Energy storage technologies as techno-economic parameters for master-planning and optimal dispatch in smart multi energy systems

The present article is a critical literature review about studies which are based on LCA (life cycle assessment) and about studies which include environmental issues about concentrating solar systems (concentrating photovoltaic (CPV), concentrating solar power (CSP), etc.). The results reveal that CPV environmental profile depends on several factors such as the materials of the concentrator and the direct solar radiation. On the other hand, there are different factors which influence CSP profile (from environmental point of view), including water use and materials e.g. for storage. By considering the literature review presented it can be noted that: 1) Regarding CPV, there is a need for more studies which investigate different concentration ratios, CPVT (concentrating photovoltaic/thermal) systems, low-concentration CPV, strategies to reduce the impact of certain components such as the tracking (especially for large-scale applications) and the concentrators, 2) Concerning CSP, there is a need for more investigations about dish-Stirling, storage materials, strategies for water savings, soiling effect, 3) In general, regarding concentrating solar systems, there is a need for more studies with Fresnel lenses and reflectors, for small-scale systems for buildings and for multiple final applications (desalination, drying, etc.), 4) With respect to the adopted methods/environmental indicators, certainly CO2.eq emissions, embodied energy and EPBT (energy payback time) can provide useful information for concentrating solar systems; nevertheless, there is a need for utilization of additional methods (e.g. based on midpoint, endpoint approaches) which can also offer useful information.

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Concentrating solar systems: Life Cycle Assessment (LCA) and environmental issues

Recent trends of supercritical CO2 Brayton cycle: Bibliometric analysis and research review

Urban waste management is one of the most challenging issues in energy planning of medium and large cities. In addition to the traditional landfill method, many studies are investigating energy harvesting from waste, not as a panacea but as a foreseeable solution. Thermo-chemical conversion to biogas, or even bio-methane under certain conditions, could be an option to address this challenge. This study focuses on municipal solid waste conversion to biogas as a local energy supply for the cities. Three urban models and their subdivision into urban areas were identified along with a typical Organic Fraction of Municipal Solid Waste (OFMSW) matrix for each urban area. Then, an energy analysis was carried out to provide an optimization map for an informed choice by urban policy-makers and stakeholders. The results highlighted how the urban context and its use could affect the opportunity to produce energy from waste or to convert it in fuel. So, in this case, sustainability means waste turning from a problem to a renewable resource.

Energy Contribution of OFMSW (Organic Fraction of Municipal Solid Waste) to Energy-Environmental Sustainability in Urban Areas at Small Scale

In EU where the architectural heritage is significant, enhancing the energy performance of historical buildings is of great interest. Constraints, such as the lack of space especially within the historical centers and architectural peculiarities, make the application of technologies for renewable energy production and storage a challenging issue. This study presents a prototype system consisting in using the renewable energy from a Photovoltaics (PV) array to compress air for a later expansion to produce electricity when needed. The PV-integrated small scale Compressed Air Energy Storage system is designed to address the architectural constraints. It is located at the unoccupied basement of the building. An energy analysis was carried out for assessing the performance of the proposed system. The novelty of this study is to introduce experimental data of a CAES prototype suitable for dwelling application as well as its integration accounting for architectural constraints. The simulation, carried out for a summer average day, shows that the compression phase absorbs 32 % of PV energy excess in a vessel of 1.7 m3 and the expansion phase covers 21.9 % of the dwelling energy demand. The electrical efficiency of a daily cycle is equal to 11.6 %. If air is compressed at 225 bar, instead of 30 bar, 96.0 % of PV energy excess is stored in a volume of 0.25 m3, with a production of 1.273 kWh, 26.0 % of the demand.

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Small scale Compressed Air Energy Storage application for renewable energy integration in a listed building

Design and off-design performance comparison of supercritical carbon dioxide Brayton cycles for particle-based high temperature concentrating solar power plants

Flexible electricity dispatch for CSP plant using un-fired closed air Brayton cycle with particles based thermal energy storage system

In this paper, a solar tower power plant with a closed Joule-Brayton cycle, of 5 MW rate power, with molten salts thermal storage, located in Seville is presented. The peculiarity of the cycle, using air like fluid work, is to vary, by an auxiliary compressor and a vent valve, the pressure, so that fluid average density, at gas turbine inlet. An adjustment of the mass flow rate, in order to regulate the exit air temperature from the receiver of concentrating solar tower, is obtained. During energy surplus production, the thermal storage energy is loaded. Particular attention is placed to the energy thermal storage, which uses molten salt KCl-MgCl2, suitable for this application due to its high melting temperature, in double tank configuration. The thermodynamic model of the entire plant was implemented using Thermoflex® software, while, for the concentrating tower, WinDelsol software was used. Using time data relating to the locations, the performance of the entire plant, during a year, has been simulated. Preliminary results show that this plant can achieve relevant benefits in total energy production and equivalent operation hours per year, therefore it is competitive with conventional energy production systems. Furthermore, a performances estimation with a cost analysis, using a LCOE parametric analysis, has been performed.

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Francesco Rovense

Papers

Design and off-design performance comparison of supercritical carbon dioxide Brayton cycles for particle-based high temperature concentrating solar power plants

Flexible electricity dispatch for CSP plant using un-fired closed air Brayton cycle with particles based thermal energy storage system

Analysis of a Concentrating Solar Power Tower Operating with a Closed Joule Brayton Cycle and Thermal Storage

A Case of Study of a Concentrating Solar Power Plant with Unfired Joule-Brayton Cycle☆

Optimization of Heliostat Field in a Thermal Solar Power Plant with an Unfired Closed Joule-Brayton Cycle