Green Innovation

Having examined digital health and the convergence of medical devices with health informatics, this chapter turns to green innovation, a domain that spans the broadest range of technology areas in ACT 6 and whose growth trajectory is increasingly intertwined with AI-driven optimization.

Climate change constitutes one of the defining challenges of the 21st century, and the patent system provides a valuable lens through which to observe the technological response. This chapter traces the growth of green innovation through patents classified under the CPCCooperative Patent Classification — a hierarchical system jointly managed by the USPTO and EPO that categorizes patents by technology area (e.g., H = Electricity, G = Physics).'s Y02A CPC classification section for technologies related to climate change mitigation. Sub-categories include renewable energy (Y02E), transportation (Y02T), carbon capture (Y02C), buildings (Y02B), and industrial production (Y02P). and Y04S codes, encompassing solar panels, wind turbines, electric vehicles, carbon capture, and smart grids.

Green patent filings increased from 3,000 per year in the late 1970s to 30,000 per year by the early 2020s (peaking at 35,693 in 2019). Patent filings continued to grow following the 2015 Paris Agreement, with batteries and electric vehicles exhibiting particularly strong growth. Green patents represented 9–10% of all utility patents granted annually during 2015–2024.

Green technologies have not followed a uniform growth trajectory. Renewable energy generation (solar and wind) led the early expansion, but batteries/storage and transportation (particularly electric vehicles) have grown to become the largest categories in recent years, with batteries/storage reaching 7,363 patents and transportation/EVs reaching 5,818 patents in 2024, compared to 3,453 renewable energy patents. Carbon capture remains a smaller category at 374 patents in 2024.

Japan has historically been the second-largest green patent filer, led by Toyota (12,636 total patents) and Honda (5,807) in automotive technologies and Mitsubishi Electric and Toshiba in energy systems. South Korea's annual green patent count grew from 174 in 2005 to 2,989 by 2024 (reaching 67% of Japan's 2024 count of 4,455), led by Samsung (13,771 total patents), LG, and Hyundai (4,888). US firms such as General Electric (10,812) and Ford (7,383) have maintained strong positions.

The competitive landscape of green patenting has shifted substantially over the past two decades. Traditional energy firms and early-moving automakers established initial leadership positions, but electronics conglomerates and newer entrants have risen rapidly, reflecting the broadening of green innovation beyond energy generation into batteries, vehicles, and digital infrastructure.

Individual inventors in the green technology space reflect the breadth of the field, spanning automotive engineers, battery chemists, power electronics specialists, and solar cell researchers. The most prolific inventors tend to be associated with major corporate R&D laboratories.

Quality metrics for green patents provide insight into the depth and breadth of climate technology innovation. Average claims counts, backward citations, and technology scope indicate whether green patents are becoming more complex and better integrated with prior art.

Green patents are by nature cross-cutting — Y02/Y04S codes are applied alongside primary CPC codes from other technology sections. Tracking co-classification patterns reveals how green innovation diffuses across electricity, chemistry, mechanical engineering, and physics.

AI is increasingly applied to climate-related challenges, particularly in energy grid optimization, industrial process control, and transportation logistics. Patents classified under both green (Y02/Y04S) and AI-related CPC codes represent a growing intersection of two consequential technology domains.

This chapter continues PatentWorld's examination of 50 years of US patent innovation. From the broad contours of the innovation landscape to the specific domains of AI and green technology, the preceding chapters have traced how the patent system has evolved in structure, geography, and character. The convergence of artificial intelligence and climate technology examined here represents a significant frontier of contemporary innovation — a domain where the patterns documented throughout this book come together in the service of addressing global challenges.

Across the twelve technology domains examined in ACT 6 — from semiconductors and quantum computing through artificial intelligence and green innovation — several cross-cutting themes emerge: the concentration of patent activity among a small number of resource-intensive firms, the accelerating convergence of formerly distinct technology fields, and the growing role of international competition in shaping domestic innovation trajectories. These domain-level patterns reinforce and extend the structural insights developed in the preceding acts, confirming that the US patent system is simultaneously becoming more specialized in its technical content and more interconnected in its organizational and geographic character.