Hydrogen based energy

Hydrogen is often cited as the solution to global energyNet Energy
problems and the perfect energy carrier for aIt takes energy to make energy. We use energy to
sustainable society due to its’ non pollutingfind and pump oil but, luckily for industrial society, oil has
nature and suitability to store and transport energyhuge net energy and we can usually obtain more than
generated from renewable sources. This essay200 times the amount of energy from oil than is
examines the practicalities of a hydrogen-basedrequired for its’ extraction. Oil has the highest
energy system and its’ ability to provide anet energy return of any fuel; gas, coal, wind and solar
sustainable future.all have dramatically less. Hydrogen has negative net
Many people including Romano Prodi, president of theenergy meaning it takes more energy to produce it
European Commission, President Bush and numerousthan it contains, this highlights the first problem of a
"deep greens" including Amory Lovins, author ofhydrogen society.
Natural Capitalism advocate the "hydrogen economy"Counting Calories
as the future of world energy supply. The justificationAlthough it is the most abundant element in the
seems well founded; a renewable energy plantuniverse hydrogen is not very easy to obtain. Ironically,
generates electricity sporadically, hydrogen can bepetrol is the most concentrated form of hydrogen
produced by the electrolysis of water, storing energy inavailable for human consumption containing more
the form of hydrogen negates the need for large andhydrogen by volume than pure hydrogen itself, since
inefficient batteries (and associated pollution) and fuelthe structure of the atoms in hydrocarbons use less
cells (fig. 2) can turn hydrogen back into usefulspace. Hydrogen also has a very low calorific value (a
electrical energy (using oxygen from the atmosphere)gallon of petrol has 115,000 btus, a gallon of liquid
as and when required, the only by-product beinghydrogen has only 30,000 btus) so it takes about 4
steam or water.times the volume of hydrogen (compared with petrol)
The associated benefits include the elimination ofto travel the same distance, requiring larger and
exhaust pollution (sulphur dioxide, carbon monoxide,heavier fuel tanks (compressing or liquifying hydrogen
carbon dioxide and other particulates associated withuses more energy) which require additional energy to
the combustion of fossil fuels) particularly in cities, thetransport. This low calorific value dictates increased
associated reduction in global warming and the abilityvolumes (or high pressures) throughout the entire
to generate power locally promoting the developmenthydrogen system.
of a decentralised energy system. It is even suggestedHydrogen manufacture
that ultimately a hydrogen economy would help avoidThere are several ways to obtain hydrogen; by
global economic downturn due to unmanageableelectrolysis of water, by splitting water using light, by
increase in peak demand and the limited supply andcollecting and reforming gas from biomass, by
increasing costs of fossil fuels.reforming natural gas or any other fossil fuel. Each of
Don’t believe the hypethese processes is extremely energy intensive and
It’s easy to be convinced by stories wealways results in hydrogen with a negative net energy,
want to believe. Ergo magazines claims hydrogenelectrolysis (the cleanest and most appropriate
‘is the one’. Jeremy Rifkin, head ofprocess for obtaining hydrogen from wind and solar
the Foundation on Economic Trends claims thepower) is the most energy intensive of them all
hydrogen economy will be ‘the next great– roughly 75% efficient and costs roughly
economic revolution’ James Burges thinks itfour times as much as reformation. The simplest,
‘may be our only option forcheapest and most efficient process is the
survival’; hydrogen is the answer. However,reformation of natural gas, an established industry, yet
critical analysis of the properties of hydrogen and thethis is still only 85% efficient. It is therefore less polluting
necessary steps in a hydrogen society reveal a farand resource intensive to simply burn natural gas.
less optimistic picture.