3.1. Scale-Dependent Variability Trends of Wind Speed
The temporal averaging of the hourly wind speed data for the selected six regions was compared for their dependency on various time scales. At the smallest scale, the diurnal variations indicate considerable deflections in the forenoon hours compared to the afternoon and night periods across all six regions of India. The periodic and orthogonal occurrence of southwest and northeast monsoons crossing the coastal boundary has significant effects on the onshore moisture flux and the precipitation pattern in the eastern and western states. Among the Southern Peninsular States (SPSs), Andhra Pradesh and Tamil Nadu have shown the highest wind speed with a minimum variation throughout the day, while Kerala and Telangana have the lowest wind profile except in the afternoon hours (
Figure 6a). Further, the sea breeze circulation on the western coastal regions has higher variability compared to the eastern coastal regions, thereby exhibiting diurnal variations between the forenoon and afternoon sessions (with a difference of 1.2–2.5 m/s) in the western coastal locations.
As far as the high-altitude locations in these states are concerned, the diurnal variations are more profound and show bimodal distribution, with peaks in the early morning and evening hours (
Figure S4). This is particularly distinct for the windward and leeward sides of the Western Ghats due to the influence of sea–land breezes and localized heat fluxes, while the hilly locations in the interior of the Deccan plateau experience highly variant and lesser irregular wind patterns during most of the monsoon reversals. This is in combination with the observation that peninsular Indian states receive a large number of turbulent winds from oceans that are redirected by the mountainous belts, resulting in irreducible heterogeneity in the subsequent flow patterns [
34]. Being the most productive zone in the country, the wind energy farms operating in the SPSs are, by and large, favored by the monsoon patterns.
Considering the diurnal wind flow pattern in the WMSs, higher wind speeds were recorded in Gujarat and Maharashtra in the summer seasons, with bimodal peaks occurring in the mid-noon hours (
Figure 6b). Being the top-rated wind-producing states in India, both these states have sufficiently stable diurnal wind profiles, irrespective of the altitudes for the selected locations. It is understood that the speed of wind at an altitude of 100 m from the surface will have an accelerating effect caused by surface heating during the daytime, while the turbulence present in the higher altitudes transfers sufficient momentum to the flow at lower altitudes during the nighttime [
35]. Therefore, Rajasthan and Odisha experienced similar diurnal variations with lower velocity distributions, although subjected to two different climatic conditions. The middle-altitude location in the state of Uttar Pradesh has shown a single-peaked normal distribution trend, which was typical for the selected day of the month and is found to be quite reversible according to the seasonal climatic variations.
Among the NBS states, highly stable diurnal wind flow patterns were observed for the states of Punjab, Haryana and Bihar, where altitude variations did not make any significant difference in the average wind speed values (
Figure 6c). The diurnal wind speeds showed a single-peaked normal distribution trend for Jammu & Kashmir, as well as West Bengal, where the differences for the altitudes were more significant for West Bengal, while the highest value of the statistical range was observed for the selected locations in Jammu & Kashmir (2.5–4.0 m/s). It is interesting to note that the northcentral states show significant diurnal wind flow stability, although they experience extreme climate conditions, as revealed in the seasonally averaged data. One plausible reason for this invariability in the diurnal time scale is the absence of a moderating influence from the sea, causing the vertical mixing of ground-level heat waves with turbulent winds at higher altitudes [
35,
36]. Nonetheless, as a small-scale phenomenon, the diurnal variations can be viewed as an intrinsic signatory proof for local atmospheric stability, giving moderately uniform wind flow throughout the days.
The typical hourly wind speed profiles for the NESs clearly depict unimodal peaks of wind speed during the early morning hours, followed by a drastic reduction in the afternoon hours (
Figure 6d). This is primarily associated with the prevalence of orographic interference over the convectional air currents. Most of the NESs have highly undulating topography, creating a mountain–valley wind circulation pattern over the local surface-layered convection. It is notable that the average rainfall is quite heavy in the NESs (about 2000 mm annually), which are mostly concentrated on the monsoon winds [
37]. It is observed that Assam, Meghalaya and Arunachal Pradesh have the highest wind speed with unimodal peaks during the forenoon hours, while the afternoon and night flows are fairly uniform without any considerable variations. The highest average wind speed (6.2 m/s) was noted for the high-altitude location of Assam (Mahur), while the highest variability (statistical range of 3.7 m/s) was observed for the low-altitude location of Arunachal Pradesh (Itanagar). The lowest wind profile was recorded by Mizoram (maximum wind speed of 1.9 m/s), making it unfit for further wind energy exploration studies. It is interesting to note that the wind profile of Assam is similar to that of Chhattisgarh, though there are considerable differences in other climatic features.
The wind speed profiles observed for the NMS states indicate that a consistent and significant diurnal wind distribution is available for the central state of Madhya Pradesh, whereas the high-range regions, such as Uttarakhand and Himachal Pradesh, have productive wind availability only during the forenoon hours owing to the atmospheric diversions caused by several mountains in the state (
Figure 6e). The Northeastern States of Manipur and Nagaland also experience a consistent diurnal wind profile, mostly unaffected by the local climate conditions, but the average wind speed is found to be quite low compared to the other states in the selected region. There is a considerable difference in the dynamic nature of wind distribution traversing through the central plateau regions compared to the Himalayan valley regions, where the latter locations experience higher atmospheric mixing effects, resulting in a more consistent wind speed profile [
38]. The highest difference in diurnal wind speed was observed for high-range regions, while the lowest was observed for the Northeastern States. As we observe in this study for the first time, the wind speed characteristics of the central regions of India can be significant evidence for their exploration compared to those regions with low wind availability.
For the selected locations in the EBS region, the diurnal WSD is found to be consistent and reliable, except for the state of Sikkim, which experienced a typical unimodal distribution profile (
Figure 6f). The average diurnal wind speed varied from 2.8 m/s to 5.6 m/s for the selected locations in this region, except for TP2 (Udaipur), which had a value of 1.5 m/s. Similarly, the highest difference in wind speed is observed for the state of Sikkim, while Tripura has the lowest difference. It is interesting to note that a comparable wind stabilization pattern exists in the selected locations in the state of Jharkhand, similar to the coastal regions, giving evidence for the scope of exploration of wind energy production in the state. Based on the above observations, one can interpret that the diurnal variations in the wind speed can provide a good insight for the expected strategies for wind energy exploration attempts at a suitable scale.
In order to differentiate the impact of temporal scaling in this context, the average monthly and average yearly wind speed profiles were compared among the six selected regions. It is observed that the effect of averaging has a significant smoothing effect on the wind speed profiles while expressing the distributions at larger scales. The monthly average wind speed profiles invariably show considerable wind flow during the monsoon months from June to August, especially for the locations with comparatively high diurnal wind speed values. Among the SPS states, an average monthly wind speed above 5 m/s is consistently observed for Tamil Nadu and Andhra Pradesh for all three levels of locations (
Figure 7a). The early onset trends of the southwest monsoon in the states of Kerala and Karnataka are found to be associated with heavy winds compared to other months [
28,
35]. In other words, the effect of seasonal variations in the wind speed is more profoundly visible in the coastal states of India compared to the middle lands, as well as the upland hilly regions.
The average monthly wind speed for the WMS region has shown a distinct profile compared to the SPS region based on the availability of high-speed winds during the months of June–August (
Figure 7b). Except for the locations in the states of Rajasthan and Uttar Pradesh, all other locations have considerable variability in their wind flow patterns, with a maximum speed (8.5 to 10.5 m/s) during July compared to a minimum speed (2.8 to 4.8 m/s) during October. Therefore, the monthly averaged wind speed data provides quite consistent estimates of the expected variations in the wind speed and their levels of significance in the context of wind energy production strategies.
The monthly variation in the wind speed profiles for NBSs and NESs showed similar distribution characteristics, with a typical peak speed season during the months of April to August (
Figure 7c,d). A transition of the peak windy month is observed from April (for Punjab and Haryana) to June (Bihar and West Bengal). As observed in the diurnal variations, the lowest average wind speed values were observed for the states of Punjab and Jammu & Kashmir. The monthly profiles of Bihar and West Bengal are quite impressive, suggesting the availability of consistent and high winds throughout the seasons of the year. The average monthly wind speed values for the NES region showed seasonal fluctuations only for the locations in the states of Chhattisgarh and Assam, while all other locations experienced a uniform but low wind distribution pattern. The windiest months for these regions are expected to vary between April and July owing to the influence of other climatic variables. In comparison, the availability of a reliable wind flow is limited to those states with a modal distribution, which should be explored for utilization at suitable scales.
Based on the mean monthly wind speed variation for the selected locations in the NMS and EBS regions, several distinct profiles can be obtained, similar to the inconsistency observed in their diurnal variations (
Figure 7e,f). Among the locations in the NMS region, the highest wind speed was obtained for Madhya Pradesh, but with the modal distribution peaking during the months of May to August. Considering the consistency and significance, the locations in the states of Uttarakhand and Himachal Pradesh represent attractive wind speed profiles in the range of 3.2 to 4.8 m/s. Notably, the wind speed profiles of the locations in Nagaland and Manipur do not suggest a productive range of wind speed, though the speed was quite consistent in those regions. The comparative analysis of wind speed variations for different temporal scales performed in this study provides a clear and comprehensive picture of the nature of challenges that exist in identifying suitable locations for wind energy extraction in a sustainable way.
Wind speed variations based on the annual average values were compared for the selected study period in order to inspect the historical trend for change in wind speed records. It is observed that most of the states have a consistent track record of annual wind speed, with short spikes of rising and falling appearing in a few consecutive years. Apart from the hydrologic and climatic considerations, it can be safely argued that the observed wind speed profile has a seasonally repeating pattern with a short recurrence interval range (in the range of 5–10 years), resulting in a more or less similar wind flow pattern throughout the study period. However, when we analyze more specifically, there is a reducing trend for the annual average wind speed values for a few selected locations in the SPS region (
Figure 8a,b). Similarly, the deviations in the average wind speed values are quite similar for most of the locations in the NBS and NES regions (
Figure 8c,d).
As far as the NMS and EBS regions are concerned, the average annual wind distribution profiles are distinct and consistent for the records during the study period (
Figure 8e,f). Hence, based on the comparative evaluation of wind speed profiles for different time scales, it is possible to critically propose strategies for exploring wind energy at suitable scales. Considering the acute demand for sustainable energy production and distribution for a wide range of applications, there is an immense possibility to translate these observations into suitable workable models by making them compatible with the local site’s climate and other economic factors.
3.2. Spatial Distribution of Wind Speed
The distribution of wind within the Indian peninsular region has been viewed primarily with the onset, progress and dispersion of the monsoons. Apart from this, occasional convective drifts, occluded fronts, atmospheric inversions and local heating effects contribute to the wide variety of wind speed patterns observed in lateral and vertical directions [
22,
23,
24,
25,
27,
28,
29,
36,
37]. The exponential trends of wind speed variations according to the height are observed to be consistent for the selected study regions (
Figure S4). The shear exponent, α, is considered to be 0.14 for the extrapolation of wind speed at higher altitudes for studying enhanced production strategies. The results are based on the projected wind speed at various demarcated vertical profiling sections, such as 10 m, 50 m, 100 m and 120 m. The WMS and NMS regions have shown a minimum increase in wind speed with respect to the height above ground up to 120 m compared to the other regions. The extrapolated values of wind speed at 120 m are quite different among the locations within a region, and this variation is more clearly visible for the regions where the temporal wind speed profiles have shown distinct ranges owing to the particular atmospheric and topographical conditions. In the absence of any unexpected situations, the availability of wind at 100 m and 120 m is considered to be the most promising for exploring wind energy in the developing locations in the study area.
Apart from the wind speed values, the direction at different heights above the terrain plays a significant role in evaluating the productive wind availability in a given location. By looking at the wind rose diagrams derived from the collected wind speed data at a height of 100 m (also done for 120 m), it is possible to ascertain the potential of the prevailing wind in order to propose a suitable direction for the erection and sustainable operation of wind farms (
Figure S5). It can be inferred that the majority of the locations in the SPS and WMS regions will benefit only from western winds, with fewer contributions from other directions. Similarly, the NBS and NMS regions have shown the highest distribution of wind in multiple directions, indicating the availability of consistent wind flow without the adverse impact of seasonality. However, the NES and EBS regions are favored by the wind flows mostly coming from the south and west directions, indicating the possibility of benefiting from the availability of consistent and significant wind flow patterns.
In an attempt to evaluate the inconsistencies existing in the implicit interactions between the geographic altitude and the prevailing wind speed, an analysis of the wind speed characteristics according to different altitude zones is proposed. Based on the inferred input database and the updated history of strategies for wind power exploration, the selected locations in the six study regions are separated into groups of varying altitudes above mean sea level (MSL), namely low altitude (LA) [<100 m], medium altitude (MA) [100–500 m], high altitude (HA) [500–1000 m], very high altitude (VHA) [1000–2000 m], and extremely high altitude (EHA) [>2000 m]. It is found that out of the 87 study locations, 17 locations are under LA, 30 are under MA, 16 are under HA, 14 are under VHA and 10 are under EHA categories of altitude. It is important to note that this classification tends to overrule the previous considerations of the relative identification of three locations at the local scales (i.e., low, medium, and high) within every administrative state. It is imperative that some of the medium stations in certain states merge into the new LA category and vice versa. The purpose of this analysis is to get a more stable scenario of average WSD in various altitude classes that belong to different regional groups defined earlier.
It is observed that most of the sites under the LA category belong to the SPS and WMS regions, which are mostly located on the west coast (
Figure 9a,b). The average wind speed under this category is found to be 4.44 ± 1.36 m/s. In comparison to the results from the temporal-scale variations, these locations ensure significantly consistent wind flows and therefore justify harvesting strategies for future explorations. The average wind speed variations for the locations under the MA category cover the largest area of India [
39]. The average wind speed under this category is 4.01 ± 1.26 m/s (
Figure 9c,d). The majority of locations under this altitude class belong to the WMS (Gujarat, Rajasthan) and NBS (Punjab, Haryana) regions. The WMSs have distinct wind exploration strategies, considering the economic, social, and eco-friendly readiness of the locations.
The average wind speed among the locations under the HA category is found to be 3.59 ± 1.40 m/s, for which the majority of stations are spread in the SPS, NES and NBS regions (
Figure 9e). The reason for the lower average value of wind speed at this altitude range may be attributed to the grouping of locations belonging to the NESs and NBSs, which have very poor wind profiles despite their high-altitude mountainous terrains. The average wind speed decreases to 3.40 ± 1.32 m/s when considering even higher locations in the VHA category. The main contributors in this category belong to the NES and EBS regions, where the presence of high-altitude mountains has not significantly contributed to the redistribution of consistent wind profiles. Adding further to the topographic diversity of India, the regions grouped under the EHA category have resulted in the lowest average wind speed values of 3.21 ± 0.94 m/s. The results of this analysis indicate that a mere grouping of regions on account of their similarity in altitudes does not provide sufficient linkage to the generation of consistent wind profiles at higher altitudes, counter to conventional interpretations. Based on this inference, we further investigate the validity of our hypothesis on the non-dependency of topographic altitudes on the wind power production potential.
Based on the calculations of average, maximum and Cube-Root Mean Cubed (CRMC) wind speed values for the selected locations in the six regions, the distribution profiles are depicted in the Indian map (
Figure 10). All three maps show similar trends, but vary in their range of obtained values (
Figures S1–S3). The maps show a gradual interpolation based on the wind speed data taken from the given locations, resulting in other locations with similar opportunities for wind energy exploration. However, it must be noted that land use practices, terrain features and other unnoticed obstacles must be addressed to make it more convenient to propose wind farms. Given the available wind energy production units in the country at present, the results indicate the possibility of identifying further locations for installing wind farms, thus making this more conservative, reliable and cheap.
3.3. Spatial Distribution of Wind Power Potential
The estimation of wind power based on the cubic law indicates a direct correlation with the wind speed for the selected six regions of the country. The existing potential for exploring wind power for a selected location is typically expressed in terms of WPD and has been evaluated based on diurnal, monthly and annual wind speed profile variations,
Figure 11a–e. This discussion omits the plots of the resulting trends, which closely resemble the corresponding wind speed profiles. However, this exercise was necessary to assess the possibility of temporal scale dependency on wind power potential, similar to the WSD presented in the previous sections. Although the variabilities in wind speed are quite inconsistent at lower temporal scales, one can very well appreciate the untapped potential existing in the central as well as some of the high-altitude regions of the country by deploying suitable means of extraction to cater to the growing energy demands.
Based on the average annual WPD obtained for the selected locations, a comparison has been made here to attribute the influence of regional altitudes on the observed average values (
Table S4 and
Figure S6). It is observed that the highest value of the average WPD (110.6 W/m
2) is for the lower altitude (LA) group, with the majority of the locations belonging to the SPS and WMS regions,
Figure 11a. This average value, nonetheless, depicts the minimum wind flow condition despite the highest values of TN1 (214.7 W/m
2) and GJ1 (208.4 W/m
2) because of the dampening effect of poor wind-flowing locations within this group (such as Mn1, AS1 and WB1). The largest group under the elevation-based categories is MA, which has 30 locations where the average WPD is found to be quite low (84 W/m
2) despite the peak values for GJ3 (304.8 W/m
2), AP2 (233.7 W/m
2), and GJ2 (222.1 W/m
2),
Figure 11b. For the HA group, the average WPD is found to be 70.2 W/m
2, while the high-performing locations are MR2 (190.2 W/m
2) and TG2 (163.3 W/m
2), see
Figure 11c. On a similar note, the average values for the VHA (
Figure 11d) and EHA (
Figure 11e) groups are observed to be 58 W/m
2 and 45 W/m
2, owing to the large number of contributing locations from the NES and EBS regions. This comprehensive analysis supports the hypothesis that wind power potential in India is not a direct function of high-altitude locations available in any particular state but depends primarily on the characteristic wind speed profiles and the prevailing topographic features.
3.4. Reliability Analysis of Wind Power Potential Using Variability Indices
Based on the statistical distribution of the wind power potential across the selected regions, the seasonal variability in the estimated wind power values is further evaluated in terms of wind power indices. As indicated by Equations (9) and (10), the wind variability index (WVI) has a normalizing effect on the wind power distribution, whereas the WSI index makes this variability proportionate by attributing the frequency factor (percentage of occurrence of data for a set lower limit) [
40]. Therefore, a comparison of WVI and WSI can ensure the reliability of the site for the expected production potential of wind, considering the effect of wind variability over the selected duration of data collection.
As mentioned in the previous results, the top three locations in the SPS region with the highest WPD are found to be AP2 (233.7 W/m2), TN1 (214.7 W/m2), and KT1 (192.7 W/m2). This is based on the average wind speed values observed during the selected period of data collection. The selection of top values is made under the consideration of a fixed target WPD value of 200 W/m2 to compare the wind power potential throughout the country. When we evaluate the wind variability indices for all the stations, it can be observed that the highest values of the MWVI were obtained for KT2 (3.10), KR2 (2.82), and TN3 (2.60). By definition, the MWVI incorporates all possible biases originating from extremities. Therefore, this indicates the influence of extremities on the average estimated values. However, the monthly WSI values were again found to be highest for TN1 (9.73), AP2 (5.79), and KT1 (2.18), strongly supporting the influence of the frequency factor in relating to wind power potential variability, thereby indicating the reliability of sustainable exploration for a future time. The variability in terms of annual predictions indicates that the highest values of the AWVI were obtained for TG3 (0.71), TN2 (0.68), and KR1 (0.67), while the highest annual WSI (AWSI) values correspond to the same locations with the highest monthly WSI (MWSI). The results relate to the fact that a mere statistical distribution analysis can be extended for reliability estimation in order to propose the suitability of wind power potential at a certain location.
Considering the variability in WPD for the locations in the WMS region, it is observed that the highest wind power producing locations are GJ3 (304.8 W/m2), GJ2 (222.1 W/m2), and GJ1 (208.4 W/m2) while the MWVI is highest for MR1 (2.74), MR2 (2.69) and RJ2 (2.45) and AWVI is highest for OD1 (0.61), OD2 (0.59), and OD3 (0.54). The ambiguity for a stable WPD in these locations may be correlated with the typical climatic extremities, in addition to the wind speed variations. The highest values of WSI (in terms of MWSI and AWSI) are unanimously attributed to GJ1 (3.10 and 48.87), GJ2 (3.52 and 56.57), and GJ3 (7.01 and 87.87). It is also observed that the WSI of Maharashtra is higher than that of Rajasthan, while only a few other locations have significant AWSI values, such as OD1 (15.92) and UP3 (15.97).
A comparison of the wind variability indices for the locations in the NBS region revealed that the highest WSI is closely related to the highest WPD potential, although some differences exist for a few stations. The top three locations based on WPD are WB3 (97.3 W/m2), BH2 (91.6 W/m2), and BH1 (90.6 W/m2), while the highest values of MWSI are observed for WB3 (0.76), HR3 (0.76), and BH1 (0.66), and the highest values of AWSI are noted for WB3 (1.80), BH1 (1.37), and HR2 (1.31). The MWVI is highest for WB2 (1.75), WB3 (1.69), and BH2 (1.66), while the highest values for AWVI are observed for JM3 (1.34), JM1 (0.82), and BH2 (0.82). A quick analysis of the results indicates that the stability of WPD is the essential feature for qualifying to be identified, as per the WSI values, in contrast to the WVI values. It is important to understand that the numerical values of the WSI decrease significantly, even more so than the reduction in WPD across the regions.
The observed trends in the variability of wind profiles among the NES region revealed that the top three locations with the highest AWSI values are AS3 (3.47), CG3 (1.49), and CG1 (1.46); the MWSI values are highest for AS3 (1.35), CG1 (0.75), and CG3 (0.68). It is important to note that most of the other states could not produce any reasonable stability profile for the WPD due to the poor or negligible frequency of the occurrence of opportunities that sufficiently match the target value WPD value of 200 W/m
2. This finding is in accordance with the poor values of WPD, as well as wind speed, recorded in these locations [
38,
39,
40]. The top three values of WPD for this region are AS3 (120.7 W/m
2), CG3 (87.1 W/m
2), and CG1 (84.1 W/m
2). However, these values are quite low compared to those of the other regions, such as the SPSs and WMSs. Based on the point of potentiality analysis, these results can be critical in selecting suitable locations for wind power exploration. In other words, the variability indices are quite indicative of the possibility of more suitable, unknown locations.
In order to evaluate the suitability of wind power production from the middle states of India, the wind variability indices for the NMS region are further considered. It was observed that the top three locations having the highest values of WSI (in terms of MWSI and AWSI) are MP1 (0.98 and 3.27), MP3 (0.79 and 3.04), and MP2 (0.79 and 2.76), which is in accordance with the WPD values (112.9, 104.6, and 103.1 for MP1, MP3 and MP2, respectively). The highest values of WVI were also observed to follow similar trends for the locations in MP and HP (
Figure 12). One interesting result is observed for the locations in the state of UK, indicating that altitudes and frequencies of wind speed are strongly inversely related, resulting in poor WSI values. One may also infer from the results that any occasional occurrence of extremities cannot be considered reliable in choosing a site for wind power production.
Based on the WPD results, GA1 (162.3 W/m2), GA2 (105.0 W/m2), and GA3 (81.0 W/m1) are the top three locations in the EBS region with the highest wind power production potential. Nonetheless, the wind stability analysis indicated that GA1, GA2 and TP3 are the locations with the highest values of the WSI, while the monthly variability indices are highest for GA3, GA1, and GA2, and the annual variability indices are highest for TP1, JK1, and TP2. It is important to note that although the WPD and WVI values are quite comparable for the EBS and NMS regions, the AWSI values of the EBS regions are almost three times higher than those of the NMS regions. Compared to the NES and NMS regions, the number of locations with insignificant WSI values is much lower for EBS regions. It is also to be noted that the locations with the highest WPD values have the highest frequency contributions set against the target value of 200 W/m2.
3.5. Comparison of Wind Power Exploration Potential in Terms of Rating Indices
The capacity for wind energy production from proposed wind turbines, based on the prevailing wind conditions at individual locations, is evaluated using standard terminologies such as PCF, COE, and time distribution at different power loading conditions.
Figure 13 provides an understanding of the relationship between PCF (%) and the corresponding value of Time to Zero Power (%), considering the various methods employed, i.e., SPS, WMS, NBS, NES, NMS, and EBS, which show the general trend of the dataset. A strong negative correlation is observed, which indicates that when PCF is low, i.e., within the range of 0–5%, the value of Time to Zero Power is very high, i.e., within the range of 80–100%. This indicates the ability of the system to retain power for a longer period before reaching zero. When PCF increases from 5% to 20%, a sharp decline in the value of Time to Zero Power is observed, which indicates the ability of the system to reduce the time taken to reach zero power when PCF increases, i.e., the system decays faster when PCF is high. When the value of PCF increases from 20 to 25%, the value of Time to Zero Power stabilizes in the range of below 20%, which indicates the ability of the system to stabilize when PCF increases; i.e., the system becomes stable when PCF increases. Considering the various methods employed, i.e., SPS, WMS, NBS, NES, NMS, and EBS, the techniques show a high degree of variability in the range of PCF, i.e., SPS and WMS, which indicates the sensitivity of these methods to the changing value of PCF. On the other hand, the other methods, i.e., NBS, NES, and EBS, show a high degree of clustering, which indicates the stability of the results obtained. The scatter plot indicates the importance of PCF as a controlling parameter, which influences the performance of the system; i.e., the system decays faster when PCF increases, and the value of PCF is high.
Figure 14 shows a comparative analysis of the COE in various selected regions, highlighting spatial variations in energy economics. The spatial distribution of economic footprints indicates that the COE is not constant and differs significantly depending on various factors, including regional factors. Regions with low energy costs tend to enjoy abundant energy resources, effective energy production mechanisms, and better energy transmission infrastructure. Conversely, regions with higher energy costs tend to experience problems such as scarce energy resources, higher energy consumption, inefficient energy production mechanisms, and poor energy transmission infrastructure. Another factor that contributes to the variation in energy costs among various regions is the variation in energy mixes that each region has adopted [
3,
9,
33,
41]. Regions that use alternative energy sources, such as solar, wind, and hydro energy, tend to experience moderate to high energy costs, which may vary with time. Regions that use conventional energy sources tend to experience fluctuating energy costs depending upon various factors, including market prices. Thus, from
Figure 14, one can conclude that region-specific energy planning and optimization strategies play a significant role in energy economics. The above analysis has been made by keeping in view the importance of energy economics and how one can use this concept to promote alternative energy sources, which would be more sustainable and cost-efficient.
In the pursuit of energy resource exploration and harvesting, many intrinsic correlations exist between total GHG emissions and expected energy utilization in the context of wind farms. For the selected regions of India, one can easily perceive obvious differences between the various regions with regard to the efficiency of energy utilization while maintaining environmental sustainability (
Figure 15). Regions with high GHG emissions are the ones with high energy utilization due to the use of fossil fuels in the region’s energy system. This metric is the carbon footprint of the region’s energy system, which is normally a result of traditional energy production methods like the use of coal and oil as a source of energy. On the other hand, regions with low GHG emissions and high energy utilization are those that have shifted towards a cleaner and more sustainable source of energy. One of the most important observations from this study is the decoupling of the GHG emissions and energy utilization of the selected regions. This evidences the efficiency of the energy system of the region with regard to environmental sustainability, the use of cleaner sources of energy, and the effectiveness of the environmental policies of the region [
42]. On the other hand, the regions with high GHG emissions and high energy utilization are the ones with a high carbon footprint, and thus, there is a need to reform the energy system and policies of the region with regard to environmental sustainability. The results indicate the significance of the shift towards a low-carbon footprint energy system while maintaining the required level of energy supply and utilization in the region.
In summary, the performance of the selected sites for sustainable wind power production potential can be evaluated under two categories—exploration and extraction. The exploration phase comprises a reliable assessment of wind flow patterns, while the extraction phase consists of effective transformation for useful power production. In this aspect,
Table 1 shows the three best-performing sites from the top nine Indian states based on mean wind speed as well as plant capacity factor. All three sites from the states of Gujarat, Andhra Pradesh, and Maharashtra show significant performance metrics, while only one site each from the remaining states shows comparative potential (
Table 1).
Most previous investigations evaluate wind-resource potential using individual metrics, often emphasizing either statistical wind characteristics or energy-production indicators. In contrast, the proposed framework combines wind speed distribution characteristics, energy potential metrics, and techno-economic performance measures within a standardized rating scheme, thereby enabling a comprehensive comparison of site suitability. However, it should be understood that direct interpretation of the various performance measures of this ranking framework should be done with due consideration of the external factors governing the physical processes of wind flow. This is particularly significant in the case of Indian states with multiple levels of heterogeneous features governing wind power production estimates. Hence, further studies are required to elucidate a detailed scope for dynamically tapping the wind resource from potential sites despite their variability in rating-based rankings.