
Turning gravity into light
Harnessing kinetic energy from falling rocks, GravityLight produces a safe, renewable source of light to those with no access to electricity.
Shell is working with GravityLight, a company that uses gravity to produce a safe, limitless source of light for people living off the energy grid. Having initially helped expand GravityLight’s reach with a Shell Springboard grant, we’re now working together to launch and sell the product to people across Kenya. Starting in Nairobi we’re travelling from village-to-village on a 50-night tour demonstrating the health benefits and cost savings of GravityLight versus traditional kerosene lamps.
Smarter Every Day
Destin Sandlin is an aerospace and mechanical engineer from Alabama. He’s also the brains behind Smarter Every Day, a YouTube channel with over 4 million subscribers. As anyone who watch’s Destin’s videos will testify, he likes to explore and explain the world through science – helping his viewers become, well, smarter every day.
So naturally we thought he’d be perfect person to pull apart a GravityLight and share his opinions on the impact this bright energy idea will have on developing nations. Watch the video below to grow a little smarter.
Creating Electricity From Gravity – Smarter Every Day
Title: Creating Electricity From Gravity - Smarter Every Day.
Duration: 8:25 minutes
Description:
Destin Sandlin from Smarter Every Day shows how gravity and human ingenuity can create electricity in even the most difficult of situations - including the middle of a rainforest.
[Animated sequence]
Scene starts in complete darkness.
Destin Sandlin
Hey it's me, Destin.
[Animated sequence]
Destin switches on a small light, which illuminates his face.
Destin Sandlin
Light-emitting diodes. Game changer right? Super-efficient power for the masses. Really cheap - really big deal but there's a problem. It only works if you have a power source. Last week I was in the Amazon rainforest and I had a headlamp and it didn't work because my batteries were dead.
[Animated sequence]
Destin takes out a headlamp to reveal the batteries inside.
Destin Sandlin
I was in the middle of the rainforest, you can't just go pick up batteries. This is the same story for billions of people. Let me explain.
[Animated sequence]
Destin turns off electric light. Room goes into darkness.
Destin Sandlin
For the 1.3 billion people who still don’t have steady access to electricity in the world, kerosene lamps or one of the most common forms of lighting in the home.
[Animated sequence]
Destin strikes a match and lights a kerosene lamp.
Destin Sandlin
This is a really big deal because kerosene lamps can be dangerous. Think about it.
[Animated sequence]
Family at table with a kerosene lamp providing light for a studying child.
Destin Sandlin
You've got an open flame in your home. You've got fumes; you've got burn hazards. There's a lot going on here that's bad.
There's a company in London that wants to change this in developing nations. They want to replace kerosene lamps with LEDs.
[Animated sequence]
Destin blows out the lamp.
Destin Sandlin
Let's go to London.
[Animated sequence]
Scene switches to the GravityLight office in London
Destin Sandlin
This is Jim Reeves, co-inventor of GravityLight.
Destin Sandlin
So it's a plastic gear box which drives a generator internally. There's no batteries and no power storage. You fill the bag with rocks, lift the weight and it drives the plastic gear chains inside, that runs through to a DC motor which is running backwards generating power and that creates our live, on demand, to run the LEDs.
Destin Sandlin
This device is incredibly simple to use. You simply tie it overhead and then hang a weight from it and boom you've got light.
Destin Sandlin
Jim let me inside the secret lair where they develop GravityLight.
Destin Sandlin
Well it’s a workshop; this is home. I get it man; this is what I like to do.
Destin Sandlin
OK, so this is the… this is the side under tension
Jim Reeves
That's right
Destin Sandlin
And so it's pulling the outside of the planetary gearset.
Jim Reeves
And the outside there, the annulus - or the ring gear – turns at about 2 RPM.
Destin Sandlin
Wait so this is the annulus?
Jim Reeves
This is the annulus part. It’s prototyped up out of several pieces but in the end it's going to be one moulding.
Jim Reeves
This is what it looks like when it's out. So this is an internal gear and it drives three planet gears which are these gears which are all the same, and that shares the torque because it's a plastic gearbox. You've got a torque limit that you can deliver before you damage the gears. These pinions are driven by the ring gear. Each planet takes the load across two teeth, so you get… you’re sharing the load across six teeth all in all. When you come to the centre here, you've got each of these driving an external…
Destin Sandlin
So you'll have three teeth in contact.
Jim Reeves
Precisely.
Destin Sandlin
And so you can cut that contact stress down by a factor of…
Jim Reeves
Down to a third.
Destin Sandlin
Yeah.
Jim Reeves
So we've shared it across six where it’s high torque. We've shared it across three where we get to a lower torque stage and then we get onto the final stage where this sun gear is going to drive the pulley wheel, and that's just a single gear. It has to be arranged very efficiently so we can't afford to lose any torque or loss of efficiency throughout the system, because by the time you get to here, there’s a very small amount of torque: it’s equivalent to hanging a few coins on a thread as to what's being pulled onto the shaft of the motor.
Destin Sandlin
Jim this is the engineering room?
Jim Reeves
That's right.
Destin Sandlin
All right and who’s this?
Jim Reeves
This is Rob Ford, our mechanical engineer.
Destin Sandlin
Nice to meet you.
Rob Ford
Pleasure.
Destin Sandlin
How are you, yeah? So what do we have here? This is your CAD model?
Destin Sandlin
The annulus, right?
Rob Ford
This is… exactly, yeah, this is the outside face of the annulus gear.
Destin Sandlin
So Jim showed me, on the inside of that we should have multiple teeth meshing, right? Let’s go in.
Rob Ford
Exactly.
Destin Sandlin
Got it. and so he said on an internal gear… is this right, Jim? On an internal gear you have more than two contact points for each gear mesh, right? Six teeth here, so you distribute that contact stress… OK, got it. So you're not gonna break a tooth off. Let's go further. Nice… OK, so now, because we're no longer doing an internal gear mesh on the planets we are doing an external gear, so three teeth in all sharing the load. OK, what's next? We just have a single contact point here, right?
Jim Reeves
That’s right.
Destin Sandlin
All right, but because torque is lower at this point, we have far less contact stress, so this thing’s gonna work for a really long time.
Jim Reeves
So the pulley wheel has got the rubber belt around it, which drives straight to the DC motor pulley…
Destin Sandlin
So that's the motor, there.
Jim Reeves
It’s really quiet.
Destin Sandlin
If you think about a traditional bulb, you actually have to heat up the tungsten filament to make it work, which requires an incredible amount of current. LEDs are way different. If you applied voltage to an LED it draws no current until it gets to a certain threshold. Then it starts to draw current and emit light. But the voltage gets to a point where it won't increase. It’s like it hits a wall. If you've ever powered up a motor, you know that the more voltage you apply, the faster it will turn. The generator is just the opposite though. If you limit the voltage, you can also limit the speed. That's exactly what the LED does. It hits a wall. Think about it. When you hook up the LED to the generator, eventually you run into that voltage wall and the generator won't turn any faster. That's the magic of GravityLight. The LED is not only super-efficient, it acts as a self-regulating escapement. If you hang 10 rocks on it, or if you hang 12 rocks on it, it's always going to fall at the same rate. This is how GravityLight can run for so long.
Jim Reeves
The gearbox will accelerate up until that voltage is reached where the LED will want to draw current. As soon as it starts to draw current, that then limits the speed at which that motor’s gonna drive. It sets the voltage, because the voltage stays pretty well constant - not entirely, but almost. So if you add more weight, you don't shorten the drop time, you're always running at the same voltage, but you produce more current, because current is directly related to torque. So you're increasing the torque through the gear train, driving that motor with more force although it’s at the same speed and that enables you to take more current.
Destin Sandlin
So it always drops at the same speed, but it might be brighter, but has to reach a threshold current in order to operate.
Jim Reeves
That's right, yeah.
Destin Sandlin
How is this not an issue for these people, because I can imagine this is much more expensive than that cup of kerosene they would buy.
Jim Reeves
It is as a one-off purchase, but if you if they can access a GravityLight then it would pay for itself within 10 to 12 weeks for the outlay, and then of course they’ve got free lighting after that time. We crowdfunded earlier this year to set up an assembly line in Kenya. One of the things that we want GravityLight to do, aside from just provide people with low-cost lighting, is also to provide livelihoods in the economy.
Destin Sandlin
So you’re not going to make them here in London?
Jim Reeves
No, absolutely not. So the most of the components will initially be manufactured in China, and then containers of those components will be shipped to Nairobi, and in Nairobi there will be an assembly line. That's where all the work opportunities are around GravityLight. It’s the process of putting it together as opposed to the process of manufacturing it. We did look to try and do manufacturing fully in Kenya, but at the moment a lot of the industries are still in their infancy out there, so they don't have high tolerance moulding capabilities and things like that - although there is moulding. So, over time we want to transition to making more and more of the product fully in country but we're starting out with a plan to have a local assembly line. We've partnered with an existing factory there, that are called Burn Cookstoves who make and sell low emissions cookstoves. So they're going to assemble GravityLight for us, provide employment, and then that means we've got a supply of spare parts and we've got expertise in country and we can then supply the distribution networks that already exist across Kenya.
The Shell funding is very unusual because it’s unrestricted funds which means that really, you can use them for whatever purpose is best appropriate for your project.
Destin Sandlin
Like coffee and sandwiches to keep you working around the clock?
Jim Reeves
Well though, we normally do those ourselves. But there's very few sources of funding which come unrestricted which lets you apply them as is the best way to enable your venture. An awful lot of the funding that comes, you have to jump through - you know - the normal hoops. You're going to be getting funds in for a very prescribed task. You’re then on a path once that’s defined. The Shell funding is for us to apply flexibly and to deliver the product.
Destin Sandlin
So in summary, it looks like we had a problem with an obvious solution, but there was a disconnect. The people that needed the solution didn't have the technology to pull off GravityLight, and the people who had the technology to pull off GravityLight didn't have the funding to make it happen. So kudos to Shell for seeing this gap and bridging it with their springboard funding to actually bring GravityLight to all the people that want it and need it. It's not done yet, obviously. They just created their engineering solution, now the next step is to try to make it happen. So if you're interested in learning more about this project I'll leave links in the video description: go check those out and learn more about how Shell is working to make the world literally a brighter place.
[Text displays]
What if your idea could change the world? See how we support bright energy ideas. Search #makethefuture on Google.
Light without kerosene
Kerosene is a widely-available fuel used throughout the world. It can however be a costly and dangerous source of energy. Studies show that kerosene expenses can consume up to 30% of the monthly income for some of the world's poorest families. Worst yet, open kerosene flames are common causes for burn trauma and the destruction of homes. Much like cigarette smoke, the fumes from gas lamps may also contribute to cancer.
GravityLight helps break the poverty cycle as it pays itself off thereby replacing a dependence on kerosene. The light empowers children and adults as it gives them a safer and healthier way to study at night. And because GravityLight uses local distribution partners and sales agents Kenyans can even earn a living selling the products. We believe this is a bright energy idea that just keeps on giving.
GravityLight - The Mind of an Innovator
Title: GravityLight – The Mind of an Innovator
Duration: 0:30 minutes
Description:
Inventor Jim Reeves explains how GravityLight works.
[Background music plays]
Simple phrase played on a glockenspiel at different octaves is echoed by the gradual introduction of light percussion, a piano and then a bass guitar to create a crescendo.
[Animated sequence]
Dramatic, abstract images of pulsating energy against a dark background.
Jim Reeves
One billion people live without electricity.
[Text displays]
Shell supports energy innovators who are developing new ways to harness and generate power.
[Animated sequence]
Close-up showing the cogs of a GravityLight moving. Cuts into still photograph of two bare-foot children on a dust track holding a GravityLight box. Cuts into a still photograph of two men in a hut, smiling and demonstrating a GravityLight. Cuts to a woman in a hut, smiling next to a GravityLight.
Jim Reeves
Wouldn’t it be amazing to design solutions that impact people’s lives in a positive way?
[Animated sequence]
Cuts to a head shot of Jim Reeves talking to an unseen person in a dark room.
Jim Reeves
GravityLight is a small DC generator.
[Animated sequence]
Video showing a close-up of the GravityLight housing. Cuts to a close-up video of the bag.
Jim Reeves
You fill the bag with rocks
[Animated sequence]
Video showing Jim in a dark room pulling the cord.
Jim Reeves
and then you pull on a cord. It turns that lift into light.
[Animated sequence]
Close up of clean, grey floor as hundreds of ball bearings fall and bounce.
Jim Reeves
Using gravity to create power. There’s a certain amount of magic in that.
[Animated sequence]
Cut to white background and Shell pecten.
[Text displays]
It only takes one idea to change the world. #makethefuture. NYTimes.com/Shell
The GravityLight - Now This News
Title: NowThis News Gravity Light
Duration: {01:30} minutes
[Background music plays]
Upbeat music plays.
Description:
Trees in a park with a street lamp
[Text displays over animation]
Can you power A Lamp
[Animated sequence]
Arrows point towards a street lamp.
Cut to scene of rocks. Words then appear from the bottom right
[Text displays over animation]
With a Bag of Rocks?
[Animated sequence]
{Pan to a girl standing in central park}
{Girl} Transcript
Girl ansswers – I don’t think so
[Animated sequence]
{Cut to a couple in Central Park, nYC The couple look at each other and shake their head.
}
{Couple} Transcript
Girl - No
Boy – Don’t think so
[Animated sequence]
Pan to a man standing with a coffee in Central Park
{Man} Transcript
Nah
[Animated sequence]
Cut back to the first girl
{Girl} Transcript
I’ll just use the flash light on my phone.
[Animated sequence]
Pan to the bridge in Central Park, NYC.
[Text displays over animation]
Words animated in from the top right hand side
What if all you had access to were some rocks?
[Animated sequence]
Pan to a slum scene
[Text displays over animation]
a large segment of the world lives without reliable sources of electricity
[Animated sequence]
We travel through a village
[Text displays over animation]
About a billion people most who live without electricity use Solutions like Kerosene lamps. Which is not only a fire risk but a health risk as well.
It is estimated that using a Kerosene could be the equivalent of smoking up to 40 cigarettes a day
Kerosene lamp lights up in the background (a cigarette being lit)
[Animated sequence]
Pan to a child writing under a kerosene lamp
[Text displays over animation]
An alternative?
The GravityLight a project recognised and supported by Shell Springboard. The system uses Gravity … and kinetic energy to provide power to a light. You take a few pounds of rocks, place them in this bag, and let gravity do the rest. A simple lift can provide 20 minutes of reliable light for everyone and the best part is the Gravity Light is designed to be incredibly affordable
[Animated sequence]
background to show how agravity light works and arrows animate to the kinetic energy and then show a light turning on, show a bag of rocks, a bag is lifted with a pulley style GravityLight, the scene zooms out to show the entire pulley scene cuts to a GravityLight lit in the dark above a child’s study book. We see a man look into the GravityLight, we see a small clips of people from a developing country smile while they uses the GravityLight and unlike Kersoene, its sustainable. It pays for itself within 2-3 months {scene of a gas station, to someone filling a bottle with kerosene}
[Animated sequence]
Pan back to Central Park, NYC
Transcript
Couple - Wow really,
Girl – that’s pretty cool,
Man with coffee – alright, I’m sorry
[First Shell end screen appears with copy: See how we support bright energy ideas Search #makethefuture on Google.]
GravityLight - Simply Energy
Title: Simply energy - GravityLight|#makethefuture
Duration: 0.13
[Background music plays]
Bright, uplifting music
[Background animation].
Video light bulbs flickering in a dark room
[Text displays over animation]
GravityLight
Gravity and some rocks to turn lights on around the world, reducing the harmful effects of kerosene on health and wallets
[End frame]
End frame appears over the video of the lightbulbs.
It has the Shell red and yellow pecten
It reads:
See how we support bright energy ideas
#makethefuture
More in make the future
Empowering a community through footsteps
To help empower a small community in the heart of Rio de Janeiro we created the world’s first player-powered football pitch floodlights.
A new spin on efficiency
What if we could capture the wind created by passing cars with roadside turbines, and turn it into usable energy?