All of that electricity in a thunderstorm. All that lightning, all those kilojoules of power, just waiting to be harnessed, if only we knew how do it!  Could we really harness the electricity from lightning?



There are several reasons why the current answer is probably no — safety, for starters — but earlier this month, some lightning scientists in the UK demonstrated that someday, the answer could be maybe.

Nokia approached Neil Palmer, who directs Southampton University’s Tony Davies High Voltage Laboratory, to research harnessing lightning to charge a phone. “We wanted to look at whether we could harvest enough power to charge a Lumia 925 after the energy had moved through the air,” Palmer told DVICE. Palmer set up a transformer providing an alternating current, and 200,000 volts of electricity sparked across about a foot (300 mm) of empty space.

The signal was stepped down in a second controlling transformer, and connected to the phone. It worked: the phone charged up, and nothing fried. The lack of damage to the phone was the biggest surprise. “The Lumia 925 still worked perfectly, and is still working as good as new,” Palmer says.

Palmer says the team chose 200,000 volts even though it’s a lot less voltage than would be found in cloud-to-ground lightning. These strikes pack a much bigger punch and travel across two or three miles, rather than 11 or 12 inches. Instead of a current jumping across a transformer, real lightning is a discharge of electrons between ionized regions in clouds, or from clouds to the ground. Because of this, it’s unpredictable, so the experiment is not exactly analogous.

Catching Lightning in Real Life

No academic papers were to be produced as a result of the experiment, Palmer says. It’s proof-of-concept research into harnessing the power of lightning. Still, it does show some promise for one potential way to do it, which is through batteries. If we ever harnessed energy from lightning, we would have to store it somehow, which is one of the biggest challenges with the idea.

A lightning strike produces one billion to 10 billion joules, according to the lightning library at theUniversity of Illinois Department of Physics. That’s enough to power a light bulb for almost four months — but it’s not exactly helpful when it’s all at once, and creating a device that can deal with such a huge range of potential lightning bolt energies is very challenging. A lightning-harvesting device would likely have to somehow store the incoming energy and add it to the electrical grid gradually. “Research into storing energy from intermittent supplies would reduce demands from power stations,” Palmer notes. But designing transformers that can handle such a jolt is still a major challenge.

Another alternative is a two-stage approach, which would use lightning to power another renewable energy source, like a hydroelectric generator. Here’s how it could work: lightning rapidly powers a pump, which forces water uphill into a reservoir. Once it’s full, the reservoir slowly drains, using the falling water to spin a turbine and generate electricity. This concept, explored by Daniel Helman when he was a graduate student at California State University in Long Beach. “The lightning effectively becomes a two-stage hydroelectric generator. This energy is available on demand,” he wrote in a 2011 research paper.

Lightning Never Strikes Twice

We always hear that lightning never strikes twice, but it isn’t exactly true, because lightning can repeatedly hit the same tall object, lightning rod or building. So, well-situated lightning farms could conceivably catch lightning bolts more than once. But it’s also true that no one can predict which clouds will form lightning. Remember Back to the Future? Doc Brown could only catch that lightning bolt to get his 1.21 gigawatts because he already knew where it would strike. Without the benefit of time travel, a lightning farm even in a thunderstorm-prone area (like eastern Kansas) could easily miss any given storm.

Agencies like NOAA, NASA, and the National Center for Atmospheric Research keep track of lightning and monitor where it strikes most often. Earth experiences about three million lightning flashes each day, or more than 30 per second, according to NCAR. It happens most often in the tropics, where atmospheric convection is conducive to thunderstorms. Moving up to the middle latitudes, North America gets the most lightning, with roughly 20 million cloud-to-ground flashes per year across the United States. This means lightning-capture devices would be located on high mountains, or in storm-prone areas in the tropics. Unfortunately, this also means that they would be very remote, making them difficult to connect to power grids, and they’d be at risk from storm damage.

Lightning harvesting may not be practical in terms of energy generation, but the most serious objection to catching lightning is simple: it’s incredibly dangerous. Lightning sparks wildfires, fries transformers, and kills humans and animals. Trying to capture it intentionally would be highly hazardous.

Still, charging a cellphone even with simulated lightning shows it could conceivably happen. Someday.

Via Dvice