Abstract

In the last decade in Europe, the power generated by Renewable Energy Sources (RES) has significantly increased. For the electric power system, the integration of a high amount of power generated by RES represents a big challenge. Energy Storage Systems (ESS) may help to solve problems related to the grid integration of RES. In this study, an analysis of the benefits that a planned and dedicated Adiabatic Compressed Air Energy Storage (A-CAES) system may provide to a distribution network with a high penetration of RES will be carried out. The A-CAES system, taken into account in this investigation, is based on the proposed German study so-called “ADELE project”. The technical benefits as well as the corresponding costs that A-CAES brings to the system which were analyzed using the load and RES generation time series for 2010 and 2020, and were based on technical data from a selected part of a German distribution power network, were evaluated and results of those broad investigations are presented in this study. The result of the investigations shows that the direct technical benefits are quite limited for the A-CAES technology as it exists today.

Abstract

Electric vehicles (EVs) have the potential to play a crucial role in clean and intelligent power systems. The key to this potential lies in the flexibility that EVs provide by the ability to shift their electricity demand in time. This flexibility can be used to facilitate the integration of renewable energy sources by adjusting EV demand to the variable production of wind or solar energy. On the other hand, the same flexibility can be employed to reduce peaks in network load that could result from a massive adoption of EVs. This PhD thesis aims to improve the understanding of the value of flexible EV demand in the context of multi-actor power systems with a high share of renewable energy sources. We first explore flexible EV demand from a distribution network point of view, and then in the light of renewable energy integration. Moreover, we also bring these perspectives together and investigate mechanisms to align the different objectives related to the distribution networks and renewable energy integration. This thesis thus demonstrates the value of demand response in the sustainable power systems of the future.

Abstract

Electric mobility is assuming a central role in the new world energy scenario where Renewable Energy Sources (RES) have increased their contribution to the electricity production, mainly due to the fact they are characterized by a reduced environmental impact; in the aforesaid context, Electric Vehicles (EVs) can play a significant role to facilitate the integration of RES into the power grid, also within smart grid infrastructures. Public administration represents one of the sectors that can mostly benefit from the use of the EV technology in its fleets; in many countries, governments have introduced incentive policies to support the spread of the electric mobility and car manufacturers are developing EVs for urban transportation users. In this paper, the attention is focused on a smart microgrid project developed at the University of Genoa and based on the integration of RES, EVs and storage systems. In particular, the attention is here pointed on the use of the EVs to highlight the different habits of recharge adopted at the Genoa University. The paper describes the smart microgrid test-bed facility at the Savona Campus and reports the most significant results relative to an experimental campaign conducted on EVs.

Abstract

International audience; Africa is on the way of a long term development to give access to energy to all citizens wherever they live, either in urban or rural areas. The energy access is mandatory to accelerate the economic growth. Besides, African citizens also require a better access to mobility, both individual or collective. African countries also encourage initiatives for clean electricity generation and clean mobility. Thus, considering the innovative smart grids solutions that are already proposed or will be proposed in the future, electric mobility means could bring distributed energy storage capacities to the electrical grids. This could mainly be true in the case of islanding areas were photovoltaic generation will likely deliver the main part of electrical energy. The present paper aims at promoting the idea of a coupled approach for energy and mobility developments considering the storage capacities of electric vehicles or electric motorcycles.

Abstract

Gas pressure reduction stations are commonly applied to decrease the pressure of natural gas in the transmission pipelines. In such stations, natural gas is expanded in throttling valves without producing any energy. Through the use of expander in natural gas pressure reduction stations, it is possible to recover the pressure energy of the natural gas during expansion, and drive the electrical generator. Possible solutions include turbines and volumetric expanders. However, turbines are complicated and expensive, while volumetric expanders are simple and cheap. This paper presents an analytical modeling of rolling piston expander work conditions when adopted to natural gas expansion. The main objective of this research was therefore a comprehensive analysis of influence of varied sizes of the expander components and natural gas thermal properties at the inlet and at the outlet of the expander, on the expander output power. The analysis presented in this paper indicates that the rolling piston expander is a good alternative to the turbines proposed for energy recovery in natural gas pressure reduction stations. Document type: Article

Abstract

The share of renewable energy sources (RES)’ production in energy mixes, especially the ones of PV panels and wind farms, has been continuously increasing during the last few years. Similarly, a strong development of battery electric vehicles (EV) is expected within the next years. However, these two new innovations could trigger security issues on electrical grids, in particular local congestions and voltage deviations from the required standards. One way to mitigate these problems could be to combine the charging periods of the EVs with the local RES production. This paper aims at analysing the possibility to implement this kind of smart charging strategy in France by 2020, taking into account the wide diversity of local energy mixes in France and their seasonal dependencies. First, the authors identify four different energy mixes representative of most of the local French mixes, each one related to a region in France. Then, we model the charging load curves of the EVs at the substation level for the same regions. We deduce the “green charging ratio” (GCR) without any charging management strategy. The same ratio is then computed assuming that an Energy Management System (EMS), which goal is to maximize this ratio, controls the EV charging patterns. The results are provided for each region and seasons. They show a wide diversity of green charging ratio achievable: in very windy regions, the GCR without any EMS is already rather high on the contrary, in sunny regions, the GCR is much improved with the implementation of the EMS. In such regions, the GCR can also be enhanced with the penetration of charging stations at working places. Document type: Article

Abstract

Electric vehicles (EVs) are recognized as promising options, not only for the decarbonization of urban areas and greening of the transportation sector, but also for increasing power system flexibility through demand-side management. Large-scale uncoordinated charging of EVs can impose negative impacts on the existing power system infrastructure regarding stability and security of power system operation. One solution to the severe grid overload issues derived from high penetration of EVs is to integrate local renewable power generation units as distributed generation units to the power system or to the charging infrastructure. To reduce the uncertainties associated with renewable power generation and load as well as to improve the process of tracking Pareto front in each time sequence, a predictive double-layer optimal power flow based on support vector regression and one-step prediction is presented in this study. The results demonstrate that, through the proposed control approach, the rate of battery degradation is reduced by lowering the number of cycles in which EVs contribute to the services that can be offered to the grid via EVs. Moreover, vehicle to grid services are found to be profitable for electricity providers but not for plug-in electric vehicle owners, with the existing battery technology and its normal degradation. Document type: Article

Abstract

The aim of the study is to analyze how the country with the highest percentage of electric vehicles as is Norway has managed to become it and analyze the case of Japan and Spain with the charact of each country. The batteries are evolving and increasing their performance, but it is necessary a safe network of charging stations for electric vehicles to reduce the "range anxiety". A discuss of the electric car penetration with different Policies and Legislacy to incentivize the electric vehicle will be made to see the Spanish situation respect to Norway and Japan.