Can renewables replace fossil and nuclear fuels?

[slowtech]

Renfe (Spain) gave a HSR trainset contract to Siemens. 30 Velaro Novo will join the fleet starting with 5 units in 40 months (and completed in 62 months). The trainsets are similar to the ones announced for Brightline West (10 sets).

Cool! I don't know anything about high speed trains, so I looked this one up:

https://en.wikipedia.org/wiki/Siemens_Velaro#Velaro_Novo

So, faster and lighter? What else do you think is important about this upgrade?

 

[tucu]

Energy consumption is down and in-service speed is up compared to the existing Velaros from the 2000s. Passenger capacity grows from 404 to 520 in the Renfe seat configuration.
They are adding batteries for last mile operation in case of power failure.
They will also be right on time to replace the Alstom/CAF units from the 90s (the first ones and still in operation between Madrid and Seville)

 

[demultiplexer]

How would it not replace heating? It's literally providing heat, and most industrial uses of heat are below the temperature provided by their technology.

It doesn't replace gas heating, which is the majority use case. You can't pipe this into central heating, paper mill gas burners, etc., without extensive retrofitting to work on direct heat. At least in the Netherlands and Germany, the vast majority of natural gas is used in burner applications, of which residential and commercial space heating and electricity generation is the vast majority.

This is the exact same problem that hydrogen heating has. It requires retrofitting a very finely distributed network that already exists and has negligible infrastructure costs. Any cost advantage of the energy source is immediately negated by the infrastructure cost.

Plus it has the exact same first mover disadvantage; those companies or municipalities that would like to use something like this have to bear the full costs, there is no initial cost distribution like there is with universal networks like electricity and gas. Contrary to popular engineering belief, this is actually where almost every centralized new energy proposal has stranded in the past 50 years.

If we then get into the actual decarbonization goals of, because I am in this industry, the Netherlands, the places where natural gas goes are:

• Electricity generation (38%). Not replaced by heat batteries
• Household and commercial space heating (34%). Heat pumps
• Agriculture - horticulture (4%): CHPs and CO2 generation. Easily replaceable with geothermal heat, heat pumps and industrial CO2
• Agriculture - fertilizer (3%): probably green hydrogen
• Industry - refineries (7%): should just go away
• Industry - chemical sector (6%): vast majority is syngas, heat is a byproduct or catalytic, so probably green hydrogen
• The rest: I'm sure there is some potential opportunity for heat batteries here?

 

[tucu]

It doesn't replace gas heating, which is the majority use case. You can't pipe this into central heating, paper mill gas burners, etc., without extensive retrofitting to work on direct heat. At least in the Netherlands and Germany, the vast majority of natural gas is used in burner applications, of which residential and commercial space heating and electricity generation is the vast majority.

This is the exact same problem that hydrogen heating has. It requires retrofitting a very finely distributed network that already exists and has negligible infrastructure costs. Any cost advantage of the energy source is immediately negated by the infrastructure cost.

Plus it has the exact same first mover disadvantage; those companies or municipalities that would like to use something like this have to bear the full costs, there is no initial cost distribution like there is with universal networks like electricity and gas. Contrary to popular engineering belief, this is actually where almost every centralized new energy proposal has stranded in the past 50 years.

If we then get into the actual decarbonization goals of, because I am in this industry, the Netherlands, the places where natural gas goes are:

• Electricity generation (38%). Not replaced by heat batteries
• Household and commercial space heating (34%). Heat pumps
• Agriculture - horticulture (4%): CHPs and CO2 generation. Easily replaceable with geothermal heat, heat pumps and industrial CO2
• Agriculture - fertilizer (3%): probably green hydrogen
• Industry - refineries (7%): should just go away
• Industry - chemical sector (6%): vast majority is syngas, heat is a byproduct or catalytic, so probably green hydrogen
• The rest: I'm sure there is some potential opportunity for heat batteries here?

Over here the government and industry associations keep pushing for solar thermal and thermal batteries for industry decarbonization (industry counts as 50% of natural gas use) but they keep getting beaten by alternatives. Certified biomass seems abundant and cheap at the moment and a combo of PV, heat pumps and chemical batteries gets cheaper (relatively to natural gas).
Recently, Stellantis said that a natural gas partial replacement in their Madrid plant is going well. They installed heat pumps, 12.4 MW of PV and 25 MWh of batteries and emissions for thermal use in the plant are down 57% .
Mahou (beer) installed this year 20 MW of biomass boilers for heat in their plant not far from Madrid.

The 2023 project at Heineken Seville (30MW/68MWh) seems to be the few successes for solar thermal and thermal batteries.

 

[demultiplexer]

Same here, for a concrete example there was a large feasibility study for horticulture heating in our local area (Bleiswijk horticultural development area) and the end result is now actually here: 4 geothermal wells with - currently being constructed - hot water distribution. They've even considered using the geothermal reservoirs as thermal batteries by 'charging' them in summer, but it was not deemed cost effective.

A pilot project for recharging geothermal reservoirs is underway on our campus though, same company building them as the other geothermal projects: https://www.gaiaenergy.nl/project/slimme-warmtebuffer-met-ates-technologie

But nobody is considering purpose-built thermal batteries anymore, they get outcompeted by everything.

 

[Demento]

I don't really get the hype over hydrogen in the gas supply. If you want to make gas heating a bit greener, just create methane instead of pure H2. The Sabatier reaction is very efficient once you've climbed the hurdle of creating the hydrogen itself, and you have something that works in the existing infrastructure and takes in as much CO2 as it gives out. Ideally we wouldn't burn anything in our homes, and I think green methane to nothing at all is a saner jump than fossil methane to hydrogen to nothing.

 

[wco81]

Energy consumption is down and in-service speed is up compared to the existing Velaros from the 2000s. Passenger capacity grows from 404 to 520 in the Renfe seat configuration.
They are adding batteries for last mile operation in case of power failure.
They will also be right on time to replace the Alstom/CAF units from the 90s (the first ones and still in operation between Madrid and Seville)

Unfortunate, tragic news regarding RENFE today.

 

[tucu]

Unfortunate, tragic news regarding RENFE today.

yes. It seems the LZB (continous train control) stopped working in a segment of the track and with auto mode offline a controller allowed an Alstom unit from Renfe to advance while a Frecciarrosa (from Iryo/Trenitalia) was stuck. The crash was bad and they are still recovering victims.

 

[paulfdietz]

I don't really get the hype over hydrogen in the gas supply. If you want to make gas heating a bit greener, just create methane instead of pure H2. The Sabatier reaction is very efficient once you've climbed the hurdle of creating the hydrogen itself, and you have something that works in the existing infrastructure and takes in as much CO2 as it gives out. Ideally we wouldn't burn anything in our homes, and I think green methane to nothing at all is a saner jump than fossil methane to hydrogen to nothing.

If you are creating methane, where are you getting the carbon?

 

[Quarthinos]

If you are creating methane, where are you getting the carbon?

The sabatier process strips it from carbon dioxide to make water and methane... I don't know what concentration of CO2 you need, but the atmosphere has too much anyway?

 

[demultiplexer]

I don't really get the hype over hydrogen in the gas supply. If you want to make gas heating a bit greener, just create methane instead of pure H2. The Sabatier reaction is very efficient once you've climbed the hurdle of creating the hydrogen itself, and you have something that works in the existing infrastructure and takes in as much CO2 as it gives out. Ideally we wouldn't burn anything in our homes, and I think green methane to nothing at all is a saner jump than fossil methane to hydrogen to nothing.

OK, so to your specific question: it's not considered scope 1 closed cycle if you synthesize methane, with any realistic process. If you're going to make this kind of stuff at a large scale, it's going to be syngas synthesis, so the inputs are (H2O+)CO+H2 and the output is going to be a process-dependent mix of CnHn. Even if you try your best to make as much CH4 as possible, you're also going to make CO2 and larger hydrocarbons which then need to be purified. Altogether, even if you use atmospheric CO2 as a carbon source, the whole process wastes a whole lot of energy and input gas on unwanted products which, in this hypothetical scenario where you're replacing fossil gas, will be produced at such a massive scale that they can't be feasibly repurposed elsewhere.

So this is why synthetic methane is so much more inherently polluting and not considered a viable solution, whereas e.g. biological origin methane (e.g. biomethane, algae-derived methane) is considered closed-cycle climate neutral.

Hence, injecting hydrogen, with all its problems as well, Or injecting other synthetic or bioderived combustibles. All of these ideas are really 2000s coded. Back then, it was genuinely impossible to envision a world where we could decarbonize fossil industries, heating, etc., with just renewables and batteries. The scale of fossil gas production is in the cubic kilometers, it's a mind-boggling amount of natural gas that we use each year around the world, and even at (then) unimaginable growth rates, solar, wind and batteries wouldn't be able to get there in time.

But now we have heat pumps, renewables, batteries and even some individual categories in there (e.g. solar, LFP batteries) getting well into the TW|TWh/year range and still growing tens of percent per year. Total natural gas (primary) usage is in the 10 000TWh/year, so we're basically there with nameplate renewables generation and if you include the COP of heat pumps we're nearing global fossil replacement territory for battery deployment in ~5-10 years as well.

 

[paulfdietz]

The sabatier process strips it from carbon dioxide to make water and methane... I don't know what concentration of CO2 you need, but the atmosphere has too much anyway?

Ah, so you're depending on Direct Air Capture of CO2. This is quite expensive. Your idea doesn't make sense.

 

[Demento]

OK, so to your specific question: it's not considered scope 1 closed cycle if you synthesize methane, with any realistic process. If you're going to make this kind of stuff at a large scale, it's going to be syngas synthesis, so the inputs are (H2O+)CO+H2 and the output is going to be a process-dependent mix of CnHn. Even if you try your best to make as much CH4 as possible, you're also going to make CO2 and larger hydrocarbons which then need to be purified. Altogether, even if you use atmospheric CO2 as a carbon source, the whole process wastes a whole lot of energy and input gas on unwanted products which, in this hypothetical scenario where you're replacing fossil gas, will be produced at such a massive scale that they can't be feasibly repurposed elsewhere.

So this is why synthetic methane is so much more inherently polluting and not considered a viable solution, whereas e.g. biological origin methane (e.g. biomethane, algae-derived methane) is considered closed-cycle climate neutral.

Hence, injecting hydrogen, with all its problems as well, Or injecting other synthetic or bioderived combustibles. All of these ideas are really 2000s coded. Back then, it was genuinely impossible to envision a world where we could decarbonize fossil industries, heating, etc., with just renewables and batteries. The scale of fossil gas production is in the cubic kilometers, it's a mind-boggling amount of natural gas that we use each year around the world, and even at (then) unimaginable growth rates, solar, wind and batteries wouldn't be able to get there in time.

But now we have heat pumps, renewables, batteries and even some individual categories in there (e.g. solar, LFP batteries) getting well into the TW|TWh/year range and still growing tens of percent per year. Total natural gas (primary) usage is in the 10 000TWh/year, so we're basically there with nameplate renewables generation and if you include the COP of heat pumps we're nearing global fossil replacement territory for battery deployment in ~5-10 years as well.

I wasn't hoping that it would replace renewables taking over. Just that I didn't understand why H2 over the existing gas system was so popular in some circles. It needs so much retrofitting that it makes no sense vs. either a (hopefully) direct switch to renewables, or at least a greener way of generating methane. Thank-you for the details on the methane side, which I was ignorant of.

 

[paulfdietz]

Terraform: PV power for $0.016/kWh (off grid, 1.8 MW scale)

https://terraformindustries.wordpre...rm-built-the-cheapest-solar-in-north-america/

 

[Quarthinos]

Ah, so you're depending on Direct Air Capture of CO2. This is quite expensive. Your idea doesn't make sense.

I didn't have any ideas about sabatier, I was just giving you an uninformed but technically possible answer, based on a quick wikipedia of sabatier reaction, since you seemed to not know how sabatier works. If you're super informed about the field, why did you need to ask a question about the sabatier process? It's been mooted as being useful on Mars for making methane fuel. I think the martian atmosphere is thin enough that getting CO2 out of it would be much more difficult than Earth? But again, I'm not a Chem E guy, just someone who doesn't appreciate being called out for having an "idea that doesn't make sense."

 

[MilleniX]

If I'm doing the math about Earth vs Mars right, Mars's atmosphere has a partial pressure of CO₂ about 14x that of Earth's, with the remaining 5% almost entirely Ar and N₂ (i.e. no pesky oxygen to fraction out)

The math:

Spoiler

Earth: ~1 atm, 400 ppm CO₂ = 4e-4 atm CO₂
Mars: 0.006 atm, 95% CO₂ = 5.7e-3 atm

Ratio of the two: 14.25x

 

[Technarch]

Terraform: PV power for $0.016/kWh (off grid, 1.8 MW scale)

https://terraformindustries.wordpre...rm-built-the-cheapest-solar-in-north-america/

JFC that's cheap. Hard to believe any other energy besides wind gets any attention at all.

 

[paulfdietz]

JFC that's cheap. Hard to believe any other energy besides wind gets any attention at all.

The take away should be there's a huge overhead for going onto the grid. I'm leaning toward a future where the grid disintegrates due to defection, at least outside dense areas.

 

[Shavano]

Mahou (beer) installed this year 20 MW of biomass boilers for heat in their plant not far from Madrid.

Is this burning the byproducts of beer production for process heat needed for the process, or are they supplementing?

 

[tucu]

Is this burning the byproducts of beer production for process heat needed for the process, or are they supplementing?

Both it seems. It burns biogas generated in the plant and biomass from agriculture and forestry (SURE certification)

 

[tucu]

In California the CAHSR authority also awarded Siemens a contract for the Velaro Novo. 3 trainsets initially with an option for 19 more.

 

[Tom the Melaniephile]

Both it seems. It burns biogas generated in the plant and biomass from agriculture and forestry (SURE certification)

Hm. This article seems to indicate that the biogas and use of brewing waste is aspirational.

I started thinking about heat demand in breweries. Here's that tangent:

If the brewery is dark-roasting the malted grain onsite, there's going to be demand for higher temperatures than brewing. A heat pump probably isn't feasible for this step.

If they are simply drying the grain after malting (and maybe a light roast) the brewery should only need low-grade heat. Looked up some information, and the vast majority of the beer that brewery makes doesn't use roasted grain.

Let's focus in on the actual brewing process, which would only need low-grade heat. An initial rough evaluation seems to indicate that using heat pumps could be quite advantageous if set up correctly. Breweries need heating and chilling at different stages in the process, making heat pumps especially interesting. Presume multiple batches in process so that we can move heat between batches.

Mashing the malted grain and water is typically ~65°C. The grain is then separated and the wort is typically boiled. Dissolved solids (mostly sugars) will elevate the boiling point slightly, but we'll just say ~100°C . Might take us into high temperature heat pump (HTHP) territory, so I'll go with that assumption.

This is conceptual. Actual feasibility study would need an actual engineer (I expect ChemE the most likely) to do the math. I'm both oversimplifying and ignoring some interim steps in the commercial brewing process.

Potential layout:

Tank 1: Mashing. Heat malted grain and water with conventional ASHP* from ambient to ~65°C. Dwell time of ~60 minutes. ~65°C wort goes to Tank 2.
Tank 2: Boil. Heat wort to ~100°C with HTHP sourcing heat from Tank 3. Dwell time of ~60 minutes. ~100°C wort goes to Tank 3.
Tank 3: Chill. Chill wort to ~15°C with HTHP dumping heat to Tank 2. ~15°C wort goes to fermentation tank where fermentation will slowly generate heat.

Based on this site, it sounds like a CoP of at 2-3 would be achievable for an air source HTHP needed for the boil. CoP for the proposed process should be meaningfully better due to how we're sourcing the heat. Tank 2 starts out at ~65°C and is sourcing heat from Tank 3 initially at 100°C, so initially our heat source is hotter than the destination.

*Lots of options for a ChemE to explore. Maybe Tank 1 should also source heat from Tank 3. Maybe Tank 1 should source heat from the fermentation tanks. Fermentation tanks generally need chilling. Maybe source from both Tank 3 and fermentation tanks then use dynamic adjustment depending on where heat needs to be moved to achieve/maintain desired temperatures. How would better insulation change the design? Interesting puzzle.

 

[Tom the Melaniephile]

JFC that's cheap. Hard to believe any other energy besides wind gets any attention at all.

"Off grid" and rapid construction timeline seem key to the low cost. We've previously had some discussion of the cost and timeline advantages of staying off grid, though the one I specifically recall was using solar panels to power thermal storage.

 

[tucu]

Hm. This article seems to indicate that the biogas and use of brewing waste is aspirational.

I started thinking about heat demand in breweries. Here's that tangent:

If the brewery is dark-roasting the malted grain onsite, there's going to be demand for higher temperatures than brewing. A heat pump probably isn't feasible for this step.

If they are simply drying the grain after malting (and maybe a light roast) the brewery should only need low-grade heat. Looked up some information, and the vast majority of the beer that brewery makes doesn't use roasted grain.

Let's focus in on the actual brewing process, which would only need low-grade heat. An initial rough evaluation seems to indicate that using heat pumps could be quite advantageous if set up correctly. Breweries need heating and chilling at different stages in the process, making heat pumps especially interesting. Presume multiple batches in process so that we can move heat between batches.

Mashing the malted grain and water is typically ~65°C. The grain is then separated and the wort is typically boiled. Dissolved solids (mostly sugars) will elevate the boiling point slightly, but we'll just say ~100°C . Might take us into high temperature heat pump (HTHP) territory, so I'll go with that assumption.

This is conceptual. Actual feasibility study would need an actual engineer (I expect ChemE the most likely) to do the math. I'm both oversimplifying and ignoring some interim steps in the commercial brewing process.

Potential layout:

Tank 1: Mashing. Heat malted grain and water with conventional ASHP* from ambient to ~65°C. Dwell time of ~60 minutes. ~65°C wort goes to Tank 2.
Tank 2: Boil. Heat wort to ~100°C with HTHP sourcing heat from Tank 3. Dwell time of ~60 minutes. ~100°C wort goes to Tank 3.
Tank 3: Chill. Chill wort to ~15°C with HTHP dumping heat to Tank 2. ~15°C wort goes to fermentation tank where fermentation will slowly generate heat.

Based on this site, it sounds like a CoP of at 2-3 would be achievable for an air source HTHP needed for the boil. CoP for the proposed process should be meaningfully better due to how we're sourcing the heat. Tank 2 starts out at ~65°C and is sourcing heat from Tank 3 initially at 100°C, so initially our heat source is hotter than the destination.

*Lots of options for a ChemE to explore. Maybe Tank 1 should also source heat from Tank 3. Maybe Tank 1 should source heat from the fermentation tanks. Fermentation tanks generally need chilling. Maybe source from both Tank 3 and fermentation tanks then use dynamic adjustment depending on where heat needs to be moved to achieve/maintain desired temperatures. How would better insulation change the design? Interesting puzzle.

The Mahou press release says that SURE biomass and biogas from the water treatment installation are in use and that they are looking into burning the "bagazo" too (should translate as bagasse).
Heatpumps and batteries would be nice, complementing the existing 5 MW PV installation that they added around 2021.

 

[Shavano]

Both it seems. It burns biogas generated in the plant and biomass from agriculture and forestry (SURE certification)

I was thinking more burning the malted barley, after fermentation. You can produce methane from that with the right environment, and maybe that's easier to control.

edit: actually I'd be surprised if some brewers didn't always burn dried grain after making wort, for part of the heat needed to boil the next batch of wort.

 

[tucu]

I was thinking more burning the malted barley, after fermentation. You can produce methane from that with the right environment, and maybe that's easier to control.

edit: actually I'd be surprised if some brewers didn't always burn dried grain after making wort, for part of the heat needed to boil the next batch of wort.

They are working on burning the leftovers from malting barley. That is the "bagazo" they are trying to burn; the definition of bagazo is wider than bagasse in englIsh it seems. It also appear that the processed bagazo is also valuable as an ingredient in breadmaking (as it contains proteins, fibre and minerals) and as animal feed. So further separation might be needed before burning: