Green Hydrogen is NOT a Renewable Power Source

I know the title is suggestive of a click-bait post, but do read on, won’t you?

This post is a result of some of my business acquaintances giving me miffed calls yesterday after I called green hydrogen hot air. ( https://lnkd.in/gbt5VdGh )

Quite a few of these folks complained that it was not fair to compare green hydrogen with storing solar power in batteries – a contest in which GH2 does abysmally on efficiency.

Some of them said that 𝐈 𝐬𝐡𝐨𝐮𝐥𝐝 𝐜𝐨𝐧𝐬𝐢𝐝𝐞𝐫 𝐠𝐫𝐞𝐞𝐧 𝐡𝐲𝐝𝐫𝐨𝐠𝐞𝐧 𝐚𝐬 𝐫𝐞𝐧𝐞𝐰𝐚𝐛𝐥𝐞 𝐞𝐧𝐞𝐫𝐠𝐲 𝐬𝐨𝐮𝐫𝐜𝐞. Here, I can tell you something – 𝐜𝐨𝐧𝐬𝐢𝐝𝐞𝐫𝐢𝐧𝐠 𝐠𝐫𝐞𝐞𝐧 𝐡𝐲𝐝𝐫𝐨𝐠𝐞𝐧 𝐟𝐫𝐨𝐦 𝐞𝐥𝐞𝐜𝐭𝐫𝐨𝐥𝐲𝐬𝐢𝐬 𝐚𝐬 𝐫𝐞𝐧𝐞𝐰𝐚𝐛𝐥𝐞 𝐩𝐨𝐰𝐞𝐫 𝐬𝐨𝐮𝐫𝐜𝐞 𝐢𝐬 𝐚 𝐬𝐭𝐮𝐩𝐢𝐝 𝐢𝐝𝐞𝐚.

Why?

First, let’s consider why someone could think it is a renewable energy source – the argument is, if one is using renewable solar power and converting it into green hydrogen to be used for heating or power applications, isn’t green hydrogen a renewable power source as well?

If you wish to insist on technicalities, yes, it is a “source” of renewable energy.

But you may not wish to stress too much on this technicality, because of the simple but important concept of 𝐄𝐑𝐎𝐄𝐈 – 𝐞𝐧𝐞𝐫𝐠𝐲 𝐫𝐞𝐭𝐮𝐫𝐧𝐞𝐝 𝐨𝐧 𝐞𝐧𝐞𝐫𝐠𝐲 𝐢𝐧𝐯𝐞𝐬𝐭𝐞𝐝 (also called just EROI).

For any energy source (renewable or otherwise), you need to get more energy out of the system than the energy you pump in to recover that. Otherwise, what is the point?

For petroleum, EROEI can be as high as 10 or even higher depending on where you dig for oil – you can get 5-10 times the energy in a Kg of oil compared to the energy you put in to extract it, and this is why oil is still relatively cheap. For renewable power sources such as solar and wind, EROEI can start from 5 and easily exceed 10 in many scenarios. For biofuels, it is in the 1.5-3 range (so, relatively poor).

You get the idea.

Now, to green hydrogen. To produce one Kg of hydrogen from water, it takes about 50 units of electricity. And 1 Kg of hydrogen contains the energy equivalent of about 33 units of electricity.

That is, you get about 65 units of energy from green hydrogen for every 100 units of energy you put in to produce it by splitting water – an EROEI of 0.66.

Why would anyone give 100 Rs to get back 65….unless there is a special reason to do so…?

And the special reason is that green hydrogen is an excellent avenue for long-duration storage of green power, especially surplus electricity from solar and wind power plants that cannot be fed to the grid for various reasons.

Thus, the 𝐨𝐧𝐥𝐲 𝐰𝐚𝐲 electrolysis-based GH2 makes sense in the context of power is, if it is considered as a storage medium or as a carrier. The earlier para also gives a hint of one way GH2 can compete in power applications with far superior efficiencies of batteries – think long term.