sponsored links
TED2012

Donald Sadoway: The missing link to renewable energy

March 1, 2012

What's the key to using alternative energy, like solar and wind? Storage -- so we can have power on tap even when the sun's not out and the wind's not blowing. In this accessible, inspiring talk, Donald Sadoway takes to the blackboard to show us the future of large-scale batteries that store renewable energy. As he says: "We need to think about the problem differently. We need to think big. We need to think cheap."

Donald Sadoway - Materials engineer
Donald Sadoway is working on a battery miracle -- an inexpensive, incredibly efficient, three-layered battery using “liquid metal." Full bio

sponsored links
Double-click the English subtitles below to play the video.
The electricity powering the lights in this theater
00:15
was generated just moments ago.
00:18
Because the way things stand today,
00:21
electricity demand must be in constant balance
00:24
with electricity supply.
00:27
If in the time that it took me to walk out here on this stage,
00:30
some tens of megawatts of wind power
00:33
stopped pouring into the grid,
00:36
the difference would have to be made up
00:39
from other generators immediately.
00:41
But coal plants, nuclear plants
00:45
can't respond fast enough.
00:48
A giant battery could.
00:50
With a giant battery,
00:52
we'd be able to address the problem of intermittency
00:54
that prevents wind and solar
00:57
from contributing to the grid
00:59
in the same way that coal, gas and nuclear do today.
01:01
You see, the battery
01:05
is the key enabling device here.
01:07
With it, we could draw electricity from the sun
01:10
even when the sun doesn't shine.
01:13
And that changes everything.
01:15
Because then renewables
01:18
such as wind and solar
01:20
come out from the wings,
01:22
here to center stage.
01:24
Today I want to tell you about such a device.
01:26
It's called the liquid metal battery.
01:29
It's a new form of energy storage
01:31
that I invented at MIT
01:33
along with a team of my students
01:36
and post-docs.
01:38
Now the theme of this year's TED Conference is Full Spectrum.
01:40
The OED defines spectrum
01:43
as "The entire range of wavelengths
01:46
of electromagnetic radiation,
01:49
from the longest radio waves to the shortest gamma rays
01:51
of which the range of visible light
01:54
is only a small part."
01:57
So I'm not here today only to tell you
01:59
how my team at MIT has drawn out of nature
02:01
a solution to one of the world's great problems.
02:04
I want to go full spectrum and tell you how,
02:07
in the process of developing
02:10
this new technology,
02:12
we've uncovered some surprising heterodoxies
02:14
that can serve as lessons for innovation,
02:17
ideas worth spreading.
02:20
And you know,
02:23
if we're going to get this country out of its current energy situation,
02:25
we can't just conserve our way out;
02:29
we can't just drill our way out;
02:32
we can't bomb our way out.
02:35
We're going to do it the old-fashioned American way,
02:37
we're going to invent our way out,
02:39
working together.
02:41
(Applause)
02:43
Now let's get started.
02:46
The battery was invented about 200 years ago
02:48
by a professor, Alessandro Volta,
02:51
at the University of Padua in Italy.
02:53
His invention gave birth to a new field of science,
02:56
electrochemistry,
02:58
and new technologies
03:00
such as electroplating.
03:02
Perhaps overlooked,
03:04
Volta's invention of the battery
03:06
for the first time also
03:08
demonstrated the utility of a professor.
03:10
(Laughter)
03:12
Until Volta, nobody could imagine
03:14
a professor could be of any use.
03:16
Here's the first battery --
03:19
a stack of coins, zinc and silver,
03:22
separated by cardboard soaked in brine.
03:25
This is the starting point
03:27
for designing a battery --
03:29
two electrodes,
03:31
in this case metals of different composition,
03:33
and an electrolyte,
03:35
in this case salt dissolved in water.
03:37
The science is that simple.
03:39
Admittedly, I've left out a few details.
03:41
Now I've taught you
03:45
that battery science is straightforward
03:47
and the need for grid-level storage
03:49
is compelling,
03:51
but the fact is
03:53
that today there is simply no battery technology
03:55
capable of meeting
03:58
the demanding performance requirements of the grid --
04:00
namely uncommonly high power,
04:04
long service lifetime
04:06
and super-low cost.
04:08
We need to think about the problem differently.
04:10
We need to think big,
04:13
we need to think cheap.
04:15
So let's abandon the paradigm
04:17
of let's search for the coolest chemistry
04:19
and then hopefully we'll chase down the cost curve
04:22
by just making lots and lots of product.
04:24
Instead, let's invent
04:27
to the price point of the electricity market.
04:29
So that means
04:32
that certain parts of the periodic table
04:34
are axiomatically off-limits.
04:36
This battery needs to be made
04:38
out of earth-abundant elements.
04:40
I say, if you want to make something dirt cheap,
04:42
make it out of dirt --
04:45
(Laughter)
04:47
preferably dirt
04:49
that's locally sourced.
04:51
And we need to be able to build this thing
04:54
using simple manufacturing techniques and factories
04:57
that don't cost us a fortune.
05:00
So about six years ago,
05:04
I started thinking about this problem.
05:06
And in order to adopt a fresh perspective,
05:08
I sought inspiration from beyond the field of electricity storage.
05:11
In fact, I looked to a technology
05:15
that neither stores nor generates electricity,
05:18
but instead consumes electricity,
05:21
huge amounts of it.
05:23
I'm talking about the production of aluminum.
05:25
The process was invented in 1886
05:29
by a couple of 22-year-olds --
05:31
Hall in the United States and Heroult in France.
05:33
And just a few short years following their discovery,
05:36
aluminum changed
05:39
from a precious metal costing as much as silver
05:41
to a common structural material.
05:44
You're looking at the cell house of a modern aluminum smelter.
05:47
It's about 50 feet wide
05:50
and recedes about half a mile --
05:52
row after row of cells
05:54
that, inside, resemble Volta's battery,
05:57
with three important differences.
06:00
Volta's battery works at room temperature.
06:02
It's fitted with solid electrodes
06:05
and an electrolyte that's a solution of salt and water.
06:08
The Hall-Heroult cell
06:11
operates at high temperature,
06:13
a temperature high enough
06:15
that the aluminum metal product is liquid.
06:17
The electrolyte
06:19
is not a solution of salt and water,
06:21
but rather salt that's melted.
06:23
It's this combination of liquid metal,
06:25
molten salt and high temperature
06:27
that allows us to send high current through this thing.
06:30
Today, we can produce virgin metal from ore
06:34
at a cost of less than 50 cents a pound.
06:37
That's the economic miracle
06:40
of modern electrometallurgy.
06:42
It is this that caught and held my attention
06:44
to the point that I became obsessed with inventing a battery
06:47
that could capture this gigantic economy of scale.
06:51
And I did.
06:55
I made the battery all liquid --
06:57
liquid metals for both electrodes
07:00
and a molten salt for the electrolyte.
07:02
I'll show you how.
07:04
So I put low-density
07:24
liquid metal at the top,
07:27
put a high-density liquid metal at the bottom,
07:31
and molten salt in between.
07:37
So now,
07:43
how to choose the metals?
07:45
For me, the design exercise
07:48
always begins here
07:50
with the periodic table,
07:52
enunciated by another professor,
07:54
Dimitri Mendeleyev.
07:56
Everything we know
07:58
is made of some combination
08:00
of what you see depicted here.
08:02
And that includes our own bodies.
08:05
I recall the very moment one day
08:07
when I was searching for a pair of metals
08:10
that would meet the constraints
08:13
of earth abundance,
08:15
different, opposite density
08:17
and high mutual reactivity.
08:20
I felt the thrill of realization
08:22
when I knew I'd come upon the answer.
08:24
Magnesium for the top layer.
08:29
And antimony
08:32
for the bottom layer.
08:34
You know, I've got to tell you,
08:37
one of the greatest benefits of being a professor:
08:39
colored chalk.
08:42
(Laughter)
08:44
So to produce current,
08:47
magnesium loses two electrons
08:50
to become magnesium ion,
08:52
which then migrates across the electrolyte,
08:55
accepts two electrons from the antimony,
08:57
and then mixes with it to form an alloy.
09:00
The electrons go to work
09:03
in the real world out here,
09:05
powering our devices.
09:08
Now to charge the battery,
09:14
we connect a source of electricity.
09:17
It could be something like a wind farm.
09:20
And then we reverse the current.
09:24
And this forces magnesium to de-alloy
09:28
and return to the upper electrode,
09:33
restoring the initial constitution of the battery.
09:36
And the current passing between the electrodes
09:41
generates enough heat to keep it at temperature.
09:44
It's pretty cool,
09:47
at least in theory.
09:50
But does it really work?
09:52
So what to do next?
09:54
We go to the laboratory.
09:56
Now do I hire seasoned professionals?
09:58
No, I hire a student
10:02
and mentor him,
10:05
teach him how to think about the problem,
10:07
to see it from my perspective
10:10
and then turn him loose.
10:12
This is that student, David Bradwell,
10:14
who, in this image,
10:16
appears to be wondering if this thing will ever work.
10:18
What I didn't tell David at the time
10:21
was I myself wasn't convinced it would work.
10:23
But David's young and he's smart
10:26
and he wants a Ph.D.,
10:28
and he proceeds to build --
10:30
(Laughter)
10:32
He proceeds to build
10:34
the first ever liquid metal battery
10:36
of this chemistry.
10:38
And based on David's initial promising results,
10:40
which were paid
10:43
with seed funds at MIT,
10:45
I was able to attract major research funding
10:48
from the private sector
10:51
and the federal government.
10:53
And that allowed me to expand my group to 20 people,
10:55
a mix of graduate students, post-docs
10:58
and even some undergraduates.
11:00
And I was able to attract really, really good people,
11:02
people who share my passion
11:05
for science and service to society,
11:07
not science and service for career building.
11:09
And if you ask these people
11:13
why they work on liquid metal battery,
11:15
their answer would hearken back
11:17
to President Kennedy's remarks
11:19
at Rice University in 1962
11:21
when he said -- and I'm taking liberties here --
11:24
"We choose to work on grid-level storage,
11:26
not because it is easy,
11:28
but because it is hard."
11:30
(Applause)
11:32
So this is the evolution of the liquid metal battery.
11:39
We start here with our workhorse one watt-hour cell.
11:42
I called it the shotglass.
11:45
We've operated over 400 of these,
11:47
perfecting their performance with a plurality of chemistries --
11:50
not just magnesium and antimony.
11:53
Along the way we scaled up to the 20 watt-hour cell.
11:55
I call it the hockey puck.
11:58
And we got the same remarkable results.
12:00
And then it was onto the saucer.
12:02
That's 200 watt-hours.
12:04
The technology was proving itself
12:06
to be robust and scalable.
12:08
But the pace wasn't fast enough for us.
12:11
So a year and a half ago,
12:13
David and I,
12:15
along with another research staff-member,
12:17
formed a company
12:19
to accelerate the rate of progress
12:21
and the race to manufacture product.
12:23
So today at LMBC,
12:25
we're building cells 16 inches in diameter
12:27
with a capacity of one kilowatt-hour --
12:29
1,000 times the capacity
12:31
of that initial shotglass cell.
12:34
We call that the pizza.
12:36
And then we've got a four kilowatt-hour cell on the horizon.
12:38
It's going to be 36 inches in diameter.
12:41
We call that the bistro table,
12:43
but it's not ready yet for prime-time viewing.
12:45
And one variant of the technology
12:47
has us stacking these bistro tabletops into modules,
12:49
aggregating the modules into a giant battery
12:53
that fits in a 40-foot shipping container
12:56
for placement in the field.
12:58
And this has a nameplate capacity of two megawatt-hours --
13:00
two million watt-hours.
13:03
That's enough energy
13:05
to meet the daily electrical needs
13:07
of 200 American households.
13:09
So here you have it, grid-level storage:
13:11
silent, emissions-free,
13:14
no moving parts,
13:17
remotely controlled,
13:19
designed to the market price point
13:21
without subsidy.
13:24
So what have we learned from all this?
13:27
(Applause)
13:29
So what have we learned from all this?
13:35
Let me share with you
13:37
some of the surprises, the heterodoxies.
13:39
They lie beyond the visible.
13:42
Temperature:
13:44
Conventional wisdom says set it low,
13:46
at or near room temperature,
13:48
and then install a control system to keep it there.
13:50
Avoid thermal runaway.
13:53
Liquid metal battery is designed to operate at elevated temperature
13:55
with minimum regulation.
13:58
Our battery can handle the very high temperature rises
14:01
that come from current surges.
14:04
Scaling: Conventional wisdom says
14:08
reduce cost by producing many.
14:11
Liquid metal battery is designed to reduce cost
14:13
by producing fewer, but they'll be larger.
14:16
And finally, human resources:
14:19
Conventional wisdom says
14:21
hire battery experts,
14:23
seasoned professionals,
14:25
who can draw upon their vast experience and knowledge.
14:27
To develop liquid metal battery,
14:30
I hired students and post-docs and mentored them.
14:32
In a battery,
14:35
I strive to maximize electrical potential;
14:37
when mentoring,
14:40
I strive to maximize human potential.
14:42
So you see,
14:44
the liquid metal battery story
14:46
is more than an account
14:48
of inventing technology,
14:50
it's a blueprint
14:52
for inventing inventors, full-spectrum.
14:54
(Applause)
14:57

sponsored links

Donald Sadoway - Materials engineer
Donald Sadoway is working on a battery miracle -- an inexpensive, incredibly efficient, three-layered battery using “liquid metal."

Why you should listen

The problem at the heart of many sustainable-energy systems: How to store power so it can be delivered to the grid all the time, day and night, even when the wind's not blowing and the sun's not shining? At MIT, Donald Sadoway has been working on a grid-size battery system that stores energy using a three-layer liquid-metal core. With help from fans like Bill Gates, Sadoway and two of his students have spun off the Liquid Metals Battery Corporation (LMBC) to bring the battery to market.

The original video is available on TED.com
sponsored links

If you need translations, you can install "Google Translate" extension into your Chrome Browser.
Furthermore, you can change playback rate by installing "Video Speed Controller" extension.

Data provided by TED.

This website is owned and operated by Tokyo English Network.
The developer's blog is here.