Urban decarbonization is essential for meeting global climate goals; however, progress toward integrated low-carbon urban energy systems remains inadequately slow. The SolarEV City Concept integrates rooftop photovoltaic (PV) generation with electric vehicles (EVs) as city-scale distributed mobile energy storage, using EV batteries to increase the value and flexibility of urban rooftop PV. Modeling studies suggest that high-penetration PV+EV systems could supply 60–95% of municipal electricity demand under scenarios aligned with future sustainable-city development, but real-world integration remains limited. Despite rapid worldwide growth of both PV and EV markets, bidirectional Vehicle-to-Home/Building (V2H/V2B) and Vehicle-to-Grid (V2G) applications have advanced unevenly, revealing a persistent PV-EV integration gap. This critical integrative review analyzes this gap using a socio-techno-economic framework encompassing six interdependent dimensions: climate, urban structure, technology, economics, policy, and society, across nine countries: Australia, China, France, India, Indonesia, Japan, the Netherlands, South Korea, and the United States. Cross-national comparison shows that implementation is constrained by fragmented bidirectional-charging standards, immature value-stacking and compensation models, distribution-grid and market-access constraints, regulatory separation between energy and transport sectors, and equity barriers that disproportionately limit access for renters, apartment residents, and lower-income households. Five transition-pathway archetypes, ranging from Japan’s resilience-driven V2H pathway to regulation-enabled commercial V2G pathways in France and the Netherlands, demonstrate that SolarEV Cities require a transition from parallel PV and EV promotion toward shared urban-energy visions, interoperable digital infrastructure, feeder-aware planning, inclusive market designs, and multi-stakeholder implementation platforms that convert rapid PV and EV innovation into scalable, resilient, and socially inclusive urban decarbonization.
The growing demand for sustainable, high-performance energy storage is accelerating the transition toward cleaner and more efficient battery manufacturing technologies. Dry battery electrode (DBE) processing is emerging as a key enabler of this shift, as it eliminates toxic solvents, energy-intensive drying, and the large-scale recovery systems required in conventional wet electrode production. In this review, we provide a comprehensive overview of DBE from the perspectives of processing technology, materials chemistry, sustainability, and application potential. Established and emerging DBE routes are summarized including binder fibrillation-based coating, powder-film formation, hot pressing, roll-to-roll lamination, and additive manufacturing. Furthermore, the influence of binder choice, powder interactions and microstructural design on electrode integrity and electrochemical performance is investigated. The review also highlights the sustainability advantages of solvent-free manufacturing and outlines how DBE can support next-generation battery concepts, including solid-state systems. Additional dry-processible components, such as separators, membranes, and current collectors, are examined to illustrate broader opportunities for solvent-free cell fabrication. Finally, current challenges in scale-up, process control, and interface engineering are discussed, and strategies that may accelerate industrial implementation are presented. Together, these insights position DBE as a promising pathway toward more efficient, flexible, and environmentally friendly battery production.
The global electric vehicle fleet already stores more energy than all dedicated grid-scale batteries combined, yet this capacity remains largely untapped. Vehicle-to-grid could unlock it, but only if participation is profitable for vehicle owners. In this review, we harmonize 680 outcomes from 86 modeling studies to assess the profitability of vehicle-to-grid. We classify each article by the market segment generating vehicle-to-grid revenue, the model linking vehicles to that market, the point in the value chain the reported value describes, and the underlying modeling assumptions. Reported profitability estimates range from net losses to several thousand euros per vehicle, and most describe the value realized in the market rather than what a vehicle owner retains. The median study reports 201 EURper EV per year and 86% report a gain, yet study medians span more than an order of magnitude. Within individual studies, profitability increases with deployable flexibility and decreases with cycling costs. However, these relationships are obscured across studies because key design choices (including cost scope, market environment, and vehicle availability) vary simultaneously and cannot be disentangled. Genuine market heterogeneity and differences in modeling realism therefore co-vary and cannot be separated with the available evidence. At the same time, the conditions for profitability are improving, driven by falling battery prices, lower-than-assumed real-world degradation costs, and regulations beginning to recognize bidirectional storage. The question is no longer whether vehicle-to-grid can be profitable, but under which market and regulatory conditions it can scale.
