One of the most significant benefits of developing biodiesel as a sustainable power option is the wide variety of feedstocks available for biodiesel processing [46]. More than 350 oil-bearing plants are classified as a possible source for renewable oils, such as soybean, sunflower, palm, cottonseed, safflower oil, peanut oil, and oilseed rape [44,47]. Many other un-edible oils such as neem, Karanja, and Jatropha are also gaining interest [48]. The abundance of fuel sources for producing biodiesel depends on both the country’s geographical position and farming activities. The usage of the right raw material is thus critical in maintaining nominal manufacturing costs for biodiesel. Studies have shown that only raw material accounts for more than 75% of the total cost of manufacturing biodiesel. The feedstock for biodiesel can usually be classified into four major groups [49]:

• Fats of animals: black butter, seaweed, and animal fat.
• Recycled or surplus crude.
• Non-edible vegetable oil: halophytes, Karanja, coral, Jatropha, and ocean plum.
• Edible vegetable oil: rape, sunflower, soybean, coconut oil, and hemp oil.

Worldwide, there are several policies for biodiesel, which have been set out by several countries. These policies have been encouraging biodiesel within the energy mix and raised the goal for the planned utilization of biodiesel. A list of certain biodiesel goals in chosen countries across the world is displayed in Table 1.

The Mid-Term Policy (MTP) was subordinated to upgrades in 2006. Thus, the MTP would excel in this year’s latest short-term Renewable Energy (REP) strategy. Given that such a program’s instruments would continue to boost the growth of the sustainable energy market in the household by 2014 and beyond, the approach path is then decided. The MTP seems to be the culmination of several years of change, involving experts, advisors, and members from across Pakistan and other nations in exchanging protocols and lessons learned [62,63]. In early 2006, this approach was a successful one [64,65]. In increasing the MTP, renewable energy facilities were aimed at assisting the work of various departments of government. Due to this, the power shortage has increased Pakistan’s usage of sustainable technology. The key aims were to promote trade and encourage investment from the private sector by offering opportunities and expenditure and supporting the efficient usage of energy capital and revenue-generating behavior. It aimed to aid in developing specific scientific, organizational, and prepared competencies [62,66].

The Mid-Term Policy was developed in the short term, utilizing an extended summary of alternative options and renewables, to contend with participant interests, decide on policy disagreements, including the knowledge gained, and to establish that sustainable and renewable technologies are being supported. It also proposes a biodiesel strategy that extended opportunities through innovative funding, i.e., alternate energy production funds [67,68]. Intending to develop and use biofuel as an alternative fuel in Pakistan, the AEDB (Alternate Energy Production Board) has provided strategic guidelines for reducing import fuel bills, meeting the need for biofuel raw materials, and promoting a pollution-free environment. Additionally, as of 14 February 2008, the National Cabinet’s ECC (Economic Coordination Committee) approved the plan to use biofuel as an alternative fuel in its hearing. The canon’s critical ends will be as follows:

• The Petroleum and Natural Resources Ministry can establish fuel standards of quality for B-100 (spiffy biofuel) and mix up to B-20 (20% biodiesel/80% diesel mixture).
• AEDB is perhaps the main preparation and support agency for the nationwide biofuel scheme.
• Oil Marketing Companies (OMCs) will be sourcing biofuel (B-100) from biodiesel manufacturers and, at the time of selling, providing this processed diesel-mixed biodiesel (getting started with B-5).
• The gradual introduction of biofuel combined with petroleum fuel will reach a minimum of 5% by volume of a state’s total diesel use by 2015, and 10% by 2025.

Pakistan State Oil (PSO) arranged the biodiesel pilot scheme in 2010, with the involvement of the AEDB and the Pak Agricultural Research Council. The progress of the 2012 pilot plant led to an oil marketing firm’s blend of biofuel in 2013 [69]. Pakistan’s long-term comprehensive energy strategy accounts for four core values: availability, affordability, sustainability, and responsibility (use). As part of the overall strategy, the alternate and renewable energy) (ARE) 2019 Strategy aims to create an effective, reliable, safe, accessible, productive, and environmentally safe power grid, while encouraging the indigenization of sources of energy and the growth of local production potential in these technologies.

ARET’s key goals for 2019 are as follows:

• ARET energy projects guarantee quick routes and open growth.
• To protect the atmosphere by raising the proportion of “carbon” resources in the global energy mixture.
• Encouraging and ensuring local capital is exploited.
• Providing the minimum expense of producing energy while considering certain restrictions.
• Encouraging private industry expenditure, thus maintaining reasonable return rates.

Different goals are established under this Framework which can be changed occasionally through administrative intervention instead of legislative reform. Currently, the GOP also set goals of at minimum 20% renewable power capacity generation by 2025, as well as at least 30% by 2030 (20 by 25 and 30 by 30). To accomplish such goals, the GOP must obtain a higher proportion of additional power through the alternate and renewable energy (ARE) Policy 2019, considering the limitations of baseload, variance production criteria, and alternate and renewable energy technologies (ARET’s) alternative options that are like baseload power variables [70].

Pakistan seems to have a huge potential for generating biodiesel if the resources are being used in a sustainable manner and action is taken in the right direction. As per a report focused on evaluating the Environmental Kuznets Curve (EKC) assumption to evaluate the ability of renewables in Pakistan data collected spanning the duration from 1970 to 2012, militant enthusiasm for EKC has been identified. Renewable electricity plays a major role in lowering CO₂ pollution, and current non-renewable activities are the key contributors to CO₂ pollution, as per previous research. The policy will also promote the extension of investment in renewable energy initiatives to offset and alleviate the effects of climate change and global warming [71]. The major economic dependency on agriculture in Pakistan affects 70% of the country’s citizens. People’s living conditions may be improved by planting oil seed plants. Less expenditure is expected in a mini-scale production facility which can aid in biofuel development [72]. The barren land areas that can solve water scarcity problems and soil salinity are being used for the development of oil plants. Expanding energy plants can be advantageous for the welfare of farmworkers and the state’s economy. The use of specific technology rather than several technologies is needed for effective commercially and mainstream biomass energy production settlements in Pakistan’s rural locations [29]. Pakistan has been one of the fast-growing power economies in the world during the last 20 years due to the increasing population and rising per capita energy use, rapid urbanization, and sound economic development [73].

Pakistan’s main contributors to a power crisis are strong electricity demand, poor energy source expertise, rising oil import prices, increasing manufacturing requirements, and accelerated demographic development. Electrical power requirements for homes and factories have risen due to fast demographic development. The world’s rural sector, which accounts for around 62% of an overall world demographic, is largely reliant on non-commercial assets [74]. The world’s economic recession has arisen over the last five years due to an unforeseen energy crisis. Lower output along with higher losses stems from a lack of modern knowledge when using energy sources [72]. The long-term energy problems confronted can be resolved by leveraging alternative energy sources in developed countries. Expanding the resources available and finding new outlets is necessary to keep those assets competitive. The environmental effect is indirect due to poor productivity in extra carbon emissions [75].

In February 2008, the Ministry for Water and Power in Pakistan issued guidelines which the Cabinet’s Economic Coordinating Committee considers helpful for the use of biofuels as an alternate fuel. The plan is accepted and as per this overview, the Water and Power Ministry and Alternative Energy Development Board (AEDB) will organize the National Biodiesel System to include the services. To fulfill the criteria for consistency in fuel in accordance with the Ministry of Petroleum and Natural Resources, up to 5% of the total quantity should be mixed with biofuel by 2015 and 10% by 2025 [63,76]. To guarantee biodiesel’s price competitiveness with Petroleum Diesel OGRA, the price process of different biodiesel variants (B-5, B-10, etc.) should be liable. In addition to making the usage of biodiesel mandatory for public-sector automobiles operating on diesel at such a cost decided by OGRA, the government must provide biodiesel manufacturers with incentives for buying back. Manufactured plants, supplies, machines, and similar products are excluded from customs duties and taxes used in biofuel development [77].

As with the ramifications of solar energy, the bioenergy industry still suffers from a shortage of financing, adequate policymaking, and execution. Similarly, AEDB, Pakistan’s Higher Education Commission (HEC), Pakistan’s Ministry of Climate Change (MOCC), Pakistan’s Environmental protection Agency (Pak-EPA), and PSO will take steps to cooperate with universities and institutes and distribute funding for bioenergy development and research. They need to evaluate and update the Mid-Term Policy (MTP), identify the inefficiencies in meeting the standards set in 2015, and create a detailed plan to accomplish 10% (B-10) to 20% (B-20) biofuel blends in diesel in 2025 at PSO station in Pakistan, with biofuel that will conform with ASTM requirements [71,78]. For meeting energy needs and discovering sustainable and anti-conventional power options, numerous problems such as analysis, growth, promotion, network creation, decentralized model of the power distribution system, business development, education, outreach initiatives, public perception, incentives, policy involvement, technology transition, acceptance, tracking, and assessment should be recognized, and there also needs to be a clear framework for consistently tracking and incorporating them at the state level [79].

Biodiesel has certain benefits and deficiencies that are summarized in Table 2 as follows.

The idea of sustainable development has been included in the United Nations Commission on the Environment’s 1987 study entitled Our Shared Future, organized by Gro Harlem Brundtland. In this study, sustainability was described as addressing the needs of today’s generation without undermining future generations’ needs. The growing concern in spreading biofuel output on a worldwide scale, in addition to the shortage of traditional fossil fuels, their increasing pollutant pollution, their growing costs, and the need to develop biodiesel sustainability and qualification requirements, has been established globally [81,82]. Biodiesel is used as a way out of misery for developed countries. Besides, biodiesel will offer new opportunities for innovation in agriculture research and production, and provide farmers with an income stream [83] and promote connections to already non-existing food stores [84]. Biodiesel usage will render any country self-dependent to a certain degree, but it is still far behind in making a substantial change in crude oil imports, which is required nowadays.

The biodiesel sustainability standards were drawn mainly from current standards established by the Sustainable Biofuels Roundtable (RSB). The following are some principles of these concepts [85,86]:

• Biodiesel output shall lead to the growth of local communities in economic and social terms.
• Biodiesel development shall prevent adverse impacts of higher ecological importance on habitats, communities, and regions.
• Biodiesel shall lead to climate change mitigation by substantially reducing greenhouse gas pollution from the lifecycle relative to fossil fuels. Producers will continue to work to boost the use of biodiesels.
• The biodiesel sector shall incorporate management processes in the supply chain that preserve and aim to enhance habitats, areas with high ecological value, and the efficiency of natural resources, including land, climate, and water.
• The development of biodiesel would aim to enhance food protection.
• The development of biodiesel shall own the rights to natural resources, including water and land.
• Biodiesel’s development shall foster human and civil rights and maintain healthy and fair work conditions.

Achten et al. [87] conducted a qualitative assessment of Jatropha production’s future feasibility, focused on the environmental, economic, and social aspects, and decided that the agriculture is viable when conducted in barren or depleted fields but not where productive regions are used that could be used to plant more lucrative grain or other crops.

J. Curcas is a small and medium sized fern tree, rising to around 5–7 m tall, belonging to the Euphorbiaceae genus [37,42,99,100,101,102,103,104,105,106], consisting of approximately 800 species, around 321 genera. Many plants of global economic importance come from this family, as follows [107]:

• Physic nut
• Roots: esculenta Manihot (cassava)
• Chinese sebiferum (Sapium sebiferum); J. Linn Curcas
• Hydrocarbon: spp euphorbia
• H. brasiliensis: Rubber
• Oils: linn ricinus communis (castor bean); spp aleurites (Tung Tree)
• Nuts: The orinocense caryodendron tacay nut
• Medical: croton spp.; jatropha spp
• Vegetables: Sauropus androgynus (katuk)

Jatropha is an herb immune to famine, with a lifespan of around fifty years [37,106,108,109]. It is also called physic nut and Ratanjayot [38,42,102,108]. It may grow within the forest, parched and semi-parched [109,110]. The plants grow a large flower stalk and initially four deep, superficial roots. The tapering root can strengthen the ground toward mudslides, while the deeper roots are believed to avoid and monitor air or water-borne soil degradation, but this ability is not being scientifically examined. The leaf is flat, with 4–6 lobes, and is about 10–15 cm long, and wide. The plant is polygamous, so there are bisexual plants in the marginal leaf buds. The proportion of female to male plants varies between 1:13 and 1:29 and reduces with plant age. Usually, JCL flowers in the rainy season once per year. JCL grows almost year-round in chronically moist areas or under deluge conditions. The black seeds with certain authenticity produce contaminants, such as phytates, phorbol esters, lectins, trypsin agonists, and curcin, to prevent detoxification of seeds, oil, and seed cake [100,111,112].

J. Curcas may grow from 250 to above 1200 mm per year under a wide variety of rainfall climates [101,113]. The growing temperature is 20–26 °C, and these plants can also adjust between 5.0 to 6.5 pH, fertile soil, not stagnant, and decent drainage [114]. The J. Curcas plant grows in well-drained fields with good air circulation and is well-suited to little land with a lower nutritional quality, and it sheds its leaves during the hot season [99,101]. Planting spaces of 2 by 2 m, 2.5 by 2.5 m, and 3 by 3 m have been stated to be enough and to produce greater fruit outputs [105]. It grows fruit from the second year of creation, and from the fourth or fifth year onwards, the growth stabilizes economic production. The plant is a kernel, with 3 seeds in each. It yields approximately 2–4 kg/seed/plant/annually. The yields in bad soils were stated to be 1 kg/sow/plant/annually [115]. J. Curcas oil outputs are estimated at 1590 kg/ha [38,104,116,117].

J. Curcas will generate 2000 L/ha of oil annually [118]. JCL oil is transesterified primarily into (m)ethyl esters (biofuels) and glycerol [43]. Currently, J. Curcas fuel development and use are no longer restricted to a geographical area or just a small range of final products, and significant amounts of J. Curcas fuel are used worldwide, as components in various goods produced by a broad number of sectors. J. Curcas was discovered to have been ideal in the oleochemical industries as a non-edible vegetable oil raw material (biofuels, cosmetics, soap, fatty acids, kerosene, fat nitrogen compounds, and cleaning products, etc.) [42,118,119]. The J. Curcas oil industry was developed over the years to provide J. Curcas oil as well as its associated products [107]. Figure 1 illustrates several major J. Curcas usages.

The J. Curcas plant was noticed to be ideal in several cultures for usage in different facets. It is typically grown across Indonesia’s farm fields as a live fence, as cows or goats do not consume it. It can also be sliced or clipped to the required size. Aside from the use of J. Curcas oil as a biofuel, biocides (herbicide, molluscicide, nematicide, and pesticide) and soap may also be generated using the oil [120].

The properties of raw J. Curcas oil (CJCO) differ according to the area in which it was produced. The actual quantity of fuel collected from a provided seed sample relies on the nature of the raw material and the extracting process. J. Curcas kernel oil content was observed to have been greater than sunflower oil, soya, and palm kernels, 33.33%, 18.35%, and 44.6% respectively [121], while in several other sources, the oil content of the J. Curcas kernels was 63.16% and 66.4% [119,122]. The specifications that are chosen and set to determine biodiesel efficiency can be split into two classes. Each class includes basic criteria that are often used for mineral oil-based fuel, such as physical and chemical characteristics. The other category defines the chemical structure and cleanliness of methyl esters of fatty acids [123]. Table 3 describes the physicochemical characteristics of boorish J. Curcas fuel. Moreover, some properties of J. Curcas in Pakistan is shown in Table 4.

The main fatty acids in JCL seed oil are linoleic, oleic, stearic, and palmitic acids. Oleic acid recorded the largest compositional proportion, followed by linoleic acid [37,100,102,108,110,119,127,128]. Fatty acids’ formation of J. Curcas oil is provided in Table 5.

Since the mechanical stickiness of J. Curcas oil is quite strong, the friction coefficient of J. Curcas oil for use in biodiesel must be decreased [85]. The large viscosity of J. Curcas oil frequently contributes to compliance issues, including carbon accumulation, fuel ring trapping, oil thickening, and gelatinizing due to vegetable oils. The smoother flow of oil in the motor can also be influenced by the increased viscosity of J. Curcas oil. Varied methods such as preheating, drying, transesterification of ultrasonic methanol, and supercooled methanol are being used to reduce viscosity to render it suitable for motor operations [130,131,132]. After transesterification, the kinematic viscosity of raw J. Curcas fuel could be reduced by around 82% and corresponds to 4.8 mm2/s [87,133]. J. Curcas fuel’s flashpoint is higher relative to fossil fuels. Jatropha fuel has many benefits over diesel, including increased protection in preparation, processing, and transportation, due to its increased ignition point. The high flashpoint may, therefore, affect the motor’s initial start issue [132].

Like biodiesel derived from plant oils, including palm oil, J. Curcas fuel has a low pouring level. Therefore, it can be utilized in countries with four certain seasons [134]. The iodine content is an indicator of oils’ and fats’ unsaturation. High iodine content indicates a greater unsaturation of oils and fats [135]. The iodine quality of JCL fuel reached 101 gl2/100 g, where the normal iodine quality for diesel is less than 120 for European standard 14214 EN. The restriction of fatty acids is also important since the heat of highly unsaturated fatty acids resulted in glyceride polymerizing. It may contribute to development of deposit accounts, oil decay, and the creation of dense effluent in the motor tank [119]. Table 6 describes the characteristics of JCL fuel and JCL methyl esters with all the requirements of ASTM D6751 and EN 14214. Table 7 demonstrates the physicochemical characteristics of JCL fuel in comparison to diesel as well as its variants.

JCL methyl esters and diesel scientists in several countries worldwide have been studying Jatropha in engines, and have contrasted the engine output tests with those of conventional fuels in identical circumstances. Due to Jatropha’s peculiar characteristics, ingestion, alienation, and burning features continue to vary. All such differences in the usage of Jatropha methyl esters in engines may create other problems. The research indicates a major difference in results from the states listed. Many engine output specifications were gathered in this analysis, such as braking strength, fuel usage, brake capacity, torque, thermal brake efficiency, emissions, etc.

3. Jatropha Curcas Oil Effect as Biodiesel

3.1. Emission Impacts

Biodiesel releases fewer pollutants as opposed to fossil fuels, such as HC, CO, and PM. It therefore produces higher NOx pollution than diesel [164,165,166,167,168,169,170]. Table 8 describes the cumulative emissions adjustments for B-20 and B-100 reported by the EPA. Reports often display slightly lower emission rates of different harmful substances, such as nitro-polyaromatic hydrocarbons, PAH, and aldehydes, for biodiesel and biodiesel mixes [37,171,172]. Table 9 reveals diesel and biodiesel CO₂ pollution levels, accordingly. Additionally, the possible mitigation of mid- and long-term CO₂ emissions generated from biodiesel substitutes can be seen in Table 10.

Table 8. The average effect of 20% and 100% biodiesel on heavy-duty emissions compared to average typical diesel [37,171,172].

Air Pollutant	Change for B-20 (%)	Change for B-100 (%)
Nox	+2.0 to −2	+10
PM	−10.1	−47
CO	−11.0	−48
Hydrocarbon	−21.1	−67
Sulfates	−20	−100
PAH (polycyclic aromatic hydrocarbons)	−13	−80
nPAH (nitrated PAH’s)	−50	−90

Table 9. Aspects of emissions of CO2 from biodiesel and diesel [173].

Fuel Type	Emissions CO2 (kg/TJ)
Biodiesel	70,800
Diesel	74,100

Table 10. The possible CO2 emissions’ mitigation generated from biodiesel [173].

Parameter	Unit	Middle Term (2010–2015)	Long Term (2015–2025)
Substitution	Ton oil	6,000,000	16,000,000
Mitigation of CO2 emission	Million ton	19.12	50.98

3.2. Environmental Impacts

The evaluation of the long-term environmental effects of the development of biodiesel raw material is a dynamic activity. Reductions in the lifespan of carbon dioxide emissions rely on the raw material sources, the processing processes, and the assumptions about the new uses of the lands from which the feedstock was generated, particularly if the field had been wooded before [174]. One of the most desirable qualities of Jatropha is its capacity to survive scarcity and to develop in droughty and semiarid regions with poor rainwater and poor land quality [101,108]. In semiarid regions, Jatropha could be used to manage erosion and its seedcake could be used to boost soil [109,175]. The JCL plant is nitrogen-fixing and developed as among the finest methods to draw additional oxygen back into the ozone layer. Jatropha may help farmers avoid collisions with protected species as a natural barrier. The significance chain of Jatropha biofuels may result in important reductions in greenhouse gas discharges.

At the same time, additional studies are needed to determine such effects throughout the growth, power generation, and then use lifecycle. Current work suggests that Jatropha biofuel output is expected to be relatively positive relative to fossil fuel use, but the importance of such an energy balance depends on the ways of developing, transportation, and processing that appear to be unique to the plant. Nonetheless, land-use adjustments related to new farms may involve years of new plant growth to re-sequester the lost carbon through land clearing, particularly on land not initially used for agriculture. The toxicity of Jatropha will pose possible problems for the atmosphere and the health of the public. One scientist has cautioned that the curcanoleic acid present in the fuel can encourage cancer of the skin, and that field staff may be annoyed by the oil. In other areas of the country, Jatropha is often deemed invasive, such as Australia, Hawaii, and South Africa [176].

3.3. Socio-Economic Impacts

Jatropha oil provides higher labor and farmland returns and other advantages such as shortened fallow times. Kumar and Sharma [100] underscored some of Jatropha’s cultural significances. The establishment of JTC oil conversion factories will generate job opportunities, offer a good income source for growers and feed providers, and finally, provide a significant revenue source for governments. It would also reduce fossil-fuel reliance and decrease the expense of producing crude oil [177].