lightning energy can’t be harnessed. Why?

11 September 2022

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Autor: Emilia Obluska

Scientists have been dreaming of efficiently obtaining electricity from lightning strikes for years. Such technology would solve a lot of ecological problems that we are facing today (or at least slowed their progress down significantly). Unfortunately, dreams of using this huge potential are quite utopian. At least that’s what most specialists say. Still, some try – with poor results and more questions than answers. Why haven’t we managed to tame lightning and use them to produce – perhaps the most effective – renewable energy yet? Will lightning energy ever be available for us to use?

What is the lightning energy potential?

Lightning is undoubtedly a powerful element. On average, one lightning strike transports as much as 5 billion joules of electricity [1]. This is equivalent to approximately 1390 kWh (kilowatt hours). In turn, the annual power consumption in an average European home is around 4000 kWh [2]. Conseqently, one lightning could potentially supply one household with electricity sufficient for approximately 4 months.

During a year, around 1.4 billion atmospheric discharges occur worldwide. Unfortunately, ¾ of them take place inside clouds or between clouds, which – so far – cannot be “caught” (although it might be a good idea?). Therefore, those we could potentially catch are relatively few – approximately 350 million [3]. Assuming that we would capture them losslessly, in one place on Earth, it could still be quite promising support for renewable energy.

lightning

The reality, however, is slightly less optimistic. Problems occur at the very beginning. How do we know, for example, where does the lightning strike?

Lightning energy would pay off only in a few places on Earth

The vision of supporting world energy with lightning discharges is a thought experiment rather than the reality of our nearest future. Lightning bolts are in fact unpredictable in terms of both time and space. In some places on Earth they occur so rarely and are so dispersed that building any apparatus / power plant would make no sense at all. This is the first real obstacle that makes lightning energy so difficult to tame.

Still, there are places such as the village of Kifuka in the Democratic Republic of Congo, where lightning strikes are common. There are almost 160 lightning strikes per square kilometer annually. If all of them were caught from an area of ​​approx. 5 km2 with 100% efficiency in obtaining and storing energy, it would be possible to power several hundred houses with electricity for a year [4]. It may not be much for highly developed countries, but it would certainly be a great convenience for local, poor societies. Even more so in the case of small, isolated villages that do not have access to the electricity network.

strikes in kongo

How to catch bolt’s energy?

Lightning energy is a complicated and expensive matter. The development of the necessary technology and construction of power plants would be so expensive, that small communities (and probably even governments) of developing countries could not afford them. Even assuming financial assistance for such investments, we still do not quite know how to do it on a larger scale than a specialized laboratory. Lightning energy is currently beyond our technological range for several reasons.

First – how to “catch” lightning? We need a conductor that could lead electricity from the lightning to the capacitor / battery. It must be both very fast (average lightning strike is 30 milliseconds) and extremely resistant to destruction. Electrical circuits would also have to be extremely durable – they could not, for example, melt when conducting such high power in such a short time. This is a huge technological challenge.

However, we have a potential – although little studied – solution. Some believe that lightning energy could be safely conducted through specialized lasers [5]. However, it is still a field open for research. In the literature, such technology is considered as an element of protecting buildings against lightning, not obtaining them.

Discharge too fast, capacitors too slow

Suppose, however, that lightning energy can be quickly, safely and efficiently transported to a power plant. What next? How to store such a large amount of electricity in several dozen milliseconds? In the laboratory – yes, but on a functional scale – unfortunately not. The technology known to us today is not able to provide this even through highly specialized batteries or supercapacitors.

That is why some people think in an alternative way. For example, they try to bring water to a boil with lightning energy, and obtain electricity from the boiling process. Such a solution would be better because the vast majority of energy from lightning dissipates in the form of heat. However, this requires additional processes, which undermines the already questionable profitability of such an undertaking.

Vortex Generator – more design than technology

Despite all obstacles – some are still trying. For example, American architects from Brooks + Scarpa have designed an interesting object that combines a small photovoltaic power plant and lightning catcher with a visually interesting publically available structure. Vortex Generator, as the object is called, is to stand in Florida.

Vortex Generator

The concept itself is great. During a thunderstorm, which is a common phenomenon in Florida, a “vortex” structure rises between pedestrian platforms. This almost sculptural form is supposed to attract lightning and convert its energy into usable energy, while enabling viewers to safely observe the element. Sounds utopian – and at the moment, unfortunately, it is. The creators themselves admit that lightning energy is not yet obtainable in a cost-effective and efficient manner [6]. Nevertheless, they put their hope in the fact that their unique design will prompt scientists to further search. Let’s hope it really does – and one day they will succeed.

Sources:

[1] Davies A.: Can we harvest the energy of lightning? How Stuff Works Science: https://science.howstuffworks.com/environmental/energy/harvest-energy-lightning.htm [access 16.12.2019].
[2] ODYSSEE-MUREE, Electricity consumption per dwelling: https://www.odyssee-mure.eu/publications/efficiency-by-sector/households/electricity-consumption-dwelling.html [access 16.12.2019].
[3] Adlparvar P., 2015: Why can’t we extract electricity from lightning? Independent: https://www.independent.co.uk/news/science/why-cant-we-extract-electricity-from-lightning-10162498.html [access 18.12.2019].
[4] Forbes, 2015: Can We Harvest Lightning For The Power Grid?: https://www.forbes.com/sites/statoil/2015/01/28/can-we-harvest-lightning-for-the-power-grid/#951036a1e6c4 [access 18.12.2019].
[5] Helman, D. S., 2011: Catching lightning for alternative energy. Renewable Energy, 36, 5, 1311–1314.
[6] Hobson B., 2018: Brooks + Scarpa’s inflatable pavilion concept captures energy from lightning storms. Deezen: https://www.dezeen.com/2018/08/23/video-interview-brooks-scarpa-vortex-generator-captures-lightning-pod-system-architecture-movie/ [access 18.12.2019].

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