The National Security Patent Act – How the U.S. Quietly Sits on Energy and Power Tech

Overview: the quiet patent throttle

There is no statute on the books literally called the “National Security Patent Act.” The phrase people use online is a shorthand for something real but more boring: the Invention Secrecy Act of 1951 and a cluster of sections in U.S. patent law, codified at 35 U.S.C. §§ 181–188.

That framework allows the U.S. government to issue secrecy orders on patent applications when officials decide that public disclosure “might be detrimental to the national security.” Once that decision is made, your invention effectively goes into a black box:

• Your application is frozen; no normal publication and no grant.
• You are legally barred from talking about it or filing abroad without permission.
• The government and its contractors retain the option to use the underlying idea, often without you ever seeing a meaningful check.

Declassified review lists make it clear that this system has covered more than just weapons and spy gear. High-efficiency solar, energy conversion systems above certain thresholds, batteries, advanced power electronics, and other energy-adjacent technologies have been explicitly flagged for national-security review.

This article walks through the actual statute, the numbers, the documented case studies, and the energy-tech angle. The goal is not to LARP conspiracy or defend the system, but to lay out how it really operates and what it does to innovation and energy in the real world.

What law actually exists?

The Invention Secrecy Act and 35 U.S.C. §§ 181–188

The legal core is the Invention Secrecy Act of 1951, implemented in the patent code as sections 181 through 188. In plain language, those provisions:

• Authorize the government to review patent applications for national-security implications.
• Allow the imposition of secrecy orders that block publication, grant, and foreign filing.
• Allow criminal and civil penalties for unauthorized disclosure or foreign filing in violation of an order.
• Provide a limited mechanism for compensation if the government uses the invention or if the secrecy order plainly destroys commercial value.

Crucially, the statutory trigger is vague by design: disclosure that “might be detrimental to the national security.” That is broad enough to cover everything from nuclear weapon design to a solar-battery system that would radically extend the range of a drone.

It’s a gag and a freeze, not a clean “taking”

One accuracy point that gets lost online: in most cases the government does not simply reassign the patent to itself. Instead, the patent application is:

• Held in limbo at the USPTO.
• Kept out of public databases and foreign filings.
• Wrapped in a gag order that follows the inventor.

Meanwhile, government agencies or contractors may build on or implement the invention internally. If you can prove that, you can pursue compensation under §183, but the burden of proof is high and the historical payouts have been modest compared to what inventors thought their work was worth.

The hidden playbook: Patent Security Category Review List (PSCRL)

Patent examiners do not screen by intuition. They work from a classification document called the Patent Security Category Review List (PSCRL), originally prepared by the Armed Services Patent Advisory Board and updated by defense agencies.

The PSCRL is essentially a menu of technology categories that must be referred to defense and intelligence agencies for possible secrecy orders. Classic entries include:

• Nuclear weapon design and special materials.
• Advanced radar, anti-stealth, and missile guidance.
• Cryptography and secure communications.
• Space-based imaging, reconnaissance, and targeting.
• Gyroscopes, navigation systems, advanced sensors and materials.
• Efficient solar generators, energy conversion systems, and certain batteries.

A declassified 1971 edition of this list is where the specific “solar efficiency” and “energy conversion efficiency” thresholds show up in black and white.

How the secrecy pipeline works

From filing to gag order: the pipeline

When you file a patent in the United States, you are automatically opting into this security screen. The rough sequence looks like this:

1. Normal filing. You submit your application to the USPTO. On paper, it is just another patent.
2. Security screening. Internally, the application is checked against the PSCRL categories. If it appears to fall into a sensitive domain, it is forwarded to one or more “defense agencies” (DoD, NSA, DOE, NASA, DHS, etc.).
3. Agency review. Those agencies decide whether public disclosure of the invention would harm national security. Historically, during WWII and the Cold War, this captured large volumes of radar, communications, cryptography, and weapons-adjacent work.
4. Secrecy order issued. If the answer is “yes,” the USPTO issues a secrecy order under §181. That order:
   • Blocks publication and grant of the patent.
   • Prohibits foreign filing without special permission.
   • Prohibits disclosure to unauthorized parties, under threat of penalties.
5. Renewal and duration. In peacetime, secrecy orders are reviewed annually and can be renewed indefinitely. During war or a declared emergency, they can be automatically extended until after the emergency ends.
6. Compensation channel. Under §183, an inventor may petition for compensation if the government uses the invention or if the order clearly wipes out commercial prospects. Historically, a few inventors have won small settlements after long fights; most do not.

Functionally, this is a national-security throttle on the patent system. It is not a visible “ban” on a technology field; it is a targeted ability to silence specific patents that cross certain red lines.

By the numbers: how many inventions are hidden?

World War II program: tens of thousands reviewed, thousands gagged

Archival research on the WWII secrecy regime shows how aggressive the system can be when the state is fully mobilized:

• Roughly 11,000 patent applications were reviewed for secrecy between 1940 and 1945.
• About 8,500 of those were actually placed under secrecy orders during the war.
• Researchers identify 6,352 patents that were granted after the war which had previously been secret.
• In total, on the order of 11,182 secrecy orders were issued during the WWII period.

Economically, firms caught in these secrecy nets tended to:

• Reduce their patenting activity in the affected technology classes.
• Delay or abandon commercial products based on the secret inventions.
• Generate fewer follow-on patents and citations while secrecy orders were in place.

Modern era: roughly 6,500 active secrecy orders

In the modern Invention Secrecy Act era (post-1951), we do not have a public list of the inventions themselves, but we do have counts. Federation of American Scientists, using USPTO FOIA data, reports:

• FY 2021: 5,976 secrecy orders in effect.
• FY 2022: 6,057.
• FY 2023: 6,155.
• FY 2024: 6,471.
• FY 2025: 6,543.

That is the money line for charts: in the mid-2020s, on the order of six and a half thousand U.S. patent applications sit under secrecy orders at any given time, and the number has been creeping higher.

“John Doe” secrecy orders: private inventors in the crosshairs

The FOIA data also distinguishes secrecy orders on government-funded work from those on private-sector or individual inventors. These latter are sometimes called “John Doe” orders:

• In recent years, John Doe orders have ranged from zero to a few dozen per year.
• Examples: around 29 in FY 2021, 25 in FY 2023, 18 in FY 2025.
• In the late 1990s, investigative reporting noted that John Doe orders approached nearly 100 in a single year (1998).

Put differently: most secrecy orders hit government-linked work, but a visible minority fall on private inventors whose ideas intersect with national-security red lines.

Energy & solar: the efficiency thresholds

The 1971 thresholds: solar >20% and conversion >70–80%

A declassified January 1971 version of the Patent Security Category Review List spells out several energy-related triggers. Summaries of that document highlight two particularly important lines:

• Solar photovoltaic generators that exceed roughly 20% efficiency are subject to referral and possible restriction.
• Energy conversion systems that achieve efficiencies “in excess of 70–80%” are likewise flagged.

The same list groups “efficient solar voltaic generators,” “batteries of unusual performance,” and certain gyroscopes and sensors under technology headings that must be screened by specific agencies.

This is almost certainly the original root of the online claim that “they won’t let solar be more than X% efficient” or “any engine over Y% gets classified.” It is not pure rumor; there really is a document that tells examiners to pull aside high-efficiency energy systems for security review.

Screening trigger, not hard efficiency cap

It is important to draw the line correctly. The 1971 list does not say:

• “All solar cells over 20% are banned,” or
• “All energy-conversion devices over 80% are automatically suppressed.”

It says that surpassing those thresholds triggers mandatory security review, with the option of imposing a secrecy order. That is a filter and a veto power, not a blanket public cap.

Reality check: modern solar in the open record

The public record on solar efficiency makes it obvious that there is no simple, universal “cap” being enforced at 20–30%:

• The Shockley–Queisser limit puts the theoretical maximum efficiency of a single-junction silicon cell in the low-30% range. Commercial silicon modules today hit around the mid-20% range in best-case lab tests.
• Multi-junction cells used in space and concentrator systems have achieved nearly 40% efficiency under one sun and close to 50% under concentrated light in well-documented, publicly available research.
• Perovskite/silicon tandem cells have passed the high-20% range for practical module-sized devices, with multiple firms racing to commercialize them.

If there were a hard rule that “solar cannot exceed 20–30%,” these public records, commercial products, and peer-reviewed papers simply would not exist as they do.

The more precise and defensible claim is: ultra-efficient solar and energy conversion systems are treated as strategic and may be selectively screened and restricted, especially where they intersect with military use cases.

Why ultra-efficient energy is a security issue

From a security planner’s perspective, certain energy leaps have obvious national-security implications:

• Space and remote operations. High-efficiency, radiation-tolerant solar plus dense storage massively extend satellite, drone, and remote-base endurance.
• Submarines, drones, and unmanned systems. Step-change improvements in electric drives or storage translate directly into range and stealth advantages.
• Hardened infrastructure. Compact, ultra-efficient conversion systems make it easier to harden critical sites off grid and against attack.

In that world, it is not surprising that the same bureaucratic machinery that screens missile guidance systems is also scrutinizing certain solar, battery, and power-electronics patents.

Export controls as the second gate

Secrecy orders are only one tool. There is also a dense web of export-control regimes (ITAR, EAR, and related lists) that restrict the export of dual-use components, including advanced power electronics, sensors, and energy systems with straightforward military applications.

Together, secrecy orders and export controls form a two-layer system:

• Secrecy orders manage what becomes public at all.
• Export controls manage where and to whom those technologies can legally be shipped.

Real inventors and case studies

To keep this grounded, here are documented examples of real inventors who ran into secrecy orders or classification problems. These are not forum rumors; they show how the system behaves in practice.

• World War II inventors. Archival work identifies over six thousand patents that were once secret and later declassified, mostly in explosives, chemicals, radar, and communications. Thousands of civilian and company inventors spent years under gag orders before their work surfaced.
• Gordon Gould – the laser. Gould’s early work on the laser became entangled in secrecy restrictions and classification, partly because of its obvious military applications. That classification context fed into decades of bitter patent litigation over who owned the core laser patents.
• The “Phasorphone” – NSA and scrambled voice. In the 1970s, inventors developed a device that digitally scrambled voice calls for privacy over ordinary phone lines. NSA pushed a secrecy order on the patent application. Only after the inventors went public and pressed the issue did the agency rescind the order.
• James Constant – radar tracking (1960s–70s). Constant patented methods for radar tracking of objects such as shipping containers. His application was subjected to a secrecy order and later became the basis for a failed bid for compensation.
• James Greer – anti-stealth radar (2000–2008). Greer’s application for technology that could detect stealth aircraft was reportedly kept under a secrecy order for eight years. By the time the order was lifted, the commercial window for his invention had effectively closed.
• Budimir & Desanka Damnjanovic – missile countermeasures (2009–2014). Their idea: spray a liquid from the back of an aircraft to confuse heat-seeking missiles. The government slapped secrecy orders on their patent twice, FBI agents visited them, and years of legal conflict followed. Eventually the orders were lifted and the couple received a roughly $63,000 settlement, without any admission of wrongdoing.
• James Linick – Army-related invention. Linick’s work, developed while employed by defense contractors, was placed under a secrecy order. When he later sued for several million dollars in compensation, the government argued that his inability to secure commercial buyers proved the invention’s limited value. He lost.

These stories show how the system lands on real people: sometimes scientists in a war, sometimes small inventors who suddenly find themselves across the table from the U.S. security state.

What technologies are actually targeted?

Confirmed categories

From declassified documents and statistical studies, we can say with confidence that secrecy orders and related controls concentrate in areas such as:

• Nuclear weapons design, triggers, and special materials.
• Guidance systems, radar, anti-stealth methods, and missile technology.
• Cryptography, secure communications, and some forms of cybersecurity.
• Space-based imaging, reconnaissance, targeting, and certain sensors.
• Advanced lasers, directed-energy concepts, and related optics.
• High-performance batteries, energy conversion, and efficient solar when clearly tied to strategic use cases.

Plausible but unproven edge cases

Without breaching classification, you can make reasonable inferences about other categories that would likely attract attention:

• A battery chemistry that doubles energy density in a form factor ideal for drones or submarines.
• A propulsion approach that quietly extends hypersonic missile or long-range strike capability.
• A sensing or imaging technique that makes current stealth aircraft or submarines easily trackable.

If you were running the Pentagon and saw a civilian patent that made stealth aircraft obsolete or cracked modern encryption, you would almost certainly reach for the Invention Secrecy Act. That is the logic you are up against as a private inventor in strategically sensitive domains.

Free energy, solar caps, and the myth layer

Three layers of “suppressed technology” talk

When people talk about the “National Security Patent Act,” they tend to blend three different layers of reality together:

1. Confirmed mechanisms and categories. The Invention Secrecy Act, the PSCRL, secrecy orders, and the focus on weapons, sensors, and some energy systems.
2. Plausible but unproven edge cases. High-leverage batteries, drives, or sensors that would obviously matter for war-fighting but are not publicly documented as suppressed.
3. Pop-culture and conspiracy favorites. Zero-point energy, water-powered cars, anti-gravity craft, and other devices that mostly live in rumor.

The solar-efficiency meme

The claim that “solar panels are not allowed to be more than 30% efficient” is a good example of how a real document morphs into a distorted talking point.

The actual facts:

• There is a declassified document that tells examiners to flag PV generators above ~20% and energy converters above ~70–80%.
• There is no statute that sets a hard public cap on solar efficiency.
• There are many published, well-documented devices in the open literature that exceed those thresholds.

The right way to say it is: the security establishment has reserved the right to quietly screen and gag some high-efficiency energy systems, not that it has prevented all of them from ever seeing the light of day.

Free energy, over-unity, and anti-gravity

Around the edges of the secrecy-order system, an entire mythology has grown up: water-powered cars that vanish, anti-gravity craft that get classified, zero-point generators that “they” will not allow.

What we actually have in the public record is:

• A secrecy mechanism that absolutely exists and has been used on thousands of real patents.
• No public, verifiable list of working over-unity, free-energy, or anti-gravity devices that were proven to function and then gagged.
• Basic physics reasons to treat many of the most dramatic claims with skepticism.

The honest statement is: the state has the legal machinery to bury game-changing energy tech if it appears; whether it has done so for truly paradigm-breaking devices is something we cannot answer from open sources.

Economic and innovation impacts

System-level drag on innovation

When secrecy orders hit an entire class of technology during a wartime surge, the effect on innovation is measurable:

• Firms under secrecy orders shift away from the affected domains.
• Commercial products based on that research are delayed or never launched.
• Follow-on patents and citations in those fields drop while secrecy is in effect.

From a national-security perspective, this is exactly what the system is supposed to do. From a long-term economic perspective, it is a hidden tax on innovation.

For a private inventor in energy or drives

If you are working on solar, batteries, power electronics, or novel electric drives, the practical risk profile is:

• You may spend years and significant capital developing an idea, file a U.S. patent, and then discover that you are legally barred from discussing or licensing it at scale.
• If the government quietly implements or spins your idea into a classified program, you may never be able to prove it in a way that wins substantial compensation.
• Investors who understand the secrecy regime may apply a discount to anything close to PSCRL categories, especially in batteries, long-endurance drives, and military-adjacent power systems.

None of this means “never innovate in energy.” It means that filing in the U.S. system is not a neutral act; it enrolls you in a screening process whose priorities are not aligned with your startup’s cap table.

Pattern Nexus lens: energy as a control layer

In the Pattern Nexus framework, energy is not just another sector. It is a control layer that shapes everything upstream: industry, logistics, AI compute, war-fighting capability, and the daily living standards of households.

The Invention Secrecy Act and the PSCRL are part of how the state manages that layer:

• Flagging high-efficiency solar and ultra-efficient conversion systems keeps strategic options open for military and intelligence use.
• Selectively allowing some energy innovations into the open while suppressing others shapes where the benefits accumulate: domestic vs. foreign, civilian vs. military, allies vs. rivals.
• Coupling secrecy orders with export controls turns energy technologies into levers of foreign policy and geopolitical influence.

From this vantage point, the real story is not a cartoonish “they capped solar at 30%.” The real story is that there is a formal, documented mechanism to treat certain energy breakthroughs as national assets first and global technologies second.

Whether you view that as necessary prudence in a predatory world or as a brake on human progress depends on which time horizon and which constituency you care about: the next conflict, or the next century.

FAQ

Is there actually a “National Security Patent Act”?

Not by that name. The phrase people use online refers to the Invention Secrecy Act of 1951 and its codification in 35 U.S.C. §§ 181–188. That is the legal machinery behind secrecy orders on patents.

Can the government just take my patent?

The typical mechanism is not a clean “taking” where the government’s name replaces yours. Instead, your application is frozen in a secret state and you are gagged from disclosing or foreign filing. The government and its contractors may still implement the idea internally. You can seek compensation, but historically that process is difficult and payouts are limited.

Why not keep it as a trade secret instead of filing a patent?

Trade secrecy avoids the patent-screening pipeline but creates other risks: if someone else independently develops and patents the idea later, you have no patent shield, and trade secrets can be lost the moment the information leaks. In some defense-relevant areas, though, inventors explicitly choose trade secret over patent to avoid drawing the attention that comes with filing.

Are electric motors or engines above a certain efficiency automatically suppressed?

There is no public rule that says “all motors above X% are classified.” What we do see is that some power-electronics and conversion categories are on the PSCRL, and that export controls cover dual-use components. That makes it very plausible that certain high-leverage drives end up reviewed and sometimes restricted, but there is no public master list.

Is it dangerous to write about this?

Summarizing public, unclassified information about the Invention Secrecy Act, secrecy orders, and known cases is legal. Journalists, policy analysts, and academics do it routinely. Legal risk arises if you disclose classified information you obtained under a clearance, or if you reveal details covered by a secrecy order you personally received.

Could transformative clean-energy tech be under secrecy orders right now?

It is entirely possible in principle and impossible to verify from open sources by design. We know that:

• Energy and high-efficiency conversion systems are explicitly on the security-review list.
• On the order of 6,500 secrecy orders are active at any time.
• Secrecy measurably slows downstream innovation where it is applied.

That combination guarantees that some energy-related inventions are being throttled. What we cannot see is how many of those would have been incremental improvements versus genuine step-changes.

Does this only apply inside the U.S.?

The Invention Secrecy Act governs U.S. patents and U.S. citizens, but many other states have their own mechanisms for classifying and restricting sensitive inventions. On top of that, international treaties, export-control regimes, and alliance structures create overlapping layers of control over how advanced energy and military-adjacent technologies move across borders.

Sources

• Invention Secrecy Act overview and 35 U.S.C. §§ 181–188 text – https://en.wikipedia.org/wiki/Invention_Secrecy_Act
• Federation of American Scientists – Invention Secrecy statistics and FOIA data – https://fas.org/sgp/othergov/invention/
• FAS – “Invention Secrecy Still Going Strong” and follow-up updates on secrecy-order counts – https://fas.org/blogs/secrecy/
• Daniel P. Gross – “The Hidden Costs of Securing Innovation: The Manifold Impacts of Compulsory Invention Secrecy,” NBER and Management Science – https://www.nber.org/papers/w25545
• Patent Security Category Review List (declassified 1971) – energy and solar thresholds – https://sgp.fas.org/othergov/invention/pscrl.pdf
• NREL – Best Research-Cell Efficiencies chart (Shockley–Queisser context and current records) – https://www.nrel.gov/pv/cell-efficiency.html
• “Solar-cell efficiency” – overview of photovoltaic efficiency records and physical limits – https://en.wikipedia.org/wiki/Solar_cell_efficiency
• Wired and other reporting on secrecy-order “John Doe” cases and inventor stories (Greer, Damnjanovic, etc.) – https://www.wired.com/
• Case discussions: Gordon Gould and laser patent disputes – https://patentlore.com/gordon-gould-laser-patents
• Gregory Saltz – “Patently Absurd: The Invention Secrecy Order System” – https://scholarship.law.tamu.edu/journal-of-property-law/vol8/iss2/6/
• Additional legal analysis on secrecy-order compensation and due-process issues – https://tiplj.org/wp-content/uploads/Volumes/v20/v20p471.pdf