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Abstract Enhancing microalgae biomass productivity through different abiotic and environmental factors optimization is crucial. Design of experimental (DOE) methodology using Taguchi orthogonal array (OA) was studied to evaluate the specific influence of eight important factors (light, pH, temperature, carbon concentration, nitrates, phosphates, magnesium ion concentration and carbon source) on the biomass production using three levels of factor (2 1 × 3 7 ) variation with experimental matrix [L 18 -18 experimental trails]. All the factors were assigned with three levels except light illumination (2 1 ). Substantial influence on biomass productivity is observed with carbon concentration contributing 16.8%, followed by nitrates 12.8% and light 9.3%. Experimental setup eight (Light, pH-8.5, Temperature 25°C, Carbon concentration 10 g/l, nitrates 1.5 g/l, phosphates 0 g/l, magnesium 150 mg/l, Carbon source (glucose)) showed maximum biomass growth (5.26 g/l) and good substrate degradation (63%, COD removal efficiency) contributing to carbohydrate production (257 mg/g biomass) which is further converted to lipids (20% Total lipid and 10% Neutral lipids). Chlorophyll ( a , b ), carbohydrates composition, FAME analysis for lipid percentage were monitored during process operation. Elemental analysis reveals that the carbon to hydrogen and oxygen ratio present in dried algal biomass can be hydrothermally liquefied (HTL) to produce biocrude.

Abstract Small hydropower projects (SHPs), though generally considered more environmentally benign and socially acceptable as compared to large projects, yet their overall sustainability is under suspicion in the Himalayan regions. Almost all SHPs in this region are being developed as run of the river mode which generally causes less/no submergence and quite less displacement of people as compared to large reservoir based hydropower production mode. However, in the absence of proper planning and monitoring mechanism, these projects are causing implacable tunnelling of hills, choking of streams, conversion of streams into dry ditches and long term socio-environmental impacts. This paper presents a SHP development study from hydro rich Beas river basin of Himachal Pradesh, a state nestled in western Himalayan region of India. In depth field studies, focus group discussions with the project affected people and interaction with project proponents of five SHPs in this region suggest that sustainability issues with respect to SHPs are not small vis-a-vis size of their installed capacity. There is an urgent need to take steps to include SHPs having an installed capacity of above 10 MW into the ambit of environment clearance process which is absent in many countries of the world at present.

In the present world, renewable sources of energy have begun to make a significant contribution to meeting heat and power needs. In India, the Government is implementing a wide ranging programmes on renewable energy technologies. Several policy and fiscal measures have contributed to the rapid expansion of the progress during the last few years. This paper presents a review of renewable energy programme and vision in India. The present situation is seen to be much more promising and favourable for renewables.

Abstract In India, utility-scale power plants face problems like, availability of larger land, Transmission & Distribution losses (T&D), Aggregate Technical & Commercial losses (AT&C) and availability of the grid because of which around 240 million of people do not have access to electricity. Increasing installed capacity of fossil-based power plants to meet the power requirement will increase the greenhouse gas emissions, our dependency on fossil fuels, adverse environmental and social impacts. Decentralized solar rooftop PV system, because of its proven technology and environmental benefits, will overcome these factors in a sustainable way. The growth and development of solar rooftop PV, as per the current status, are of substandard level despite the fact that the Government of India has set a target of installing 40 GW of decentralized solar rooftop PV up-to 2022. Therefore, this paper highlights the solar power policies adopted for the decentralized solar rooftop PV segment along with various business models adopted and current status in India. The author has also analyzed various factors which motivate the end consumer to invest in solar rooftop PV. At the end, the author has summarized some key barriers to the growth and development of the solar rooftop PV segment in India.

In this study, two freshwater cyanobacteria, Oscillatoria sp. 50A and Synechocystis sp. NN have been evaluated for biodiesel production. Among the two cyanobacteria, Synechocystis sp. NN was isolated, identified by its 16S rRNA gene sequencing. Effects of sodium bicarbonate (SBC), tannery effluent (TE), coir pith (CP) and light stress (L1) on biomass and lipid production of Synechocystis sp. NN were studied. Result showed that maximum biomass productivity of 18.7 ± 0.9 mg/L/day (1.9 folds) was observed in TE supplemented BG-11 media than normal BG-11 media. Meantime, maximum lipid productivity of 2.6 ± 0.4 mg/L/day (1.4 folds) was observed in CP supplemented BG-11 media than normal media. Further, fatty acid composition analyses by GC–MS showed that C16, C18:1 in Oscillatoria sp. 50A and C16, C20:1, C22:1 in Synechocystis sp. NN were predominant and the fuel properties were also in accordance with the international standards. Besides gene expression of acetyl CoA carboxylase D of Synechocystis sp. NN, analyzed by RT-PCR revealed that transcripts of accD were up-regulated by 1.2–4.7 folds in different media conditions. The findings of this study showed that Synechocystis sp. NN can be utilized as a suitable feedstock that is amenable for cultivation using wastes as nutrient source.

Abstract The investigation first time reports the efficacy of de-oiled algal biomass extract (DOABE) for mixotrophic cultivation of Chlorella sp. MCC27 to enhance biodiesel production in open tray systems and in BioXpert-V2 software connected photobioreactor (PBR). The cultivation systems with addition of DOABE (PBR systems + DOABE and open tray system + DOABE) as media were tested for quality and quantity of biodiesel. The presence of organic carbon and low nitrogen in DOABE caused >2 folds higher biomass productivity and >4 folds enhanced lipid productivity for the cells cultivated in PBR system + DOABE and open tray system + DOABE as compared to control (i.e. BBM). Biochemical analysis of cells from both the systems revealed the decrease in total carbohydrates and protein contents. The FAMEs analyses showed vehicular quality biodiesel. PBR system + DOABE showed edge over open tray system + DOABE in terms of biomass productivity and lipid content. The physical properties of biodiesel produced from Chlorella sp. MCC27 were more close to the fuel standards (ASTM D6751), when cells were cultivated in open tray system + DOABE than in PBR system + DOABE. Collectively, this study highlights the use of DOABE as a low cost feedstock for enhancing vehicular quality biodiesel production from microalgae.

Abstract In order to meet the energy requirements, there has been growing interest in alternative fuels like biodiesels, methyl alcohol, ethyl alcohol, biogas, hydrogen and producer gas to provide a suitable diesel oil substitute for internal combustion engines. Biomass is basically composed of carbon, hydrogen and oxygen. A proximate analysis of biomass indicates the volatile matter to be between 60–80% and 20–25% carbon and the rest, ash. The first part of sub-stoichiometric oxidation leads to the loss of volatiles from biomass and is exothermic; it results in peak temperatures of 1400–1500 K and generation of gaseous products like carbon monoxide, hydrogen in some proportions and carbon dioxide and water vapor, which in turn are reduced in part to carbon monoxide and hydrogen by the hot bed of charcoal generated during the process of gasification. Therefore, solid biomass can be converted into a mixture of combustible gases, and subsequently utilized for combustion in a CI engine. Producer gas, if used in dual fuel mode, is an excellent substitute for reducing the amount of diesel consumed by the CI engine. Downdraft moving bed gasifiers coupled with an IC engine are a good choice for moderate quantities of available biomass, up to 500 kW of electric power. Vegetable oils present a very promising alternative to diesel oil since they are renewable and have similar properties. Vegetable oils offer almost the same power output with slightly lower thermal efficiency when used in diesel engines [1] , [2] , [3] , [4] , [5] , [6] , [7] . Research in this direction with edible oils have yielded encouraging results, but their use as fuel for diesel engines has limited applications due to higher domestic requirement [8] , [9] , [10] . In view of this, Honge oil (Pongamia Pinnata Linn) is selected and its viscosity is reduced by the transesterification process to obtain Honge oil methyl ester (HOME). Since vegetable oils produce higher smoke emissions, dual fuel operation could be adopted in order to improve their performance. A gas carburetor was suitably designed to maximize the engine performance in dual fuel mode with Honge oil–producer gas and HOME–producer gas respectively. Thus bio-derived gas and vegetable oil, when used in a dual fuel mode with carburetor, resulted in better performance with reduced emissions.

Abstract This study focusses on the experimental analyses of two active horizontal solar dryers viz., mixed mode (Case-I) and indirect solar dryer (Case-II) integrated with latent heat storage system designed for drying Piper nigrum (black pepper). The drying time required to reach the desired moisture content of 0.14(d.b) from 3.46 (d b) in both cases were 14 h and 23 h, respectively. While, it took 59 h in open sun drying (case-III). The developed dryers operated in case-I and case-II saved 76% and 60% of drying time respectively compared to case-III. Form economic point of view, the developed solar dryers are more beneficial. It is seen that the overall dryer efficiency of the case-I is 20% higher than case-II. Quality analyses in terms of proximity analysis and anti-oxidants of the fresh and dried samples in all the three cases were carried out. The carbohydrates and protein values were rich in case-I compared to other two cases. The anti-oxidant contents of samples dried in case-I and case-III were 45.69 μ mol TE/g sample and 23.25 μ mol TE/g sample, respectively. The ash substance of the samples dried under case-III was high compared to the other two cases.

Abstract Pyrolysis of deodar has been carried out at 350 and 400 °C at 0.1, 1, 2 and 3 MPa hydrogen pressure. Pyrolysis under nitrogen atmosphere has been carried out at 300, 350, 400 and 450 °C. The favourable process conditions under hydrogen environment were found to be 400 °C and 2 MPa pressure and in case of nitrogen environment was found to be 350 °C. The products have been characterised using GC–MS, 1 H NMR, FT-IR and SEM. It has been observed that the bio-oil is rich in phenolic compounds under nitrogen and hydrogen atmospheres. Selectivity towards certain compounds such as catechol, vanillin and its derivatives etc. are high under hydrogen atmosphere. Deodar has undergone decomposition significantly which is evident by the absence of most functionality in bio-char and loss of crystallinity. The products formed under hydrogen and nitrogen environments are different from each other owing to the differences in reaction mechanism.