4.1. Cross-Sectional Dependence and Stationarity Results
Table 4 presents the results of the Cross-Sectional Dependence test. The null hypothesis (H0) is cross-sectional independence across panel units, against the alternative (H1) of cross-sectional dependence. Given the large CD statistics and
p-values of 0.000 (<0.01) for all variables (lnESS, lnEEQ, lnENSS, ESGUI, GO, TGO, EGO, FGO, lnEG, IND, lnEDU, URB), H0 is rejected for every series and H1 is accepted—indicating strong cross-sectional dependence (common shocks/spillovers), so subsequent estimation should use second-generation panel methods that accommodate CSD.
Table 5 presents the result of the CADF test. The Null hypothesis (H
0) states that each series has a unit root (is non-stationary) and alternative (H
1) states that the series is stationarity. The CADF statistics show H
0 is rejected at levels for lnESS, lnEEQ, lnENSS, GO, TGO, FGO, IND, and URB—these are I(0). H
0 is not rejected at levels for ESGUI, EGO, lnEG, and lnEDU, but their first differences are significant, so these are I(1). Overall, the data mix I(0) and I(1) variables, supporting methods that allow heterogeneous integration orders (e.g., Driscoll–Kraay, FGLS and Lewbel IV-2SLS with CSD controls).
4.3. Baseline Results
As a first step, we present baseline results based on Driscoll–Kraay standard errors (
Table 7) alongside FGLS estimates (
Table 8). The tables report 12 specifications (four for each pillar of the trilemma) that rotate the definition of globalisation (GO/EGO/TGO/FGO).
Across both estimators, globalisation (GO) is positively associated with all three pillars of the Energy Trilemma (ET), while ESG-related uncertainty (ESGUI) tends to erode—if modestly—performance, most visibly for energy security. In the Driscoll–Kraay (DK) models, ESGUI carries consistently negative and statistically significant coefficients for energy security (≈−0.002 to −0.003), whereas the corresponding FGLS estimates are smaller in magnitude and often insignificant, signalling estimator sensitivity but a common direction.
For energy security (ESS), the DK results show a robust pattern: higher ESG uncertainty is linked to lower security (columns 1–4, −0.002 to −0.003, mostly at ≥1% significance). FGLS mirrors the sign but weakens the precision (−0.001 to −0.002, largely insignificant, with one specification reaching significance), implying that the adverse effect of ESG uncertainty is present but not always precisely estimated once cross-sectional heteroskedasticity/correlation are modelled explicitly.
For energy equity (EEQ), ESGUI effects are generally small and imprecise in both tables (columns 5–8). This suggests that access/affordability outcomes—proxied by the equity dimension—are less contemporaneously sensitive to sustainability-related uncertainty than security, perhaps because equity is anchored by long-lived infrastructure and social policies that buffer short-run information shocks.
The environmental sustainability (ENSS) pillar shows similarly muted ESGUI effects (columns 9–12): coefficients are negative but typically insignificant under both DK and FGLS. Interpreted cautiously, this indicates that annual movements in a news-based ESG uncertainty signal do not systematically map into the pace of greening within the sample, once income, industrial structure, education, urbanisation, and time effects are held constant.
By contrast, the composite globalisation index (GO) displays consistently positive, precisely estimated associations with ET across estimators. Under DK, coefficients are about 0.018 (security), 0.003 (equity), and 0.012 (sustainability); FGLS delivers very similar magnitudes (≈0.015, 0.003, and 0.012, respectively). Given the log specification for ET, these are semi-elasticities: a 10-point rise in GO (roughly two SDs in this sample) aligns with ≈15–18% higher energy security, ≈3% higher equity, and ≈12% higher sustainability, highlighting especially strong links for resilience and decarbonisation.
Decomposing GO clarifies where the lift comes from. Economic globalisation (EGO), trade globalisation (TGO), and financial globalisation (FGO) are all positive and significant across pillars and estimators. For energy security, FGO tends to have the largest coefficient (≈0.011–0.013), followed by EGO (≈0.009–0.011) and TGO (≈0.007–0.008), consistent with deeper financial integration easing capital constraints for reliability and grid hardening. For environmental sustainability, EGO and FGO are similarly strong (≈0.008), with TGO slightly smaller (≈0.006–0.007), suggesting that both financial depth and broader economic integration help scale low-carbon investment and technology diffusion. Equity gains are positive but smaller (about 0.001–0.002), which fits the idea that inclusion improves gradually as integration expands markets and lowers delivered energy costs.
Comparatively, DK and FGLS tell the same story on globalisation—signs, magnitudes, and significance are remarkably robust—while diverging mainly on the strength of ESGUI’s penalty for energy security. DK’s heteroskedasticity- and cross-sectional-correlation-robust inference may better capture common shocks that propagate across countries, inflating the precision of the ESGUI effect; FGLS, which explicitly models the error structure, yields more conservative significance. The stability of the GO and subcomponent estimates across both methods strengthens confidence that integration—especially financial and broad economic channels—systematically supports ET outcomes in this panel.
Goodness-of-fit (R2). DK models fit equity best (R2 ≈ 0.900, 0.892, 0.880, 0.898), then security (0.709, 0.683, 0.650, 0.712), then sustainability (0.701, 0.708, 0.730, 0.649). FGLS often lifts fit for security in the first two specs (0.861, 0.901) but drops when replacing GO with sub-indices (0.678, 0.569). For equity, FGLS R2 are respectable (0.726, 0.696, 0.738, 0.784), and for sustainability they are high but more variable (0.881, 0.814, 0.562, 0.725). In short: equity equations are the most tightly explained in DK, while FGLS shows strong but specification-sensitive fit, especially for security and sustainability when different globalisation facets are entered.
4.4. Results of Lewbel Two-Stage Least Squares Method
Table 9 reports Lewbel IV-2SLS estimates that instrument the potentially endogenous regressors using heteroskedasticity-generated instruments. With time fixed effects and the same specification set (12 models: four per pillar), the IV results sharpen the picture: ESG uncertainty (ESGUI) is consistently harmful, while globalisation—aggregate and by facet—remains consistently beneficial to the energy trilemma. Across columns (1)–(4), (5)–(8), and (9)–(12), the ESGUI coefficients are negative (≈−0.001 to −0.003) and statistically significant, whereas GO/EGO/TGO/FGO are positive and highly significant. In short, uncertainty hurts the trilemma while globalization helps it.
For energy security, the IV estimates in columns (1)–(4) indicate that a rise in ESG uncertainty meaningfully reduces the stability and resilience of energy supply (ESGUI ≈ −0.002 ** to −0.003 ***). This pattern fits standard real-options logic: when policy, standards, and disclosure expectations are noisy, firms defer or down-scale irreversible, long-lived energy investments (generation, storage, LNG terminals, interconnectors), elevating supply risk [
11,
12]. In the G7—where energy systems rely on capital-intensive assets and cross-border fuel and equipment chains—ESG policy whiplash and credibility gaps amplify risk premia, delaying capacity additions and upgrades that would otherwise harden security [
16].
Turning to energy equity (affordability and access), columns (5)–(8) show ESG uncertainty again enters negatively and significantly (≈−0.001 to −0.002). In practice, uncertainty raises financing costs for utilities and project developers, especially for low-carbon and network assets with long payback periods. Higher risk premia and a stronger “option to wait” propagate to retail tariffs and connection backlogs, eroding affordability for households and SMEs [
13]. G7 markets, with sophisticated but risk-sensitive capital pools, are particularly exposed to this mechanism: small changes in perceived policy durability can reprice billions in capex and shift cost recovery onto consumers.
On environmental sustainability, the IV results in columns (9)–(12) show a clear and precise negative ESGUI effect (−0.002 *** throughout). This aligns with evidence that credible, predictable rules are a prerequisite for directed technical change toward cleaner technologies; uncertainty blunts incentives to invest in green R&D, slows diffusion, and prolongs reliance on higher-emitting capital [
14,
15]. For the G7, where much of the global low-carbon innovation originates, uncertainty thus has outsized global externalities by dampening innovation pipelines and deployment learning curves.
In contrast, overall globalization (GO) is positively associated with energy security, equity, and sustainability (0.018 ***; 0.004 ***; 0.013 ***). For security, deeper integration diversifies supply sources, enhances cross-border balancing, and broadens access to fuels, equipment, and critical minerals—classic portfolio effects that reduce exposure to idiosyncratic shocks [
16]. G7 countries are structurally positioned to benefit as they operate dense interconnection networks, liquid fuel and power markets, and have strong contracting institutions that translate openness into resilience.
Decomposing globalization clarifies channels. Economic globalization (EGO) is strongly positive across the trilemma (0.011 ***; 0.002 ***; 0.008 ***), consistent with the idea that cross-border flows of goods, services, and value chains scale markets for clean tech, lower unit costs via learning-by-doing, and accelerate replacement of inefficient capital [
35]. In the G7, this means cheaper access to turbines, PV modules, batteries, and digital grid components—improving affordability and enabling faster decarbonization without sacrificing reliability.
Trade globalization (TGO) also shows positive and significant links (0.009 ***; 0.002 ***; 0.007 ***). Trade expands the feasible set of energy mixes by enabling imports during domestic shortfalls and exports when local supply is abundant; it also speeds technology diffusion through embodied know-how in traded intermediate goods [
17]. For the G7, robust trade in fuels, equipment, and balancing services supports smoother integration of variable renewables and lowers system costs, jointly advancing security and equity while cutting emissions intensity.
Financial globalization (FGO) registers the largest security coefficient among the components (0.014 ***; with 0.003 *** for equity and 0.009 *** for sustainability). International capital deepens funding pools for large-scale, capital-intensive projects (offshore wind, grids, storage), spreads risk, and reduces the cost of capital when policy frameworks are credible [
13]. The G7’s sophisticated financial sectors, green bond markets, and disclosure regimes (e.g., TCFD-style reporting) help channel global savings into domestic and cross-border low-carbon infrastructure, reinforcing all three trilemma goals.
Comparing with
Table 7—Driscoll–Kraay and
Table 8—FGLS confirms the pattern but highlights why IV matters. In 7, ESGUI is strongly negative for energy security but often imprecise for equity and sustainability; in 7b, most ESGUI estimates are small and statistically weak. By contrast,
Table 9’s Lewbel IV-2SLS yields uniformly negative and significant ESGUI effects across all pillars, and consistently positive, significant effects of GO/EGO/TGO/FGO. This is exactly what we expect if (a) measurement error in ESG uncertainty or (b) reverse causality (e.g., deteriorating trilemma outcomes fuelling sustainability-related uncertainty) biases conventional estimators toward zero; Lewbel’s heteroskedasticity-based instruments help recover exogenous variation, sharpening inference [
36]. The similarity in signs—and the IV’s tighter precision—suggest
Table 8’s results are broadly consistent with
Table 7 and
Table 8 but arguably more credible causally.
4.5. Examining the Nonlinear Effect of Globalisation on the Energy Trilemma
Since the relationship between globalisation and environmental and energy indicators can exhibit nonlinear connection, the current investigation included the squared terms of the compositive globalisation and trade globalization (TGO), economic globalisation (EGO) and financial globalisation (FGO) variables in our estimations. The results are reported in
Table 10. With the linear terms generally retaining their positive coefficients, the squared terms of FGO, EGO and EGO all negative and statistically significant. Accordingly, the hypothesized nonlinear effect is supported; higher levels of globalisation—FGO, EGO, and TGO—are associated with improvements in energy security, equity, and environmental sustainability at low to moderate degrees of integration, while the negative and statistically significant squared terms indicate diminishing marginal returns (and possible reversal) at very high integration.
The Lewbel IV–2SLS estimates in
Table 10 indicate a robust nonlinear (concave) relationship between globalisation and the three pillars of the energy trilemma in the G7. Across the overall globalisation index (GO) and its subcomponents—economic (EGO), trade (TGO), and financial (FGO)—the linear terms are positive while the squared terms are negative, implying diminishing marginal returns to openness at higher levels of integration. Using the reported coefficients, the implied turning points for GO occur around ≈94 for energy security, ≈44 for energy equity, and ≈73 for environmental sustainability
consistent with the G7’s location near the global openness frontier [
19].
For energy security, the positive GO coefficient (0.561 ***) with a negative GO
2 (−0.003 ***) suggests that incremental integration initially diversifies supply portfolios, strengthens cross-border balancing, and deepens markets, thereby reducing outage and price-spike risk [
16]. As openness approaches the turning point (≈94), marginal gains taper, consistent with higher exposure to correlated external shocks, chokepoints in global logistics, and potential import dependence that partly offsets diversification benefits. This concavity is mirrored in EGO, TGO, and FGO, indicating that the underlying channels—production networks, trade logistics, and cross-border capital—each improve security up to a point before delivering smaller incremental benefits at very high integration [
17].
For energy equity (affordability and access), the positive GO term (0.087 ***) and negative GO
2 (−0.001 ***) yield a lower turning point (≈44), implying that early-to-mid stages of openness reduce delivered energy costs via market scale, competition, and technology cost compression; beyond that, global price pass-through becomes more salient, attenuating equity gains. This pattern aligns with trade-and-environment models where scale and technique effects dominate at moderate openness, while price transmission and volatility exposure rise at advanced openness [
35,
37]. In liberalised G7 retail and wholesale markets, such pass-through is typically strong, which rationalises the relatively low equity turning point.
For environmental sustainability, the GO estimates (0.145 ***; GO
2 −0.001 **) indicate substantial green gains up to ≈73 on the GO scale, consistent with technology diffusion, embodied knowledge flows, and learning-by-doing that accelerate the uptake of low-carbon capital [
17]. Beyond that threshold, rebound dynamics, offshoring of emissions-intensive stages, and the rising prominence of embodied emissions across global value chains jointly produce diminishing returns, curbing additional environmental gains. In the absence of complementary policies—such as carbon pricing with leakage safeguards, embodied-carbon standards, and green procurement—these channels temper, and can even reverse, the earlier sustainability improvements [
35]. These results align with directed technical change, which holds that innovation follows incentives and policy certainty. Predictable, credible rules—stable carbon pricing with leakage safeguards, technology-neutral performance standards, taxonomy-aligned finance, green procurement, and transparent embodied-carbon disclosure—shift relative prices and risk-adjusted returns toward clean technologies, crowding in private R&D and deployment rather than inducing “wait-and-see” behavior. In short, openness becomes a durable engine of low-carbon investment only when anchored by consistent, forward-looking policies that direct search, learning, and capital deepening toward cleaner trajectories [
14].
The subindex decomposition clarifies mechanisms. EGO exhibits pronounced concavity across pillars (EGO > 0; EGO
2 < 0), indicating that market enlargement and integration initially compress costs and speed diffusion, but frontier economies require coordination and standards rather than additional openness to extract further gains. TGO is consistently positive; curvature is material for security and equity, whereas for sustainability the squared term is statistically weak, suggesting trade integration continues to facilitate decarbonisation in the G7 by keeping clean hardware and intermediate inputs inexpensive and available. FGO shows strong concavity: moderate financial openness expands green funding pools and lowers the cost of capital, but at very high levels short-termism, volatility, and “too-much-finance” effects may erode the marginal benefits for long-horizon infrastructure [
13,
18].
The G7-specific concavity is economically intuitive. These economies already possess dense interconnectors, liquid commodity and power markets, and sophisticated green-finance channels. Consequently, the first-order benefits from additional openness are smaller, while exposure to globally correlated shocks (geopolitical disruptions, pandemics, critical-mineral bottlenecks) becomes relatively more important. This frontier-saturation mechanism naturally produces inverted-U patterns in the data: openness is beneficial on average, but its marginal impact declines as systems approach best-practice integration [
16,
19].