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Standing hundreds of feet above ground, wind turbines — like tall trees, buildings, and telephone poles — are easy targets for lightning. Just by virtue of their height, they will get struck.

Lightning protection systems exist for conventional wind turbine blades. But protection was needed for blades made from a new type of material—thermoplastic resin composites — and manufactured using an innovative thermal (heat-based) welding process developed by scientists at the National Renewable Energy Laboratory (NREL).

Thermoplastic materials, like plastic bottles, can be more easily recycled than the thermoset materials commonly used to make wind turbine blades today. While thermoset materials need to be heated to cure, thermoplastics cure at room temperature, which reduces both blade manufacturing times and costs.

NREL’s patent-pending thermal welding process for thermoplastic blades allows for these benefits and even adds to them by replacing the adhesives currently used to bond blade components. The use of welding instead of adhesives eliminates the downsides of added weight and cracking potential.

While thermal welding offers benefits, it also requires adding within the blade a metal heating element — which can attract lightning. As a result, a team of NREL researchers led by Robynne Murray and supported by General Electric (GE) and LM Wind Power (a GE subsidiary) invented a new lightning protection system to keep the novel thermoplastic materials safe.

Thermal Welding Goes for the Patent

In 2018, Robynne Murray, an NREL engineer who specializes in advanced manufacturing methods and materials for wind turbine blades, received a two-year NREL Laboratory Directed Research and Development award to research thermal welding of thermoplastic wind turbine blades.

To make one of these new blades, a vacuum pulls liquid thermoplastic resin into the fiberglass material that is placed in a mold for each blade half. To weld the blade halves together, scientists sandwich a conductive material — such as an expanded metal foil or carbon fiber — between the two blade components and attach a wire to a power source. This creates the heating element. As current flows through this element, the thermoplastic materials melt. Once they are melted, the current is switched off and the bond cools under pressure.

Murray’s research demonstrated that thermal welding can effectively bond thermoplastic wind turbine blade segments. She submitted a patent application on the process in 2018.

A Pathway for Lightning

Thermal welding works. But it leaves the conductive heating element, which can attract lightning, within the blade.

“Thermal welding is an important step in the progression of commercializing thermoplastic materials for wind blades, but what happens when lightning strikes a thermal-welded blade? That was an unanswered question and a big concern,” Murray said. “For thermal welding of thermoplastic blades to become commercially viable, it is critical that the conductive bond lines be protected from a lightning strike.”

Partnering with GE and LM Wind Power, Murray submitted a research proposal to the U.S. Department of Energy’s (DOE’s) Technology Commercialization Fund (TCF). TCF awards are designed to advance technology developed at national laboratories toward commercialization while encouraging lab-industry partnerships.

“With our partnership with GE, a company that can take the thermal welding process to commercialization, our TCF was a strong proposal,” Murray said. “Together, we wanted to determine whether we can protect these blades from lightning strikes and eliminate a big reason to stop us from using the technology.”

In 2019, the team received $150,000 in TCF funding; GE matched that amount.

The research partners set up shop in NREL’s Composites Manufacturing Education and Technology (CoMET) Facility to demonstrate that thermoplastic blades sealed using thermal welding can be protected from lightning strikes.

The team infused an expanded aluminum foil into the blade skin to divert lightning current away from the metal heating elements. They then completed experiments using a simulation that showed that a lightning strike would not cause blade failure with the lightning protection system in place.

Lightning protection To build a lightning shield for their innovative wind turbine blade design, the research team added an expanded aluminum foil layer (left) and a carbon-fiber heating element at the bond lines (right) to enable thermal welding of the blade parts. Photos by NREL

Lightning strike.  Researchers used a lightning simulation technique to see where lightning might strike the blade and found that, typically, electricity hit the tip of the blade or one of the edges—but not inside the blade or welded seams where it could cause excessive damage. Photo by NREL

Physical damage tests — which subject the blades to high currents of electricity — demonstrated that about 80% of the electric current went into the expanded aluminum foil layer for lightning protection and not into the blade skin. The carbon fiber beneath the damaged area of the tip was also unscathed.

The research confirmed the design can protect wind turbine blades against failure caused by lightning strikes.

“LM Wind Power and GE Research were excited to work with NREL on the development of this technology and appreciated the support by DOE’s Technology Commercialization Fund. Thermal welding technology for thermoplastic, recyclable wind blades offers a significant opportunity to impact the sustainability and carbon footprint of wind blade structures,” said James Martin, director of blade platform deployment for LM Wind Power. “NREL’s focus on mitigating the lightning damage risks associated with the electrically conductive elements in the welded bond is a key challenge to be overcome, and their work has helped mature the technology toward potential commercialization.”

Still More Questions To Answer

The project has already delivered two strikes against lightning. Murray’s work developing a market-ready thermal welding system, however, is still at bat.

“We answered the question about lightning. But there are more questions to answer and more work to be done,” Murray said. “The next step for us is to do structural validation of thermally welded blade bond lines and blade tip segments. I hope we can do this in the next year or so.”

Read more about this project in Wind Engineering.

Article courtesy of NREL.



 


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Paris’ popular bike share program has a big sticky finger problem

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Paris' popular bike share program has a big sticky finger problem

Paris’ bike-share system, Vélib has long been considered one of the shining success stories of urban micromobility. With a massive fleet of over 20,000 pedal and electric-assist bicycles around Paris, the service has helped millions of residents and tourists get around the City of Light without needing a car or scooter. But lately, a growing problem is threatening to knock the wheels off this urban mobility marvel: theft and joyriding.

According to city officials and the service operator, more than 600 Vélib bikes are now going missing every single week. That’s over 30 bikes a day simply vanishing from the system – some stolen outright, others taken on “joy rides” and never returned.

“At the moment we’re missing 3,000 bikes,” explained Sylvain Raifaud, head of the Agemob company that currently operates the Velib system. That’s nearly 15% of over 20,000 Vélib bikes across Paris.

The sticky-fingered culprits aren’t necessarily professional thieves or organized crime rings. Instead, they’re often regular users who treat the shared bikes like disposable toys.

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The city estimates that many people have figured out how to pry the bikes out of the system’s parking docks, unlocking one for a casual cruise and then ditching it somewhere far from a docking station.

Once pried free, the bikes are technically usable for the next 24 hours until their automatic locking feature kicks in. At that point, the bikes are often simply abandoned. Some end up in alleyways. Others get tossed in rivers. A few just disappear completely.

And since the bikes are intended to be parked at their many docking stations around the city, they don’t have GPS chips, further complicating recovery of “liberated” bikes.

The issue started small but has grown into more than an inconvenience – it’s beginning to undermine the entire purpose of the service. With bikes going missing at such a high rate, many Vélib docking stations are left empty, especially during rush hours.

Riders looking for a quick commute or a convenient hop across town are increasingly finding themselves without available bikes, or having to walk long distances to find a functioning one.

That kind of unreliability chips away at user confidence and threatens to drive potential riders back into cars, cabs, or other less sustainable forms of transport at a time when Paris has already made great strides to dramatically reduce car usage in the city.

The losses are financially painful, too. Replacing stolen or vandalized bikes isn’t cheap, and the resources spent on tracking down missing equipment or reinforcing anti-theft measures are stretching thin. Vélib has faced theft and vandalism issues before, especially during its early years, but this latest surge has officials sounding the alarm with renewed urgency.

Officials acknowledge that there’s no easy fix. Paris, like many cities with bike-share systems, walks a fine line between accessibility and accountability. Part of what makes Vélib so successful is its ease of use and widespread availability. But those same features make it vulnerable to misuse – especially when enforcement is limited and the consequences for abuse are minimal.

The timing of the problem is especially unfortunate. In recent years, Paris has seen impressive results in reducing car traffic, expanding bike lanes, and promoting cycling as a key part of its sustainable transport strategy. Vélib is a cornerstone of that plan. But if the system becomes too unreliable, it risks losing the very people it was designed to serve.

Meanwhile, as Parisians increasingly find themselves staring at empty docks, the challenge for the city and Vélib will be to restore confidence in the system without making it harder to use. That means striking the right balance between freedom and responsibility, between open access and protection against abuse.

In a city where cycling is supposed to be the future of mobility, losing thousands of bikes to joyriders and sticky fingers isn’t just frustrating; it’s unsustainable.

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CNBC Daily Open: Elon Musk, founder of companies and political parties

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CNBC Daily Open: Elon Musk, founder of companies and political parties

U.S. President Donald Trump and Elon Musk attend a press event in the Oval Office of the White House in Washington, D.C., U.S., May 30, 2025.

Nathan Howard | Reuters

When they lose a significant other, most men do indeed become a “TRAIN WRECK.” Then they pick up the pieces of their lives and start living again — paying attention to their personal grooming, hitting the gym and discovering new hobbies.

What does the world’s richest man do? He starts a political party.

Last weekend, as the United States celebrated its independence from the British in 1776, Elon Musk enshrined his sovereignty from U.S. President Donald Trump by establishing the creatively named “American Party.”

Few details have been revealed, but Musk said the party will focus on “just 2 or 3 Senate seats and 8 to 10 House districts,” and will have legislative discussions “with both parties” — referring to the U.S. Democratic and Republican Parties.

It might be easier to realize Musk’s dream of colonizing Mars than to bridge the political aisle in the U.S. government today.

To be fair, some thought appeared to be behind the move. Musk decided to form the party after holding a poll on X in which 65.4% of respondents voted in favor.

Folks, here’s direct democracy — and the powerful post-separation motivation — in action.

 — CNBC’s Erin Doherty contributed to this report.

What you need to know today

And finally…

An investor sits in front of a board showing stock information at a brokerage office in Beijing, China.

Thomas Peter | Reuters

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CNBC Daily Open: Most people don’t start a political party after separation

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CNBC Daily Open: Most people don't start a political party after separation

US President Donald Trump, right, and Elon Musk, chief executive officer of Tesla Inc., during a news conference in the Oval Office of the White House in Washington, DC, US, on Friday, May 30, 2025.

Francis Chung | Bloomberg | Getty Images

When they find themselves without a significant other, most men finally start living: They pay attention to their personal grooming, hit the gym and discover new hobbies.

What does the world’s richest man do? He starts a political party.

Last weekend, as the United States celebrated its independence from the British in 1776, Elon Musk enshrined his sovereignty from U.S. President Donald Trump by establishing the creatively named “American Party.”

Few details have been revealed, but Musk said the party will focus on “just 2 or 3 Senate seats and 8 to 10 House districts,” and will have legislative discussions “with both parties” — referring to the U.S. Democratic and Republican Parties.

It might be easier to realize Musk’s dream of colonizing Mars than to bridge the political aisle in the U.S. government today.

To be fair, some thought appeared to be behind the move. Musk decided to form the party after holding a poll on X in which 65.4% of respondents voted in favor.

Folks, here’s direct democracy — and the powerful post-separation motivation — in action.

 — CNBC’s Erin Doherty contributed to this report.

What you need to know today

Trump confirms tariffs will kick in Aug. 1. That postpones the deadline by a month, but tariffs could “boomerang” back to April levels for countries without deals. Trump on Friday said letters with “take it or leave it” offers will go out to 12 countries Monday.

U.S. stock futures slipped Sunday. Despite the White House pushing back the return of “reciprocal” tariffs, some investors could be worried trade negotiations would result in higher-than-expected duties. Europe’s Stoxx 600 index dropped 0.48% Friday.

OPEC+ members to increase oil output. Eight members of the alliance agreed on Saturday to hike their collective crude production by 548,000 barrels per day, around 100,000 more than expected.

Elon Musk forms a new political party. On Saturday, the world’s richest man said he has formed a new U.S. political party named the “American Party,” which he claims will give Americans “back your freedom.”

[PRO] Wall Street is growing cautious on European equities. As investors seek shelter from tumult in U.S., the Stoxx 600 index has risen 6.6% year to date. Analysts, however, think the foundations of that growth could be shaky.

And finally…

Ayrton Senna driving the Marlboro McLaren during the Belgian Grand Prix in 1992.

Pascal Rondeau | Hulton Archive | Getty Images

The CEO mindset is shifting. It’s no longer all about winning

https://www.cnbc.com/2025/07/06/the-ceo-mindset-is-shifting-its-no-longer-all-about-winning.html

CEOs today aren’t just steering companies — they’re navigating a minefield. From geopolitical shocks and economic volatility to rapid shifts in tech and consumer behavior, the playbook for leadership is being rewritten in real time.

In an exclusive interview with CNBC earlier this week, McLaren Racing CEO Zak Brown outlined a leadership approach centered on urgency, momentum and learning from failure. 

— Spriha Srivastava

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