# Presentation: 523522

## Overview of Storage DevelopmentDOE Hydrogen Program

- George Thomas
- Sandia National Laboratories
- Livermore, CA
- Hydrogen Program Review
- San Ramon, CA
- May 9-11, 2000

***Safe, efficient and cost-effective storage ******is a key element in the development of ******hydrogen as an energy carrier***

## Hydrogen storage requires something more than a can or a bucket

- Hydrogen has the highest mass energy density of any fuel:
- 120 MJ/kg (LHV)  144 MJ/kg (HHV)
**however**
- At ambient conditions (300 K, 1 atm.):
-  the energy content of 1 liter of H2 is only 10.7 kJ,
- three orders of magnitude too low for practical applications.
- Issues:
- 1. What are the options available for storage?
- 2. What are the theoretical limits to storage density and how close can we come?
- 3. How do we organize a development program to achieve adequate stored energy in an efficient, safe and cost-effective manner?

## Mass energy densities for various fuels

**Increasing molecular wt.**

## Maximum energy density is achievedin liquid state

## Hydrogen energy content in liquid fuels

- Hydrogen density is nearly the same in all fuels.
- This narrow range suggests a natural benchmark for comparison of storage performance.

## Maximum storage densities (w/o system) 

- High pressure gas
- ambient temperature	3600 psi: **2.0**	5000 psi: **2.75**
- cryogenic system		    150 K: **3.5**	      20 K: **8.4**
- Liquid hydrogen			 **8.4**
- Reversible storage media
- carbon structures
- nanotubes			   **?**
- fullerenes			   **?**
- hydrides
- intermetallics			 **10.8 - 12.0**
- alanates			  **8.25**
- composite materials		   **?**
- Chemical methods		 _Eff_.     _gasoline_	         _methanol_
- liquid fuel + reformer	50%:	 **6.6**		**5.9**
- 					75%:	 **9.9**		**8.9**
- off-board reprocessing		  **?**

_**Energy Density MJ/liter**_

## Programmatic guidelines

- A balanced program between scientific discovery and engineering validation is needed.
- Portion of program invested in high risk approaches.
- Collaboration with industry at all levels.
- International partnerships beneficial.
- Leverage off other programs.
- Program should not downselect technologies too early
- Options should be fully explored.
- Different technologies suited for different applications.
- Realistic goals should be set as metrics for progress.
- Evaluate goals on a continuing basis
- continue to refine roadmap

## Slide 8

## Materials Development

- Carbon nanotubes			M. Heben, NREL
- near-term goal: ~6 wt.%
- synthesis, processing, hydrogen absorption/desorption
- Carbon fullerenes			R. Loutfy, MER
- feasibility of fullerene-based storage
- Alanate hydrides			C. Jensen, Univ. of Hawaii
- NaAlH4 : 5.5 wt.% hydrogen capacity
- catalysts, properties
- Hydride development			K. Gross, SNL
- near-term goal: 5.5 wt.% at <100 C (NaAlH4)
- bulk synthesis, scaled-up beds, characterization, safety studies
- Catalytically enhanced storage		C. Jensen, Univ. of Hawaii
- new start
- Polymer dispersed metal hydrides	T. Jarvi, United Technologies
- new start

## Pressure Tank Development

- Lightweight tanks		F. Mitlitisky, LLNL
- goal: >10 wt.% 5000 psi
- Conformable tanks		R. Golde, Thiokol Propulsion Co.
- high pressure tanks with improved packing efficiency
- cryogenic hydrogen vessels	S. Aceves, LLNL
- design and testing for improved volume density
- Composite tank testing		B. Odegard, SNL
- comparison of high pressure hydrogen tank failure to other fuels.
- CNG, gasoline, methanol.

## Engineering Validation

- PV/electrolysis/metal hydride		K. Sapru, ECD
- modeling and integration of storage with renewable energy sources
- Metal hydride/ organic slurry		R. Breault, Thermo Power
- chemical hydride for PEMFC vehicles
- hydrogen transmission and storage
- Fuelcell/hydride powerplant		G. C. Story, SNL
- for underground mine and tunneling locomotive
- Thermal hydrogen compression 		D. DaCosta, Ergenics, Inc.
- new start

## Other hydrogen storage programs (US) 

- DOE/OTT
- Fuels for Fuel Cells Program (P. Devlin)
- 	Parallel development of fuel processor and onboard H storage.
- DOE/OIT
- Low cost hydrides for mine vehicles (SRTC)
- 	Part of Mining Industry of the Future initiative.
- IEA
- Task 12 will be completed Oct. 2000
- New task being formed: Advanced Solid and Liquid State Hydrogen Storage Materials (G. Sandrock)
- Industry Projects

## Other hydrogen storage programs (non US) 

- Canadian Projects
- Alanates (A. Zaluska, McGill Univ.)
- Nanocrystalline Mg-based hydrides (Hydro-Quebec)
- Carbon adsorption (IRH)
- European Projects
- liquid hydrogen storage (BMW)
- refueling station (BMW)
- WENET (Japan)
- Metal-H complex ions (S. Suda, Kogakuin Univ.)
- others

## Some highlights from this year

- Continuing progress in nanotubes
- high purity synthesis and processing methods.
- > 6 wt.% appears feasible.
- Important progress achieved on alanates
- 5.5 wt.% at low temperatures appears feasible.
- Continued improvement in lightweight and conformable tanks
- more efficient packing of high pressure tanks
- integration of storage with applications
- PV system
- mine vehicle
- Three new starts
- catalyst enhanced storage
- polymer dispersed hydride
- thermal hydrogen compression