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Second-generation bioethanol can be produced from various lignocellulosic biomasses such as wood, agricultural or forest residues. Lignocellulosic biomass is inexpensive, renewable and abundant source for bioethanol production. The conversion of lignocellulosic biomass to bioethanol could be a promising technology though the process has several challenges and limitations such as biomass transport and handling, and efficient pretreatment methods for total delignification of lignocellulosics. Proper pretreatment methods can increase concentrations of fermentable sugars after enzymatic saccharification, thereby improving the efficiency of the whole process. Conversion of glucose as well as xylose to bioethanol needs some new fermentation technologies to make the whole process inexpensive. The main goal of pretreatment is to increase the digestibility of maximum available sugars. Each pretreatment process has a specific effect on the cellulose, hemicellulose and lignin fraction; thus, different pretreatment methods and conditions should be chosen according to the process configuration selected for the subsequent hydrolysis and fermentation steps. The cost of ethanol production from lignocellulosic biomass in current technologies is relatively high. Additionally, low yield still remains as one of the main challenges. This paper reviews the various technologies for maximum conversion of cellulose and hemicelluloses fraction to ethanol, and it point outs several key properties that should be targeted for low cost and maximum yield.

The current status and challenges associated with the production and utilization of cellulosic ethanol in Korea are reviewed in this paper. Cellulosic ethanol has emerged as a promising option for mitigating Korea's CO(2) emissions and enhancing its energy security. Korea's limited biomass resources is the most critical barrier to achieving its implementation targets for cellulosic ethanol. Efforts to identify new suitable biomass resources for cellulosic ethanol production are ongoing and intensive. Aquatic biomasses including macroalgae and plantation wastes collected in the Southeast Asia region have been found to have great potential as feedstocks for the production of cellulosic ethanol. R&D explorations into the development of technologies that can convert biomass materials to ethanol more efficiently also are underway. It is expected that cellulosic ethanol will be in supply from 2020 and that, by 2030, its use will have effectively reduced Korea's total gasoline consumption by 10%.

Biogas is a viable alternative for supplying clean and sustainable energy. Despite all manner of policy measures introduced by the Government of India, biogas is not widely used in India. This article tries to identify factors that influence the decision to adopt biogas at household level. We examine a conceptual framework empirically in which a household wants to maximize utility from biogas by using the India Human Development Survey (IHDS) I, which is a nationally representative, multi-topic survey. By applying both maximum likelihood and penalized likelihood methods (Firthlogit) of logistic regression on a sample size of almost 10,384 households, it has been found that wealthy people are more likely to adopt biogas compared to the marginalized section of the society. We recommend more inclusive policy measures for the weaker section of the society to create an enabling environment to make it a self-promoting technology.

Improving access to safe drinking water can result in multi-dimensional impacts on people's livelihood. This has been aptly reflected in the Millennium Development Goals (MDG) as one of the major objectives. Despite the availability of diverse and complex set of technologies for water purification, pragmatic and cost-effective use of the same is impeding the use of available sources of water. Hence, in country like India simple low-energy technologies such as solar still are likely to succeed. Solar stills would suffice the basic minimum drinking water requirements of man. Solar stills use sunlight, to kill or inactivate many, if not all, of the pathogens found in water. This paper provides an integrated assessment of the suitability of domestic solar still as a viable safe water technology for India. Also an attempt has been made to critically assess the operational feasibility and costs incurred for using this technology in rural India.

Abstract Natural resources exist independent of human intervention. Although these interventions can and do affect the balance between ecological and biological diversity conditions these resources support, and their use to promote economic development. Currently, the unsustainable use of these resources threatens this balance, calling for more sustainable patterns of natural resource use and conservation. The primary responsibility for ensuring the proper balance lies with governments, leading to various policies and programs to preserve natural resources. The ultimate goal is to make the masses aware of natural assets’ importance and encourage their sustainable use. To successfully implement, however, these government practices require public communication and participation, and the full consideration of public opinion at various levels of governance. A predictive analytics framework is proposed for understanding public opinion on government policies to improve sustainable water governance. An integrated policy initiative to balance water resources use and conservation launched by the Indian government served as a test case for applying the framework in an attempt to accurately classify the opinion polarity related to the policy. The conventional feature extraction is applied to pre-processed datasets to extract the relevant features. Subsequently, swarm-based feature selection is applied to filter out optimal features. Lastly, opinion mining and textual analysis are performed to determine the most relevant water management factors that need immediate attention. The proposed framework serves as a policy evaluation strategy in the water management domain. The paper closes with a discussion of the general applicability of the proposed framework.

Fruit and vegetable marketplace waste (FVMW) is an appealing alternative for energy production and should be utilized as a single substrate in anaerobic digestion (AD)–based biogas plants at an industrial-scale level in subtropical climatic countries. India alone generates 961,000 tons of FVMW annually from the major fruit and vegetable markets (FVMs). Utilization of FVMW to produce useful energy by AD could be helpful in meeting the ever-increasing energy demands of these countries. AD of fruit and vegetable waste (FVW) by two-phase systems has revealed good results in terms of stability, performance, and biogas generation; however, innovative approaches like plug flow tank reactor (PFTR) with passive solar heating with no mixing and no energy heating coupled with heat balance models and resistance network–based heat balance models need to be researched for subtropical climatic conditions in order to optimize the economics and energy balance of an AD system. Food waste and slaughter house wastes could be utilized successfully as co-substrates with FVW. C/N ratio is a critical performance parameter in the AD systems involving co-substrates; however, the synergistic relationship among co-substrates and characteristics, viz., macro- and micronutrients of individual co-substrates, must be investigated to improve the AD process. The optimum proportions of co-substrates could be determined by individual substrate characterization, biomethanation potential (BMP), and biodegradation kinetic models, thereby saving time and money as compared with random experimentation. Thermal, ultrasonic, and electrical pre-treatment in addition to physical pre-treatment could be effectively used for pre-treating FVW; however, synergy between co-substrates and pre-treatment method must be researched in order to justify the increased cost in extra pre-treatment.

Renewable energy-based off-grid projects have played a crucial role in Sri Lanka’s universal electrification effort. The paper, in this context, unravels two crucial and quite interrelated aspects of decentralised off-grid electrification in the country: a) it critically analyses the off-grid electricity sector development and assesses its contribution to the universal electrification in the country and; b) it examines the current set of challenges associated with the off-grid electrification in the larger context of massive grid expansion. A mix of quantitative and qualitative research methods is employed as tools of analysis. The paper brings out several policy-relevant findings. Strategic policy interventions coupled with targeted policy goals, robust community-centric management structures, well-designed credit systems, and well-structured capacity-building initiatives are identified as key leveraging points for the success of off-grid electrification projects. The techno-economic analysis of an existing micro-hydro project reveals that there exist opportunities for more productive use of existing capacity. Grid interconnection of off-grid energy projects emerges as a major challenge beset with a whole gamut of technical, legal, regulatory, financial, and social conundrums. Interestingly, the intensity of such challenges differs across ownership types.

This paper analyses the impact of postponing global mitigation action on abatement costs and energy systems changes in China and India. It compares energy-system changes and mitigation costs from a global and two national energy-system models under two global emission pathways with medium likelihood of meeting the 2 °C target: a least-cost pathway and a pathway that postpones ambitious mitigation action, starting from the Copenhagen Accord pledges. Both pathways have similar 2010–2050 cumulative greenhouse gas emissions. The analysis shows that postponing mitigation action increases the lock-in in less energy efficient technologies and results in much higher cumulative mitigation costs. The models agree that carbon capture and storage (CCS) and nuclear energy are important mitigation technologies, while the shares of biofuels and other renewables vary largely over the models. Differences between India and China with respect to the timing of emission reductions and the choice of mitigation measures relate to differences in projections of rapid economic change, capital stock turnover and technological development. Furthermore, depending on the way it is implemented, climate policy could increase indoor air pollution, but it is likely to provide synergies for energy security. These relations should be taken into account when designing national climate policies.

Abstract Biodiesel offers to be one of the renewable fuel that is in great demand due to hike in price and exploitation of various conventional resources. Biodiesel has gained wide attention as it emits less carbon monoxide and other pollutants. Biodiesel is known as mono-alkyl esters of long fatty acid, produced by transesterification in the presence of triglycerides and alcohol. The choice of catalyst and feedstock are the most important criteria for effective production of biodiesel. Catalyst and raw material selection play a significant role in the cost of biodiesel production. The heterogeneous catalyst offers a wide option for the catalytic selection because of its high selectivity and reusability characteristics. Recent advances in the field of catalytic technology for biodiesel production using nanosized catalyst is because of high stability over the repeated use. Nanocatalyst solves various bottleneck problem associated in the production of biodiesel. The present review is focused on various technologies and challenges linked to the production process, including some important aspects of feedstock selection. Thus the present review is maily focused on various catalytic technology used for biodiesel production using different production methods and potential feedstocks.

This work was carried out in search of a suitable fuel alternative to fast-depleting fossil fuel and oil reserves and in serious consideration of the environmental problems associated with the major use of fuels based on petrochemicals; research work is in progress worldwide. Researchers have been re-directing their interests to biomass-dependent fuels, which currently seem to be the only logical substitute for green development in the context of economical and environmental aspects. Renewable bioresources are available worldwide in the form of residual agricultural biomass and wastes, which can be converted into liquid biofuels. However, the process of converting, or chemical conversions, can be very expensive and not worthwhile to use for an economical large-scale commercial supply of biofuels. Hence, there is still need for souch research to be done on an effective, economical, and efficient conversion process. The objective of this review is to provide a deep overview of liquid biofuels and the present knowledge produced by scientists throughout the world.