A patent is often described as providing 20 years of exclusivity. For technologies that take many years to develop, test, license and bring to market, the period of commercially meaningful protection can be much shorter.
That issue is particularly relevant to nuclear fusion. Commercially viable fusion energy may still be some way off, while key inventions may need to be protected now.
Significant resources are therefore being invested in technologies that may have limited remaining patent life by the time they are ready to be commercially exploited.
This raises a practical policy question: if patents are intended to encourage investment and disclosure, should the law take into account industries where the route from invention to deployment is unusually long?
The 20-year patent term is not necessarily 20 years of commercial protection
A European patent has a term of 20 years from its filing date. However, the clock may start running long before the technology is capable of being brought to market.
This is a feature, rather than a defect, of the patent system. The bargain is 20 years exclusivity in exchange for disclosure; allowing others to develop and exploit the underlying technology once the patent expires. But for highly regulated technologies, mandatory approval processes can erode the period during which that exclusivity has real commercial value.
The European patent system already provides a mechanism based on this principle through supplementary protection certificates (SPCs). SPCs currently apply only to pharmaceutical and plant protection products, compensating for patent term lost during the lengthy regulatory processes required before those products can be placed on the market.
The underlying rationale, however, is potentially relevant to the nuclear industry. If a similar problem arises where a patented nuclear technology cannot be commercially deployed until lengthy mandatory regulatory authorisation has been obtained, the question is whether a comparable supplementary protection mechanism should be available.
Why nuclear technologies are different
Nuclear fission provides a useful comparator. New nuclear power projects may involve design development, site assessment, safety analysis, environmental review, licensing, construction and authorisation to operate. The International Atomic Energy Agency has observed that moving from initial consideration of a nuclear power programme to operation of a first plant can typically take around 10–15 years.
Fusion may face a similar challenge. Foundational patents may be filed years before a commercial fusion plant is ready, particularly for magnets, materials, control systems, manufacturing processes or reactor subsystems. The result is that early patents may be approaching expiry just as the technology becomes commercially valuable.
What could reform look like?
Any extension would need to be carefully limited. The case should not be that fusion is difficult as many sectors could say the same. The stronger argument is that part of the patent term has been consumed by mandatory regulatory processes outside the patent owner’s control.
A defensible model might therefore provide additional protection only where:
- the patented invention relates directly to a qualifying fusion energy system or component;
- commercial deployment requires a defined regulatory authorisation; and
- the applicant can identify the relevant period of regulatory delay.
The aim would be to compensate for regulatory delay, not development delay generally.
Balancing incentives and access
While a patent may expire before widespread commercial deployment, the patent term can still provide value by allowing companies to build expertise, develop collaborations and establish market-leading positions, including in adjacent applications. However, there is still a credible investment argument for a targeted extension of patent term. Fusion requires substantial funding long before commercial deployment, and investors will consider not only whether the technology works, but how long meaningful exclusivity remains once it does. A patent that expires shortly after market entry may therefore provide limited commercial comfort.
A targeted extension could also encourage earlier disclosure. If innovators fear that early filing leaves too little useful protection, they may delay filing or rely more heavily on secrecy. That would be unhelpful in a field where technical disclosure can reduce duplication and support wider collaboration.
A counterargument is that fusion could become an important low-carbon energy technology. Extending exclusive rights could restrict competition and slow further innovation. The pharmaceutical SPC model provides a useful comparison because the regulatory endpoint is clear and the additional protection is capped at five years. Fusion is less predictable: projected commercialisation dates can move repeatedly as technical and regulatory challenges emerge. A system based simply on the time between patent filing and commercial deployment could therefore produce excessive extensions.
Any supplementary protection would therefore need to balance incentives for investment against timely access to energy technologies. A fixed cap, potentially similar to the five-year cap used for SPCs, may be more defensible than any open-ended extension linked simply to the time taken to reach commercial deployment.
Conclusion
The issue is not whether fusion companies deserve longer patents. It is whether, where the state requires a lengthy regulatory process before a patented technology can be commercialised, the patent system should restore a limited portion of the patent life consumed by that process.
Fusion may therefore be a useful test case for a broader question: in highly regulated sectors, does 20 years of legal protection always translate into a fair period of meaningful commercial protection?
This article has been prepared by European Patent Attorney James Tagg.