Nostromo: thermal energy storage breakthrough?

Nostromo technology review

Nostromo technology review. Nostromo is a public company, founded in 2016, with c40 employees in Israel and California. Website here. It is commercializing a thermal energy storage system, which integrates with AC, to store coolness (e.g., during peak wind/solar generation), then re-release the coolness at ‘peakload’, (e.g., in mid-late afternoon, or after sunset).


The flagship product is called ‘IceBrick’, a modular, water-based energy storage cell, which can be retro-fitted onto most commercial buildings in about 4-6 months. It claims 86-92% round-trip energy efficiency, 94% depth of discharge over 4-hours and <1% degradation over 20-years.

We have reviewed the company’s patents on our usual patent framework. Nostromo’s patent library is concentrated, but it scores highly on our framework, as it lays out specific challenges that have hampered other designs, very specific details on how Nostromo’s system improves efficiency and consistency, and the patent library is also easy-to-understand, focused and considers deployments.

The technology is an exciting alternative and complement to lithium ion batteries for energy storage, or more specifically demand shifting. It may be particularly well-suited to commercial buildings in hot climates, where AC can comprise 50% of peakload power generation, per our note here. The main challenge is system costs, explored in the data-file and compared with lithium cells and lithium battery storage. Finally, we think there may be other applications of phase change materials that do not simply accomplish energy storage, but also reductions in total energy consumption (note here).

Full details of our Nostromo technology review can be downloaded in our data-file below.

Further conclusions are linked in the recent article sent out to our distribution list, here.

PureCycle: polypropylene recycling breakthrough?

PureCycle technology review

This technology review gives an overview of PureCycle Technologies, founded in 2015, headquartered in Ohio/Florida, USA, went public via SPAC in 2021 and currently has c150 employees. The company aims to recycle waste polypropylene into virgin-like polypropylene, preventing plastic waste, while saving 79% of the input energy and 35% of the input CO2 compared with virgin product.


Why is this challenging? Even after sorting and washing, plastic waste is still contaminated with spoiled food, chemicals, dyes and pigments, resulting in recycled product being dark and low-quality. Several other patents have sought to address these issues, but with only varying success, and via complex and/or costly methods.

Controversies have been raised by a critical report from a short-selling firm. However, our usual patent review allowed us to infer how the process is envisaged to work, including good, specific and intelligible details, covering the solvents, filtration methods, medium temperatures and medium-high pressures (data here). This de-risks some of the risks.

This note contains our observations from our PureCycle technology review, the company’s ambitions, challenges, and scores the patent library on our usual dimensions of problem specificity, solution specificity, intelligibility, focus and manufacturing readiness. We also tabulated technical data that is presented in several patents.

Further research. Our recent commentary on PureCycle technology is linked here.

Aurubis: copper recycling breakthrough?

Aurubis technology review

Aurubis Technology Review. Aurubis recycles scrap metals and concentrates into high-purity products, mostly copper products. The company is listed in Germany, has 7,200 employees and revenues of €16bn in 2021,  as it processes 1MTpa of recycled materials, plus 2.25MTpa of concentrates from 30 mining partners.


Its flagship Hamburg facility employs 2,000 people and is said to be “one of the most modern and environmentally friendly copper smelters in the world”.

Environmental credentials include two-thirds lower energy (at 2 MWH/ton) and lower carbon than (at 1.7 tons/ton) primary copper production. Improving sustainability is also a key focus for the company, per our overview.

Another target is growth. Metals recycling is growing 4% pa in Europe (from 7.3MTpa in 2019, and only 40-45% of metal waste is collected) and 5% pa in North America (5.6MTpa in 2019, only c30% is collected).

The conclusion in our Aurubis technology review is that the company does have a partial moat around its business, as it has patented several process improvements, to remove pollutants (30%), enhance product purity (25%), energy efficiency (20%) and optimize specific products/alloys (40%) in its copper processing operations.

Some of the most interesting innovations, and further observations on the patent library, are covered in our usual technology review.

Further research. Our outlook on growth in global copper demand as a result of the energy transition is linked here.

TerraPower: nuclear breakthrough?

TerraPower technology review

TerraPower was founded in Washington State in 2008, employs around 600 people and has received early and consistent backing from Bill Gates. Our TerraPower technology review is based on its patents.


TerraPower describes itself as a nuclear/energy technology company, whose centrepiece technology is a traveling wave reactor for next-generation nuclear energy. 300-1,000MWe reactors were designed. But a 2015 MoU to develop the TWR technology further, with China’s National Nuclear Corporation, was abandoned in 2019 due to technology transfer limitations from the Trump administration. TerraPower has more recently seemed to de-prioritize the traveling wave reactor, instead developing a 345MWe, sodium fast reactor called Natrium, under a partnership with GE-Hitachi.

Our usual patent search returned 143 distinct patents for TerraPower, which is more than other next-gen nuclear, or other pre-revenue companies we have reviewed.

We reviewed TerraPower’s 20 most recent patent filings, to see where it is currently focused. This shows a large library of process enhancements around different energy technologies, mostly fission technologies, and most recently, sodium fast reactors fueled by the circulating flow of radioactive salts. However, given the broad range of patents, it was difficult for us to identify what is the “front-runner” closest to commercialization, and which patents de-risk it or create a moat around it. Full details are in the data-file.

To read more about our TerraPower technology review, please see our article here.

24M: semi-solid battery breakthrough?

24M battery technology review

24M was founded in Cambridge, MA in 2010, spinning out of MIT. It now has over 100 employees and has raised over $100M in venture investments. It is licensing a “semi-solid” lithium ion battery technology, offering greater energy density and lower costs. It is the main technology provider for Freyr, Kyocera’s Enerezza product line, and being fine-tuned for use in Volkswagen’s electric vehicles, under a 2021/22 deal where the auto-maker took a 25% stake in 24M.


Semi-solid electrodes are aimed at “dramatically reducing” costs of lithium ion batteries, with higher energy density, safety and reliability, for use in battery storage (to replace gas peakers) and in electric transportation solutions. The process requires 50% less capex versus a conventional manufacturing line, mixing active materials in a clay-like slurry, and a dry coating process. Next-generation research is looking to couple the cells with lithium anodes for electric aviation.

Our patent review focuses in on a sample of c15 out of c50 distinct patents that 24M has filed. This clearly shows how the technology improves upon the prior art. Specifically, the traditional method for manufacturing battery electrodes is to coat a metallic current collector with a solution. The solvent is commonly N-methyl-pyrrolidone. As it evaporates, a thin layer remains, including the active materials and a ‘binder’ that acts as a glue. A common binder is polyvinylidene difluoride. The first drawback is that the electrode layer is thin (<100μm), whereas thicker materials can store more energy. The second drawback is that the binder does not store energy, it may even block energy from flowing (tortuosity), while it adds mass, volume and potential degradation pathways (oxidizing). The third issue is that evaporating the solvent and post-processing the material is time-consuming and complex.

24M battery technology review. Overall, 24M’s patents explain why large battery companies have licensed its simpler, more energy dense, lower-degradation battery manufacturing technology; the general workings of which are locked up for at least another decade. We see a moat and can partially de-risk the scale-up of semi-solid electrodes. However, we think there is one technical challenge that decision-makers should still factor in, plus three smaller risks.

To read more about our 24M battery technology review, please see our article here.

Nexwafe: PV silicon breakthrough?

Nexwafe technology review

Nexwafe technology review. Nexwafe is developing a next-generation PV silicon technology called the EpiWafer process, growing standalone silicon wafers onto mono-crystalline seed wafers, with no need to slice ingots and surrender 30-50% of the PV silicon as ‘kerf’ sawdust.


This should improve the manufacturing efficiency, module efficiency and energy intensity of solar PV, and possibly also the costs. Silicon efficiency also matters more in the solar industry, to deflate future costs, after improved passivation has decreased the relative contribution of surface losses.

Data from the patent library shows how the resulting wafer can have 98% lower levels of oxygen impurities, and 4-5x narrower distributions of dopant distributions. 1.1% total efficiency gains are also targeted through a combination of optimizing wafer width and dopant distributions.

Our Nexwafe technology review found 60 filings and re-filings of 8 separate patents. We conclude that many underlying aspects of Nexwafe’s PV silicon ambitions are locked up with high-quality patents. However, our main surprise was the simplicity of the process, which is both a blessing and a curse (details in the data-file).

Company. Nexwafe spun out from Germany’s Fraunhofer Institute in 2015, has c40 employees, closed a €32M financing round in October-2021, lead by Reliance and including Saudi Aramco Energy Ventures.

Terrestrial Energy: small modular reactor breakthrough?

Terrestrial Energy technology review

Our Terrestrial Energy technology review focuses on a next-generation nuclear fission company, founded in 2013, based in Ontario, Canada, has c100 employees and is aiming to build a small modular reactor, more specifically, an Integral Molten Salt Reactor.

Game-changer? A plant with 2 x 442MWth and 2 x 195MWe reactors might use 7 hectares of land, get constructed within 4-years, and for less than $1bn per reactor (long-term target is $2,600/kWe), yielding levelized costs of 5c/kWh (company target, we get to 5-7c/kWh for a 5-10% equity IRR in our own models), a CO2 intensity below 0.005 kg/kWh and multiple ways to back-up renewables.

Our patent review shows one of the strongest patent libraries to cross our screens from a pre-revenue company. 80 patents, filed in 25 geographies, lock up 8 core innovations, and give a clear picture for how the reactor achieves high efficiency, high safety and low complexity.

To read more about our Terrestrial Energy technology review. please see our article here.

Albemarle: lithium, bromine, catalyst improvements?

Albemarle technology review

Albemarle technology review. Albemarle is a specialty chemicals company, headquartered in North Carolina, with 6,000 global employees and over $3bn pa of revenues, derives 40% of its business from producing lithium, 35% from bromine-based flame retardants, and c25% from catalysts, especially for FCC and cleaner-burning fuels.


Overall, our patent screen de-risks the idea that Albemarle is continuing to improve its product offering, by developing an array of novel fire-proofing bromine compositions, further and better lithium pathways, and longer-lasting catalysts. But the patents are more for incremental improvements than world-changing new technologies.

We think 70% of the patents are for technologies that will advance the energy transition in some way, as discussed in the data-file.

Lithium remains one of the most challenging bottlenecks in the energy transition, with demand set to rise 30x (model here). Our overview of the industry is here. We have not been able to de-risk game-changing new DLE technologies that would disrupt the industry (note here). This helps incumbents, including Albemrarle and other leading companies, which are screened here.

To read more of our Albemarle technology review, please see our article here.

General Fusion: magnetized fusion breakthrough?

General fusion technology review

General Fusion technology review. General Fusion is developing a magnetized target fusion reactor, to fuse heavy isotopes of hydrogen (deuterium and tritium). It confines 100MºC plasma within a vortex of liquid lithium/lead, then compresses the plasma via hundreds of high-pressure pistons (effectively a modern-day update of the Linus concept).


It is currently working towards building a 70%-scale demonstration plant by 2025 in Oxfordshire; and ultimately hopes to build a $4bn order book by 2027-30, commercializing a 100-200MWe fusion reactor with 5-6.5c/kWh levelized costs of electricity.

Our patent review allows us to de-risk the idea that General Fusion has made genuine, specific and practical innovations towards development of a magnetized target fusion reactor.

The downside of such a candid patent library is that it also highlights the complexity of its ambitions. There are four focus areas which we would highlight in our General Fusion Technology Review.

To read more about General Fusion innovations, please see our see our article here. Fusion remains a theme that could be a game-changer for energy transition. Other companies with good innovations have also crossed our screen. A summary of all this research can be found here.

Tricoya: engineered wood breakthrough?

Tricoya technology review

This data-file serves as a Tricoya technology review, based on evaluating the company’s patents, using our usual framework.


Tricoya is an engineered wood product like MDF, but it has been “acetylated”, in order to confer >50-year longevity, even when exposed to the elements. This could make it one of the most ‘sustainable’ construction materials and wood uses, on a full life cycle CO2 basis, per our recent research here.

Accsys Technologies is the parent company commercializing acetylated wood products such as Accoya and Tricoya. It was founded in 2005, is headquartered in the UK, and is listed on AIM and Euronext Amsterdam. The company generated €100M revenues in FY 2021 and 50,000 tons of CO2 were sequestered in the products that it sold.

This data-file is a Tricoya technology review,  covering its technology and patent library, on our usual patent assessment framework. It is one of the “highest scoring” patent libraries that we have reviewed to date.

Key details on the production process, technology “moat” and challenges are outlined in the technology review.

Recent Commentary: please see our article here.

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