The Energy Center

Hydrogen Storage: Status, Perspectives, and Industrial Applications

Dr. Timothée L Pourpoint

Purdue University, School of Aeronautics and Astronautics, West Lafayette, IN 47907

Email: [email protected] November 2017 Office Phone: 765 494 9423 Outline The Energy Center

. Applications for storage

. The good and “less good” news

. Hydrogen storage options

. Matching application with options

• Chemical hydrides

• Aerospace applications

. Conclusions

2/30 Why are we here?... The Energy Center

. The good news… High energy density

High efficiency

Multiple and renewable sources…

SOFC, up to 60% efficicient (70% in hybrid mode) Solar Biomass

SOFC: Solid Oxide Fuel Cell Wind Hydro Renewable Energy and Recyclable Vehicular Hydrogen Storage Adapted from http://www.sc.doe.gov/bes/hydrogen.pdf 3/30 Why are we here?... The Energy Center . The “less good” news…

External tank length distribution

Length 96.7 ft (29.5 m) Diameter 27.6 ft (8.4 m) Volume 52,882 ft3 (1.5 million L)

LH2 Mass 230,000 lb (104,308 kg) Operational Pressure 34 psi (2.3 bar) Operational Temperature -423 F (-253 C)

LH2 Flow Rate 26,640 lbs/min (12,000 kg/min) 4/30 Why are we here?… Many applications The Energy Center

“hydro-dolphin” - Automobiles 2009

Linde Hydrogen Forklift - 2008 GM’s HydroGen4 - 2008 “Controlled” “Controlled” Land/Sea Aerospace

Portable

Hybrid rocket motor test, 50 wt.% NaBH4 DCPD (Fall 2011 – Purdue Univ.) NH3BH3 Portable Power System General Atomics - 2009 5/30 The Need for Hydrogen Production The Energy Center . Current U.S. energy systems are not sustainable ⇒ Need a carbon-neutral system of energy production and use

. Global hydrogen production: • 48% from natural gas • 30% from oil • 18% from coal • water electrolysis ~4%

. Challenge #1: • Cost-effective production based on renewable resources

6/30 The Need for Hydrogen Production The Energy Center

9,645,000 as of Nov. 10, 2017

Challenge #2: Accurate energy demand and production estimates 7/30 Why are we here?… The Energy Center Reduced emissions Hydrogen has the potential to be produced, stored, and used “based on secure, local, and renewable energy sources that reduces harmful air pollutants, and is accessible and affordable to all.”

⇒ Hydrogen is not an energy resource itself (because no natural hydrogen reserves exist), it has the potential to serve as an energy carrier at the core of a carbon-neutral system of energy production and use.

References: http://www.hydrogenhighway.ca.gov/ & http://www.c2es.org/technology/factsheet/HydrogenFuelCellVehicles 8/30 Hydrogen “Cycle” The Energy Center

Hydrogen Distribution

) Fuel H Solar 2 Off-board

Biomass and on- Byproduct ProcessingC l Fuel board facility hydrogen storage

Wind Hydro

Hydrogen Production

Renewable Energy and Recyclable Vehicular Hydrogen Storage Adapted from http://www.sc.doe.gov/bes/hydrogen.pdf

9/30 Production from Fossil Fuels The Energy Center . Hydrogen is currently produced on an industrial scale (~9 Mtons/yr in the U.S.) through steam reforming of natural gas.

. Basic requirements: • High temperatures (700 – 1100°C) • Metal-based catalyst (nickel) ⇒ steam reacts with to yield carbon monoxide and hydrogen:

CH4 + H2O → CO + 3 H2

. At present, most of the hydrogen made from fossil fuels is used in the , petroleum, and chemical industries.

. Assuming that hydrogen powered vehicles have 2.5 times the energy efficiency of improved gasoline vehicles, this reduction in petroleum use would require the annual production of approximately 150 Mtons of hydrogen by 2040.

Source: US DoE, http://www.sc.doe.gov/bes/hydrogen.pdf 10/30 Production from Fossil Fuels The Energy Center . Coal or biomass feedstocks can be used to generate hydrogen via reforming processes, however:

1. These resources generate approximately twice as much CO2 per amount of hydrogen produced (relative to natural gas) ⇒ Development and economics of

2. Feedstocks also contain variable amounts of water, sulfur, nitrogen, and nonvolatile minerals that substantially complicate reforming process engineering ⇒ Drives cost of using H2 for transportation because low-temperature (<130°C) fuel cells and most hydrogen storage materials are very sensitive to contaminants, some require ultra- pure hydrogen > 99.999% Irreversible damage after 1 hr . There is however a lot of merit to using biomass (or “cheap” coal) if economic and safe methods can be found to process the

impurities and CO2

Sources: US DoE, http://www.sc.doe.gov/bes/hydrogen.pdf &: Journal of The Electrochemical Society (2002), Vol. 149, pp. A293-A296 11/30 Solar Production The Energy Center . Hydrogen produced by: • driving water electrolysis with solar cells, • by direct photocatalytic water splitting into hydrogen and oxygen, • by photobiological water splitting, • or by solar thermal processes, represents a highly desirable, clean, and abundant source of hydrogen.

. Hydrogen made this way is suitable for use, without further purification, in low-temperature fuel cells.

. Challenge #3: Current solar cells are either too expensive or too inefficient for widespread application (Changing rapidly)

Source: US DoE, http://www.sc.doe.gov/bes/hydrogen.pdf 12/30 Just last week The Energy Center

References:

• https://arstechnica.com/science/2 017/11/converting-natural-gas-to- hydrogen-without-any-carbon- emissions/

• Nature Energy, 2017. DOI: 10.1038/s41560-017-0029-4 • Science, 2017. DOI: 10.1126/science.aao5023

13/30 The Need for Hydrogen Storage The Energy Center Systems . “Two” kinds of hydrogen storage: 1. Stationary applications - residential heating and air-conditioning, neighborhood electrical generation, and many industrial applications 2. On-board applications: transportation of any kind

. Stationary storage can: • occupy a large area, • employ multistep chemical charging/recharging cycles that operate at high temperature and pressure, • and compensate for slow kinetics with extra capacity.

. In contrast, hydrogen storage for transportation must: • operate within minimum volume and weight specifications, • supply hydrogen to enable 300-mi driving range (~6 kg for light weight car), • charge/recharge near room temperature, • and provide hydrogen at rates fast enough for fuel cell locomotion of cars, trucks, and buses.

. Challenge #4: Finding onboard hydrogen storage solutions for transportation applications 14/30 What are our options? The Energy Center

Compressed Liquid Gas

STORAGE OPTIONS

Chemical PHYSISORPTION Solid State Hydrides

CHEMISORPTION Source: P. Jena – J. Phys. Chem. Lett. 2011, 2, 206–211 15/30 Hydrogen storage options The Energy Center . High gravimetric energy density: 141.8 MJ/kg • vs. 47.30 MJ/kg for gasoline

. Low volumetric energy density: 0.0117 MJ/STD-L • vs. 34 MJ/L for gasoline (~3000x higher)

. “Standard” Storage • Compression → Low density (3-5 MJ/L) • Cryo-Compression → Up to 9 MJ/L • Liquefaction → Low temperature, 1 high energy input, boiloff BMW LH2 Tank issues (10 MJ/L)

1 http://www.blewbury.co.uk/energy/images/LH2tank.jpg 16/30 Hydrogen storage options The Energy Center . Other Storage Mechanisms • Adsorption

o Van der Waals forces between surfaces and H2 molecules o Must overcome thermal kinetic energy (KE = 1.5kBT) 6-8 MJ/L (@ 77 K)

• Metal Hydride Formation o Solid solution of H in metal lattice 8-10 MJ/L

Example: MgH2

• Chemical Storage Schlapbach et al., Nature, 414 (2001), pp 353 o For example: NH3BH3 and NaBH4 20-25 MJ/L 17/30 Why are we here?... The Energy Center No “silver bullet”

Gaseous H2 - simplest but low density

Liquid H2 - High density Adapted from: P. Jena – J. Phys. Chem. Lett. 2011, 2, 206–211 but boil-off limits 18/30 Matching options with applications The Energy Center

Automobiles

Compressed Liquid Gas

“Controlled” “Controlled” Land/Sea Aerospace

Chemical Solid State Hydrides Constraints: Constraints: • Reversibility • Safety • Kinetics • Weight • Cyclability Portable • Volume • Temperature • Cost • Pressure 19/30 Chemical Hydrides The Energy Center

Automobiles

Compressed Liquid Gas

“Controlled” “Controlled” Land/Sea Aerospace

Chemical Solid State Hydrides Constraints: Constraints: • Reversibility • Safety • Kinetics • Weight • Cyclability Portable • Volume • Temperature • Cost • Pressure 20/30 Demonstration of AB thermolysis The Energy Center reactors at multiple scales Glass milligram scale reactor (130 mg) Steel multi-gram reactor ( 2 g per batch) Vehicle demonstration (~200 g per reactor module)

Source: DoE funded project – Purdue Univ. – Annual Merit Review 2011 21/30 Demonstration Vehicle System The Energy Center

MOVIE See: https://engineering.purdue.edu/H2Lab/Ammonia _Borane/index.html for details

Source: DoE funded project – Purdue Univ. – Annual Merit Review 2011 22/30 Aerospace applications The Energy Center

Automobiles

Compressed Liquid Gas

“Controlled” “Controlled” Land/Sea Aerospace

Chemical Solid State Hydrides Constraints: Constraints: • Reversibility • Safety • Kinetics • Weight • Cyclability Portable • Volume • Temperature • Cost • Pressure 23/30 Rocket Propulsion Applications The Energy Center

Hybrid rocket motor, Top: DCPD, Bottom: 50 wt.% NaBH4 DCPD Source: (Fall 2011 – Purdue Univ.) S. Shark, et al. AIAA-2011-5556 24/30 Practical requirements to H2 storage The Energy Center materials requirements . Operating requirements for effective hydrogen storage for transportation include: • Appropriate thermodynamics (favorable enthalpies of hydrogen absorption and desorption), • Fast kinetics (quick uptake and release), • High storage capacity (specific capacity to be determined by usage), • Effective heat transfer, • High gravimetric and volumetric densities (light in weight and conservative in space), • Long cycle lifetime for hydrogen absorption/desorption, • High mechanical strength and durability, • And… • Safety under normal use and acceptable risk under abnormal conditions.

25/30 Conclusions The Energy Center “Enormous” knowledge/technology gap is getting narrower with recent technological advances include: many recent advances in chemistry, materials research, and computation

. Need: • To understand the atomic and molecular processes that occur at the interface of hydrogen with materials • To develop new materials for: o membranes, o catalysts, o Storage media, o and fuel cell assemblies (higher levels, lower cost, and longer lifetimes)

In short, for any system:

Full circle efficiency H2 storage safety

On-board H2 capacity H2 filling speed

26/30 Infrastructure Requirements The Energy Center “Finding a hydrogen fueling station can be like getting a car loan with lousy credit these days.” KEN THOMAS, Associated Press November 04, 2008

Above: Operational Hydrogen Refueling Stations as of this morning. http://www.afdc.energy.gov/fuels/hydrogen_locations.html

Source: http://www1.eere.energy.gov/vehiclesandfuels/facts/2008_fotw523.html 27/30 Conclusions The Energy Center . Matching an application with hydrogen storage options requires clear understanding of constraints . Hydrogen accessibility and density compete but many avenues exist to find a middle ground

HYDROGEN ACCESSIBILITY HYDROGEN DENSITY

Source: P. Jena – J. Phys. Chem. Lett. 2011, 2, 206–211 28/30 The Energy Center

. Any questions?

29/30 Why are we here?... The Energy Center . A possible future?…

https://www.youtube.com/watch?v=4AXU2wqQe00 30/30 The Energy Center

APPENDIX

31/30 Safety Considerations

Credit: Dr. Michael Swain - University of Miami BMW Hydrogen 7 Car The Energy Center

Most current hydrogen car concepts and demonstration vehicles store hydrogen in high pressure compressed gas tanks (5000 to 10,000 psi)

BMW chose to store hydrogen in liquid form (at −423.17 °F, 20 K)

http://www.youtube.com/watch?v=LjWCXD4P3XQ

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