1. Introduction
In the economic and social advances of all societies, access to energy has had a decisive impact [
1,
2]. Biofuel, as sustainable energy produced from a biomass resource, does not release as many GHGs as fossil-based fuels, generally is not a risk to food security, especially for non-edible-based feedstock, and does not threaten biodiversity [
3]. Biomass is a sustainable and eco-friendly renewable energy resource (RES) with a significant potential to be a substitute for fossil fuel energy sources [
4]. In fact, the amount of comparable energy from existing resources of biomass is about eight times larger than current global energy requirements [
2,
5].
Biomass resources are categorized into three prime groups as first-, second-, and third-generation [
6], considering the feedstock and conversion procedure utilized for their production [
7]. First-generation biofuels are produced from crop-based plants, which can be considered as food, such as biodiesel generation from peanuts and rice [
8]. Second-generation biofuels are produced from food, agricultural, forest, and municipal solid waste [
9,
10]. The prime concern related to first-generation biofuel resources is that there is a competition between energy generation and food production for arable land use [
11]. First-generation biofuel may also pay raise the net GHG emissions of energy generation structures as a result of deforestation and chemical-based input consumption such as chemical fertilizer [
12]. Alternatively, the drawbacks of second-generation biofuels are their high costs and numerous technical concerns [
13].
Third-generation biofuels generate energy from algae and seaweed [
14]. The biofuels produced in this manner primarily comprise the production of bio-diesel, bio-ethanol, and bio-hydrogen with green algae [
15]. The bio-diesel production potential of microalgae is apparently 15–300 times greater than that of conventional crops in terms of land-use source; furthermore, microalgae has a short harvesting sequence [
16]. However, biofuel production from third-generation biofuel resources (algal biomass) encounters specific complications such as high water requirements on an industrial scale, several technical issues such as lipid extraction, dewatering, and geographical-based difficulties in various regions where the temperature is below freezing for a significant duration of the year [
17].
In this context, India is the world’s third-largest energy-consuming country, and a significant portion of India’s energy needs are met through fossil fuels, which continue to depend mostly on imports. India’s share of global energy consumption is projected to double by 2050 [
18]. A growing energy demand and high dependence on imports raise substantial energy security concerns. It is also evidence of a huge foreign cash outflow. Additionally, excessive utilization of fossil fuels raises maximum GHG emissions and related health issues. Biofuels in India are of tactical significance as they augur well with current initiatives of the government, namely Make in India (MII) and Swachh Bharat Abhiyan (SBA), and provide great prospects for incorporation with ambitious goals of doubling farmers’ revenue, import reduction, job creation, waste-to-wealth generation, and decreasing air pollution [
18]. Consequently, it is extremely crucial to rank biomass resources in terms of energy production in this region.
Numerous models have been utilized to find suitable biomass resources for biofuel production. However, conventional single-attribute decision analysis (SADA) models are no longer capable of solving these complex problems [
2], and, accordingly, ranking the local biomass resources alternatives for biofuel production must be taken from a multi-attribute decision analysis (MADA) perspective. MADA is one of leading innovative and practical models for assessment and can be utilized to rank diverse biomass resources in terms of biofuel production. Numerous MADA tools have been implemented for treating this complex problem in the bioenergy and biofuel sectors [
19,
20,
21]. Each MADA model has its cons and pros, and the procedure could be enhanced with the hybridization and implementation of two or more models [
22]. Consequently, this study aims to rank suitable biomass resources for biofuel production in India by unifying diverse MADA tools under uncertainty.
The doctrine of IFS is an influential and appropriate way to manage the uncertainty and fuzziness occurring in various realistic MADA issues. Considering the flexibility and applicability of IFSs, the aim of this study is to develop an integrated framework for evaluating the MADA problem on IFSs. For the first time, a hybridized MADA model created by uniting the IFSs, the IF-symmetric-point-criterion (SPC)-rank sum (RS) weighting model, and the multi-attributive ideal real comparative assessment (MAIRCA) model, referred to as the IF-SPC-RS-MAIRCA model, is presented. The IF-SPC-RS model is utilized the integrated weighting of parameters by combining objective and subjective weights. The objective parameters are determined from the decision matrices and derived based on the information presented by the “decision-making experts” (DMEs). The IF-SPC approach has been presented to estimate attribute weights using the utility of the attribute that is described by its symmetry, that is, using the absolute rating of symmetry of the attribute to measure its impact on the weight of attribute. The symmetry point is located in the middle of interval [
a,
b], where
a and
b present the lower and upper degrees of the criterion, respectively. The subjective criteria weights offer the DMEs subjective opinions on the relative significance of the criteria. For the subjective weighting model, a “rank-sum” (RS) weighting method was applied to assist DMEs in giving their preference ratings for the considered criteria [
22]. Further, the combined MAIRCA method is introduced for the sake of prioritizing appropriate biomass resources for biofuel production under the context of IFS, which combines the benefits of criteria weighting model, aggregation function, and the gap between the ideal ratings and empirical ratings of options with intuitionistic fuzzy information. The novel contributions of this work are as follows:
Identifying the key indicators of sustainability for prioritizing biomass resource options for biofuel production using the literature survey method.
Estimating the indicator weights and proposing an IF-SPC-RS model by considering the symmetry of criteria and the rank-sum model.
Introducing a MAIRCA model integrated with the IF-SPC-RS model to rank the biomass resource options for biofuel production.
Completing a case study of selection biomass resource options for biofuel production to exemplify the performance and advantages of the developed IF-SPC-RS-MAIRCA method.
Certifying the developed IF-SPC-RS-MAIRCA model, we present its sensitivity and undertake comparative discussions.
The rest of the study is arranged thusly:
Section 2 confers the literature associated with the biofuel sector and IFSs and MADA models under uncertain settings.
Section 3 introduces fundamental notions of IFSs.
Section 4 introduces a hybrid intuitionistic fuzzy-SPC-RS-MAIRCA method for MADA problems to rank the biomass resource options for biofuel production.
Section 5 implements the developed model with a case study of the selection of biomass resource options for biofuel production.
Section 6 concludes the whole study and provides further research recommendations.
4. An Integrated IF-SPC-Rank-Sum-MAIRCA Model
In this section, the IF-SPC-RS-MAIRCA model using the IF-SPC model and IF-rank-sum model is introduced. Here, the IF-SPC model is presented to generate the objective weight of the indicators and the IF-RS is applied to estimate the subjective weight of the indicators. Finally, the preference for the option is obtained using the IF-SPC-RS-MAIRCA model. The procedural steps of the developed model are given as follows:
Step 1: Construct an intuitionistic fuzzy decision-matrix (IFDM).
A team of DMEs is formed to assess a set of options with respect to criteria set A team offers assessment ratings for each option over different indicator in the form of “linguistic ratings” (LRs). Consider , to be the IFDM offered by the DMEs, where denotes the LR of each option over an indicator provided by the DME.
Step 2: Evaluate the weights of the DMEs.
The significance ratings of the DMEs are described in the form of LRs and converted into IFNs. Let
be an IFN, and then the weighted value is given as the normalized IF-score
degree of each DME, which is estimated as
where
and
Step 3: Create the “aggregated IFDM” (AIFDM).
The IFWA (or IFWG) operator is applied to define the AIFDM
where
Step 4: Find the normalized AIFDM (N-AIFDM).
The N-AIFDM
is calculated from the AIFDM
, where
and where
and
symbolize the benefit and cost type indicators, respectively.
Step 5: Compute the weights of the criteria with the IF-SPC model.
Let be the weight of the indicator set, where and In the following, we present the procedure for deriving the numerical weights of the criteria.
Step 5.1: Obtain the IF score rating of the N-AIFDM.
We estimate the IF score rating of each N-AIFDM grade using Equation (2), as
Step 5.2: Estimate the symmetry value of each indicator.
Let
be IF score value of
n1 indicator over a set of options. If the minimum and maximum grades of an interval
are described as
and
respectively, then the symmetry point
is defined by
Step 5.3: Calculate the matrix of the absolute distances.
The matrix of the absolute distances is computed in the following form:
Step 5.4: Create the matrix of the moduli of symmetry.
Let
be the column value of the absolute distances for indicator
n1. Therefore, the matrix of the moduli of symmetry is in the following form:
Step 5.5: Determine the modulus of symmetry of the criterion.
We find the mean value (
Q) of matrix
M, where each value
qj signifies the modulus of symmetry of the
jth indicator as
Step 5.6: Find the objective weight of the indicator.
In this step, each objective criterion weight is computed using the vector of the moduli of symmetry. The following equation is used for assessing the weight of criteria:
Case II: Computation of the subjective weight using the IF-RS tool.
Step 5f: Estimate the rating of each indicator with the LR grades provided by the DMEs from the
IFWA operator, obtained as
Step 5g: Find the IF-SM.
Applying Equation (2), the IF-SM
of each IFN
is computed as
Step 5h: Obtain the indicator weight
, where
is the preference of each indicator. Now, the normalized weight of the indicator is described as
where
t represents the total criteria,
j = 1, 2, 3,…,
t.
Case III: Determine the combined weight of the criteria.
To obtain the combined weight of the criteria, we merge both the subjective and objective weighting models. The procedure for integrating the weight of the criteria is given by:
where
is a decision precision parameter.
Step 6: Derive the distances of each indicator from the IF-PIS and IF-NIS.
Initially, an IFN has an IF-PIS and an IF-NIS, which take values
= (1, 0, 0) and
= (0, 1, 0), respectively. To find the distances, a normalized IF-Euclidean distance is implemented. Let
and
be the distances of
from IF-PIS and IF-NIS using Equation (18) and Equation (19), respectively.
Step 7: Estimate the relative closeness decision matrix (RC-DM).
Step 8: Make the normalized RC-DM.
Each assessment indicator is normalized using the linear max–min normalization procedure and the normalized RC-DM
is obtained as follows:
Step 9: Obtain the theoretical IF decision matrix (TDM).
Initially, the preference of each possible option is computed as
Afterwards, ratings for the selection of options are multiplied with indicator weights, thus the TDM
is estimated as
Step 10: Develop the real IF assessment matrix.
To create a real assessment matrix
, the ratings of the normalized RC-DM are multiplied by rating each TDM as
Step 11: Build the IF discrimination matrix.
The IF discrimination matrix
is obtained by subtracting the real IF assessment matrix from the TDM as
Step 12: Determine the utility degrees (UDs) of the alternatives.
The UDs of options can be computed by adding the ratings of the IF discrimination-matrix using Equation (26), as
Step 13: Prioritize the options and select the optimal one.
We determine the preferences of the options using the UDs, from the smallest to largest ratings. The option with the smallest UD is the optimal one among the others because it is near to the ideal best option.
5. Case Study: Selection of Biomass Resources for Biofuel Production
India has significant prospects for the further use of bioenergy, mainly via the substitution of coal with solid biomass in extant assets, substitution of conventional bioenergy with more modern (and less-polluting) bioenergy practices, or an increase in utilizing transport biofuels created with domestically accessible agricultural residues. There are various prospects for RES from MSW as portion of the development of waste management structures. As an agricultural and forestry region, northeast India has encouraging prospects for biofuel production from first-, second-, and third-generation biomass resources. Thus, northeast India has been used as the case study for the assessment. Northeast India primarily depends on an agricultural zone which comprises 2.2% (in mountainous regions such as Arunachal Pradesh) and 35.4% (in Assam) of the cultivated region to the whole geographical region of India. Rapid increases in urban population alongside the modernization of markets and industries have produced a huge quantity of solid waste in the northeast region. Consequently, agricultural residues and MSW have become other sources for biofuel production in the northeastern states [
10].
In this study, a vivid model in which data were collected with a questionnaire is presented. To handle MADA questions, an indicator to assess the options was required. The questionnaire was prepared after a detailed review of appropriate literature and conferring with academic researchers/scholars in northeast India. It contains thirteen indicators or decision parameters, as shown in
Table 1. Five sets of biomass resources were used, considering the available biomass resources in the northeast region: peanut waste (
m1), municipal solid waste and sewage (
m2), rice waste (
m3), livestock and poultry waste (
m4), and forest and wood farming waste (
m5). Of the biomass resources used in this study, rice and peanuts belong to the feedstock category of first-generation biofuels. A snowball sampling model was used to recognize the four DMEs. Snowball sampling, also known as chain-referral or network sampling, is a nonprobability sampling method where new units are recruited by other units to form part of the sample. Although specific steps can vary depending on the research subject or sampling method, all snowball sampling techniques follow a similar pattern. We considered these steps to apply snowball sampling to the research: (a) identify potential population subjects, (b) contact potential subjects, (c) ask subjects to participate in the research, (d) encourage referrals, (e) evaluate referrals if using discriminative sampling, and (f) repeat until the desired sample size is reached. To offer respondents a perfect understanding of the indicators, we provide a detailed description of each indicator. The respondents were examined to score the practicality of these options with thirteen considered indicators on an 11-point scale (from AB = absolutely bad to AG = absolutely good), which is depicted in
Table 2.
Step 1:
Table 2 defines the LRs for estimating the DMEs’ weights, indicators, and sub-criteria for prioritizing biomass resources for biofuel production, which are then transformed into IFNs. The decision matrix is in the form of LRs for ranking suitable biomass resources for biofuel production given by four DMEs is presented in
Table 3. As it is difficult to find a conclusive agreement, the evaluation data investigated and provided by each DME are found in
Table 3. The variables
e1,
e2,
e3, and
e4 represent the DMEs in different related disciplines,
n1–
n13 represent the eleven sustainability sub-criteria, and
m1–
m5 represent five biomass resources for biofuel production.
Step 2: Using the IFN scale in
Table 1 and Equation (5), the weights of the DMEs are obtained and discussed in
Table 4 for ranking suitable biomass resources for biofuel production.
Step 3: Using Equation (6) and
Table 2 and
Table 3, the AIFDM
which uses the IFWAO is constructed and is shown in
Table 5.
Step 4: Since
n4,
n5, and
n6 are cost indicators and others are benefits, we are thus required to create a normalized AIFDM
using Equation (7), which is given in
Table 6.
Step 5: From Equations (8) and (9), we find the IF score matrix with the AIFDM and the symmetry point of each indicator, presented in
Table 7. Applying Equation (10), we determine absolute distances, presented in
Table 8. Following this, we generate the moduli matrix and the modulus of the symmetry point of the criterion with Equations (11) and (12), presented in
Table 9. As a final step, we find the objective weight of the indicator from Equation (13) in
Table 9, depicted in
Figure 1.
From Equations (14)–(16), the subjective weights of the indicators and sub-criteria are calculated for ranking suitable biomass resources for biofuel production, which is presented in
Table 10 and
Figure 1.
From Equation (17), we integrate the IF-SPC and the IF-RS models. The integrated weight for
for ranking suitable biomass resources for biofuel production is depicted in the
Figure 1 and is given by:
wj = (0.0734, 0.0502, 0.1044, 0.0490, 0.0968, 0.1129, 0.0824, 0.0865, 0.0526, 0.0742, 0.0978, 0.0581, 0.0618).
Figure 1 presents the variation of the weights of the diverse indicators for ranking suitable biomass resources for biofuel production. The cost of biomass supply (EC-3), with a weight of 0.1129, turned out to be the best indicator for ranking suitable biomass resources for biofuel production. Maturity (T-3), with a weight of 0.1044, is the second-best indicator for ranking suitable biomass resources for biofuel production. Local acceptability (SP-1) is third, with a significance value of 0.0978, and cost of biomass conversion process (EC-2), with a weight value of 0.0968, is the fourth most important criterion for ranking suitable biomass resources for biofuel production. The others are considered crucial criteria for ranking suitable biomass resources for biofuel production.
Steps 6–7: From Equations (20)–(28), we find the RC-DM
, which is given in
Table 11.
Step 8: Using Equation (21), we obtain the normalized RC-DM
which is computed and presented in
Table 12.
Step 9: From Equations (22) and (23), we estimate the TDM
which is calculated and presented in
Table 13.
Step 10: Based on Equation (24), we obtain the real IF assessment matrix
which is determined and presented in
Table 14.
Step 11: Based on Equation (25), we obtain the IF discrimination matrix
which is determined and discussed in
Table 15.
Step 12: Using Equation (26), we compute the UDs ui of biomass resources for biofuel production mi, where i =1, 2, 3, 4, 5; u1 0.136; u2 0.086; u3 0.135; u4 = 0.107; and u5 = 0.095. The preference order is u2 > u5 > u4 > u3 > u1.
Step 13: The RO of the biomass resources for biofuel production m1, m2, m3, m4 and m5 is: Thus, municipal solid waste and sewage (m2) is the best biomass resource for biofuel production.
5.1. Sensitivity Analysis
We have varied and analyzed the significance of the objective to subjective weights for the considered indicators in the proposed weight-finding technique over the parameter
γ = 0.0 to
γ = 1.0 of the IF-SPC-RS-MAIRCA method to show the performance of the utility scores of biomass resources for biofuel production selection. We show the sensitivity investigation associated with the parameter
γ.
Table 16 and
Figure 2 signify the sensitivity of biomass resources for biofuel production selection with different values of parameter
γ. According to the assessments, we find the preference order to be
for
γ = 0.0 to
γ = 0.5 and
for
ϑ = 0.6 to
ϑ = 1.0, which implies that municipal solid waste and sewage (
m2) is the top biomass resource for biofuel production for
ϑ = 0.0 to
ϑ = 1.0, while peanut waste (
m1) is ranked last for
ϑ = 0.0 to
ϑ = 0.5 and rice waste (
m3) is ranked last for
ϑ = 0.6 to
ϑ = 1.0. Consequently, it is found that the IF-SPC-RS-MAIRCA model holds ample steadiness with parameter
γ values. From
Table 16, is can be seen that the proposed IF-SPC-RS-MAIRCA model is proficient at creating stable, and, simultaneously, flexible prioritization outcomes for diverse parameter values.
5.2. Comparison and Discussion
To show the effectiveness of the IF-SPC-RS-MAIRCA model, we relate the results of the proposed model using various extant tools, namely the “IF-COPRAS” [
56], “IF-WASPAS” [
57], “IF-TOPSIS” [
58], and “IF-CoCoSo” [
59] models.
5.2.1. IF-TOPSIS Model
The steps of the IF-TOPSIS model are as follows:
Steps 1–5: Similar to the above-mentioned model.
Step 6: Calculate the IF-PIS and IF-NIS.
Let
and
be the benefit and cost indicators, respectively. Let
and
be the IF-PIS and IF-NIS, which are given as
where
Step 7: Assess the distances from IF-PIS and IF-NIS.
The weighted distance of option
from IF-PIS
is estimated as
and the distance of options
from IF-NIS
is calculated as
Step 8: Estimate the “closeness coefficient” (CC) as
Step 9: Select the optimal option with the highest CC degree.
Using
Table 5 and Equations (27) and (28), the IF-PIS and IF-NIS are determined as
{(0.698, 0.216, 0.087), (0.730, 0.199, 0.071), (0.678, 0.238, 0.084), (0.300, 0.600, 0.101), (0.255, 0.644, 0.101), (0.280, 0.619, 0.101), (0.685, 0.241, 0.074), (0.803, 0.163, 0.035), (0.712, 0.246, 0.042), (0.798, 0.155, 0.047), (0.732, 0.221, 0.048), (0.756, 0.200, 0.043), (0.817, 0.146, 0.037)},
{(0.509, 0.381, 0.111), (0.527, 0.372, 0.102), (0.591, 0.321, 0.088), (0.420, 0.475, 0.105), (0.368, 0.530, 0.102), (0.335, 0.543, 0.122), (0.583, 0.313, 0.103), (0.554, 0.341, 0.104), (0.661, 0.251, 0.088), (0.599, 0.299, 0.102), (0.569, 0.326, 0.104), (0.643, 0.271, 0.086), (0.631, 0.266, 0.103)}.
Using Equations (29)–(31), the results of the IF-TOPSIS model are presented in
Table 17.
Therefore, the ranking of biomass resources for biofuel production is , indicating that municipal solid waste and sewage (m2) has the highest degree of RCC.
5.2.2. IF-COPRAS Model
The steps of the IF-COPRAS tool are as follows:
Steps 1–5: Follow the proposed tool in
Section 4.
Step 6: Create the ratings of benefit and cost indicators as
Step 7: Define the “relative degree” (RD) of each choice as
Step 8: Compute the UD of each choice as
Applying Equations (32)–(35), the outcomes are given in
Table 18. Consequently, municipal solid waste and sewage (
m2) was obtained as the most suitable biomass resource for biofuel production with a maximum RD (0.4625).
5.2.3. The IF-CoCoSo Model
Steps 1–5: Follow the proposed tool in
Section 4.
Step 6: Find the WSM and WPM degrees by using Equation (36) and Equation (37), respectively,
Step 7: Estimate the “balanced compromise degrees” (BCDs) of choice as
Step 8: The “overall compromise degree” (OCD) of choice is determined as
Step 9: Rank the alternatives with the OCD
Applying Equations (37)–(41), the OCDs are given in
Table 19. From
Table 19, municipal solid waste and sewage (
m2) was shown to be the best choice of biomass resource for biofuel production.
The comparative results are presented in
Table 17,
Table 18 and
Table 19 and
Figure 3. From
Table 17,
Table 18 and
Table 19, it can be found that the best biomass resource for biofuel production is municipal solid waste and sewage (
m2) when ranking suitable biomass resources for biofuel production with each MADA tool. The benefits of the IF-SPC-RS-MAIRCA tool are thus:
The developed model employs the linear normalization process and symmetric point criterion, while the IF-COPRAS tool applies a vector normalization process [
60]; the IF-TOPSIS and IF-CoCoSo models also utilize linear normalization process [
61]. Thus, the proposed method avoids the information loss associated with other methods and provides more accurate decision results by means of different criteria.
The IF-CoCoSo model considers WSM and WPM to find the OCDs of options. In the IF-COPRAS model, the IFWAO and IF score value are used to determine the UDs of each option. In the IF-TOPSIS model, the CCs are found using the distances of each option from the reference points, while the IF-SPC-RS-MAIRCA model proposes the gap between the ideal ratings and empirical ratings [
44]. For each option, the sum of the gaps for all attributes offers the overall gap, and the option with the lowest utility score is taken as the appropriate option. The MAIRCA approach is more stable than the IF-TOPSIS or IF-VIKOR models because it uses a diverse linear normalization procedure characterized by simple mathematical computations and result permanence [
45].
The proposed tool defines the indicator’s objective weight using the IF-SPC (symmetric point criterion) and the IF-rank sum-based model. In contrast, in the IF-CoCoSo model, the indicator’s weight is estimated using the IF divergence measure and an IF score value-based tool, and in the IF-COPRAS and IF-TOPSIS models, the indicator’s weight is determined randomly.
Next,
Table 20 specifies the ranks the five models assigned to various biomass resources for biofuel production; a definite degree of deviation can be examined. The outcomes of the new method introduced in this paper and those of the existing methods are depicted in
Table 20. From
Table 20, the Spearman rank correlation coefficients (SRCCs) are greater than 0.7, with the exception of the IVFF-TOPSIS model results [
58]. Also, the WS coefficients are greater than 0.901, with the exception of the IVFF-TOPSIS method [
62], which are presented in
Figure 4. The properties of the WS coefficient [
63] indicate that it is a suitable procedure for comparing the similarity of priorities, which means the similarity of the ranking order of biomass resources for biofuel production options is high. As a result, it can be said that there is a strong relationship between ranking outcomes. Thus, it can be concluded that the results from the proposed tool are consistent with the extant models.