You know. Doc Brown style. Into a flux capacitor...

June 24, 2008 5:04 PM

Is anyone working on harvesting the energy of lightning?

It seems like it would be a great technological breakthrough and might alleviate some of our energy needs (a green technology if there ever was one). Surely someone (Tesla?) has made attempts at harnessing this natural resource...

Any links/thoughts will be welcome.

posted by cinemafiend to technology (13 comments total)

When you turn on a light bulb the power company must generate that much more power, instantaneously. There is no storage of power. Storage of wind and solar power is a serious engineering challenge. There's not a good solution yet. Lightning is so incredibly quick that it would be almost useless as an energy source without a perfect storage system ready to suck it all in.
posted by odinsdream at 5:22 PM on June 24

Leaving aside storage...

Lightning is so incredibly quick that it would be almost useless as an energy source

Wouldn't it make more sense to tap the potential difference that creates lightning before the lighting forms naturally?
posted by ROU_Xenophobe at 6:06 PM on June 24

It's like 50 watts per acre, when you distribute a few lightning strikes over an entire month and a patch of land. (citation needed)
posted by sebastienbailard at 6:08 PM on June 24

An interesting calculation to do would be the relative power released by lightning (per acre per month or whatever) compared the the power released by falling rainwater. I would think that, even neglecting engineering and material costs, you could get much more energy from a system of roofs and gutters draining to waterwheels.
posted by fantabulous timewaster at 7:02 PM on June 24

Here's PesWiki's link

Two answers from that site:

Building A Lighting Harnessing Power Plant

How hard would it be to build a power plant that harnesses the electricity generated by lightning? Then, store the electricity and use it on-demand on the electric grid? Pie-In-The-Sky?

This concept is perhaps not as impractical as it once was. The main limiting factor of implementing a lightning capturing scheme such as this was the inability to be able to store large amounts of electricity for later use. However, new Utility Scale Battery technology or other energy storage technologies such as Flywheels or Capacitors could be used to store the electricity captured from lightning in massive quanties, for later grid use.

Obviously, a lightning capturing power plant would only be practical in regions with frequent thunderstorms, such as Florida.

How hard would it be to build an array of lighting rods to capture periodic thunderstorm electricity? The biggest hurdle would really be creating power plant infrastructure that could survive the harsh surges created by lightning strikes, but even that seems possible with current technology and materials. Electrical and building design engineers could come up with an innovative way to make it work. Specially designed buffer/insulation and transformer materials could be used to safely capture and harness the massive amounts of electricity generated during a lighting strike, and transfer it to large storage device for later use.

---

* Q. "I have heard that one lightning strike would provide enough energy for a medium sized town for a month. Is this true? How much power would it provide?"

Answer by Weatherwise.org (http://www.weatherwise.org/qr/qry.lightningpower.html)

"Capturing and using the energy in lightning has been the subject of many imaginative proposals over the years, but there are practical reasons for not even trying. If I relocated my house in central Florida, where the greatest flash density in the United states occurs, I could maximize the chances of lightning hitting my house. This area experiences about 10 cloud-to-ground strokes per square kilometer per year. Because my house occupies much less than a square kilometer of area, I could build a tall tower to attract or trigger lightning, thereby preventing it from hitting neighboring houses but probably violating the local covenants and greatly irritating my neighbors. I would also have to install a very large capacitor to store the energy in each bolt so that it could be used as needed during the days between lightning strikes. If my tower could attract 100 bolts a year‹and a real 300 meter (984-foot) tall tower in Florida does‹I could reduce or perhaps eliminate my electric bill, but I'd have to be very careful to stay away from the base of the tower during storms. It would not profit my neighbor to build a similar tower because there wouldn't be enough lightning to go around.

"To summarize, the energy in lightning bolts is far too small to satisfy the voracious energy appetites of a small town in an industrialized country. The equipment needed to store the energy would probably not fit with the decor of your living room, and if lightning were your only source of electrical power, you would find yourself in the dark during dry spells."
posted by Comrade_robot at 7:03 PM on June 24 [1 favorite]

A little Google work turned up this lengthy and apparently well cited wiki article on the subject.

If any energy source isn't being exploited by now, there are usually plenty of reasons.

On preview, Comrade_robot wins.
posted by Ookseer at 7:15 PM on June 24

Why can't we capture lightning and convert it into usable electricity?

Not that much energy in them, all things considered, and then add the reliability and storage problems on top, and it's just not feasible.
posted by chrisamiller at 7:53 PM on June 24

If you have the capability to predict the presence of lightning to the point where it's economically feasible to harness it, you're probably also capable of several other technological gymnastics that make harnessing lighting beside the point.
posted by Cool Papa Bell at 8:44 PM on June 24

(I hope this doesn't count as a derail, but why can't we store energy? I thought energy storing was in the bag - I've got batteries *full* of energy all over my house!)
posted by moxiedoll at 8:52 PM on June 24

why can't we store energy? I thought energy storing was in the bag - I've got batteries *full* of energy all over my house!)

The short answer is that batteries are not very efficient and current technologies do not scale well. The batteries around your house are absolutely puny in comparison to your household's day-to-day needs. Refrigerator? Air conditioner? Nevermind the power it takes to light up a city. Moreover, chemical batteries are, you know, chemical in nature. Not exactly friendly to the environment.
posted by Cool Papa Bell at 9:00 PM on June 24

The LA department of water and power has a neat trick where they pump water up from a lower reservoir to a higher one when power is cheap (off peak), and use the water flow back down to generate power during peak times. But there is a lot of inefficiency in the process, it's more of a load averaging solution than a power storage one.
posted by BrotherCaine at 4:21 AM on June 25

The LA department of water and power has a neat trick where they pump water up from a lower reservoir to a higher one when power is cheap (off peak), and use the water flow back down to generate power during peak times.

I think a lot of hydro plants do that. But they can do it because there are quite regular, well-defined peak and off peak times (pretty much day and night). Also you require two big water reservoirs to do it.

why can't we store energy?
Yeah household batteries are horribly inefficient. Industrial solutions are still not good enough to allow us to use renewable energy as well as we might. This is one reason why people point out that renewable energy souces should be as varied as possible: since you can't store energy you might be able to even out the production a bit by using different types of source. Since renewables became trendy there is a lot of research into the energy storage problem going on (fuel cell type things, flywheels, etc), and it might turn something interesting up in the next 10-15 years.
posted by theyexpectresults at 5:03 AM on June 25

Batteries are not horribly inefficient regarding energy in vs energy out, particularly if you compare them to something like a natural gas fired powerplant. They are horrible as far as energy density in terms of either volume or weight when compared to fossils fuels. They are also very expensive when compared to the cost of a tank that would hold a similar quantity of energy in the form of a fossil fuel.
posted by Good Brain at 12:15 PM on June 25