July 24, 2017


The future of hydrogen fuel (Alan Finkel, 7/23/17, Cosmos)

When the hydrogen is used for stoves, or space heating, the only combustion product is water vapour! So what's standing in the way of this utopian fuel? Problem one is that producing hydrogen from electricity is only 70% efficient, so you need a very cheap electricity supply. It could be coming.

As our electricity is increasingly sourced from wind and solar, the amount available will often exceed the electrical load. Owners of the generators will seek an economically worthwhile purpose for this excess, such as charging batteries, desalinating water, or making hydrogen.

Problem two is that the current large-scale electrolysis units are so expensive that the cost of producing hydrogen is several times more than natural gas. But one thing we know for sure is that as manufacturing volumes increase, costs come down. We've seen it already in related industries. Wind turbine prices have halved in the past five years and solar prices have dropped even faster. Similar cost reductions are likely for electrolysis units.

Problem three is that steel pipes - a major part of the current gas delivery infrastructure - aren't suited to transporting hydrogen. They become brittle because the hydrogen molecules work their way into the spaces between the iron atoms and eventually cause cracks to form.

Fortunately, modern piping used for gas distribution is mostly made from polypropylene and does not suffer from this problem. Hydrogen can be mixed at up to 10% with the methane in the existing gas distribution network without any risk of corrosion nor need to change the nozzles on stoves or space heaters. Above 10% hydrogen concentration it's easier to commit and convert all gas appliances to run on pure hydrogen.

Posted by at July 24, 2017 7:41 AM