Cost of H2 production via electrolysis of water as a function of electricity cost
In a not too distant past the “hydrogen economy” was thought to be the follow up of the fossil fuel economy. The idea was to use hydrogen as the central storage medium.
||Energy density [kWh/kg]
[wikipedia.org] – Hydrogen economy
Enthusiasm for that concept has come down considerably since, mostly because of fundamentally low conversion efficiency (50-80%) and storage problems. But that doesn’t mean that hydrogen couldn’t play a role in a renewable energy future. This IEA article makes the case that renewable hydrogen production for NH3 (Ammonia), to be used as fertilizer in agriculture, could become viable in the near future, circumventing at least the hydrogen storage problem (boiling point −252.879 °C (−423.182 °F, 20.271 K)), by converting it immediately into Ammonia (boiling point −33.34 °C (−28.01 °F; 239.81 K)).
Indeed, producing hydrogen via renewable energy is not a new idea. Until the 1960s, hydrogen from hydropower-based electrolysis in Norway was used to make ammonia – a key ingredient for agricultural fertilizers. But with increasingly lower renewable costs, renewables-based hydrogen production could once again be competitive with SMR (steam methane reforming)…
But under the right conditions, producing industrial hydrogen in this fashion could have massive consequences for the sustainability of one industry in particular – agriculture. About half of industrial hydrogen is used in ammonia production. Ammonia production alone is responsible for about 360 million tonnes of CO2 emissions each year, or about 1% of the world’s total emissions. By 2050, we expect that the consumption of ammonia will increase by around 60%.
[iea.org] – Producing industrial hydrogen from renewable energy
[wikipedia.org] – Energy density
[amazon.com] – The hydrogen economy, Jeremy Rifkin (2003)