Least-cost targets and avoided fossil fuel capacity in India’s pursuit of renewable energy

India has set aggressive targets to install more than 400 GW of wind and solar electricity generation by 2030, with more than two-thirds of that capacity coming from solar. This paper examines the electricity and carbon mitigation costs to reliably operate India’s grid in 2030 for a variety of wind and solar targets (200 GW to 600 GW) and the most promising options for reducing these costs. We find that systems where solar photovoltaic comprises only 25 to 50% of the total renewable target have the lowest carbon mitigation costs in most scenarios. This result invites a reexamination of India’s proposed solar-majority targets. We also find that, compared to other regions and contrary to prevailing assumptions, meeting high renewable targets will avoid building very few new fossil fuel (coal and natural gas) power plants because of India’s specific weather patterns and need to meet peak electricity demand. However, building 600 GW of renewable capacity, with the majority being wind plants, reduces how often fossil fuel power plants run, and this amount of capacity can hold India’s 2030 emissions below 2018 levels for less than the social cost of carbon. With likely wind and solar cost declines and increases in coal energy costs, balanced or wind-majority high renewable energy systems (600 GW or ≈ 45% share by energy) could result in electricity costs similar to a fossil fuel-dominated system. As an alternative strategy for meeting peak electricity demand, battery storage can avert the need for new fossil fuel capacity but is cost effective only at low capital costs (≈ USD 150 per kWh).

India emitted 3.2 billion metric tons of CO₂e in 2016, or 6% of annual global greenhouse gas emissions, placing it third only to China and the United States (1). One-third of these emissions were from coal-based electricity. At the same time, both per capita emissions and energy use remain well below global averages, suggesting a massive potential for growth of electricity generation and emissions (1). India’s primary energy demand is expected to double by 2040 compared to 2017 (2). Whether this energy comes from fossil or low-carbon sources will significantly affect the ability to limit average global temperature rise to below 2 °C.India is already pursuing significant technology-specific renewable energy targets—100 GW of solar and 60 GW of wind by 2022—and, in its Nationally Determined Contributions (NDC), committed to a 40% target for installed generation capacity from nonfossil fuel sources by 2030 (3). In 2019, in part to fulfill its NDC commitment, the Indian government proposed to install 440 GW of renewable energy capacity by 2030, with 300 GW of solar and 140 GW of wind capacity (4). Although costs of solar photovoltaic (PV) and wind technologies have declined significantly in recent years (5–7), the low cost of coal and integration costs associated with variable renewable energy (VRE) technologies like wind and solar may hinder India’s cost-effective transition to a decarbonized electricity system. This paper seeks to answer a number of questions that arise in the Indian context. What targets for wind and solar capacity have the lowest associated integration costs? Will these targets significantly offset the need to build fossil fuel generation capacity? What additional measures can we take to mitigate VRE integration costs?Merely comparing the levelized costs of VRE with the costs of conventional generation ignores additional cost drivers, which depend on the timing of VRE production and other conditions in the power system (8, 9). Quantifying these drivers requires models that choose lowest-cost generation capacity portfolios and simulate optimal system operation with detailed spatiotemporal data. Several prior studies address these system-level integration costs in a capacity expansion planning framework (10–16), often making decisions based on a limited sample of representative hours. Other studies explicitly estimate the relationship between long-run economic value (including integration costs) of VRE penetration levels (17, 18) but do not include VRE investment costs in their analysis. Few prior studies explore the impacts of high VRE penetration on India’s electricity system, and those that do either use the capacity expansion framework and do not evaluate the economic value of multiple VRE targets (4, 19, 20) or do not optimize capacity build around proposed VRE targets (21).Here we address this gap by estimating how different VRE targets affect the cost to reliably operate the Indian electricity system. To do so, we work with three interrelated models. First, using a spatially explicit model for VRE site selection, we identify the lowest levelized cost wind and solar sites to meet different VRE capacity targets, and study how the resource quality—and corresponding levelized cost—of selected sites changes with increasing VRE targets.Second, using a capacity investment model that accounts for VRE production patterns and optimal dispatch of hydropower and battery storage, we determine the capacity requirements and investment costs for coal, combined cycle gas turbines (CCGT), and combustion turbine (CT) peaker plants. Due to uncertainties in their future deployment (22), and because their current targets are relatively low (4), we did not consider new nuclear or hydro capacity in the main scenarios but include those in the sensitivity scenarios presented in SI Appendix, section 2. Third, we use a unit commitment and economic dispatch model to simulate hourly operation of the electricity system and estimate annual system operational costs. This model captures important technical constraints, including minimum operating levels, daily unit commitment for coal and natural gas plants, and energy limits on hydropower and battery storage. Rather than cooptimize VRE capacity, we compute the system-level economic value of a range of VRE targets by comparing the sum of the avoided new conventional capacity and energy generation costs to a no-VRE scenario. The net cost for a scenario is then the difference between the levelized cost of the VRE and the system-level economic value. Materials and Methods provides more detail on this process.Our results show that, despite greater levelized cost reduction forecasts for solar PV compared to wind technologies, VRE targets with greater amounts of wind have the lowest projected net carbon mitigation costs. This finding is robust to a range of scenarios, including low-cost solar and storage, and lower minimum generation levels for coal generators.We find that, although VRE production displaces energy production from conventional generators, it does very little to defer the need for capacity from those generators due to low correlation between VRE production and peak demand. Our findings suggest that VRE in India avoids far less conventional capacity than VRE in other regions in the world. These capacity requirements are slightly mitigated if India’s demand patterns evolve to more closely resemble demand in its major cities. Overall, we conclude that the importance of choosing the right VRE mix is significant when measured in terms of carbon mitigation costs: Whereas most solar-majority scenarios we examined lead to costs greater than or equal to estimates of the social cost of carbon (SCC), wind-majority mixes all cost far less than the SCC.     

Relationship between frontal craniofacial morphology and horizontal balance of lip‐closing forces during lip pursing

The objectives of this study were to quantitatively evaluate the relationship between frontal craniofacial morphology and the horizontal balance of the lip‐closing forces (LCF) generated during maximum voluntary pursing‐like movements in patients with mandibular deviation. Thirty‐one subjects (median age 25·4 ± 8·9 years) without a history of orthodontic treatment were randomly selected from among the orthodontic patients who visited our hospital. Lip‐closing forces was recorded in eight directions during maximum voluntary pursing‐like lip‐closing movements. The subjects were divided into the deviation (two males and 11 females) and non‐deviation groups (four males and 14 females). There was no significant difference in the total LCF between the deviation and non‐deviation groups. In the deviation group, the mean LCF value on the deviation side of the upper lip was significantly lower than that detected on the non‐deviation side of the upper lip, while the mean LCF value for the deviation side of the lower lip was significantly higher than that for the non‐deviation side of the lower lip. In contrast, no significant difference in upper or lower lip LCF was detected between the deviation and non‐deviation sides in the non‐deviation group. The difference in the LCF generated in the lower lip between the deviation and non‐deviation sides was significantly positively correlated with mandibular menton deviation and significantly negatively correlated with the difference in maxillary height between the deviation and non‐deviation sides. These results suggest that the horizontal balance of the upper and lower lip LCF produced during pursing‐like lip‐closing movements in patients with mandibular deviation is related to frontal craniofacial morphology.     

双侧唇裂鼻畸形手术联合鼻模矫正的初步探讨

目的:探讨唇鼻同期整复术结合术前鼻模矫正对双侧不完全性唇裂鼻畸形的矫治效果。方法:10例在早期行鼻模矫正的唇裂患儿在矫正前(T0)、唇鼻手术术前(T1)、术后1周(T2)、术后半年(T3)分别拍摄面部仰头位照片,用配对t检验分析比较双侧鼻孔及鼻小柱的对称性。结果:T0-T1双侧鼻孔的高度、宽度的对称性差异改变明显(P0.05),T1-T2鼻孔高度的对称性上差异明显(P0.05),T1-T2鼻底宽度/鼻小柱高度差异明显(P0.01),鼻小柱的倾斜度各个阶段之间改善明显(P0.05)。结论:应用唇鼻同期整复术结合鼻模矫治对于双侧不完全性唇裂患者是一种可靠的治疗模式。     

Management of posterior ankyloglossia and upper lip ties in a tertiary otolaryngology outpatient clinic

ObjectivesRecent studies have shown an association between ankyloglossia (tongue tie) and upper-lip ties to breastfeeding difficulties. Treatment is commonly multidisciplinary involving lactation consultants and surgical management with tongue tie and upper lip tie release. There is currently limited data looking at posterior ankyloglossia and upper lip ties.MethodsConsecutive patients seen at an ENT outpatient clinic for ankyloglossia and upper-lip ties from May 2014–August 2015 were assessed for an outpatient frenotomy. Breastfeeding outcomes were assessed following the procedure.Results43 babies were seen and 34 patients had a procedure carried out. Babies ranged from 2 to 20 weeks old with the median age being 6.6 weeks. The most common presenting complaint was latching issues (85%) with mothers' painful nipples being the second (65%). 21 patients (62%) had a tongue tie release, 10 (29%) had both a tongue tie and upper lip tie divided, whereas 3 (9%) had an upper-lip tie alone divided. 29 (85%) of the patients who had a procedure carried out had an immediate improvement in breastfeeding, while 28 (82%) had a continued improvement at 2 weeks follow up.ConclusionsFrenotomy for posterior ankyloglossia and upper lip ties is a simple procedure that can be carried out in an outpatient setting with apparent immediate benefit. Otolaryngologists are likely to have an increasing role to play in the evaluation and management of ankyloglossia and upper lip ties in babies with breastfeeding difficulties.     

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??The position of lips directly affects facial beauty. In orthodontic treatment process??clinicians always choose incisor retraction to adjust lip protrusion?? reshaping the soft tissue beauty. However??with the retraction of incisors??the change of lip soft tissue is not in a simple same-size ratio. To ideally rebuild lip shape??the exact prediction of retraction extent of incisor is a widely-concerned problem. This study investigated the response of lip position to incisor position??aiming to provide a reference for further clinical treatment.     

Exceptionally strong easterly wind burst stalling El Ni?o of 2014

Intraseasonal wind bursts in the tropical Pacific are believed to affect the evolution and diversity of El Niño events. In particular, the occurrence of two strong westerly wind bursts (WWBs) in early 2014 apparently pushed the ocean–atmosphere system toward a moderate to strong El Niño—potentially an extreme event according to some climate models. However, the event’s progression quickly stalled, and the warming remained very weak throughout the year. Here, we find that the occurrence of an unusually strong basin-wide easterly wind burst (EWB) in June was a key factor that impeded the El Niño development. It was shortly after this EWB that all major Niño indices fell rapidly to near-normal values; a modest growth resumed only later in the year. The easterly burst and the weakness of subsequent WWBs resulted in the persistence of two separate warming centers in the central and eastern equatorial Pacific, suppressing the positive Bjerknes feedback critical for El Niño. Experiments with a climate model with superimposed wind bursts support these conclusions, pointing to inherent limits in El Niño predictability. Furthermore, we show that the spatial structure of the easterly burst matches that of the observed decadal trend in wind stress in the tropical Pacific, suggesting potential links between intraseasonal wind bursts and decadal climate variations.El Niño, the warm phase of the El Niño–Southern Oscillation (ENSO), is characterized by anomalously warm water appearing in the central and eastern equatorial Pacific every 2–7 years, driven by tropical ocean–atmosphere interactions with far-reaching global impacts (recent reviews are in refs. 1–3). These interactions and El Niño development involve several important feedbacks, including the positive Bjerknes feedback [zonal wind relaxation leads to the reduction of the zonal sea surface temperature (SST) gradient and further wind relaxation] (4). Since the year 2000, there has been a shift in the observed properties of El Niño, including its magnitude, frequency, and spatial structure of temperature anomalies (5, 6). For example, El Niño events occurred more frequently than during the previous two decades, but all were weak, and none reached the extreme magnitude of the 1982 and 1997 events. Concurrently, the rise of global mean surface temperature has slowed down with the so-called global warming hiatus (7–9). The stalled development of the 2014 El Niño presents a showcase to explore the relevant connection and mechanisms of these changes.At the beginning of 2014, many in the scientific community anticipated that a moderate to strong El Niño could develop by the end of the year (10–14) (Fig. S1). In March, the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center announced an “El Niño watch” based on predictions made by dynamical and statistical models (12), attracting attention of the general public. Admittedly, these predictions encompassed large uncertainties because of the stochastic nature of the tropical climate system (15–17). In May, the National Aeronautics and Space Administration (NASA) suggested that 2014 could potentially rival the strongest on-record event of 1997/19998 (Fig. 1B), while acknowledging the large existing uncertainty (14); their projection was supported by satellite observations of strong Kelvin waves evident in sea surface height (SSH) (Fig. 2C). The spread of spring forecast plumes from some climate models, for example that of the European Centre for Medium-Range Weather Forecasts (ECMWF), included the possibility of a failed El Niño (Fig. S1) but only as a low-probability outcome involving unusual instances of weather noise. The observed development fell near the limit of these forecast possibilities after June and July, and eventually, the 2014 warm event barely qualified as El Niño (Fig. 1A).Open in a separate windowFig. 1.El Niño development in (A and C) 2014 and (B and D) 1997. (A and B) Evolution of the Niño3, Niño4, and Niño3.4 indices; the first two indices describe SST anomalies (in degrees Celsius) in the eastern and central equatorial Pacific, respectively, whereas the last index covers the region in between. (C and D) Variation in the zonal wind stress indices. These indices are obtained by averaging wind stress anomalies (in 10⁻² newtons per meter²) in the equatorial Pacific zonally and between 5 °S and 5 °N and then selecting negative (blue; easterly anomalies), positive (red; westerly anomalies), or full values (black) (Materials and Methods). The spatial averaging is intended to take into account both the magnitude and the fetch of the wind bursts. During 2014, two early year WWBs were followed by an exceptional EWB in June (highlighted by pink and blue, respectively). This easterly burst apparently led to a rapid decrease of the Niño indices (A). In contrast, the 1997 El Niño exhibited persistent westerly wind activity throughout the year. The graphs start on January 1.Open in a separate windowFig. 2.Spatiotemporal evolution of the 2014 El Niño. (A–D) Hovmöller diagrams for anomalies in (A) SST, (B) zonal wind stress, (C) SSH, and (D) surface zonal currents in the equatorial Pacific. Time goes downward. The SSH and surface velocity plots highlight the eastward propagating downwelling Kelvin waves, especially pronounced early in the year, and a strong upwelling Kelvin wave midyear. (E and F) El Niño development in 2014 (black line) compared with several historical (E) EP and (F) CP events. The diagrams show the position of the Warm Pool Eastern Edge (degrees of longitude) vs. the Niño3 SST (degrees Celsius) for different months of the year. The Warm Pool Eastern Edge is defined as the position of the 29 °C isotherm at the equator. Numbers indicate monthly averages (1, January; 2, February, etc.). The light vertical line marks the Dateline. In 2014, both the warm pool displacement and Niño3 SST anomalies were exceptionally large during May (month 5), were similar to those in 1997 and 1982 (the strongest events of the 20th century), and then, rapidly decreased by August (month 8).Open in a separate windowFig. S1.The El Niño spring forecasts of the Niño3.4 index from the European Centre for Medium-Range Weather Forecasts (ECMWF). Red lines show 50 ensemble members of the forecast plume initiated in March of 2014; the black dotted line indicates the observed Niño3.4 index. The observed development fell outside the forecast plume in June and July and remained beyond the typical forecast spread after that. Adapted from ref. 13.The question then arises as to which dynamic factors controlled the temporal and spatial development in the tropical Pacific in 2014. This warm event began with a rapid growth, such that, in early June, all major Niño indices (Materials and Methods) along the equator were nearly identical to those during the same time of 1997 (Fig. 1 A and B). A substantial warming also developed along the Peruvian coast (Fig. 3A). Then, the event’s progression slowed down or even reversed. By year end, the equatorial warming barely exceeded 1 °C, but the SST anomaly stretched uncharacteristically across the entire equatorial Pacific almost uniformly (Figs. 1A and ​and2A).2A). Accordingly, the major goal of this study is to investigate this unusual development, identify the main factors that impeded this event, and explore its broad implications.Open in a separate windowFig. 3.The June of 2014 EWB in satellite-based data. (A) The spatial structure of anomalies in surface winds (vectors; in meters per second) and SST (colors; in degrees Celsius) on June 12, 2014, when the burst was strongest. (B) Daily vs. weekly mean values of the zonal wind stress index (10⁻² newtons per meter²) for the period 1988–2014. The blue cross marks the peak value of the June of 2014 EWB. The wind stress index is defined as anomalous zonal wind stress averaged in the equatorial Pacific zonally and between 5 °S and 5 °N (Materials and Methods). Black circles are for the year 2014, red circles are for all El Niño years before 2014, and gray circles are for all other years (La Niña or neutral). Note that the June of 2014 EWB appears strongest in the satellite record for not only daily data but also, weekly averaged values, which confirms that the observations are robust.     

钩藤天麻胶囊治疗缺血性中风急性期风火痰瘀互结证临床研究

目的：观察钩藤天麻胶囊治疗缺血性中风急性期风火痰瘀互结证的临床疗效。方法：将60例患者随机分为治疗组和对照组,每组各30例。对照组采用西药基础治疗,治疗组在对照组基础上加用钩藤天麻胶囊治疗。两组共治疗14 d,随访1个月。观察两组患者治疗前、治疗后及随访1个月后神经功能缺损程度评分、中医证候积分。结果：治疗14 d 后,两组患者神经功能缺损程度评分均较治疗前有不同程度下降（P ＜0．05）,两组患者组间比较无显著性差异（P ＞0．05）,两组患者中医证候积分比较,有显著性差异（P ＜0．05）。随访1个月后,两组患者神经功能缺损评分较治疗前有不同程度下降（P ＜0．05）,但治疗组改善更明显（P ＜0．05）;两组患者中医证候积分较治疗前有不同程度改善（P ＜0．05）,但治疗组改善更明显（P ＜0．05）。结论：钩藤天麻胶囊治疗缺血性中风急性期风火痰瘀互结证疗效显著,且无明显不良反应。     

陈宝田教授创小乌桂汤治疗顽固性痹证

小乌桂汤由陈宝田教授所创立,该方由《千金要方》的小续命汤、《金匮要略》的乌头汤和桂枝芍药知母汤三个经方的合方加减,主要用于治疗顽固性痹证,具有疏风通络,散寒除湿,益气养血的作用.陈宝田教授认为,顽固性痹证多因风寒湿邪阻滞经络肢体关节,且邪实甚重,非一般之剂能除之.临证治疗类风湿性关节炎及强直性脊柱炎,加全蝎以加强通络止痛之力;多发性动脉炎加黄连解毒汤,以增清热解毒之功;退行性骨关节病及年老病久、体质虚弱明显者,加独活寄生汤以补肝肾,强筋骨;寒盛者,加大辛温药量;化热者则减辛温药量,并加大黄芩、知母、白芍之用量.