“Wireless charging, in and of itself, is pretty darn cool. But imagine if you could charge your phone using lightning!” began a post by Nokia blogger Phil B describing the experiment involving a Nokia Lumia 925 and calling the results “nothing short of brilliant.”
A news release from the university called the research by high voltage physicist Neil Palmer “ground-breaking” and “an industry first that could potentially see consumers tap one of nature’s significant energy sources to charge their devices in a sustainable manner.”
But how close did the achievement really bring us to harnessing lightning as a clean energy source? And if we could do it, how sustainable would it be?
A typical lightning bolt can carry several billion joules of energy, and the power of lightning has captured the imagination of those looking for new clean energy sources in recent decades.
But harvesting it has remained largely elusive, and the only widely publicized commercial attempt was abandoned in 2007 by a company in the U.S. called Alternate Energy Holdings Inc. The company did not respond to CBC’s requests for an interview about those experiments.
The design for the recent Nokia experiment began as part of a program that has in the past experimented with devices such as bicycle-powered generators.
“We’re obviously always interested in looking at different energy sources and different potential energy sources,” said Thomas Messett, Nokia's head of digital marketing for Europe in an interview.
Nokia came up with the idea and then contacted Neil Palmer to see if he could carry it out.
Despite the implications in the Nokia blog post, the phone was not charged wirelessly. Instead, an ordinary charging cable was hooked up to its charging port.
The simulated lightning was generated using an alternating current, driven by a transformer that sent 200,000 volts across a 30-centimetre air gap (the only “wireless” section of the circuit), “giving heat and light similar to that of a lightning bolt,” Palmer explained in both the news release and the Nokia blog.
A second transformer on the other side of the air gap stepped down the voltage before feeding it into the phone. In fact, that transformer, along with the smoothing circuit installed in most new phones to cope with power surges, was the key piece of equipment that made the energy from simulated lightning useable at all, Messet said.
In a statement, Palmer, who declined to be interviewed by CBC News, said the experiment’s result “proves devices can be charged with a current that passes through the air, and is a huge step towards understanding a natural power like lightning and harnessing its energy.”
Messett acknowledged that on each of multiple experimental runs, the simulated lightning bolt never managed to charge the phone more than five or seven per cent.
“The problem with the lightning bolt of course is that the energy dissipates incredibly quickly and the power that has to get into the phone is a lot, lot smaller, at a steadier pace, than the power that’s delivered by a lightning bolt,” he said. “It’s not a problem we’ve solved yet. This is very much the first stage.”
He also acknowledged that tryingto charge a phone with natural instead of simulated lightning is far more complicated.
However, Nokia has no plans to do more experiments in the area and the researchers have no plans to publish their results to date in a scientific journal.
Expensive equipment needed, physicist says
Peter Castle, professor emeritus and adjunct research professor in Electrical and Computer Engineering at Western University in London, Ont., said he can believe the experiment worked as claimed, but he doesn’t think it will ever be a “feasible” method for charging cellphones.
In an email, he said the huge peak currents and voltages of lightning bolts means that making the electricity from lightning useable requires components that are “very specially designed and state of the art, extremely robust and mounted in a safe and fail safe manner (or in other words expensive).”
He added that those technical constraints combined with the “erratic nature” of lightning strikes means other alternative charging methods, such as solar cells, are more practical.
Joseph Dwyer, a lightning physicist at the Florida Institute of Technology, said that based on the description of the experiment, the simulated lightning bolt was “very far” from a real one and far less powerful.
Palmer acknowledged in an email that the voltage and distance travelled in the Nokia experiment were scaled down relative to a real lightning bolt. He said the other major difference is that a real lightning bolt lasts only a small fraction of a second, whereas the simulated lightning was continuous until turned off.
According to Dwyer, even a real lightning bolt carries surprisingly little energy because the huge amount of power it carries is dissipated in just a hundredth of a second.
And while a few billion joules — the energy of a typical lightning bolt — sounds like a lot, it is spread over an eight kilometre channel that goes up into the clouds.
“I think people that are thinking of harnessing the energy don’t understand how much energy is actually there,” he said. “There’s very little. It’s really not worth harnessing.”
Even in the case of Toronto’s CN, which University of Toronto researchers estimate is struck by lightning an average of 75 times a year, Dwyer said, the resulting energy is still only about enough to power a single 100-watt lightbulb continuously all year, “if you could somehow convert all the energy into useful electricity.”
On the other hand, he acknowledged it would theoretically be more than enough energy to charge a smaller device such as a Nokia Lumia 925.
“It would be very challenging to do it in a way that didn’t burn the thing out and didn’t kill you while you’re trying to do it, but I suppose in principle, you could somehow charge a phone with a lightning bolt.”