# Presentation: 727835

## Jerry M. Woodall

**National Medal of Technology Laureate,**
**Barry and Patricia Epstein Distinguished Professor**
**School of Electrical and Computer Engineering,**
**Discovery Park Energy Center, **
**Purdue University, West Lafayette, IN 47906, USA **

**SOLID ALUMINUM ALLOYS: A HIGH ENERGY **
**DENSITY MATERIAL FOR SAFE ENERGY **
**STORAGE, TRANSPORT, AND SPLITTING **
**WATER TO MAKE HYDROGEN ON DEMAND **

**Princeton Plasma Physics Laboratory**
**Sept. 24, 2008**

## Outline

**Energy density and technology sustainability **
**Brief history and technology overview**
**What else we know about it **
**Process flow and hydrogen delivery control**
** **
**Markets and applications**

## Energy density and

**technology sustainability **

## Energy Density and Power Density

**• ****As ****hydrogen**** from splitting water:**
**    • ****1 Kg H****2****: 142 MJ = 39.4 kW-Hrs combustible energy**
**    • ****1 Kg Al* makes 111 gms. of hydrogen**
**    • ****1 Kg Al makes**** 4.4 kW-Hrs ****as H****2**** energy**
**    • ****1 gal (10 Kg) Al makes 44 kW-Hrs as hydrogen**
**    • ****1 gal. diesel: 37 kW-Hrs **
**    • ****1 gal. liq.hydrogen: 10 kW-Hrs **
**• ****As ****heat**** from splitting water:**
**    •  ****1 Kg Al: 409 KJ x 1000/27 = 15.1 MJ = ****4.2 kW-Hrs**** **
*** 1 Kg of water is converted by this process   **

## Important facts about making aluminum

**• ****Bauxite ore mined and dressed to extract alumina **
**• ****Alumina is chemically purified to 4-9s purity**
**• ****Purified alumina is sized to a powder with a particle size of 120 micrometers**
**• ****If done by Alcoa in Australia it is shipped to one of their nine smelters around the world**
**• ****Batches of Al with customer specified impurities are made by electrolysis of high purity alumina**
**• ****Spent Al products are mostly sent to scrap yards**
**• ****Most of this scrap Al metal with impurities is currently not recycled because it’s cheaper to purify alumina than impure Al!  **

## Technology Sustainability: large scale applications

**World supply**
**• ****Al reserve in the planet’s crust: about 10****13**** Kg (as Al); 1.2 x 10****12**** Kg **
**   ****of H****2**** made by splitting water = 5 x 10****13**** kWhrs of H****2**** energy**
**• ****Current worldwide annual Al production: 32 billion Kg from bauxite;**
**   **
**• **_***400 billion Kg of ***__***impure***__*** elemental Al available for recycling!***_
**Large demand example: hybrid cars:****  **
**• ****If half of the impure “recyclable” Al was dedicated to split water, 50**
**  ****billion Kg of H****2 ****could be made = 200 billion kWhrs  (@ $0.15/kWhr)**
**• ****This could power a 100 million, 50 kW hybrid cars 200 miles**
**What about infrastructure/supply chain/vehicle fuel insertion?**
**• ****Some components either do exist or are easily realized**
**• ****Fuel insertion:  2-filler ports, one for water and one for alloy pellets**
**  ****both being hose delivered; spent fuel dumped into holding tanks **

## Brief history and technology overview

## The Discovery

**In 1968 Woodall discovered that aluminum (Al) dissolved in liquid gallium (Ga) just above room temperature would split water into hydrogen (H****2****) and aluminum oxide (alumina) plus heat via the reaction:**
**2Al + 3H****2****0  -->  3H****2**** + Al****2****0****3****  + heat**
**  **

## Slide 9

## Al in Ga Splitting Water to make Hydrogen!

**Al in Ga Splitting Water to make Hydrogen!**

## Slide 11

## How does it work?

**Aluminum loves oxygen**
**As a result, a skin of alumina (Al****2****0****3****) forms on air-exposed pure Al and protects it from further rapid oxidation**
**If this passivating oxide is disrupted, Al would react with water to produce hydrogen**
**This can be done slightly above room temperature by dissolving Al into **_**liquid**_** gallium (Ga)**
** **
**When this liquid alloy contacts water, hydrogen is  generated via Al in the Ga diffusing to the water-liquid metal interface where it splits water into hydrogen, alumina; the alumina is no longer protective****  ****	**

## Where are we now?

**• ****We can now make solid and bulk Al rich alloys (95 w% Al, 5 wt% Ga,In,Sn) that split water at temperatures between ice  (0C) and steam (>100C) and make H****2**** on demand **
**•****1st order *****projected***** materials cost of 20 cents per kilowatt hour of energy as combustible H****2**** and 10 cents per kilowatt hour of energy as heat plus combustible H****2****  **

## Menu of 

- 2
- 18
- 28
- 50*
- 80
- 95*

- wt.% Al

**Menu of **
**water splitting**
**Al alloys***
***These alloys**
**substitute **
**GaInSn for **
**Ga**** **

## Internal sample of 95-5 Alloy from vender 

**Internal sample of 95-5 Alloy from vender **

## A sample of 50-50 Al-GalInStan splitting water

**A sample of 50-50 Al-GalInStan splitting water**

## Complete centrifuge recovery of GalInStan alloy

**Complete centrifuge recovery of GalInStan alloy**

## What’s the big deal?

**•  ****Technology is a path to enable the H****2**** economy**
**•  ****It can make H****2**** on demand without storage or transport of hydrogen**
**•  ****Energy used to make H****2**** safely stored and transported as Al and generates H****2**** by splitting water, and both Al and water are abundant**
**•  ****Al, alumina and Ga,In,Sn can be of low  purity, Ga,In,Sn totally recoverable/recyclable, Al****2****O****3**** electrolyzed to Al  @ $0.66/Kg **
**•  ****No external power or chemicals needed**

## A possible supply chain/infrastructure model

## What else we know about it? 

## Slide 21

## EDX mode photomicrograph of 95-5 sample showing

**EDX mode photomicrograph of 95-5 sample showing**
**In and Sn in the grain boundaries**

## So, how does the solid Al rich alloy split water?

**We are not sure yet but our**
**preferred model is:**
**the liquid Ga,In,Sn in the grain**
**boundaries dissolves Al and **
**this Al in solution splits water  **

## Process flow and hydrogen delivery control

## Process flow and H2 delivery control: research test-bed

**• ****Prepare briquettes of 95-5 alloy from vendor**
**• ****Insert briquettes into “basket” in reaction tank, a 100 psi stainless steel paint pressure pot**
**• ****Reaction tank is valve connected to an Extrol expansion**
**   ****tank which is filled with water, valve closed**
**• ****Free space of reaction tank is evacuated and sealed**
**• ****Valve opened between Extrol tank and reaction tank**
**• ****Water flows from Extrol into reaction tank until in contact with alloy**
**• ****H****2**** pressure builds up in reaction tank and pushes water back into Extrol tank until water loses contact with alloy**
**• ****Hydrogen flow controlled into engine via a buffer tank**

## Alloy briquettes

## Experimental reactor and pressure controller 

**Up to 20 Kg of alloy (88 kWhrs of H****2****)**

## Power: Al-water-H2

**Recent data shows that we can react 1 Kg Al in one minute  = 15.8 MJ/min as H****2**** (5% of a 20 Kg charge)**
**This converts into >250 kW of hydrogen power,**
**    ****and a power density of >125 kW/Kg(Al+water)**

## Challenges/issues 

**• ****Heat use/management **
**• ****Infrastructure/supply chain to manufacture            alloys and recycle them**
**• ****Current energy efficiency is only 29%,**
**  ****i.e. energy from H****2****/recycle energy x100 = 29%**
**  ****(industrial water electrolysis about 30%)**
**• ****If not recycled, the weight of needed water **
**  ****equals the weight of alloy used.  **

## Markets and applications

## Scale of possible applications/markets 

**• ****Small: 1-100 mW and 10 W-hrs, e.g. PDAs, laptops, i-pods, etc.**
**• ****Medium:  1-200 kW and 10-10000 kW-hrs, e.g. auxiliary power, cars, boats, fuel enrichment, etc. **
**• ****Large:  >5000kW and > million kW-hrs, e.g. trains, ships, subs, off-grid community power, base load peak power demand, storage for wind and solar power ****  **

## Possible application: replace batteries

**Energy density (ED) of batteries: **
**     ****lead-acid: 31-51 W-Hrs/Kg); Li-ion: 92-189 W-Hrs/Kg; **
**	****Ni-metal-hydride (Prius): 59-119 W-Hrs/Kg**
**ED of Al-GaInSn(95-5)-H****2****0 system as hydrogen:**
**  ****1340 W-Hrs/Kg (Gibbs energy used for fuel cells) **
- Includes water weight, a 70% efficiency factor of fuel cells,
- but not container or fuel cell weight,(ED ratio is >>1 including
- weight of a high power fuel cell)
**(ED Ga-Al-H****2****0)/(ED lead-acid batteries) ****  **
**               **
**	****	****>26!  (>7  ED ratio for Li ion)**** **

## Possible applications/markets

**Replace batteries with a Ga-Al-H****2****0/fuel cell **
**system for high energy density electric power applications:**

**• ****emergency/stand-by power (AlGalCo)**
**• ****electric wheel chairs**
**• ****golf carts**
**• ****PDAs, Laptops, etc. **
**• ****hybrid cars**

**• ****range extender (GM Volt?) **
**• ****liquid fuel multiplier, e.g. diesel enrichment**
**• ****trains, subs, trucks**
**• ****large boats and other maritime applications**
**• ****desalinated/potable water!**

**Other applications: **

## Electricity costs to reduce Al+3 to Al

**The electrochemistry of reducing Al (in alumina) is:**
**   ****Al****+3**** + 3e****-****  ****--****> Al, and requires about 15 kW-hr/kg  of Al **
**   ****at a present process efficiency of 50%**
**Using autos with ICEs for example:**** **
** **
**2.9 Kg. Al will produce the same amount of energy in **
**   ****the form of hydrogen as 1 Kg of gasoline, i.e., 42 K BTU**
**It takes 20 gal. x 2.7 Kg/gal = 54 Kg gasoline to drive a midsize average car 350 mi, or 157 Kg, Al***
**At $3.50/gal for gasoline and  $2.40/Kg  for Al, the trip costs $70 using gasoline and $380 using Al (ouch!)**
*******63 Kg. on-board water will be required, assumed to be a negligible cost**
**	****and a 60% recovery rate (DOE number) for continuous reuse**

## Costs to reduce Al+3 to Al (cont.)

**For an Al recycler next to a nuclear power plant* with an on-site power cost of $0.02/kW-hr, the Al can be recycled from alumina back to Al for:**
**15 kW-hr/Kg x $0.02/kW-hr = $0.30/Kg of Al****
** ****2.9 Kg Al production cost is about ****$0.87  ($47/trip) **
** ****$3.50/gallon, (retail) 1 Kg of gasoline costs ****$1.30 ($70/trip)**
**For equal energy (as H****2****) Al can be cheaper than **
**gasoline; so its all about weight**
***For the future, Al recycling could be done at solar photovoltaic farms and/or wind turbines sites.**
****The Al smelted by electrolysis has a CO****2 ****ratio of 1/3 compared with CO****2 **** from burning gasoline.  However, this CO****2  ****could be sequestered**

## On-board H2 mass density for the 95-5 Al alloy

**2Al + 3H****2****O  -> 3H****2**** + Al****2****O****3**

** ****To get 6 mass units of H we need:**
**	****54 mass units of Al **
**	****48 mass units of O **
**           ****3 mass units of “catalytic” Ga,In,Sn **
**The total source mass units = 54+48+6+3 = 111, and**
**the on board H mass density = (6/111)x100 = 5.4%.**
**However, the only on-board source required in full**
**at the beginning is the Al+alloy; the source of H and O can **
**be added dynamically via H****2****O recovery.  Assuming a 50% **
**recovery of H****2****O, we get an H density of (6/84)x100 = 7.1% **
**at the beginning and (6/102)x100 = 5.9% at the end or an **
**average density of 6.5% (>DOE 2010 goal)**

## Costs to reduce Al+3 to Al (cont.)

**Oh, if only there were a reliable fuel cell technology    that could deliver 150 KW for $10/kW **
**For a fuel cell plus electric motor powered car: **
**If we assume a fuel cell plus electric motor efficiency of 64% only 1/3 of both the weight of Al plus water will be needed, i.e. 0.33 x 157 Kg  plus 0.33 x 63 Kg water = 52 + 21 = 73 Kg. compared with 54 lbs of gasoline for an ICE powered car.  **
** ****$0.30/Kg x 52 Kg. =  $16.00 per 350 mi. trip (wholesale) **** **

## Assumptions:

**1. A 40 KW ICE tuned for hydrogen and an efficiency of**
**     ****60 mpegg to drive a generator as the batteries run out**
**2. 13 kWhrs of hydrogen needed to drive 20 miles**
**3. 3 Kg of alloy will generate needed hydrogen, alloy **
**     ****contained in a “canister” plugged into fixture in trunk**
**4. 3 Kg water water “hosed” into the gasoline filler port**
**5. Canister exchange: e.g. convenience stores, Walmart, car dealers, etc.; spent canister sent to refineries, recharged and returned to distributor;  GM internal business model not part of supply chain**

**A Possible Model for the Volt:**
**GM’s First Hydrogen - EV Hybrid Car**

## Slide 39

## Slide 40

## Start up: EV-H2 hybrid model

**• ****Normal case: batteries are charged - no issue**
**• ****Worst case: batteries are discharged and no hydrogen**
**   ****in a buffer tank; how long will it take to start the car? **
**• ****4.4 kWhr of H****2**** energy can be generated in 1 minute, I.e. **
**  ****> 250 kW available power for one minute**

## Advantages for GM and the Volt model

**• ****First GM EV-Hydrogen Hybrid Car**
**• ****Infrastructure, distributed, diverse and in place, e.g. Alcoa, Walmart, convenience stores, gas stations, dealers, etc. **
**• ****GM does not have to make the supply chain part of their internal business model**** **
**• ****Current Volt model, 40 mile range using batteries, as the primary power source.  Auxiliary power use intermittent.  **
**• ****Gasoline degrades in the tank without use but Al alloy does not.****  **

## H2 enrichment of diesel fuel model - cars

**• ****15% H****2**** enrichment of diesel gives 30%* increase in efficiency **
**• ****No Blutech needed to get rid soot or Nox**
**• ****Assume 40 mpg car with a 10 gal. diesel fuel tank;100 gal. of diesel **
**  ****needed for 4K miles and an oil change required after 4K miles; cost of**
** ****100 gal. diesel: 100 gal. x $4.35/gal. = $435**
**• ****Weight alloy needed for 4K miles:  100+ kg;  weight of water: 100+ kg **
**• ****Total cost per 4K miles  boosted 30%, with Al-H****2 ****technology:**
**   ****$411.  Canisters swapped out during oil change operation**
**• ****Spent alumina removed at 4K mile intervals along with oil change**
*** Not a vetted number **

## H2 enrichment of diesel fuel model - trains

- • 60,000 gal. train oil tanker with 95-5 Al alloy; (2.5 million kW-h as H2)
- • Al tanker connected to 60,000 gal. water tanker both trailing train engine
- • A 50 car loaded train runs on a 4000 peak horsepower diesel-electric engine, 2000 average rolling HP, i.e. 1,500 kW, or 110.6 Kg of diesel/h
- • Train use: 4 Kg of hydrogen per hour made from the Al alloy = 157.6 kW-h
- • Al Tanker can generate 15,900 hours worth of hydrogen or over 660 days of continuous generation!!!
- • To use all the energy a heat exchanger makes steam from water in an extra tanker and drives an additional dynamo.
- • Or react the alloy in super heated steam and feed steam plus hydrogen into closed loop turbine, condense and reuse water and separate out hydrogen as input diesel electric engine.
- • Value proposition: H2 enrichment via splitting water with Al is “free”!

## Another possible application:

**Enabling Wind or Solar as Base Load Electricity Generation Capacity**
**Target cost: $0.10/kWhr, assuming 40x alloy recycling**
**All required technologies are known**
**Primarily an Engineering Development Project**
**Enables Environmentally Sound and Secure Electricity**

## Enabling Wind or Solar as Base Load

**reaction tank,**
**95-5 alloy, and**
**controls**

**H****2****0**

**  ****H****2****, 4.2 kWhr/Kg-alloy**
**  ****24/7 or on demand**

**Fuel Cell or Gas**
**Turbine/Generator**

**H****2****0**

**Electricity**

**Heat, 4 kWhr/Kg-alloy**
**24/7 or on demand**

**Steam Turbine**

**component separation**

**H****2****0**

**galinstan recovery**

**95-5 alloy**
**regeneration**

**intermittent electrical power, e.g. solar or wind**

**Enabling Wind or Solar as Base Load**
**Electric Power Model Flow Diagram**

## 1st order economics of our process

- • Cost components per pound of Al @ $2.42/Kg (retail)
- 	a. Bauxite mining and alumina separation -  $0.44
- 	b. Alumina purification and particle sizing - $1.32
- 	c. Electrolysis of alumina to Al                   - $0.66
- • Energy content of 1 Kg of Al: 8.6 kW-Hrs
- • Energy content of 1 Kg of gasoline: 12.3 kW-Hrs
- • Cost of 20 Kg. Al; 1st Kg @ rack price plus
-     19 recycles @ $0.66 = $15;  Average cost per Kg =  $0.75
- • Cost of GaInStan; 1st 0.05 Kg @ rack price $250/Kg
-      plus 19 recycles @ $0.10 =$14.40;
-     Average cost per 0.05 Kg of GaInStan = $0.72
- • Cost of Al Alloy = ($1.47/8.6 kW-hr) = $0.17/ kW-Hr
- • Cost of gasoline @ $3.50/gal = $0.10/kW-Hr

## Cost of total energy vs. number of alloy recycles 

- Cost of total energy vs. number of alloy recycles

## What about gallium and GaInStan?

**• ****Ga,In and Sn are inert and totally recoverable.**
**• ****Experiments have recycled the Ga used in **
**  ****water splitting solid alloys up to 32 times. **
**• ****Currently, the 60 ton market for Ga is for electronics**
**   ****with purities between 4 and 7-9s, about $0.35/gm!!!!!**
**• ****Our process runs on low purity Ga,In,Sn and low purity **
**   ****Al and tap water/non potable water.**
**• ****Our analysis shows that with multiple reuse, a price **
**   ****of the alloy component charge of $0.70/kg can be realized.**
**• ****For fuels with <5% Ga there is enough **
**  ****economically recoverable Ga to run 10****9 ****cars. **

## Bottom line: 

**• ****No technical show stoppers for large scale use of **
**   ****of Al rich solid alloys splitting water to make hydrogen**
**   ****and  heat on demand**
**•  ****However, there are plenty of barriers to realize it including**
**   • ****US government agencies, especially DOE**
**   • ****The fossil fuel and an motor vehicle industries**
**   • ****The $100 billion needed to build the infra-structure**