Hacker News Reader

Comment by AtlasBarfed | Hacker News Reader

All analyses of hydrogen I've read from EROEI conclude that it is more economically and thermodynamically efficient to direct power to the grid and send it to batteries.

It always seems anything this is advertised it is the fossil fuel industry trying to prop up a power generation system that will use fossil fuels, and window dressed/greenwashed by a small fraction of alt energy.

"Green Hydrogen" smells like "Clean Coal" to me.

View on HN

You're completely right but the challenge is sending the electricity from the north of Germany to the south. The construction of new transmission lines is being delayed. Generating hydrogen for use in the steel industry could be one way to take advantage of the excess energy. Long term energy storage and load following could be implemented by storing the hydrogen and burning it in natural gas plants. This is strictly necessary to increase the renewable share past 80%.

Absolutely, a lot of those wind turbines in the north sea are still not connected to the power grid because of missing infrastructure. They need to be turned by diesel generators, to not corrode. https://www.spiegel.de/international/germany/german-offshore... If they were connected there is still the problem of missing north-south transmission line.

So converting wind energy into hydrogen and using it for industry, in cars, or blending it into the natural gas pipelines is a "ok" idea. https://www.energy.gov/sites/prod/files/2014/03/f11/blending...

> Absolutely, a lot of those wind turbines in the north sea are still not connected to the power grid because of missing infrastructure.

The wind turbines mentioned in the linked article from 2013 have been in 2014 connected to the grid.

There is more to a national power system than EROEI. If hydrogen is more versatile and useful it will have advantages even if it's EROEI is lower - lets say powering remote places or powering equipment for which battery powered is not an option, but fuel cells are.

Hydrogen is difficult to transport: it leaks out of everything, it's a gas that needs to be liquified or compressed, and it is flammable.

I get that grid lines don't appear out of thin air, especially in seas/oceans.

Too bad microwave transmission cooks wildlife and humans.

Leakage is widely exaggerated. From what I read it's something like 0.1% loss from leakage.

It might well be cheaper when starting from scratch, but it’s also useful to be able to keep using existing equipment that has been built to burn gases. I don’t know how useful — it’s certainly possible it’s better to build batteries than to e.g. make hydrogen, turn that hydrogen into methane, and use that methane in existing gas plants, but I can also believe the hydrogen route might scale up faster than batteries and therefore be a decent stop-gap measure while we build enough battery-building factories.

Plus it’s always a good strategic idea to not have a single point of failure in the event of e.g. an export ban of some important input to the battery manufacture from some country you have a trade dispute with.

I've always assumed hydrogen would end up having a place as a spillover. Renewable + battery systems will need to be overbuilt for the worst parts of the year, so in the average case there's going to be an excess.

You have to do something with this power, and hydrogen allows you to store a lot of energy very cheaply at poor efficiency, perhaps for heating as gas is used today. In the summer, the excess could be used to remove carbon from the atmosphere.

You have other uses for hydrogen than using it to produce electricity: You can use it as the reducing gas in steel making. Right now coal is used.

For thermodynamic efficiency, yes, batteries are better. But they're not available at anywhere near the levels required. The global battery production capacity is at just under 300GWh per year. By comparison, the US's night-time energy consumption is ~4-5TWh. Even if we stopped producing electronics, electric cars, any any other battery product and directed the entirety of the global battery production supply to grid storage, it'd still take the US over a decade at the current production levels. And if we're trying to make the globe carbon free, you're operating on levels of demand that won't be met for the better part of a century.

Why are you assuming that we don't know how to build more battery factories? And does the wind not blow at night?

Lithium ion battery production is estimated to reach 1TWh per year in 2023 and 2TWh per year at ~2030 [1]. If you integrate that curve, you're still looking at several decades to build enough battery capacity to fulfill the world's storage demand if solar is the primary generation source.

The wind does blow at night, but intermittently. Wind generation is even when averaged out over long stretches of time, but in the near term it can vary a lot. Some estimates for how much storage we'd need to reliably meet demand for generation that comes from solar and wind at 3 days supply. The US consumes over 10TWh of energy daily.

1. https://cleantechnica.com/2019/04/14/global-lithium-ion-batt...

Why would growth slow down after 2023? And are you’re comparing primary energy to electricity? That’s a lot of waste heat that would not need to be replicated

Anyway, we don’t need all of this by 2030 if we have large scale electrification - that will have made a lot of CO2 savings in other sectors

> Why would growth slow down after 2023?

The growth is mostly linear.

> And are you’re comparing primary energy to electricity? That’s a lot of waste heat that would not need to be replicated

Are there plants that scavenge waste heat from batteries? Batteries generate some waste heat, but not at temperatures that can be used to drive a turbine.

> Anyway, we don’t need all of this by 2030 if we have large scale electrification - that will have made a lot of CO2 savings in other sectors

This is the opposite of what is true. Large scale electrification will make it so that there is even more demand on the power grid as things like cars and trains that are currently being fueled by fossil fuels now draw electricity from the grid.

It's unlikely we'll ever build enough battery factories to catch up with hydrogen based energy storage. The other guy mentioned total global battery production capacity is about 300 GWh of storage. 300 GWh can be matched by a single underground salt dome or salt cavern storing pressurized H2. A number of these facilities already exist, and the total number that could exists number in the tens of thousands worldwide.

Yes - the article states that electricity is more efficiently used directly.

Hydrogen is valuable for other processes such producing steel, high temperature heat, and chemicals.

German industry already uses large amounts of hydrogen produced from fossil methane. The first step will be to replace this with renewable hydrogen.

Interesting fact: Germany has a few 100km of hydrogen pipelines which have been in operation since the 1930s.

America has 2600 km of hydrogen pipelines:

https://hydrogeneurope.eu/hydrogen-transport-distribution#PI...

Can't hydrogen from methane be produced and the resulting carbon/CO2 effectively sequestered at production point?

Batteries are ludicrously expensive for long term energy storage, and costs don’t scale sublinearly.

Reply on news.ycombinator.com