Hydrogen Energy: An Overview

Kenneth M. Klemow, Ph.D.

Wilkes University

www.rise.org.au

www.inl.gov/

www.fuelcellstocks.com

Points to be covered Some hydrogen chemistry Hydrogen as an energy source Producing hydrogen Benefits of hydrogen as an alternative fuel Hydrogen power initiatives Disadvantages of hydrogen The WebQuest

Some hydrogen chemistry

Lightest element (consists of only one proton and one) electron

Isotopes include one or more neutrons

Most abundant element in universe (75% by mass)

Component of most stars; as plasma

discovermagazine.com

Hydrogen on earth Easily reacts with most other elements,

particularly oxygen, carbon, nitrogen, most metals.

Carbon-hydrogen compounds are basis of organic chemistry.

Basis of acid-base reactions. Occurs in diatomic form in atmosphere At typical temperatures and pressures, H2 is

a gas. Rare (ca. 1 ppm) due to ease of escape

Molecular hydrogen is combustible

2 H2(g) + O2 (g) → 2 H2O(l) H = -286 kJ/mol

Burns at concentrations

as low as 4%. Produces flame visible

only in UV spectrum

Primary industrial uses of hydrogen Create ammonia

3 H2 + N2 → 2 NH3

Cracking of high molecular weight hydrocarbons to form low m.w. hydrocarbons

Hydrogen as an energy source

Fuel for internal combustion

engines

www.global-hydrogen-bus-platform.com

Fuel cells

www.evworld.com

Hydrogen internal combustion engines

Cadillac

Hondawww.london.gov.uk

London Olympics

Hydrogen fuel cells

www.next-generation.caAnimation

Have many kinds of fuel cells Proton Exchange Membrane (PEM)

Run at low temperatures, used in automotive applications

Solid Oxide Fuel Cells Use ceramic electrolyte, central generating

stations Alkaline Fuel Cells

Long used by NASA in spacecraft Regenerative fuel cells

Self contained, uses water and sunlight Microbial fuel cells

Use bacteria and yeast under anaerobic cond.

How is hydrogen produced? Reacting metals with acids

Zn + 2 H+ → Zn2+ + H2

Processing hydrocarbons CH4 + H2O → CO + 3 H2

H = +191.7 kJ/mol

Hydrolysis of water 2H2O(l) → 2H2(g) + O2(g)

G = +474.4 kJ/mol

Commercial hydrogen production As a byproduct of coal gasification and

natural gas processing Through use of electricity generated by

burning fossil fuels, nuclear, solar, hydropower, geothermal, wind

The hydrogen economy

Elements of the hydrogen economy Hydrogen generation

Centralized Distributed

Hydrogen storage Hydrogen distribution

Benefits of hydrogen as a fuel Hydrogen exists in an unlimited supply Hydrogen is renewable Hydrogen is clean-burning

Water is main byproduct No carbon dioxide released into air

Hydrogen weighs less and generates more power than hydrocarbon-based fuels.

Hydrogen burns faster and at a lower temperature than conventional gasoline

Convert vehicles to hydrogen power Establish extensive distribution system

for hydrogen Produce massive amounts of hydrogen

No worries about carbon if using nuclear, wind, geothermal, hydropower

Use carbon sequestration techniques if using fossil fuels

The vision

Initiatives Hydrogen.gov Minnesota Renewable Hydrogen initiative National Hydrogen Association BP and GE Hydrogen initiative Icelandic Hydrogen Energy Germany Clean Energy partnership Japan Hydrogen and Fuel Cell demo project

Disadvantages of hydrogen power Hydrogen is difficult to contain; tanks are bulky Hydrogen reacts with metal in tanks causing them

to become brittle Hydrogen is explosive, can be unsafe Fuel cells are expensive, especially due to platinum

catalysts Hydrogen is an energy carrier; have inherent

inefficiencies in generation. Production via fossil fuel combustion still releases

carbon dioxide - large scale sequestration may not be feasible.

Establishing distribution facility will cost trillions of dollars

Pellet of ammonia borane weighting 240mg. Can store 0.5 L of hydrogen in small volume.

www.sciencedaily.com

So, is hydrogen power the answer to our energy concerns?

You tell me!