On this page, I regularly post developments across the world that are of relevance to energy storage, distrubution and portability. I also report on the attention that The Decarbonization Delusion is receiving.
I just picked this one up via Linkedin, so I thought I’d have a go at it with the example of Spain given in the question:
Bottom line – well, actually the top line 🙂 with the assumptions made below, the amount of water needed in Spain for the necessary hydrogen per year would be 2.6% of current agricultural use of water in Spain per year. Note, this is based SOLELY on the assumptions and information below: it is not necessarily realistic, but gives some kind of idea…
Here’s a back-of-an-envelope calculation that I’ve just done, assuming the following:
1. We very crudely equate current primary energy consumption in Spain directly 1:1 with equivalent energy from hydrogen. This definitely isn’t 100% accurate, because, for example, hydrogen-fired steel-making uses less MWh per tonne of steel than coal-fired steel making. However, it gives us a reference point from which to refine the calculation.
2. Current annual primary energy consumption in Spain is around 1,600 Terawatts per year (see https://ourworldindata.org/energy/country/spain).
3. The electrolysis reaction is H2O -> H2 plus 0.5 O2
4. Molar masses (molecular „weights“) are H2O = 18 g/mol ; H2 = 2 g/mol which means, in terms of mass (weight), we need nine tonnes of water to make one tonne of hydrogen gas.
5. Hydrogen has a gravimetric energy density of 131 MJ/kg (averaged between HHV and LHV, because we don’t know whether we can recuperate the energy of water vapour formation); this is equal to 36 kWh/kg hydrogen gas.
The calculation:
1,600 TWh per year is 1.6 x 10EXP12 kWh per year
Divided by 36 kWh/kg hydrogen gas energy content => 4.4 x10EXP10 kg hydrogen
This equals 44 million tonnes of necessary hydrogen gas.
To make that via electrolysis, the theoretical minimum mass of water is 9 x 44 million tonnes, which = 400 million tonnes of necessary water.
How much are 400 million tonnes of water? – i.e. 400 million cubic meters.
From Statista, I get a value of 15,500 million cubic meters of water used currently in agriculture in Spain per year (see https://www.statista.com/statistics/1218844/irrigation-water-used-agricultural-sector-spain/) . So, 40 divided by 15,500 gives us a relation to current agricultural usage of water, and it equals 2.6%.
Bottom line: with the assumptions made above, the amount of water needed in Spain for the necessary hydrogen per year would be 2.6% of current agricultural use of water in Spain per year.
2024, January: United Nations predicts serious environmental and social impacts of raw material mining up to 2060…
And see also report in Sustainability & Environment Network 2024.
Invited talk at the Lions Club in Lampertheim, Hessen, Germany on 17th September 2024
Interview with India Bioscience in their series “Carbon Chronicles”:
Invited talk at Colchester Royal Grammar School, in memory of Dr. Neil Cook, Chemistry Department CRGS
Download the presentation here.
Audio podcast: Andrew Moore interviewed by Adam Dixon, Adam Smith Chair of Sustainable Capitalism, Heriot-Watt University, Edinburgh
Video clip from the Panmure House interview with Prof. Adam Dixon.
Q&A with renowned American journalist Deborah Kalb.
andrewmoorescientist.com Analyses and comparisons in energy and material economies Email