Renewable technologies are considered as clean sources of energy and optimal use of these resources minimize environmental impacts, produce minimum secondary wastes and are sustainable based on current and future economic and social societal needs. Sun is the source of all energies. The primary forms of solar energy are heat and light. Sunlight and heat are transformed and absorbed by the environment in a multitude of ways. Some of these transformations result in renewable energy flows such as biomass and wind energy. Renewable energy technologies provide an excellent opportunity for mitigation of greenhouse gas emission and reducing global warming through substituting conventional energy sources. In this article a review has been done on scope of CO2 mitigation through solar cooker, water heater, dryer, biofuel, improved cookstoves and by hydrogen.

https://www.beren.sakarya.edu.tr/sites/beren.sakarya.edu.tr/file/1380752545-07-RenewEn.pdf.pdf

Role of renewable energy sources in environmental protection: A review

World energy demand is expected to increase due to the expanding urbanization, better living standards and increasing population. At a time when society is becoming increasingly aware of the declining reserves of fossil fuels beside the environmental concerns, it has become apparent that biodiesel is destined to make a substantial contribution to the future energy demands of the domestic and industrial economies. There are different potential feedstocks for biodiesel production. Non-edible vegetable oils which are known as the second generation feedstocks can be considered as promising substitutions for traditional edible food crops for the production of biodiesel. The use of non-edible plant oils is very significant because of the tremendous demand for edible oils as food source. Moreover, edible oils’ feedstock costs are far expensive to be used as fuel. Therefore, production of biodiesel from non-edible oils is an effective way to overcome all the associated problems with edible oils. However, the potential of converting non-edible oil into biodiesel must be well examined. This is because physical and chemical properties of biodiesel produced from any feedstock must comply with the limits of ASTM and DIN EN specifications for biodiesel fuels. This paper introduces non-edible vegetable oils to be used as biodiesel feedstocks. Several aspects related to these feedstocks have been reviewed from various recent publications. These aspects include overview of non-edible oil resources, advantages of non-edible oils, problems in exploitation of non-edible oils, fatty acid composition profiles (FAC) of various non-edible oils, oil extraction techniques, technologies of biodiesel production from non-edible oils, biodiesel standards and characterization, properties and characteristic of non-edible biodiesel and engine performance and emission production. As a conclusion, it has been found that there is a huge chance to produce biodiesel from non-edible oil sources and therefore it can boost the future production of biodiesel.

Non-edible vegetable oils: A critical evaluation of oil extraction, fatty acid compositions, biodiesel production, characteristics, engine performance and emissions production

Production and comparison of fuel properties, engine performance, and emission characteristics of biodiesel from various non-edible vegetable oils: A review

The use of inedible vegetable oils as an alternative fuel for diesel engine is accelerated by the energy crisis due to depletion of resources and increased environmental problems including the great need for edible oil as food and the reduction of biodiesel production cost, etc. Of a lot of inedible vegetable oils which can be exploited for substitute fuel as diesel fuel, seven vegetable oils, i.e., jatropha, karanja, mahua, linseed, rubber seed, cottonseed and neem oils were selected for discussion in this review paper. The application of jatropha oil as a liquid fuel for CI engine can be classified with neat jatropha oil, engine modifications such as preheating, and dual fuelling, and fuel modifications such as jatropha oil blends with other fuels, mostly with diesel fuel, biodiesel, biodiesel blends and degumming. Therefore, jatropha oil is a leading candidate for the commercialization of non-edible vegetable oils. There exists a big difference in the fuel properties of seven inedible vegetable oils and its biodiesels considered in this review. It is clear from this review that biodiesel generally causes an increase in NOx emission and a decrease in HC, CO and PM emissions compared to diesel. It was reported that a diesel engine without any modification would run successfully on a blend of 20% vegetable oil and 80% diesel fuel without damage to engine parts. This trend can be applied to the biodiesel blends even though particular biodiesel shows 40% blend. In addition, the blends of biodiesel and diesel can replace the diesel fuel up to 10% by volume for running common rail direct injection system without any durability problems.

Inedible vegetable oils and their derivatives for alternative diesel fuels in CI engines: A review

Performance, emission and combustion characteristics of a variable compression ratio engine using methyl esters of waste cooking oil and diesel blends

Experimental investigation of the effect of compression ratio and injection pressure in a direct injection diesel engine running on Jatropha methyl ester

Performance evaluation of a diesel engine fueled with methyl ester of castor seed oil

Greenhouse gases especially CO2 can be reduced with the help of improved biomass cookstoves. This paper deals with the design and development of biomass stoves (single pot and double pot) with better efficiency for meeting household cooking energy requirement. Thermal performance, flue gas emission of carbon monoxide (CO) and carbon dioxide (CO2) have been investigated. It was seen from the result that the flue gas emission is within permissible limit as recommended by World Health Organization. The design of improved biomass stove sent to Palampur (32o10’N,76o30’E) center situated in Himalaya in hilly terrain of India, where the acceptability of double pot stoves (85%) is quite high compared to single pot stoves (30%). Thermal efficiencies of both single and double pot stove were recorded about 21% and 25% respectively. An improved biomass cookstove can save about 161 kg of CO2 annually. Improved cookstoves was found eco-friendly in nature and suitable for the cooking requirement of hilly areas.

Mitigation of greenhouse gases by adoption of improved biomass cookstoves

This paper deals with field related experience of a low temperature industrial heat application through biomass gasification. The gasification system is essentially consists of an open top down draft reactor lined with ceramic. The experiment reveals that 6.5 kg of liquefy petroleum gas (LPG) is fully replaced by 38 kg of sized wood on hourly basis. The maximum temperature attained was 367°C in 130 min at 100.7 Nm3 h−1 gas flow rate. This system has resulted a saving of about 19.5 tons of LPG over 3,000 h of operation, implying a saving of about 33 tons of CO2 emission, thus a promising candidate for clean development mechanism. Fuel economic analysis of gasifier system showed that the saving was about 13,850 US$ for 3,000 h of baking operation.

Experimental investigation of open core downdraft biomass gasifier for food processing industry

Biodiesel produced from different vegetable oils and fats are likely to have some comparative advantages and disadvantages. Two major oil varieties, considered suitable for biodiesel making are ‘Jatropha curcas’ and ‘Pongamia pinnata’. This study targets at making a comparison of the methyl esters of these oils in a diesel engine vis-a-vis diesel fuel. The performance of the fuels was evaluated in terms of thermal efficiency, specific fuel consumption, power output and mean effective pressure, cylinder pressure, rate of pressure rise and heat release rates. The emissions of carbon monoxide (CO), carbon dioxide (CO2), unburnt hydrocarbon (HC), oxides of nitrogen (NOx) and Smoke opacity with the three fuels were also compared. Both the varieties of the oil, after transesterification, exhibit the major properties within acceptable limits of biodiesel standards set by many countries. Karanj methyl ester (KME) performed better than Jatropha methyl ester (JME) whereas shortest ignition delay is observed with JME. Both the esters performed poorer than diesel but emissions of HC, NOx and smoke were found lower with esters. The three fuels delivered almost same brake power even when the indicated power was higher with diesel.

N.S. Rathore

Papers

Experimental investigation of the effect of compression ratio and injection pressure in a direct injection diesel engine running on Jatropha methyl ester

Performance evaluation of a diesel engine fueled with methyl ester of castor seed oil

Mitigation of greenhouse gases by adoption of improved biomass cookstoves

Experimental investigation of open core downdraft biomass gasifier for food processing industry

A Comparative Study of Performance, Combustion and Emissions of Diesel, Jatropha Methyl Ester and Karanj Methyl Ester in a DI-CI Engine