INSIGHT
Power play
Alternative energy innovator ITM Power is to market a Green Box domestic electrolyser that
can produce affordable hydrogen for powering homes and cars. Berenice Baker reports
AS THE cost of petrol and domestic
energy bills hit the roof, a system that
produces and stores hydrogen that can
fuel your car and heat your home — and
remains affordable and green — sounds
like a gift from the technology gods.
28
Sadly for motorists and householders,
the much-vaunted hydrogen economy has
remained an elusive dream, dogged by
high costs and a lack of infrastructure.
Alternative energy innovator ITM
Power, based in Saffron Walden, believes
part of the solution may lie in its fridge-
freezer-sized domestic electrolyser, the
Green Box. The device, soon to enter pro-
duction, produces affordable hydrogen
using water and solar or wind energy,
which can fuel vehicles and power homes.
Jim Heathcote, ITM’s chief executive,
says the system overcomes one of the fun-
damental problems of renewable energy,
whether for domestic or commercial use.
He claims renewable energy is not a
substitute for a reliable grid system and
is impracticable without storage. ITM’s
vision is to store hydrogen produced by
wind or solar energy, or off-peak electric-
ity. ‘You can’t run a factory just when the
wind blows, and countries with a large
wind penetration have to run fossil-fuel
plants in parallel in case the wind drops.
So renewable energy systems don’t do the
job without storage,’ said Heathcote.
‘What we have to do is take this inter-
mittent renewable energy and make a use-
ful fuel. The battle for energy security is
based on whether we can make hydrogen
cost-competitive with the competing fuels,
and that is what we are attempting to do.’
The heart of ITM’s technology is a
polymer membrane that it claims is supe-
rior to existing alternatives.
Heathcote says electrolysis technology
can be difficult because of the aggressive
chemical environment it entails, which
has so far made a low-cost endurable elec-
trolyser impossible. Alkaline electroly-
sers use a liquid electrolyte that can
absorb some of the gases produced, mak-
ing it potentially explosive and requiring
the extra cost of degasification plant. Acid
chemistry electrolysers use a fluorinated
polymer membrane to keep the hydrogen
and oxygen separate, but the polymer and
Hydrogen power
may hold the key
to practical
renewables, with
applications for
the home and car,
according to ITM
the platinum catalyst used in the
process are too expensive.
Standard membrane materials cost
about £250/m 2 , but ITM Power’s mem-
brane could be produced for about
£2.50/m 2 , the company claims.
ITM has developed a new class of
material called an ionically conducting
hydrophilic cross-linked polymer, which
it claims costs one per cent of the price of
current polymers and its high ionic con-
ductivity gives increased gas output.
The materials start as liquids,
which are poured into a mould and
made to cross-link using gamma or
ultraviolet radiation. The molecules
join together in 3D so there are no ends
that would be susceptible to end-chain
degradation and no need for fluorine.
‘We have made a low-cost, endurable
polymer,’ said Heathcote, ‘and after
years of testing, we have not been able
to identify a failure mode for it.
‘Because our materials start as
liquids, we are able to add an alkaline
component or an acid component before
we polymerise it, so we got rid of the
degasification of the traditional
alkaline electrolysers and the platinum
from the acid electrolysis.’
The electrolyser could have a signifi-
cant impact in transportation. ITM is
the EnGIneeR 2–15 JUNE 2008
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