We all know that lightning bolts carry massive amounts of energy. Just think about how loud thunder is. What if we could capture and store this free energy? Lightning is just as free as wind and solar energy, maybe one day we’ll have lightning farms with rows and rows of metal capture rods.
Harnessing lightning energy, it turns out, is actually very difficult to do. The difficulty of pinpointing electric storms and their duration of microseconds doesn’t really lend to immediate second tries or gathering tons of data, so most of the studies surrounding this subject matter involve small scale simulations of man-made lightning1. The experiments range from the actual tapping of ambient energy, to doing so in a short period of time, to storing it for extended periods of time. In theory all you need to do is capture, store, convert to AC, and send off to the power grid2.
A lightning farm3
In fact, harnessing lightning energy has been theorized all over the world, lightning is universal. A team from the Institute of Chemistry at the State University of Campinas (Unicamp) in Brazil conducted experiments with electricity flowing through dust and humidity in the air. This static electricity is referred to as hygroelectricity, a phenomenon familiar to Tesla and his work. Hygroelectric charges could very well be the cause of lightning. To help this case, these charges exist in such situations as thunderstorms. Back in Brazil, Ildo Sauer, a directors of the Electro-technical and Energy Institute at the University of Sao Paulo, claims that the “basic processes of energy conversion involving ambient electricity had been known for centuries4.”
One man, Steve Le Roy, an inventor from Illinois, claims to have generated enough electricity from a simulated 3-foot bolt of lightning to power a 60 watt light bulb for 20 minutes. Each mini-bolt is produced with a tesla-coil-like electricity producer3. His system has been described as consisting of “an array of grounding wires to shunt off most of the incoming energy and a giant capacitor2.” Le Roy suggests, based on his small scale simulation, a full scale bolt would power up to 30,000 homes for one day3. Many have attempted to replicate Le Roy’s experiment, many have failed.
However, not all have failed. A research group conducted a study at the Universiti Teknikal Malaysia Melaka (UTeM) and the Universiti Teknologi Malaysia (UTM). Also working on a small scale system, the group focused on figuring out how to store energy from the bolt after capturing it. Basically they tested different types of capacitors, voltages, currents, transistors, and many other variables to create the ideal mix to capture the energy in a capacitor and keep it from discharging. A metalized propylene film capacitor proved to solve duration problems with its ability to quickly charge and discharge. Though these capacitors have a limited energy density they could sustain high temperatures, worked well with high frequencies, worked well with DC, and the best part, they were fairly cheap and readily available. After testing the capacitors ability to charge, the group needed to prevent it from discharging. They did this by adding an insulated-gate bipolar transistor (IGBT) which essentially acts as a switch and isolates the capacitor so it can’t discharge into anything. The study as a whole was a success, the capacitors used were able to capture and store 5000V at 1.2 microseconds from a single bolt5.
We can see from a decent amount of successful studies that it is possible to quickly capture large amounts of energy and store it, similar to that of a lightning bolt, just scaled down. Not much can be said, however, about capturing the real thing, scaling up a system large enough to harness non-man-made, naturally occurring lightning. When asked about practical applications the leader of the Unicamp study, Fernando Galemback, responded “we are certainly far from it4.”
Is lightning energy on par with other renewables like solar and wind? Technically it falls into the same category, ambient energy is a renewable resource, but I don’t think it has the ability to compete. Sunlight and wind are free and so is lightning but it is more scarce and harder to predict. As a whole I think lightning energy just has too many variables to compete with more developed and more stable renewables already out there.
However, this doesn’t mean that there can’t be a limited number of lightning farms dedicated to specific areas. We know where lightning storms tend, so they might be more viable in these areas. What’s better is that since lightning occurs all over the world it has the potential to provide electricity to regions that don’t currently have very much access to it4.
Lightning prone areas in lightning strikes per square kilometer per year6
Is it worth building lightning farms to not get that much energy in return? This is the age old question whose answer will either spur or subdue the push for lightning farms all over the world. This question can’t be answered until more full scale research has been done on the subject.