Transmission Benefits of Co-Locating Concentrating Solar Power and Wind

In some areas of the U.S. transmission constraints are a limiting factor in deploying new wind and concentrating solar power (CSP) plants. Texas is an example of one such location, where the best wind and solar resources are in the western part of the state, while major demand centers are in the east. The low capacity factor of wind is a compounding factor, increasing the relative cost of new transmission per unit of energy actually delivered. A possible method of increasing the utilization of new transmission is to co-locate both wind and concentrating solar power with thermal energy storage. In this work we examine the benefits and limits of using the dispatachability of thermal storage to increase the capacity factor of new transmission developed to access high quality solar and wind resources in remote locations

Capacity Value of Concentrating Solar Power Plants

This study estimates the capacity value of a concentrating solar power (CSP) plant at a variety of locations within the western United States. This is done by optimizing the operation of the CSP plant and by using the effective load carrying capability (ELCC) metric, which is a standard reliability-based capacity value estimation technique. Although the ELCC metric is the most accurate estimation technique, we show that a simpler capacity-factor-based approximation method can closely estimate the ELCC value. Without storage, the capacity value of CSP plants varies widely depending on the year and solar multiple. The average capacity value of plants evaluated ranged from 45%?90% with a solar multiple range of 1.0-1.5. When introducing thermal energy storage (TES), the capacity value of the CSP plant is more difficult to estimate since one must account for energy in storage. We apply a capacity-factor-based technique under two different market settings: an energy-only market and an energy and capacity market. Our results show that adding TES to a CSP plant can increase its capacity value significantly at all of the locations. Adding a single hour of TES significantly increases the capacity value above the no-TES case, and with four hours of storage or more, the average capacity value at all locations exceeds 90%

Comparison of Capacity Value Methods for Photovoltaics in the Western United States

This report compares different capacity value estimation techniques applied to solar photovoltaics (PV). It compares more robust data and computationally intense reliability-based capacity valuation techniques to simpler approximation techniques at 14 different locations in the western United States. The capacity values at these locations are computed while holding the underlying power system characteristics fixed. This allows the effect of differences in solar availability patterns on the capacity value of PV to be directly ascertained, without differences in the power system confounding the results. Finally, it examines the effects of different PV configurations, including varying the orientation of a fixed-axis system and installing single- and double-axis tracking systems, on the capacity value. The capacity value estimations are done over an eight-year running from 1998 to 2005, and both long-term average capacity values and interannual capacity value differences (due to interannual differences in solar resource availability) are estimated. Overall, under the assumptions used in the analysis, we find that some approximation techniques can yield similar results to reliability-based methods such as effective load carrying capability

Capacity Value of Solar Power: Report of the IEEE PES Task Force on Capacity Value of Solar Power

This paper reviews methods used for adequacy risk assessment considering solar power, and for assessment of the capacity value of solar power. The properties of solar power are described as seen from the perspective of the balancing authority, comparing differences in energy availability and capacity factors with those of wind. Methodology for risk calculations considering variable generation (VG) are then surveyed, including the probability background, statistical estimation approaches, and capacity value metrics. Issues in incorporating VG in capacity markets are described, followed by a review of applied studies considering solar power. Finally, recommendations for further research will be presented

Outcomes After Stereotactic Body Radiation Therapy as a Bridging Modality to Liver Transplantation for Hepatocellular Carcinoma

Purpose: For patients with hepatocellular carcinoma awaiting liver transplantation (LT), stereotactic body radiation therapy (SBRT) has emerged as a bridging treatment to ensure patients maintain priority status and eligibility per Milan criteria. In this study, we aimed to determine the efficacy and safety of SBRT in such situations. Methods and Materials: A retrospective analysis was conducted of the outcomes of 27 patients treated with SBRT who were listed for LT at 1 institution. Among these, 20 patients with 26 tumors went on to LT and were the focus of this study. Operative reports and postoperative charts were evaluated for potential radiation-related complications. The explant pathology findings were correlated with equivalent dose in 2 Gy fractions and tumor size. Results: Median pretreatment tumor size was 3.05 cm. Median total dose of radiation was 50 Gy delivered in 5 fractions. Pathologic complete response (pCR) was achieved in 16 tumors (62%). Median interval from end of SBRT to transplant was 287 days. Of the 21 tumors imaged before transplant, 16 or 76% demonstrated a clinical complete response based on modified Response Evaluation Criteria in Solid Tumors criteria. There was no significant correlation between pCR rate and increasing tumor size (odds ratio [OR], 0.95; 95% confidence interval, 0.595-1.53) or pCR rate and equivalent dose in 2 Gy fractions (OR, 1.03; 95% confidence interval, 0.984-1.07.) No patients experienced radiation-related operative or postoperative complications. Of the 27 patients who were listed for transplant, the dropout rate was 22%. Two of the 5 patients with Child-Pugh score 10 died of liver failure. Conclusions: These data demonstrate that SBRT as a bridging modality is a feasible option, with a pCR rate comparable to that of other bridging modalities and no additional radiation-related operative or postoperative complications. There was no dose dependence nor size dependence for pCR rate, which may indicate that for the tumor sizes in this study, the radiation doses delivered were sufficiently high

Nord Pool Ontology to Enhance Electricity Markets Simulation in MASCEM

This paper proposes the use of ontologies to enable information and knowledge exchange, to test different electricity market models and to allow players from different systems to interact in common market environments. Multi-agent based software is particularly well fitted to analyse dynamic and adaptive systems with complex interactions among its constituents, such as the complex and dynamic electricity markets. The main drivers are the markets’ restructuring and evolution into regional and continental scales, along with the constant changes brought by the increasing necessity for an adequate integration of renewable energy sources. An ontology to represent the concepts related to the Nord Pool Elspot market is proposed. It is validated through a case study considering the simulation of Elspot market. Results show that heterogeneous agents are able to effectively participate in the simulation by using the proposed ontologies to support their communications with the Nord Pool market operator.This work has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 641794 (project DREAM-GO) and from FEDER Funds through COMPETE program and from National Funds through FCT under the project UID/EEA/00760/2013.info:eu-repo/semantics/publishedVersio

Feasibility study: investigation of car park-based V2G services in the UK central hub

The increasing uptake of electric vehicles, and the established practice of long-term parking at stations and airports, offers an opportunity to develop a flexible approach to help with the energy storage dilemma. This paper investigates the feasibility of using a number of EV batteries as an energy storage and grid balancing solution within the UK Central Hub area. Here, the capital cost of the vehicle is a sunk cost to the EV owner. The potential income generated, or discount on long-term parking, is an additional benefit of ownership. This paper considers the income available to a small and large size car park from the different market mechanisms to offer grid support in the UK and contrasts this with the complexity and costs of the EV charging infrastructure required within these types of scheme

Stereotactic Body Radiation Therapy for Hepatocellular Carcinoma in Patients With Child-Pugh B or C Cirrhosis

Purpose: Our purpose was to report outcomes in patients with Child-Pugh B or C (CP B/C) hepatocellular carcinoma (HCC) treated with stereotactic body radiation therapy (SBRT). Methods and Materials: Patients with HCC suitable for SBRT were prospectively enrolled in the study from 2012 to 2018. Outcomes in patients with CP B/C were analyzed. Cox proportional hazard models were used to compare survival outcomes between baseline CP score and post-SBRT CP score. Results: Twenty-three patients with CP B/C with a total of 29 HCC tumors were treated with SBRT. Eighty-seven percent of patients were CP B8-C10. Median tumor size was 3.1 cm (range, 1-10 cm). Median dose delivered was 40 Gy in a median of 5 fractions. Eighteen of 23 patients (78.3%) had been previously treated with transarterial chemoembolization. Median follow-up was 14.5 months. Rates of 6- and 12-month local control were 100% and 92.3%, respectively. Six- and 12-month survival rates were 73.9% and 56.5%, respectively. Median survival was 14.5 months overall and 9.2, 22.5, 14.5, and 14.4 months for patients with CP B7, B8, B9, and C10, respectively. No patients exhibited symptoms of classic radiation-induced liver disease. However, 10 patients had CP score progression, with 4 patients (17%) having a \u3e /=2-point increase in CP score by 6 months (or time of censor). There were 7 liver-related deaths, and based on independent review by a hepatologist, 1 of these deaths may have been attributable to SBRT-related liver injury. Fifteen of 23 patients were listed for liver transplant (LT) at the time of SBRT and 9 went on to receive LT with a pathologic complete response rate of 63.6%. Median survival, excluding patients who received LT, was 7.3 months. Conclusions: SBRT is a reasonable treatment option for carefully selected patients with CP B7-C10. In our small cohort, there was no detectable difference between local control or overall survival and baseline CP score