• Energy Research

Artículos en revistas Similarly to other European countries, mechanisms for the promotion of electricity generation from renewable energy sources (RES) and combined heat and power (CHP) production have caused a significant growth in distributed generation (DG) in Spain. Low DG/RES penetration levels do not have a major impact on electricity systems. However, several problems arise as DG shares increase. Smarter distribution grids are deemed necessary to facilitate DG/RES integration. This involves modifying the way distribution networks are currently planned and operated. Furthermore, DG and demand should also adopt a more active role. This paper reviews the current situation of DG/RES in Spain including penetration rates, support payments for DG/RES, level of market integration, economic regulation of Distribution System Operators (DSOs), smart metering implementation, grid operation and planning, and incentives for DSO innovation. This paper identifies several improvements that could be made to the treatment of DG/RES. Key aspects of an efficient DG/RES integration are identified and several regulatory changes specific to the Spanish situation are recommended. info:eu-repo/semantics/publishedVersion

Artículos en revistas This paper proposes an approach to calibrate incentives for continuity of supply in electricity distribution in Spain. This approach consists on the estimation of the impact of continuity of supply improvements on distribution network costs. For this purpose, distribution costs resulting from different continuity of supply requirements are computed by a Reference Network Model (RNM). The results obtained from the RNM are used to estimate a cost-function that considers continuity of supply a cost driver for distribution costs. This methodology is applied to three Spanish areas of service (an urban one, a semi-urban one and a rural one) in such a way that differences in distribution costs caused by the characteristics of the area type can be taken into account. The analysis indicated that distribution costs are more sensitive to continuity of supply improvements in rural areas of service. It also demonstrated that the incentive for reducing number of service interruptions should be higher than the incentive for reducing duration of service interruptions. Finally, the current Spanish incentive scheme for continuity of supply was analyzed under the perspective of the proposed approach. info:eu-repo/semantics/publishedVersion

Artículos en revistas Under the current European market environment, transmission companies have to decide network expansion by maximizing social welfare. However, generation companies (GENCOs) decide their capacity expansion with the aim of maximizing their own profit. This process, in addition to the increasing penetration of renewable energy, storage and distributed generation, might represent a rupture between short and long-term signals. Therefore, this paper proposes a bi-level formulation for the generation and transmission coordination problem (GEPTEP). We consider a proactive framework in which a centralized TSO represents the upper level while the decentralized GENCOs, that trade in the market, represent the lower level. As a novel feature, an enhanced representative period framework is employed, which allows us to consider operation in both short and long-term storage technologies. A case study is presented to compare the results between perfect and imperfect competition in the market. info:eu-repo/semantics/publishedVersion

AbstractNowadays, the amount of distributed generation (DG) connected to distribution networks is increasing significantly. In a European context, one of the main drivers for this growth is the support of electricity generation from renewable energy sources (RES) and combined heat and power (CHP) plants. Hence, these DG units mostly consist of non‐controllable generation. Distribution is a regulated activity which is, at least, legally and functionally unbundled from the generation activity. These issues, together with the fact that distribution networks were not originally designed to accommodate generation, pose significant challenges on distribution network planning and operation. One of the major concerns of distribution system operators (DSOs) is the impact that large penetration levels of DG may have on distribution network costs. This paper presents a quantification of the impact of DG on distribution network costs in three real distribution areas. Different scenarios of demand and generation have been analysed for each region. Two possible situations are taken into account in each scenario: maximum net demand and maximum net generation. The computation of the distribution network costs was carried out by means of two large‐scale distribution planning models called reference network models (RNMs). Copyright © 2010 John Wiley & Sons, Ltd.

Artículos en revistas The promotion of electricity generation from renewable energy sources (RES) and combined heat and power (CHP) has resulted in increasing penetration levels of distributed generation (DG). However, large-scale connection of DG involves profound changes in the operation and planning of electricity distribution networks. Distribution System Operators (DSOs) play a key role since these agents have to provide flexibility to their networks in order to integrate DG. Article 14.7 of EU Electricity Directive states that DSOs should consider DG as an alternative to new network investments. This is a challenging task, particularly under the current regulatory framework where DSOs must be legally and functionally unbundled from other activities in the electricity sector. This paper proposes a market mechanism, referred to as reliability options for distributed generation (RODG), which provides DSOs with an alternative to the investment in new distribution facilities. The mechanism proposed allocates the firm capacity required to DG embedded in the distribution network through a competitive auction. Additionally, RODG make DG partly responsible for reliability and provide DG with incentives for a more efficient operation taking into account the network conditions. info:eu-repo/semantics/publishedVersion

As the penetration of distributed energy resources (DERs) escalates in distribution networks, new network tariffs are needed to cope with this new situation. These tariffs should allocate network costs to users, promoting an efficient use of the distribution network. This paper proposes a methodology to evaluate and compare network tariff designs. Four design attributes are proposed for this aim: (i) network cost recovery; (ii) deferral of network reinforcements; (iii) efficient consumer response; (iv) recognition of side-effects on consumers. Through an analytical hierarchy process (AHP), the evaluation methodology is applied to compare traditional cost allocation methods, on the basis of 100% energy, 100% demand, and 50% energy-50% demand, with more advanced pricing methods based on distribution locational marginal prices in combination with cost-reflective network charges. Numerical results are obtained through a case study based on the IEEE 34-node test feeder with DER integration. The results illustrate the advantage of advanced pricing methods to promote an efficient integration of DER and demand price-response from consumers.

Artículos en revistas The level of secondary reserve needed in a power system is traditionally settled by system operators according to engineering criteria. This paper proposes a novel methodology to determine the optimum level of secondary reserve based on both engineering and economic criteria. Within the proposed approach a price elastic-quantity demand curve for the secondary reserve is built. This approach assumes that the provision of secondary reserve is made under a competitive market. In this market, the supply curve that collects the bids from generators providing secondary reserve is matched with the calculated elastic demand cost curve. The cross of the supply and demand curves determines the optimal level of secondary reserve and the price for provision of the service. The developed approach is illustrated with a case study based on the current day-ahead secondary reserve market in Spain. info:eu-repo/semantics/publishedVersion

Capítulos en libros It is generally believed that plug-in electric vehicles (PEVs) offer environmental and energy security advantages compared to conventional vehicles. Policies are stimulating electric transportation deployment, and PEV adoption may grow significantly. New technology and business models are being developed to organize the PEV interface and their interaction with the wider grid. This paper analyzes the PEVs integration into a building s Energy Management System (EMS), differentiating between vehicle to macrogrid (V2M) and vehicle to microgrid (V2m) applications. This relationship is modeled by the Distributed Energy Resources Customer Adoption Model (DER-CAM), which finds optimal equipment combinations to meet microgrid requirements at minimum cost, carbon footprint, or other criteria. Results derive battery value to the building and the possibility of a contractual affiliation sharing the benefit. Under simple annual fixed payments and energy exchange agreements, vehicles are primarily used to avoid peak demand charges supplying cheaper off-peak electricity to the building during workdays. info:eu-repo/semantics/publishedVersion