[HN Gopher] Backing up the power grid with green methanol
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Backing up the power grid with green methanol
Author : SiempreViernes
Score : 31 points
Date : 2024-01-19 14:48 UTC (8 hours ago)
(HTM) web link (spectrum.ieee.org)
(TXT) w3m dump (spectrum.ieee.org)
| NickM wrote:
| 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.
| engineer_22 wrote:
| 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.
| hommelix wrote:
| 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.
| theptip wrote:
| > Overall, they calculated that the cost of electricity from the
| grids would be between EUR77 and EUR94 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?
| engineer_22 wrote:
| 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.
| vondur wrote:
| Sorry, had to look up TANSTAFFL... There's no such thing as a
| free lunch. Totally makes sense now.
| tomatocracy wrote:
| 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.
| photochemsyn wrote:
| 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...
| engineer_22 wrote:
| 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.
| rob74 wrote:
| 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?
| tomatocracy wrote:
| 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.
| kwhitefoot wrote:
| In the long run it is cheaper to transport the energy as
| electricity.
| tomatocracy wrote:
| 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.
| kippinitreal wrote:
| 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
| megaman821 wrote:
| 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.
| hommelix wrote:
| 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.
| user568439 wrote:
| 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.
| semi-extrinsic wrote:
| 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.
| kwhitefoot wrote:
| 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.
| BenoitP wrote:
| 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.
| IshKebab wrote:
| > 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.
| ianburrell wrote:
| 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.
| hannob wrote:
| 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.
| semi-extrinsic wrote:
| 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.
| gwbas1c wrote:
| > 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.)
| hannob wrote:
| FWIW, I had also written about this paper:
| https://industrydecarbonization.com/news/should-we-burn-meth...
| NoMoreNicksLeft wrote:
| 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.
| msandford wrote:
| 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.
| megaman821 wrote:
| 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.
| DFHippie wrote:
| You can't feed microbes the surplus energy from your wind or
| solar farm, though.
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