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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.solener.2015.04.001 Byline: Toru Kobayakawa, Tara C. Kandpal Abstract: * Electricity consumption patterns under a PV micro-grid system are investigated. * The number of beneficiary households connected to the grid is on increasing trends. * Electricity overuse is not perceived as per-household consumption is almost stable. * To identify factors that affect consumption level, a regression model is developed. * The model can be used in predicting additional load when grid extension is planned. Article History: Received 4 March 2014; Revised 22 February 2015; Accepted 1 April 2015 Article Note: (miscellaneous) Communicated by: Associate Editor S.C. Bhattacharya

India has a huge industrial demand for process heating at temperatures that can be provided with commercially available solar collectors. Government of India with support from multi-lateral agencies has initiated an ambitious programme for promoting large scale adoption of Solar Industrial Process Heating (SIPH) in the industrial sector of the country. This paper presents the details of an attempt to study the effect of several existing and potential incentives on the financial attractiveness of SIPH systems in India. A case of solar process heating in dairy industry has been presented to demonstrate the relative efficacy of different incentives on the economics of SIPH systems in terms of their impact on levelized cost of useful thermal energy delivered. Finally, policy implications of the results obtained have been discussed.

An attempt to estimate the potential of solar crop drying for some selected cash crops in India has been made. The amount of cash crops that can be dried by solar dryers and the required aperture area of solar dryers have been estimated. Estimates for unit cost of solar drying for different crops have also been worked out. The potential of net fossil C[O.sub.2] emissions mitigation due to the amounts of different fuels that would be saved by solar drying has been estimated along with the unit cost of C[O.sub.2] emissions mitigation. Keywords: Solar crop drying; Cash crops; Potential estimation; C[O.sub.2] emissions

Development and dissemination of solar energy technologies in India has been aided by a variety of policy and support measures. One of the promotional measures is the provision of financial and fiscal incentives such as capital subsidy, low interest loan and accelerated depreciation related income tax benefits to the users on the purchase of solar energy technologies. In this study an attempt has been made to determine the effective capital cost of solar energy technologies to the user with the provision of financial and/or fiscal incentives. Results of exemplifying calculations for a domestic and an industrial solar water heating system, a solar home lighting system and a solar drying system have been presented and discussed. Keywords: Financial and fiscal incentives; Effective capital cost; Solar energy technologies

An attempt has been made to evaluate the financial feasibility of hybrid power supply option during real-time grid power unavailability (continuous and intermittent) conditions and determine the optimal hybrid power supply configurations for outdoor telecom towers in India. As grid power availability is highly dependent on locations, a review of real-time hourly grid power supply availability for telecom towers at 36 locations in different parts of India has also been presented. Ten different locations across different climatic zones were analyzed, and it was found that duration and continuity (continuous and intermittent) of power outages considerably affect the LCOE of different configurations. So it is imperative that these factors be taken into account when determining the optimal hybrid power system. Solar PV-based hybrid power supply systems were found to have lower LCOE for all power outage conditions both in continuous as well as intermittent with their values in the range of Indian rupees (INR) 6.76–INR 26.32 (US $0.095–US $0.371) per kWh for the optimal cases (1 US$ = INR 76.28 (As on April 27, 2020)). While solar PV with battery is found to be the least cost hybrid power supply options for the telecom towers located in areas with continuous grid power unavailability up to 4 h, a diesel generator also needs to be included for larger hours of continuous grid unavailability. [ABSTRACT FROM AUTHOR]

The contribution of power because of the nonconventional energy sources is enhancing day by day. This gives rise to power converter connected to the grid for an integration and to utilize the nonconventional energy sources economically and efficiently. However, this causes the distortion in the grid voltages and currents. All advanced high precision operating machines and measuring instruments are sensitive to the harmonics of the grid voltages. Therefore, this work illustrates an improved control to supress the grid voltage and current harmonics caused by an integration of non‐conventional energy source and nonlinear loads. An enhanced resonant two‐degree of freedom proportional–integral–derivative (ER‐2‐DOF‐PID) controller is used to extract fundamental components from load currents. It uses a resonant controller in shunt with PI controller to suppress the multi‐order harmonics and steady state error. A DC‐offset is used in parallel of this combination to suppress the sub‐order harmonics. To suppress the peak overshoot during the load transients and insolation changes, a 2‐DOF‐PID controller is used. The presented control is investigated by developing its model in MATLAB environment and this is validated on a prototype developed in the laboratory. The controller is modelled and investigated for stability analysis using a Bode mathematical tool.. [ABSTRACT FROM AUTHOR]

An adaptive approach based on a neural network is presented here for the control of a grid interactive solar power generating system. This control approach is based on a summation and a product neuron, which are used to process the non‐linearity of load currents. A sigmoidal and Gaussian functions are used to linearise the response of summation and product neurons. In this control, the product and summation neurons, and sigmoidal and Gaussian functions are within a single layer, which reduces the complexity of control. This control algorithm is superior over artificial neural network (ANN)‐based control algorithm, which has large number of unknown weights and layers. It reduces the computational burden and complexity of the control algorithm. It shows the inherent improved performance at non‐linear balanced and unbalanced loads. The control of net active and reactive components of the power separately improves the efficacy of the control at unbalanced non‐linear load and reduces the voltage transients in the grid voltages. The ANN‐based control also plays an active role in enhancing the power quality of the grid. The reduced complexity of control and direct power feed forward of photovoltaic array (PVA) to the grid improve the dynamic response of the grid‐connected PVA‐based system. [ABSTRACT FROM AUTHOR]

In a photovoltaic array (PVA) tied grid system, PVA and the grid are connected at AC bus (ACB) to feed the power to the grid and the load connected locally at the ACB. The photovoltaic energy conversion system (PVECS) requires an improved dynamic controller to control the grid voltage harmonics under variable solar power and nonlinear unbalanced load conditions. The conventional filtering controllers are unable to remove the sub‐harmonics and DC‐offset in the input signal. Moreover, their attenuation for the dominant lower order harmonics is unsatisfactory for unbalanced loading conditions and highly nonlinear loads. A MMLSTOGI (mixed multi‐level second and third order generalized integrator) based control is used in this work. It effectively mitigates the dominant lower‐order harmonics and the DC‐offset of load currents and extracts their in‐phase and quadrature‐phase fundamental components (FCs). The PVA is connected at ACB through interfacing voltage source converter (VSC). The DC‐link voltage is ascertained by generating its reference value using an incremental conductance (InC) based maximum power point tracking. The PVA power is feed‐forwarded in the control to enhance the dynamics of the system. The control is validated on a developed model in MATLAB SIMULINK background, and using a developed prototype. [ABSTRACT FROM AUTHOR]

This work presents an improved phase‐locked loop (IPLL)‐based control for grid‐integrated photovoltaic (PV) system (GIPVS). It is used to extract amplitude, frequency, and phase angle of distorted load currents to control PV‐grid‐interfaced voltage source converter (VSC). The VSC controls active and reactive powers at unbalances and distortions in the grid voltages. The control algorithm of VSC includes power feed‐forward term, DC‐link voltage, and grid voltages. The feed‐forward term improves the dynamic performance of a GIPVS and enhances the utilisation of VSC. Three‐phase IPLLs extract the in‐phase components of three‐phase load currents at utility frequency. Further, these in‐phase components of load currents are used for estimation of reference‐grid currents. The proposed IPLL‐based control algorithm offers good dynamic response even under unbalanced load condition. The efficient working of IPLL‐based control algorithm is realised by extracting maximum power from PV‐grid system and through its power‐quality improvement. The perturb and observe (P & O) control algorithm is used for optimum utilisation of a PV array. A developed prototype of PV‐grid system is used to implement an IPLL‐based control algorithm under different operating conditions. [ABSTRACT FROM AUTHOR]

A framework to estimate the extent of various incentives required to ensure financial attractiveness of institutional solar cooking is presented with typical examples from India. Incentives considered are capital subsidy/viability gap funding, accelerated depreciation, interest subsidy, and investment tax credit have been considered for three commercially available designs of solar cookers that can be used for institutional cooking (SK-23, Scheffler dish (direct), and Scheffler dish (steam)). Depending on the location, the extent of viability gap funding (VGF) for Scheffler dish (steam) solar cooking system varies from 18.7% to 66.5% of the capital cost, while the same for SK-23 and Scheffler dish (direct) varies from 8.7% to 82.9%, and 33.4%–94.5% respectively. From the government point of view, the provision of accelerated depreciation for incentivising institutional solar cooking is found to be the least cost option followed by viability gap funding, investment tax credit and interest subsidy in the order of increasing cost to the government. At locations in the cold and cloudy climatic zone of India, there is invariably a need to provide a combination of incentives (as the current provision of 30% capital subsidy is not adequate) to ensure a breakeven condition. • Steam-based solar cooking financially more attractive than direct cooking. • Higher levels of incentives needed for direct solar cookers in India. • Accelerated depreciation costs the least to the government as an incentive. [ABSTRACT FROM AUTHOR]

Byline: Pallav Purohit, Tara C. Kandpal An attempt to develop a simple framework for techno-economic evaluation of windmills for irrigation water pumping has been made. The amounts of water delivered by five somewhat different designs of windmill pumps at different locations have been estimated. The unit cost of water delivered and unit cost of useful energy delivered by the windmills have been estimated. The monetary benefits that accrued to the end-user have been quantified in terms of the amount of diesel or electricity saved. The Net Present Value and Benefit-to-Cost Ratio for the investments made in windmill pumps have been estimated. The effect of fuel price escalation on these measures of financial performance has also been evaluated along with the estimation of the break-even prices of fuels likely to be substituted by windmill pumps.

Financial appraisal of two solar cookers (SK-23 and Scheffler dish) that may be used for institutional/community cooking is presented. For each solar cooker type, three different categories in terms of performance and cost as prevailing in the market have been considered. Annual numbers of solar cooked meals and consequently the values of several measures of financial performance are estimated for three locations in India with varying climatic conditions. As per the estimates obtained in this study a SK-23 solar cooker can cook from 39% to 60% of the meals during the year while, the corresponding range for Scheffler dish based solar cooker is from 59% to 85% at these locations. The discounted payback for SK-23 varies 6.2–9.2 years while the same for Scheffler dish varies from 9.5 to 11.7 years. The financial attractiveness of SK-23 is adversely affected by its poor performance in high wind, while the relatively higher capital cost of the Scheffler direct cooker apparently makes it financially unattractive. Thus, there is an urgent need to encourage research and development on solar cookers to reduce their cost and also to improve performance. [ABSTRACT FROM AUTHOR]

A review on various aspects of institutional solar cooking is presented. Starting with an overview of energy requirement for cooking, the review includes cooking technologies developed for institutional solar cooking, polices and programs for their promotion and case studies reported in the literature on field level application. State of the art concentrating solar technologies suitable for institutional level cooking includes Parabolic dish, Scheffler dish and ARUN ® dish. Design, construction and operational details of both direct and indirect types of concentrating solar cookers have been discussed. The case studies, mainly from India, included provide useful feedback on the experiences of using large scale institutional solar cooking systems. A Few installations of each type of solar cooker have been reviewed and major findings and observations on various aspects of the same are reported. [ABSTRACT FROM AUTHOR]

In this paper, we estimate the cost reduction potential of parabolic trough based concentrated solar Power systems in India and consequently their implications for levelized cost of electricity. Using the past as well as envisaged global cumulative diffusion of CSP systems and the learning rates reported in the literature, the expected capital cost of parabolic trough based CSP systems in India has been estimated. Present capital cost of parabolic trough based CSP plant in India has been taken as US $2540/kW. Local manufacturing of CSP components and consequently reduced logistics is expected to reduce the capital cost by 14% and 8% respectively. A learning rate of 10% for the global cumulative diffusion in the base case scenario is expected to reduce capital cost to 49% of the present cost by the end of 2050. Present LCOE of US $151/MWh of CSP plant in India is expected to reduce to US $76/MWh by the end of 2050. Provision of 6 hour thermal storage is expected to reduce LCOE of CSP plant in India by 18% as compared to LCOE of CSP plant without storage. Analysis for different learning rates (5%, 10% and 15%) for CSP plant and different discount rates (6%, 8% and 10%) has also been undertaken and results obtained are presented. [ABSTRACT FROM AUTHOR]

For large-scale dissemination of solar thermal power plants, in countries identified with huge potential, governments are offering various incentives. In an attempt towards studying the effectiveness of various incentives in reducing the levelised cost of electricity (LCOE) delivered by solar thermal power plants in India, this paper presents simple mathematical frameworks that facilitate the determination of the required level of an incentive so as to ensure that the LCOE is within a pre-specified limit. For example, for a 50 MW solar thermal power plant at Barmer (Rajasthan), LCOE of Rs. 9.75 per kWh can be achieved by providing 6.3% viability gap funding or an interest subsidy of 3% or provision of 32% investment tax credits to the equity investor or provision of production tax credits to the equity investor at the rate of Rs. 0.81 per kWh for first 10 years of operation of a plant. [ABSTRACT FROM AUTHOR]

Micro-grids are actively employed for rural electrification along with integrated renewable energy systems in developing countries. For determining their optimal configurations, it is often challenging in obtaining accurate input data, particularly prospective electricity loads and local renewable resource availability. In this study, the configuration of the off-grid 120 kWp PV system in West Bengal, India is reassessed by using the optimization software, HOMER. With an assumption that excess biomass resources would be available as a result of successful introduction of fuel-saving devices such as solar cookers, a PV–biomass–battery system, which consists of 30 kW PV array and 20 kW biomass gasification-based power plant (BGPP), turns out to be the most economically feasible option. Compared with the actual system, the net present cost (NPC) and cost of electricity (COE) are significantly lowered. Furthermore, in order to verify effectiveness of “phased approach” for developing the off-grid renewable energy system, which has been proposed in the authors' previous study, the system expansion process is simulated by HOMER according to three different load growth scenarios. It is found from the simulation that adjustment of the system size becomes possible with more accurate load estimation at the time of expansion, which may lead to lower operation and maintenance (O&M) costs and COE. As a result of the increased level of tariff revenue from additional consumers, the expansion process would provide an opportunity for enhancing community welfare and financial viability of the project. [ABSTRACT FROM AUTHOR]

This paper presents results of an analysis undertaken to determine the values of design for direct normal irradiance (DNI), solar multiple and hours of thermal storage for least cost of power generation for parabolic trough based solar thermal power plants at 4 niche locations in India. Solar radiation data source of SEC-NREL has been used and annual electricity outputs have been estimated using Systems Advisor Model. For estimation of levelized unit cost of electricity, benchmark capital cost and other financing conditions suggested by the Central Electricity Regulatory Commission, Government of India have been used. Levelized unit cost of electricity has been found to be minimum for design DNI range of 600-650 W/m 2 and corresponding range of solar multiple is 1.5-1.6. Results also show that the provision of thermal storage leads to an increase in electricity output as compared to the corresponding values for plants without storage but the cost of electricity delivered increases. [ABSTRACT FROM AUTHOR]

This paper presents the results of a preliminary assessment towards the potential estimation of solar process heating in paper industry in India. To begin with, data for (i) classification of paper mills on the basis of size and feedstock used (ii) extent of cogeneration in paper mills (iii) annual paper production (feed stock wise) (iv) specific thermal energy requirement for process heating etc. have been collected. Annual process heating requirement for paper production (based on feed stock used) in paper mills in India has been estimated. Availability of adequate solar resource in different states of the country was assessed for potential estimation. Some commercially available solar collectors that can supply heat at required temperature of paper industry (50-250 0 C) have been selected and an assessment of their performance has been made. Majority of paper mills in India those are using agro residues and recycled fibers as raw feedstock are located in the states with adequate DNI availability (1900kWh/m 2 ). Annual process heating potential for the paper industry in India has been estimated at 43 PJ. [ABSTRACT FROM AUTHOR]

An attempt to assess solar lantern based lighting option for street vendors (often without access to grid electricity) in the city of Dehradun through a questionnaire based survey is presented. Survey results indicate that the vendors are more likely to adopt a lighting device on rental mode that offers the benefit of low operation cost and high reliability. The study points that the city has potential for 10 Central Charging Stations of 1200Wp capacity each. Each station would cater to the lighting needs of 100 vendors. Based on the vendors willingness to pay for lighting services, estimated minimum acceptable daily rental to an entrepreneur operating a station is Rs 3.97. This is about 45% of the average daily rental of Rs 8.90 that the vendors are willing to pay. For daily rental ranging between Rs 4.00 to Rs 9.00, the mark-up for the entrepreneur would range from 16 to 160%. [ABSTRACT FROM AUTHOR]

Abstract: Need for renewable energy education and training at all levels is globally recognized. During the last three decades a large number of countries across the globe have initiated academic programmes on renewable energy technologies and related aspects. A review of published literature on renewable energy education initiatives across the globe, challenges faced, and potential approaches towards efficient and effective solutions are presented in the paper. [Copyright &y& Elsevier]

Results of a preliminary techno-economic appraisal of solar thermal power generation at three locations in India are presented. The study uses System Advisor Model developed by NREL, USA. The results of the study provide useful insight into (a) selecting appropriate reference direct normal irradiance for design of solar thermal power plants, (b) identifying suitable combinations of solar multiple and hours of thermal energy storage and (c) cost reduction potential. The parabolic trough technology is used for exemplifying the procedure for this purpose. The estimated levelised unit cost of electricity is in the range of Rs (US$1=Indian rupees 51.66 on 5 October 2012) 16–21 per kWh for the most likely range of input parameters. The results also indicate possibility of about 30% reduction in unit cost of electricity by year 2021. [ABSTRACT FROM AUTHOR]

Abstract: Load prediction is an essential component of the planning process of decentralized electricity supply systems based on micro-grids. However, accurate demand forecasting is a challenging task particularly for rural electrification projects. In this paper, actual operational data of a PV based micro-grid system in Sagar Island of India are analyzed in order to understand the role of different factors affecting households' connectivity, their electricity consumption and potential demands, thereby proposing an approach for planning (and designing) a micro-grid based decentralized electricity supply system. The analysis shows that potential demands for electricity within (as well as outside of) the current reach of the micro-grid are high and future expansion of the system would be effective by taking a 'phased approach’ of rural electrification. The analysis also shows that households with certain socio-economic characteristics have higher probability for connecting with the micro-grid and the relationship can be used to predict additional load requirements in case of grid extensions. Few recommendations for enhancing the connectivity further are also included in the discussion section of the paper. [Copyright &y& Elsevier]

Abstract: Results of a preliminary analysis to study the financial feasibility of a hybrid mode operation of a direct evaporative cooler (DEC) with an air conditioning (AC) unit to reduce the annual expenditure on electricity usage (as against a standalone AC unit to provide almost similar level of comfort) are presented. Four different building applications located in four different cities of India have been considered in the study. The hybrid mode operation is found financially attractive for movie theater and waiting hall building applications for all the climatic conditions considered in the present study. [Copyright &y& Elsevier]

Abstract: India has a very large potential for harnessing renewable energy sources. However, there is a large gap between the estimated potential and the cumulative achievements made so far. A variety of reasons are attributed to the current low levels of dissemination of renewable energy technologies in India as against their respective estimated potentials. Several of these attributes could, one way or the other, be related to the current status of development of the technology, its appropriateness and dissemination strategies adopted for their diffusion and deployment. Results of an attempt to assess the current status of some renewable energy technologies in India are briefly presented in this paper. The main findings of a structured questionnaire based survey undertaken for eliciting views of different categories of stakeholders on various issues affecting dissemination of renewable energy technologies in India are presented in this paper. [Copyright &y& Elsevier]

Abstract: Simple frameworks have been developed for estimating the utilization potential of: (a) solar photovoltaic (SPV) pumps; (b) windmill pumps; (c) producer gas based dual fuel engine pumps; and (d) biogas based dual fuel engine pumps for irrigation water pumping in India. The approach takes into account factors such as: solar radiation intensity, wind speed, availability of bovine dung and agri-residues, and their alternative uses, ground water requirements for irrigation and its availability, affordability, and propensity of the users to invest in renewable energy devices, etc. SPV pumps are estimated to have the maximum utilization potential in India, followed by windmill pumps. [Copyright &y& Elsevier]

Abstract: Using the past diffusion trends of four renewable energy technologies for irrigation water pumping in India (SPV pumps, windmill pumps and biogas/producer gas driven dual fuel engine pumps), results of an attempt to project their future dissemination levels, have been presented in this study. The likely contribution of the renewable energy options considered in the study to the projected energy demand for irrigation water pumping in India has been estimated. Estimates of the associated investment requirements taking into account the learning effect have also been presented. [Copyright &y& Elsevier]

Abstract: An attempt to estimate the potential of solar crop drying for some selected cash crops in India has been made. The amount of cash crops that can be dried by solar dryers and the required aperture area of solar dryers have been estimated. Estimates for unit cost of solar drying for different crops have also been worked out. The potential of net fossil CO2 emissions mitigation due to the amounts of different fuels that would be saved by solar drying has been estimated along with the unit cost of CO2 emissions mitigation. [Copyright &y& Elsevier]

This study examines the effect of several site-specific factors on the amount of carbon dioxide (CO 2) emissions stemming from operation of 4G and 5G technology-based telecommunication towers at many locations across India with focus on the assessment of the incremental change expected due to 5G technology adoption. Also, the impact of adopting solar photovoltaics (PV) based hybrid power systems on overall CO 2 emissions from operation of telecom towers. Optimal designs of solar PV-based hybrid systems are obtained using HOMER software for 25 diverse Indian locations for powering both 4G and 5G telecom towers while considering site-specific factors such as solar resource availability, availability and tariff of grid electricity and the unit price of diesel used in the Diesel Generator (DG) of the hybrid system. From the results of the study it is noted that, with the current energy supply mix, a tripling of the carbon dioxide emissions is expected if all of India's 0.71 million telecom towers adopt 5G technology. Adoption of solar PV-based systems along with grid electricity and diesel generator in hybrid mode has the potential to reduces carbon dioxide emissions by approximately 55 % for the existing telecom towers in India. For the case of all telecom towers transitioning to 5G technology, about 58 % reduction in CO 2 emissions is possible with the adoption of PV-based hybrid power systems. From the perspective of the unit cost of CO 2 emissions mitigation, the adoption of solar PV-based hybrid systems is found to be a no regret option. Results of the study have significant policy implications towards designing appropriate strategies for reducing carbon footprint of telecom tower operation in India. • CO 2 emissions from telecom towers to triple in India with 5G over 4G technology. • Solar PV hybrid systems can mitigate 55 % of CO 2 emissions for existing levels. • In case of 100 % 5G adoption, 58 % reduction in CO 2 emissions is possible with solar PV. • Solar PV hybrid systems offer a no-regret option to mitigate telecom CO 2 emissions. [ABSTRACT FROM AUTHOR]

The choice of condenser cooling option for concentrating solar power (CSP) plants is likely to affect their techno-economic feasibility. In view of this, an attempt has been made to assess relative techno-economics and net life cycle CO 2 -eq emissions mitigation (LCCM) potential for 50 MW nominal capacity wet-cooled and dry-cooled parabolic trough solar collector (PTSC) and dry-cooled solar power tower (SPT) based CSP plants with 6.0 h of thermal energy storage for two potential locations in India. It was observed that though dry cooling is likely to save significant amount of water (∼92%) in PTSC based plants, the same shall result in higher capital cost, higher performance penalty and higher parasitic power requirements leading to around 20% higher levelized cost of electricity (LCOE) as compared to wet-cooled PTSC based plants. It was also observed that the dry-cooled SPT based plants shall be able to deliver up to 4.5% higher annual electricity output and LCOE is also likely to be lowered by 13% than wet-cooled PTSC based plants. Considering emissions embodied and emissions associated with water transport/extraction from the source and water treatment, the estimation of LCCM from the PTSC and SPT based CSP plants have also been undertaken. [ABSTRACT FROM AUTHOR]

of a HOMER based techno-economic assessment of an electricity supply option based on a hybrid system comprising of a PV component, a diesel generator (DG) and electricity grid have been presented in this paper. The study includes analysis of electricity unavailability data for 132 locations in India spread over state capitals, district headquarters, municipal areas and villages. The values of Net Present Cost (NPC) and Cost of Electricity (CoE) have been estimated for 25 selected locations in the country and a comparison with corresponding values for conventional alternative (grid+DG) has also been presented. The study internalizes all relevant location specific parameters. The values of NPC and CoE are lower in the range of 9.5%–36.6% and 16%–33.6% respectively for the proposed system (grid+PV+DG) as compared to conventional system at all 25 locations considered. The inclusion of PV component results in reduced purchase of grid electricity and much lower hours of operation of DG. • Analyzed real-time hourly grid power supply outage status for outdoor telecom towers at 132 locations • Designed optimal hybrid systems for powering BTS in telecom towers at 25 selected locations in India, • Presented a detailed techno-economic comparison of solar PV based hybrid system for powering BTS • The values of NPC and CoE are lower in the range of 9.5%–36.6% and 16%–102.4% respectively for the hybrid system • The PV component results in reduced purchase of grid electricity, DG operation, electricity fed to grid, and CO 2 emissions [ABSTRACT FROM AUTHOR]

An attempt has been made to estimate the unit capital cost of parabolic trough collector (PTC) based concentrating solar power (CSP) plants in India to facilitate their financial appraisal. While reviewing approaches mentioned in the literature, a significant variation is observed in unit capital cost estimates for a 50 MW wet cooled without storage PTC based plant (US $1700 to US $2662 per kW). To internalize the effect of alternate condenser cooling options and thermal energy storage on the unit capital cost, a new approach that is based on inventory of material used and associated costs have been suggested. With the use of this approach, the unit capital cost of a 50 MW wet cooled PTC plant is estimated at US $1734 per kW. Similarly, for the same nominal capacity plant with dry cooling, the unit capital cost is estimated at US $1994 per kW. Moreover, the effects of increased nominal capacity and hours of thermal energy storage on the unit capital cost have also been investigated. • Cost estimates for a 50 MW PTC based CSP plant in India. • Review of potential approaches for estimating capital cost of PTC based CSP plants. • Study of cost implications of condenser cooling options and thermal energy storage. • Effect of the nominal capacity of the plant and hours of storage on the unit cost. [ABSTRACT FROM AUTHOR]

A significant share of final energy consumption in the industrial sector is used for meeting the process heating applications at low and medium temperatures (up to 250 °C). Solar industrial process heating is being considered as one of clean and renewable energy options in many countries of the world. An attempt to present a review of the available published literature on solar industrial process heating has been made in this paper. The aspects included in the review are utilization potential, present status, suitable solar collectors, design and integration aspects, performance evaluation, economic and environmental assessment, barriers to large scale adoption and case studies etc. [ABSTRACT FROM AUTHOR]

Financial viability is arguably the most important requirement for large scale dissemination of decentralized renewable energy systems (DRESs). Financial viability of a DRES can vary from region to region as it depends on various geographical and socio-economic factors. With sufficient solar radiation availability throughout the year, abundant forest cover, dependence of majority of population on agriculture and remote villages facing energy access related challenges, the state of Uttarakhand in India has significant potential for the application of solar and biomass based DRESs. Based on the current fuel prices, subsidies and rebates, this study is an attempt to assess the financial attractiveness of solar and biomass based DRESs under various scenarios for their potential users in Uttarakhand. Improved biomass cookstove, domestic solar water heater, solar lantern and solar home system are found to be financially viable under almost all scenarios for household applications while dish type solar cooker, solar PV pump and solar dryer are not so attractive for household applications. It has also been found that the financial attractiveness of DRESs improve significantly with the removal of subsidy presently being given to fossil fuel based energy supply options. [ABSTRACT FROM AUTHOR]

This paper reviews the available literature dealing with the barriers to the dissemination of decentralized renewable energy systems. Decentralized renewable energy systems may face a range of technical, economic, institutional, socio-cultural and environmental barrier to their dissemination. In the paper, barriers impeding the dissemination of decentralized renewable energy systems have been identified and assessed. In addition, appropriate remedial measures and corresponding responsibility centers as reported in the literature have also been discussed. Inappropriateness of technology, unavailability of skilled manpower for maintenance, unavailability of spare parts, high cost, lack of access to credit, poor purchasing power and other spending priorities, unfair energy pricing, lack of information or awareness, and lack of adequate training on operation and maintenance of decentralized renewable energy systems are found to be the most critical barriers. Long-term conducive policies, appropriate regulatory framework, financial incentives (capital subsidies and soft loans) to users, technology and skill development, internalization of externalities in the cost of energy, withdrawal of subsidies presently being given to fossil fuels, development of specialized institutions, cooperation with international agencies, participation of local community and awareness generation have been recommended for increased dissemination of decentralized renewable energy systems. [ABSTRACT FROM AUTHOR]

In India, kerosene is primarily used for domestic lighting in un-electrified rural households. The government incurs significant expenditure on subsidies and under-recoveries associated with supply of kerosene distributed through public distribution system. In addition to poor illumination and indoor pollution, kerosene lamp usage necessitates expenditure on purchase of kerosene for lighting. The study evaluates the feasibility of diverting subsidies and under-recoveries provided by government and the fuel cost incurred by the user to finance replacement of kerosene lamps with solar lanterns. It is found that such an initiative will save money for both the government as well as the users besides providing better quality illumination without any indoor pollution. [ABSTRACT FROM AUTHOR]

The capital cost of concentrating solar power (CSP) plants is relatively higher amongst other renewable energy-based electricity generation options. To make CSP plants more competitive, different possibilities to reduce capital costs of CSP plants need to be explored while making use of the recent developments in the field. Two potential modalities for parabolic trough collector based CSP plants have been considered in the study – (i) use of large aperture area parabolic troughs and advanced heat transfer fluids so as to operate at higher temperatures (Case-I) and (ii) use of larger aperture area parabolic troughs along with the use of molten salt as both the heat transfer fluid and storage medium (Case-II). The cost reduction potential has been estimated by assessing the impact of proposed changes on the number of components required to be used and consequent reduction in the material requirements in various components of different subsystems of the CSP plant. The likely reduction in capital cost of the parabolic trough collector based CSP plants for a location in India is estimated at 12.3% for Case-I and 29.9% for Case-II. • A review of recent developments in PTC technology to identify cost reduction possibilities. • Estimation of capital cost using advance collectors and heat transfer fluid. • Cost reduction of up to 29.9% is expected using advanced PTC technologies. [ABSTRACT FROM AUTHOR]

A preliminary attempt to estimate the potential of solar process heating in producing cotton based textiles in India as well as the amount of greenhouse gases likely to be mitigated consequently has been made. To begin with, all the processes involved in the production of cotton based textiles (yarn and cloth) that require thermal energy have been identified. Also an assessment of availability of solar radiation as well as the ambient conditions at various locations with clusters of cotton based textile units in the country has been made. Subsequently, the solar collector area required for meeting the process heating demand has been estimated. Further, corresponding useful thermal energy delivery of solar industrial process heating systems at identified locations has been estimated. The process heating potential in term of useful thermal energy requirements in cotton based textile production is estimated at 191 PJ annually. The estimated values of annual solar fractions for the identified locations with clusters of cotton based textile units range between 0.22 and 0.32 for systems without storage and in between 0.20 and 0.60 for SIPH system having provision of thermal storage for collection of energy that would otherwise be dumped. Solar process heating in cotton based textile industry in India have a potential to mitigate 2457–7648 thousand tonnes of greenhouse gas emissions annually depending on the location and the provision of a storage component or otherwise. [ABSTRACT FROM AUTHOR]

An attempt to estimate the potential of solar industrial process heating (SIPH) and corresponding mitigation of greenhouse gas emissions in dairy industry in India is presented. An assessment of availability of solar radiation as well as of the ambient conditions at various locations with milk processing plants has been made. The effect of the choice of design value of direct normal irradiance on the annual performance of solar process heating systems has been studied using model developed for hourly simulation of the performance of solar process heating system. Further, state wise estimates for useful thermal energy delivery and corresponding solar fraction have also been obtained. The total process heating potential in term of useful energy requirement in dairy sector in India has been estimated at 6.40 PJ/annum which reduces to 4.50 PJ per annum if the process heating requirement is restricted to only pasteurization stage of milk processing. The corresponding solar collector area requirement for process heating in dairy industry in India is estimated in the range of 1.54–1.83 million m 2 with the average solar fraction estimated in the range 0.18–0.32. The use of solar energy for meeting milk processing related thermal energy demand is expected to mitigate (32–144 thousand tonnes) of CO 2 emissions annually. [ABSTRACT FROM AUTHOR]

The sizing of a solar thermal power plant directly affects its cost and also the annual electricity output and hence its financial attractiveness. It involves deciding appropriate values of design DNI, solar multiple and hours of thermal storage to achieve high annual capacity utilization factor (CUF) with the least cost of electricity delivered. An analysis of the impact of these design parameters on the performance of parabolic trough concentrator (PTC) and linear Fresnel reflector (LFR) based solar thermal power plants is presented using System Advisor Model for eight locations in India. Annual electricity output is estimated using radiation data source of SEC-NREL. Levelized unit cost of electricity (LUCE) is estimated using benchmark capital cost and other financial conditions specified by the Central Electricity Regulatory Commission of Government of India. For a design DNI of 950 W/m 2 , LUCE is minimum in solar multiple range of 1.4–1.6 for PTC based plants and of 1.8–2.0 for LFR based plants. With a solar multiple of 1.0, LUCE is minimum in design DNI range of 550–700 W/m 2 for PTC based plants and 450–550 W/m 2 for LFR based plants. [ABSTRACT FROM AUTHOR]

A simple framework to estimate the potential of solar industrial process heating (SIPH) and corresponding CO 2 emissions mitigation in paper industry in India is presented. Geographical locations with clusters of paper mills have been identified and the annual process heating requirement for paper production (based on raw material use) at each cluster has been estimated. The total process heating potential for the paper industry in India has been estimated at 25.2 PJ/annum. Using the estimated performance of a commercially available parabolic trough based SIPH system with collector area requirement of 1.11 million m 2 annual solar fraction in the range of 0.25–0.30 have been estimated. Annual energy delivery of SIPH systems estimated at 4.34 PJ per annum. Finally at 8 main locations with clusters of paper mills in India considered in this study, adoption of SIPH without storage is expected to mitigate 0.34 million tonnes of CO 2 emissions annually. [ABSTRACT FROM AUTHOR]

Realistic assessment of utilization potential of solar energy for thermal power generation and identification of niche areas/locations for this purpose is critically important for designing and implementing appropriate policies and promotional measures. This paper presents the results of a detailed analysis undertaken for estimating the potential of solar thermal power generation in India. A comprehensive framework is developed that takes into account (i) the availability of wastelands (ii) Direct Normal Irradiance (DNI) (iii) wastelands that are habitat to endangered species and/or tribal population and/or that is prone to earthquakes and (iv) suitability of wasteland for wind power generation. Finally, using an approach developed for the allocation of wastelands suitable for solar power generation between thermal and photovoltaic routes, the potential of solar thermal power generation is assessed for two threshold values of DNI – 1800 kW h/m 2 and 2000 kW h/m 2 . With all the wastelands having wind speeds of 4 m/s or more allocated for wind power generation, the estimated potential for solar thermal power generation is 756 GW for a threshold DNI value of 1800 kW h/m 2 and 229 GW for a threshold DNI value of 2000 kW h/m 2 . Results obtained can be used for identification of best suited areas for solar thermal power generation in India. [ABSTRACT FROM AUTHOR]

Telecom services play a vital role in the socio-economic development of a country. The number of people using these services is growing rapidly with further enhance growth expected in future. Consequently, the number of telecom towers that are critical for providing such services has also increased correspondingly. Such an increase in the number of telecom towers in a country implies a corresponding increase in the electricity demand of the country. Moreover, in view of growing concerns about climate change, it is necessary that the decarbonization of telecom towers is prioritized so as to minimize their carbon footprint. In view of the above, the primary objective of this paper is to provide a comprehensive analysis of various renewable energy-based systems and the advantages they offer for powering telecom towers, based on a review of the existing literature and field installations. Telecom towers are powered by hybrid energy systems that incorporate renewable energy technologies such as solar photovoltaic panels, wind turbines, fuel cells, and microturbines. Utilizing these systems helps to reduce the consumption of fossil fuels and consequently mitigates the anthropogenic carbon emissions. Moreover, information related to growth of the telecom industry, telecom tower configurations and power supply needs, conventional power supply options, and hybrid system combinations and their benefits. Several field installations of renewable energy-based hybrid systems have also been summarized. This review can help to evaluate appropriate low-carbon technologies and also to develop policy instruments to promote renewable energy-based telecom tower power systems., (© The Author(s), under exclusive licence to Springer Nature B.V. 2023, Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)