered variables (mesophilic/thermophilic, solar field area, storage time, latitude, type of collector). Results of the economic analysis show that the economic sustainability can be reached only for some of the analysed conditions, using the less expensive collector, even if its efficiency allows lower biomethane savings. Future reduction of solar collector costs might improve the economic feasibility. However, when the payback time is calculated, excluding the Italian incentives and considering selling the biomethane at the natural gas price, its value is always higher than 10 years. Therefore, incentives mechanism is of great importance to support the economic sustainability of solar integration in biowaste anaerobic digestion producing biomethane.


2021 ◽  
Author(s):  
Lino Carnelli ◽  
Carla Lazzari ◽  
Tamara Passera ◽  
Chiara Sartori ◽  
Joseph Epoupa Mengou

Abstract According to Eni's mission to reach carbon neutrality in the countries where it operates, the development of renewable energy could be a key element in the company's strategy for evolving the business model towards a low carbon scenario. In this context, concentrating solar technology can provide a real solution in order to goal the carbon neutrality. Solar thermal energy could be an alternative source to the fossil fuel in industrial processes and also in the oil&gas sector, where the upstream operations (dewatering, stabilization, sweetening…) require substantial amounts of heat. Usually this heat is easily produced by combustion of natural gas available at the oil&gas site. Concentrating Solar Heat (CSH) technology allows to produce process heat by using specific collectors that concentrate the solar radiation onto a receiver where a heat transfer fluid is heated at medium/high temperature. A thermal energy storage can be added to the solar field to increase the solar fraction and reducing so the CO2 emissions. The fraction of thermal energy not covered by the CSH plant can be provided by a fossil source that acts as a back-up. With this in mind, a pre-feasibility study was carried out for the integration of a medium temperature(∼200-300°C) concentrating solar plant with or without a thermal storage system and a back-up gas heater in an oil&gas site located in North Africa. The solar heat partially replaces the duty necessary to the heat exchangers that heat the crude to guarantee the separation from water and best stabilization. Reflective areas of the solar field and total occupancy, thermal energy production during the year, solar multiple and preliminary evaluations of cost of investment are presented. Obviously, the reduction of CO2 emission increases with the solar fraction but the competitiveness and cost-effectiveness of the integration strongly depend on the local cost of natural gas, the presence of government incentives, CO2 credit tax, etc. In any case the proposed solution represents an important step towards energy transition.


2017 ◽  
Vol 122 ◽  
pp. 865-870 ◽  
Author(s):  
Martin Joly ◽  
Gabriel Ruiz ◽  
Franz Mauthner ◽  
Paul Bourdoukan ◽  
Morgane Emery ◽  
...  

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Elizabeth Ehrke ◽  
John R. Reisel

While ethanol use as a vehicle fuel has been promoted as a renewable alternative to fossil fuels, current production methods of ethanol from corn feedstock rely heavily on the combustion of nonrenewable fuels such as natural gas. Solar thermal systems can provide a renewable energy source for supplying some of the heat required ethanol production. In this paper, a model to analyze the feasibility of using solar thermal energy to reduce natural gas consumption in ethanol production is described and applied. Sites of current ethanol production facilities are used to provide a realistic analysis of the economic feasibility of using solar thermal energy in the ethanol production process. The results show that it is not reasonable to expect to replace all of the natural gas consumption in the heating processes in ethanol production but that application of solar thermal energy can be applied to a specific subsystem such as the preheating of boiler makeup water. Profitability of systems for replacing a fraction of the natural gas is analyzed. It is found that both location and local natural gas prices are important in determining whether to pursue such a project and that solar thermal systems should have long-term profitability.


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