Backing up the power grid with green methanol | Hacker News Reader

Backing up the power grid with green methanol

spectrum.ieee.org

> Overall, they calculated that the cost of electricity from the grids would be between €77 and €94 per megawatt-hour delivered. That is well within the range that grid operators pay today to balance supply and demand via natural gas-fired power plants. Their modeling found that the methanol backup is also 29 to 43 percent cheaper than that of alternate grids backed up with hydrogen

Interesting! I’d like to see the comparison with gas peakers. Seems they are on the order of $400/MWh, and utilized something like 5-10%. So if the numbers above are fully-baked including capital cost this seems like a potential big win.

On the TANSTAAFL principle, what’s the catch?

From the article it sounds like it's "potentially" economical, ready for large scale testing.

It's also a complex process - they're talking about a closed loop system with a supercritical carbon dioxide carrier stream and direct injection of liquid ox. Lots of pumps and heat exchangers - lots of maintenance. Unclear if they're taking into account all of that in their economic calculations, if they're being a little vague in order to pursue funding.

EDIT: I am pro-technology, and not questioning their process. The article does appear to me to be an advertisement.

Sorry, had to look up TANSTAFFL... There's no such thing as a free lunch. Totally makes sense now.

The Eur77-94 figure is a simulated average whole grid cost of electricity for a hypothetical grid built around renewables and storage only when including some of this type of storage, not the cost of this type of storage. They estimate LCOS for this storage at Eur309-366/MWh according to the article in Joule which is linked. I couldn't immediately see their estimates for cost of wind/solar and other types of storage which feed into the whole grid cost.

I've definitely wondered about doing similar things with renewable methane generation, which has the advantage of being able to also reuse existing natural gas infrastructure (and therefore lets people keep their precious gas stoves, among other things).

Methane does have the downside though of exacerbating climate change if it leaks into the atmosphere, and it takes a lot of energy to cool it down to a liquid, so I can definitely see how methanol might have the edge for grid-scale storage like this.

You may be aware methane biogas has other problems. It is typically very moist and contains corrosive contaminants.

Moisture content can be problematic because the presence of water vapor in biogas can lead to corrosion in pipelines and combustion engines, potentially shortening their lifespan. Moisture in biogas can reduce its calorific value, making it a less efficient than the genuine item.

Another issue is the presence of volatile sulfur compounds in biogas. These compounds, contribute to corrosion and also pose environmental and health risks when released into the atmosphere.

These problems aren't deal breakers by themselves, but the bottom line, is that when analyzing biogas we've got to take into account the extra capital expense associated with these drawbacks.

I understood the parent comment as generating renewable methane like methanol, using renewable electricity -> hydrogen (and CO2) -> methane.

This doesn't requires bacteries and feedstock in a wet disgester, so it removes the issue with moist and sulfur.

Methanol is extremely flammable, it's vapor is heavier than air at lower temperatures, it can float on water, and the flame is invisible, so leaks could create big problems. But industry already has a lot of experience handling methanol:

https://hero.epa.gov/hero/index.cfm/reference/details/refere...

https://www.aria.developpement-durable.gouv.fr/accident/3363...

I'm definitely no expert here, but...

"Storing" electricity using H2 is relatively straightforward: use electricity to electrolize water and get H2 (and O2), store the H2 (presumably liquefied) and then burn it to either generate electricity again or to power existing energy-intensive processes (e.g. smelting iron ore). Not sure how efficient the electricity -> H2 -> electricity conversion is, but ok...

Now, if you use methanol, you get the H2 like before, then "make it react" with CO2 (and CO2 is not really eager to react with anything IIRC) to get methanol, and then you burn it, getting CO2 which has to react with more H2 or otherwise you wouldn't be carbon neutral. Sounds to me like this process can only be less efficient (and more complicated) than the H2 process? Potentially much less efficient and much more complicated?

Where synthetic liquids (and indeed methane) can be interesting is if you want to ship the energy somewhere. So you can make the methanol somewhere with abundant cheap electricity and CO2, then ship or pipe it to places which lack that.

It's a lot easier and cheaper to transport methanol or methane (either piped or in the form of LNG) than H2 since it takes a lot leas space and we already have a lot of infrastructure for it.

In the long run it is cheaper to transport the energy as electricity.

That depends on the distances involved - eg if you want to generate cheap solar electricity in the Middle East or South America and export it to Europe or North America (which is something people in the industry have discussed as being potentially economical in the long term) this isn't really practical.

My amateur understanding is that the benefits are: A) H2 is exceptionally difficult to store at scale. Salt caverns are an option, but that is limited B) methanol can be used off the shelf by existing generators so the prices are much more economical and they can use both fuels during a transitory period

Only if you leave out the part about storing H2 in a tank vs storing methanol in a tank. There is a reason why they say without salt caverns to store H2, this is the cheaper process.

Liquid H2 requires cryogenic tanks. The tank will loose heat, so need continuous power to keep it cool. Or there will be H2 leak over time that will empty the tank. When BMW made their hydrogen combustion engine, the tank would get empty within a month of parking turned off.

The question is still what’s more efficient and cheaper. If storing a huge amount of liquid hydrogen in a tank and using a % of it to keep it liquid is cheaper than the methanol infrastructure and its multiple conversions, then it will succeed.

The continuous power though is actually quite minuscule in this context. NASA has a lot of test data published, e.g. for their 125 000 liter storage tank, the heat ingress in 24 h is 7.2 kWh while the energy content of the hydrogen in the tank is 290 000 kWh.

What is being proposed for energy storage is signficiantly larger than this, and then the square-cube-law gives even less heat ingress as compared to the energy of the tank contents.

Even the H2 process is horribly inefficient. Just use the electricity directly and store the small amount that is needed for peak levelling in ordinary batteries.

All these ways of using hydrocarbons are less efficient than batteries and only make sense when the hydrocarbon has a higher energy density and when the density is actually needed.

Just install a battery in every new home, make all new homes comply with passivhus standards, put solar panels on top of all new commercial buildings, generally stop wasting energy. And strengthen the interconnects between countries so that places like Spain can sell excess solar to France and thence on to the rest of Europe.

I'll add that German plans up to now were to build turbines that could take both gas and H2. Even though these have very different combustions. H2 was brought in to power the green transition. The turbines were to be developed.

Now they're actually planning them and cutting cost, surprise surprise, the turbines are gas only.

> Just install a battery in every new home, make all new homes comply with passivhus standards, put solar panels on top of all new commercial buildings, generally stop wasting energy.

We should definitely do all that. But even that isn't going to be enough. What do you do about the gazillions of existing homes that can't be well insulated, don't have space for solar panels or heat pumps etc.

I have a quite modern house (built in the 50s) but I can't get a heat pump because it has microbore heating.

> I have a quite modern house (built in the 50s) but I can't get a heat pump because it has microbore heating.

Get an air-to-air heat pump like we use in Scandinavia. A quarter the price and a better coefficient of performance. Doesn't heat your water of course.

There is a difference between short-term and long-term storage. Smoothing out hourly or daily variations is pretty easy with batteries or hydro. The problem is deficits on cloudy, calm winter days. The amount of batteries would to cover a week would be too expensive.

For now, this would be covered by gas plants but at some point need to have green solution. It is also possible to over build solar and wind to cover more days and produce excess capacity. Generated fuels work well for long-term storage since can be generated when there is excess, stored for long period of time, and are used by long-distance vehicles.

> There is a difference between short-term and long-term storage.

True. But there's no reason you can't use both.

So the "smooth out daily variation" and "store energy to address seasonal changes" are 2 problems that can be attacked independently. Maybe some solution(s) may be useful for both jobs, but this is not necessary.

I suspect in most cases, batteries will be more practical / economical for short-term storage. For long-term storage (or transporting energy across the globe) methanol is just one of many options.

The key argument of the paper this is based on is that storing H2 is difficult if you don't have salt caverns. Then you need H2 pressure tanks, and that is expensive and also requires a lot of energy. And you don't have salt caverns everywhere.

The authors compare this in an energy model, and come to the conclusion that methanol comes out on top if you don't have cheap (aka salt cavern) h2 storage. But of course, there are a lot of assumptions going into this.

Nice bonus: It's an open source model, so others can test it with different assumptions.

H2 storage can also be done by liquefaction, which is a lot more practical than compressed when we are talking longish-term storage. Yes, you will use energy to cool and liquefy H2, but a lot of this can be recovered when you go back again.

> I'm definitely no expert here, but... "Storing" electricity using H2 is relatively straightforward

Never assume that anything is easy at scale.

I remember watching my high school chemistry teacher generate hydrogen and oxygen, and then burn the hydrogen. (And show that a match became more intense in pure oxygen.)

But that doesn't mean it's "relatively straightforward" to do that on massive scale: It turns out the electrodes were a precious metal, and the water had to be fresh water. If you run electrolysis in seawater, you get chlorine gas instead of pure oxygen.

Also, don't forget that it's very hard to compress hydrogen. Without going into the details: Compressing hydrogen takes energy, and keeping it cold (so it stays compressed) also takes energy. (It's hard to compress hydrogen to have the same energy density as propane.) And then, getting electricity back from hydrogen isn't 100% efficient.

If you're not careful, the cost to make hydrogen, store it, and then generate electricity back can be more than what the electricity is worth.

(FYI: Estimates for hydrogen cars put the electricity -> hydrogen -> electricity path at roughly 50% efficiency, compared to electricity -> battery -> electricity, which is > 90%. This generally implies that hydrogen will cost more, per mile, than electricity.)

FWIW, I had also written about this paper: https://industrydecarbonization.com/news/should-we-burn-meth...

This technology has been around for over two decades at least [1], and the reluctance of the Department of Energy and the investor-owned-utility sector to adopt it is really only due to the political pressure applied by the natural-gas sector, as the resulting fall in demand for natural gas would have made fracking for gas uneconomical. Note that both political parties in the USA got behind this fossil fuel agenda, it's entirely bipartisan in nature (the fracking boom took place under Obama, and was continued under Trump, and was boosted by the Ukraine war and sanctions on Russia, which resulted in increased LNG exports to Europe).

[1] "Methanol synthesis from flue-gas CO2 and renewable electricity: a feasibility study" (2003) (available in full on sci-hub)

> "This paper describes a novel but proven process (CO2+3H2→CH3OH+H2O) which could be adapted to use, as input reagents, CO2 emitted from fossil-fuelled power stations and hydrogen from electrolysis of water by a zero-emissions electricity source, e.g. renewable and/or nuclear energy. This approach, in addition to addressing the above two issues, would produce methanol for which there is a ready and expanding market."

One generally solid conclusion is that the countries that have to import fossil fuels are going to be the ones leading in transitioning off fossil fuels, and as expected, China is ahead in this technological sector as well:

https://www.technologyreview.com/2022/09/30/1060508/china-be...

If I'm understanding correctly, the innovation touted in the article is not the Methanol electrolysis, but the Allam combustion cycle which sequesters the CO2 byproduct.

Maybe they are taking carbon capture credit into their accounting, since nowhere do they mention the efficiency of the Allam cycle.

Please forgive the almost-off-topic question, but I've been curious for years and can never find a straight answer. Is there no microbe out there that will ferment sugar/starch into methanol? I once found a paper on methanol poisonings in the developing world which didn't seem deliberate, and the authors suggested there were some opportunistic yeast that might be the culprit.

High energy chemistry to make methanol just seems to almost miss the point.

There probably is one out there somewhere. But there are many that ferment to ethanol and those are looked after and can probably out compete the methanol in most situations.

Honestly if you're just trying to store energy going to ethanol is fine too. It'll burn just fine provided you've dehydrated it enough.

It almost doesn't matter. These bio processes are only good for generating a small amount of the energy we need, but as you get to volume there is a need to add fertilizer in the mix. Fertilizer uses fossil fuels and energy to make, thereby negating any gains of the bio process over just using the fossil fuels and energy directly.

You can't feed microbes the surplus energy from your wind or solar farm, though.

> Microbial electrolysis cell (MEC) is a significantly sustainable bio-electrochemical system for biological hydrogen production. MEC is also regarded as an environmentally friendly method for producing clean biohydrogen from a variety of waste organic matters and for its low greenhouse gas emissions. This technology involves the oxidation of organic matter at the anode and the reduction of proton at the cathode under the nominal external voltage supply. However, bio-hydrogen production efficiency and operating costs of MEC still need further optimization to implement in large-scale applications.

https://www.sciencedirect.com/science/article/abs/pii/S13858...

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