Hurricane Ike has given us a massive object lesson on the importance of implementing the late Rick Smalley’s vision of the Store-Gen Grid (SGG; graphic courtesy Wade Adams at Rice’s Smalley Institute) – a highly distributed network of granular electric production and storage. One of the elements of the SGG concept is a household storage unit for about 100 kW-hrs of dispatch energy.
Well, we ain’t there yet. Of all the standard infrastructure services, only two seem to be reliable in a pinch: cell phones and natural gas. The electric grid is plainly extremely fragile. This is a major opportunity for nanotechnology. With a major power outage in the energy capital of the world, this topic ought to get *lot* more traction, and fast. So get your thinking caps on. According to the Houston Chronicle, nearly 3 million people lost power due to the storm. So I reckon there are about 3 million ready customers for the next big thing in distributed power. I’m one of them!
Now, when considering storage technologies, energy density *really* matters! Among practical materials, nothing is even comes close to gasoline or diesel fuel. Just before the storm, my wife was wise enough to ignore my objections and bought a neat little Honda 2kW generator. I got ten gallons of gas on Friday, and used about five gallons over a 36 hour period. This was just enough to keep the refrigerator going, charge cell phones, and run a lamp, two fans and a small TV set. This enabled us to essentially camp-out in our house. Forget about air conditioning, running the washer/dryer or taking a hot shower (the darned water heater has an electric starter).
Here are some representative (volumetric) storage energy densities (from Wikipedia):
|
Technology or Material |
Energy Density ( MJ / liter ) |
|
Capacitor Ultracapacitor |
~ 0.050 |
|
Lead acid battery |
~ 0.15 |
|
Flywheel |
~ 0.50 |
|
Lithium ion battery |
~ 1.50 |
|
Hydrogen Fuel Cell |
~ 1.62 |
|
Li Ion w/ nanowires |
~ 2.60 |
|
Ethanol |
~ 24.0 |
|
Gasoline |
~ 34.6 |
Let’s look at the Lead-Acid Battery (LAB) as an example, since it’s still the workhorse for storing electric energy. My five gallons of gas would equate to 4,383 liters of lead-acid batteries (LABs) (3.8*5*34.6/0.15). My total investment for generation and storage was $1020 ($1000 generator, $20 gas). How much does 4.3 cubic meters of LABs cost again? - about $20-$50/liter? And how much does it weigh? I can (and did) carry (lug) the generator and the five gallons of gas myself at the same time.
Overall, electrical storage energy density is worse than chemical storage a good factor of ten or more. An order of magnitude (or two) is nothing to sneeze at! It is plain that without sufficient oil/gasoline/diesel, we are in a world of hurt for the foreseeable future.
Each of the technologies listed above employs, or can be improved with, nanotechnology or nanostructured materials. Let’s do a little math and get a handle on the nano-scale challenge involved here. If gasoline has an energy density of, say, 35 MJ/l, it equivalently contains about 3.5 x 10-17 Joules per cubic nanometer. Modeling this as a parallel plate capacitor in vacuum with a 1 nm gap, you get the target energy density with a voltage difference of about 2.8 Volts. If you use a decent dielectric like TiO2 (k = 40ε0) instead of vacuum, you only need 0.44 V. About 1 V/nm is a pretty stiff electric field, but not larger than those considered routine for ultra-thin gates in the semiconductor industry. This all seems pretty doable; making the nanowire connections to the outside world will be the tricky part; it’s probably a job for carbon nanotubes or maybe graphene. Rick would have liked that.
I hope somebody out there gets to work on this pronto! Even at $100 / liter, it would be a useful technology. When you get the cost down to about $10 / liter, you’ll be a bona fide hero, and a very wealthy one at that.
Nice article. It all takes me Back to The Future reminiscing about the “fluxcapacitor.” You forgot to mention natural gas generators. You can get a 7kwh for about $1,700 and 2-4kwh for about $1,200 (just go to Home Depot or Lowe’s website) and its dead simple to use, just connect it to the natural gas grid and with an automatic transfer switch its easy to use because it automatically switches to generating electricity off the natural gas grid when the electric grid fails. Natural gas is cheap too and almost nobody lost natural gas when Hurricane Ike hit.
I know nanotechnology is cool and the future is limitless, but 99% of people don’t have any idea what a nanotube is and how it will help change the way we live. Practical solutions to current problems are always a must and nano-tech is not there yet - and it sucks! I must admit as the energy capital of the world not to have power for over 10 days and still counting is an embarrassment, large energy companies need to push the needle forward ASAP but profit, not social responsibility, drives them.
On a separate note in Houston we now have a bunch of down power lines and poles, so we have the opportunity to rebuild parts of the grid with newer technology like underground wiring. Doesn’t it make sense? But we won’t do that, because putting up the same poles is cheaper and there is apparently little government regulation in Houston with respect to requiring repaired and new sections of the grid to be built in a way that the grid can more easily withstand storms. Most people don’t want a higher electrical bill to build a stronger electrical grid.
P.S. Energy density is one thing, but the amount of renewable resources available and necessary to power the technology (e.g. gasoline engines, li-ion batteries, fuel cells, etc.) is equally important. It’s ok to use a technology with less energy density as long as the resource to power it is renewable, cheap, and does not materially affect the environment. Sorry for the long post! This is just a worthy topic.
I had the opportunity to work with a small group of people dedicated to continuing Rick Smalley’s vision of implementing his discoveries and research into the applications that will make this world a better place. Sadly, these individuals (with direct ties to Rick Smalley) were frustrated by a corporate threat towards them and Rice University that the IP was not theirs to use. I understand the importance of IP protection, but where do we draw the line on research that can better the world?
Thanks for posting this. You and I sat down together at Starbucks a year or two ago when I was consulting with Administaff. I’m now out of state (back in school to get an MBA), but I appreciate your efforts to see Houston grow its entrepreneurial initiatives.