04/10/2023

Why hydrogen?

• Excellent energy carrier• Nonpolluting• Economically competitive• As safe as gasoline • Used safely for over 50 years• Produced from a variety of sources

How fast does it rise?• “Hydrogen rises 2

times faster than helium and 6 times faster than natural gas, at a speed of almost 45 mph (20m/s).”

--National Hydrogen Association; Hydrogen Safety Fact Sheet

Courtesy of Ballard

HydrogenNatural Gas

GasolinePropane

Buoyancy relative to air

Air

How quickly does it disperse?

Courtesy of Ballard

Comparison of propertiesHydrogen Natural Gas Gasoline

Color No No Yes

Toxicity None Some High

Odor Odorless Mercaptan Yes

Buoyancy Relative to Air 14X Lighter 2X Lighter 3.75X

Heavier

Energy by Weight

2.8X > Gasoline

~1.2X > Gasoline 43 MJ/kg

Energy by Volume

4X < Gasoline

1.5X < Gasoline

120 MJ/Gallon

Comparison of flammabilityHydrogen Natural Gas Gasoline

Flammability in air(LFL – UFL)

4.1% - 74% 5.3% - 15% 1.4% - 7.6%

Explosive limits in air (LEL – UEL)

18.3% - 59% 5.7% - 14% 1.4% - 3.3%

Most easily ignited mixture in air

29% 9% 2%

Flame temperature (C)

2045 1957 1977

40 0

31 0

41 0

Gas properties & characteristics• Displaces O2

(Asphyxiant)• Burns with a pale blue

flame– near invisible in daylight

(can see what it burns)– much less radiant heat of

gasoline fire

Photos: HAMMER

How explosive is it?

0

5

10

15

20

25

30

35

40

45

gTNT/M3

Hydrogen Natural Gas Gasoline Propane

More Explosive Energy

2

7

44

20

Courtesy of Ballard

Where do we get hydrogen?Renewable sources

Solar, wind, geothermal,

hydro, biomass, algae

Traditional sources

Natural gas, gasoline, nuclear, coal

Hydrogen distribution• DOT approved…• Cryogenic liquid

transport • Pressurized gas trailers• Truck, rail, barge and

pipeline

Photo: Ovonics

Photo: Air Products and Chemicals, Inc.

Photo: Praxair, Inc.