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Night Steam or Solar/Steam is when you get enough solar panels to cover your daytime energy usage and enough steam engines to cover your nighttime energy usage. During twilight they both contribute. It is an alternative to pure steam or solar/accu, performance wise it is similar to solar/accu with steam backup, altough cheaper and simpler.

Compared with Solar/Accu it is about half as expensive and requires no oil whatsoever and is immune to blackouts (instead at worst you get a brownout)
Compared with pure steam fuel requirements are slashed by 70% and it is immune to low electricity death spiral (where there is no electricity to power the mines and no coal being mined to fuel the boilers).
Compared to Backup Steam it is logic-free and simpler.
Blueprintable Designs

Due to pressure dynamics of storage tanks designs closely following the above ratios may require small pumps to work, designs without small pumps can only be discovered by experimentation. Here are two designs which operate optimally under 70/30 conditions and require no small pumps.

My favorite design is a 1/14/32 which produces 16MW and complements 270 Solar Panels (3x shown here):

(Blueprint).

It is space-efficient, reasonably tileable and comes close to optimal ratios


This longer design is a 2/28/66 which produces 33MW and complements 560 Solar Panels:

(Blueprint)

It uses two separate strings of 14 Boilers, each with it's own offshore pump (each offshore pump requires it's own pipe - it wont work if the offshore pumps share a pipe), in practice I find strings of 28 Boilers don't work at 100% when filling tanks unless you use small pump assist, also 3 tanks in series are unable to provide enough water to 11 engines in series, hence the "short circuit" pipes which connect the boiler output to the final tank and allow all the tanks to be filled in parallel, this allows this setup to run at 100% all night, and charge at 100% all day.

It is not as neatly tileable as the 1/14/32 but being longer it makes better use of coastlines, it also has slightly closer to ideal ratios.
Not just a gimmick

I started working with Solar/Steam and hot water storage for ideological reasons, however I have found it to have some serious merits. The usual challenges of larger scale steam power is that it is not easy to blueprint, the water supply and fuel supply it not blueprintable (at least not fully). The advantage of solar/steam following optimal ratios is that the non-blueprintable parts are cut by 70%, making it more than 3x easier to deploy on a large scale.

Compared with Solar/Accu the main advantage is it is seriously cheaper (and steam can even be hand-crafted from common parts with ease). Taking a factory which consumes 30MW, the minimum number of solar panels to provide day time needs is 500, to provide the night time needs with steam requires a 2/28/66 setup. In contrast, to provide the night time needs with Solar/Accu requires adding an additional 215 Solar Panels and 600 Accumulators, not only is the steam setup much cheaper in terms of iron and copper, the accumulators would cost 3000 batteries and we need to consider the comparative advantage of investing that petroleum into other things, such as laser turrets, efficiency models, blue research packs, processing units for armor modules and more, in fact there are a lot of things better than accumulators you can invest petroleum into, in the end game the cheapness argument no longer holds any weight since you've already researched and crafted everything you need and a megabase can churn out accumulators by the thousands.

Solar/Steam has some other fringe benefits. One I like is that it is immune to both blackouts and death spirals. A blackout is when your accumulators go flat leaving you with no electricity whatsoever, but with Daystore Steam the boilers always run, giving you at worst 30% of your power generation as baseline (also designs without small pumps tend to degrade from 100% to 30% gracefully). Also during the daytime you are guaranteed 100% power, if your fuel supply is completely cut off your factory will still run on average at 70% of peak performance.

Solar/Steam does not play well with accumulators because priority will always be charging the accumulators, if you want to use large numbers of accumulators in conjunction with steam, better to use backup steam with a low power condition. Fortunately it's not hard to convert Solar/Steam to Solar/Accu w/ Backup Steam - just replace the first steam engine after the storage tanks with small pumps linked to a circuit network and activated by a low-power condition. You can also just accept that accumulators wont be charged intelligently and just have some for emergencies or as visual low-power detectors (if your accumulators are zapping, you need more electricity generation).

Although most of the guide I just skimmed through, I did learn a thing or two here. You may want to organize it into spoilers so it's easier for some people to find precisely what they are looking for

Pretty interesting guide. I am wondering though, since I've never played around with it, is there any benefit to using hotwater storage without solar? As an alternative to capacitors acculmulators as a way to handle large demand peaks from laser turrets and the such like. I'm pretty sure with a bit of tinkering such a system would be both more sturdy and more elegant than just having massive redundancy in your steam plants.

Overene wrote: Although most of the guide I just skimmed through, I did learn a thing or two here. You may want to organize it into spoilers so it's easier for some people to find precisely what they are looking for

Yikes! no need to quote the entire first post, friendo.

MalcolmCooks wrote:Yikes! no need to quote the entire first post, friendo.

Yeah, i noticed that and removed it

MalcolmCooks wrote:Pretty interesting guide. I am wondering though, since I've never played around with it, is there any benefit to using hotwater storage without solar? As an alternative to capacitors acculmulators as a way to handle large demand peaks from laser turrets and the such like.

I've experimented with such ideas and although I don't find them to particularly have much merit it is *extremely* easy to do. All you need to do is take a 1/14/10 and add 5 steam engines and 1 tank on the end of the steam engines, so you have a 1/14/15 with a tank on the end. When the steam engines are running at under capacity, the tank will fill with water. When more electricity is required all 15 steam engines can run at full performance by drawing water from both the boilers and the tank. You can even do this with a 2/28/20, just stick 10 steam engines on the end and a couple tanks, even though this results in 30 (or even 40) steam engines in a string, it still works, because when more than 20 need to run, they draw water from both ends (Note that if you use such long strings of steam engines, adding 4 small pumps before the steam engines will help a lot to fill the whole system with hot water). I wouldn't recommend going more than 25% or tops 50% over the boiler capacity - it quickly becomes smarter to just add more boilers and steam engines, or provide secondary power (i.e. solar) to give the boilers a chance to catch up.

But as for why I don't find them meritorious: Usually we are concerned with laser turrets, but laser turrets automatically get priority over anything else so with steam you'll always have enough power to fire the lasers and it doesn't really matter if the rest of your factory skips a few beats. But given the choice between building accumulators or adding steam engines and tanks, add steam engines and tanks. It's cheaper and works in about the same way (but accumulators do give a clear visual cue that your steam power needs to be upgraded, with extra-capacity steam it's not so obvious).

Interesting idea, and I like the simplicity! Wouldn't it be even simpler to use regular 1/14/10 setups and drop the water tanks, and accept that you've paid a bit too much iron?

You raise an interesting point that accus are a big oil sink in direct competition with using said oiil for powering steam engines during the night.

10 crude oil yield 1/4.5/5.5 cracked to 0/5.25/5.5. For batteries, this can be cracked further to 9 gas. For power, this yields 5.25 + 2.75 = 8 soild fuel

An accu costs 5 batteries -> 10 sulfuric acid -> 10 sulfur -> 15 petro -> 16.67 crude oil (cracking everything to gas), which could also have yielded 13.3 fuel, or 332MJ

Taking your ratios and the normal .84 accu:solar ratio , a single accu replaces 1/.84 * 60/510 = 0.14 steam engines running 30% of the time, or .042 steam engines fully running.
Since a steam engine produces 510kW with 50% efficiency, this is equal to 510*2*.042 = 42.86kW. So, the accu (plus the extra solar panels, of course, but they don't require oil) decreases energy consumption by ~43kW.

So (again assuming you care only about the oil), the time to recoup oil investment in accus compared to solid fuel powered steam engines is 332000/42.86=7758 seconds or just over two hours. Which is surprisingly short?

The oil->fuel ratio would be better if you assume central refining, where (all) gas would be used for other purposes and the heavy/light oil for fuel (so you get a better effective crude -> fuel ratio), so in essence 1 gas saved means 1.5 light oil not cracked or 1.5 extra solid fuel, so the 15 petro saved is 22.5 solid fuel, which brings the time to recoup up to just over 3.6 hours, but that is still quite short in factorio.

My conclusion: it's probably worth the complexity to build acces and an emergency switch

Interesting idea, and I like the simplicity! Wouldn't it be even simpler to use regular 1/14/10 setups and drop the water tanks, and accept that you've paid a bit too much iron?

I'm not sure how it works out cost-wise, I suspect it's pretty even. For a 1/14/33 I use 8 tanks though you can get away with fewer (I have figured even better optimized designs out), which costs 320 iron. If you're going to build 2 extra strings of 14 boilers you need 28 boilers, 28 belts (possibly...), 28 inserters, 2 offshore pumps and probably some pipes - comes to about 140 stone 200 iron/copper, sot he tanks are probably a tad pricier, but don't have the passive drain of 28 inserters, they are also likely to be more compact but that might vary.

If you make something like a 1/14/33 the fuel supply is easy to reason about - it's exactly the same as a normal 1/14 boiler setup, you can just supply it with 4 electric miner drills worth of coal. Fuel supply is harder to reason about for 3x 1/14/10 which is only going to be used at 30% capacity, technically you only need to provide the same 4 electric miner drills, but the coal needs to be buffered. Belts might suffice, but there are some benefits to storing energy in tanks - for one you can link a tank to the circuit network and get a readout of how much stored water there is.

The greatest reason for me is I always carry around iron plates, steel plates and gears and pipes just because they're all so darn useful and have them in great abundance in chests. I don't like things which require stone, I don't like to carry around stone, I usually even prefer to just convert all stone to bricks except the most token amount. A 2/28/66 can be trivially built out of the obsolete stone furnaces (replaced by steel furnaces), or a normal 2/28/20 can be upgraded to a 2/28/66 without fussing around with stone - in fact a normal power plant is trivial to upgrade to hot water storage once you know what you're doing and all you need is tanks, steam engines and pipes.

So (again assuming you care only about the oil), the time to recoup oil investment in accus compared to solid fuel powered steam engines is 332000/42.86=7758 seconds or just over two hours. Which is surprisingly short?

An obvious flaw in comparing recoup time in terms of solid fuel is that solid fuel is by far the worse use for oil - I never run night steam on solid fuel, they always run on coal. And coal is a resource which is essentially worthless beyond the relatively small amount required for plastics, long after iron and copper have run out, there will still be coal patches mocking you with their uselessness.

In terms of comparative advantage, we want to compare with the most useful things you could be using oil for - which are things like laser turrets, modules and blue science packs.

I find a pretty standard mid game factory uses about 30MW, if you're going to provide power you would need 600 accumulators, which requires 3000 batteries. The most simple way you can look at it is those 3000 batteries could be used as the battery component in 3000 science pack 3s.

If I'm not mistaken a battery uses 3 petroleum and a red circuit also uses 3 petroleum so the petroleum used to make those 3000 batteries could be used for the oily components of 1500 science pack 3s - by way of comparison the total laser turret upgrades (both damage and speed) cost a grand total of 1200 science pack 3s. In fact we have 300 science pack 3's left over, if that oil for was used for batteries for laser turrets, it would buy 150 laser turrets.

So we could say the comparative advantage of powering a 30MW base with accumulators is equal to 150 fully upgraded laser turrets .

I am an intensely militaristic player (and usually play on death worlds where oil is usually genuinely limited), I usually research bullet upgrades, then gun turret upgrades, then a bunch of robot follower count and logistic robot upgrades (mainly speed for tank repairing), then the laser turret upgrades - often I have fully upgraded bullets before small spitters even evolve. For me the comparative disadvantage of investing in 600 accumulators is huge. I'm also a heavy module user and prefer to do full chain prod3/speed beacon, this causes electricity use to skyrocket, and rather than provide 90MW of accumulator it's cheaper to just build 3 2/28/66 powerplants. It's only really once most techs have been researched, and probably the original coal patches are starting to be depleted, that accumulators start to look good. But why use solar at all? Well it cuts fuel use by 70%, or makes a coal patch last 3.3x longer, I'm lazy, and I can't be bothered transporting coal or piping water, so I usually only build power plants where coal and water are in close proximity. The solar panels let those coal patches last a very long time. If going full-steam I'd need to arrange actual coal transportation rather than just burning coal practically where it is mined.

The other thing is these power plants make absolutely fantastic laser turret capacitors, normally on death worlds I use gun turrets, but if I use lasers early in the game attacks can spike electricity usage to at least 3x higher than average (if using eff1 modules extensively, it can even be like 8x higher than average), providing enough electricity that all the lasers can fire without stuttering the power grid (or worse, losing firing rate and blacking out the grid) is much cheaper with steam engines than accumulators. The day store plants aren't perfect matches - the ideal early game laser capacitor has a huge excess of steam engines, you can do something like 1/14/50 with only a couple of tanks as a buffer. But if you build them as perfect day store powerplants when you later add solar panels they can immediately start functioning as night steam not to mention that they make pretty neat energy buffers for laser offensives as well.

Right, that makes sense. I've been playing on low coal / high oil worlds because I felt like going the solid fuel route, but especially on a low oil world I completely see your point.

Interesting topic but I'm not sure I'm convinced yet. If coal is cheap then why not run your base on steam from coal day and night? It feels weird to have 2 powerplants that are both capable taking care of all your power needs. If the reason is that you want to save oil for othe things and accumulators are affordable enough after you have done your research and made your turrets, then it doesn't really matter that much if you burn through your coal supplies 3.3 times quicker since you will stop depending on them and go solar/accus before the coal running out becomes a problem. If accumulators are too expensive then it's even cheaper to skip solar also.

Qon wrote:It feels weird to have 2 powerplants that are both capable taking care of all your power needs.

You've just described solar/accu . The accumulators are sized to take care of all your night time power needs.

Accus aren't expensive for a mega-factory, but they are surprisingly expensive say in the context of launching a rocket, and they are especially expensive in the context of a deathworld where you are generally stretched for resources. It is *so much cheaper* to build a laser capacitor using steam engines than accumulators, especially when you consider steam engines are "charged" with boilers while accumulators require a source of electricity to charge them. It's a lot like the difference between steel and electric furnace, a fair few players prefer to stick with steel furnaces because they are cheaper, more compact and can burn coal directly. The advantages aren't necessarily compelling, but are undeniably there.

And the majority of the accumulator cost is oil, costing 15 Oil, 9 iron and 5 copper. Oil is almost always a limiting resource so to me it makes a lot of sense to consider the oil cost, and what else that oil can be spent on. I'd only spend oil on accus if there is truly nothing better to spend it on.

BlakeMW wrote:

Qon wrote:It feels weird to have 2 powerplants that are both capable taking care of all your power needs.

You've just described solar/accu . The accumulators are sized to take care of all your night time power needs.

Yeah, but with solar/accu you can't run your factory at 100% on only one of them. With steam I have a powerplant that can support my factory both day and night but only use steam at night. It's just a few cheap boilers and coal away from being able to run my during the day too. So it feels more like I have two power plants that are both sized for my factory than solar/accu.

So I don't really agree that it is the same. But I'm not saying it's not a good tactic for limited resource (coal) worlds up to rocket launch. But if I had coal and wanted to save resources I would probably skip solar too and use steam all the time. Personal preference. Unless I get tired of not being able to blueprint my steam setup and just cough up the resources needed for solar/accu.

Qon wrote: Yeah, but with solar/accu you can't run your factory at 100% on only one of them. With steam I have a powerplant that can support my factory both day and night but only use steam at night. It's just a few cheap boilers and coal away from being able to run my during the day too. So it feels more like I have two power plants that are both sized for my factory than solar/accu.

Except I find the savings from using a dedicated day-store design to be significant. When you consider a 1/14/10 the "1" is fiddly and the "14" is parts intensive, the 14 is actually 14 boilers, 14 inserters and (perhaps) 14 belts. The 10 is just 10 steam engines. So if you can cut down the fiddly 1 and parts-intensive 14 the thing becomes quite a bit more convenient to build, even accounting for the need for a few tanks. The fuel supply needs are also dramatically reduced over a plant running all the time - a convenient coal patch (meaning one next to water) can run 3.33x as many steam engines. When I use daystore steam I hardly ever bother with inland coal patches, but when I use 100% steam I usually need to exploit inland coal as well, meaning significantly more logistics.

Another useful thing is if you plan ahead it's pretty easy to make a 1/14 or 2/28 design which is trivial to upgrade to a daystore when you later build solar panels, you can completely leave the 1/14 part alone and just add a few tanks and more steam engines. I like a lot that's there's no need to scrounge up stone. The flow of my game usually involves making a 1/14 or 2/28 early on, then replacing the stone furnaces with steel furnaces and recycling the stone furnaces into boilers. That'll probably give about 56-70 boilers, that's enough for more than 80MW of daystore steam and 80MW is easily enough for launching a rocket or for making prod3/speed3 beacon setups which can mass produce stuff at substantial discounts. I know it's extreme laziness to not be bothered with stone (and you can probably guess I don't play bobs) but there are literally 3 things requiring stone: Stone Bricks, Stone Furnaces and Rail. It's not worthwhile carrying stone around and it's hardly worthwhile adding it to the logistics systems when you can direct-produce stone bricks and rail. In contrast, steam engines and tanks use iron, steel, gears and pipes; materials I always carry around, always have in chests, and always have in the logistics system.

PS. Often I use Nucular Mod for 100% of electricity. The balance of Nucular is that Nucular power is a bit cheaper than solar/accu and provides all-day power, but with a substantially more complicated supply chain than coal power and with a very different dynamic to either. I don't use Solar Panels much with Nucular because it feels wrong to build two expensive redundant power systems, but the combination of expensive and cheap works great, I usually have a substantial amount of backup coal to supplement the nuclear reactors. The reason for that is Nucular is very sensitive to death spirals and it's nice to have a backup for rebooting purposes, also coal is useful for topping power as nucular generation is slow to ramp up. It has fuel reprocessing and breeder reactors which allow making cheap MOX fuel, but you need to have reactors to fuel more reactors, or you need to use much more expensive enriched uranium. Ramping up nuclear yield is cheap if done gradually (using the plutonium output from existing reactors), but expensive to do quickly (requires enriched uranium from mining). Since quick and cheap isn't an option, that leaves coal power to fill any gaps.

So in my games coal power is usually used as a cheap and flexible gap-filler, and while it's not terrible as the sole power source and still has extreme cheapness per MW going for it, it does produce significant pollution and will chew through coal patches annoyingly quickly. Both these downsides become much less when it's only used to fill gaps.

Well I see the advantages. They don't seem to be very big but I can't really say for sure until I've tried playing with very low resources. And I probably won't in the near future so it wouldn't really fit. If I ever do then I might try it out. Thanks for sharing your method anyways. It might be very good, or maybe just equally good as some other path but with some other flavour, or maybe it's just for oil deficiencies. But it still taught me something new at least since I had initially completely discarded it as mostly useless.

BlakeMW wrote: Except I find the savings from using a dedicated day-store design to be significant. When you consider a 1/14/10 the "1" is fiddly and the "14" is parts intensive, the 14 is actually 14 boilers, 14 inserters and (perhaps) 14 belts.

I've experimented a bit with belt free boilers. The thing is boilers are like mini chests. You can put fuel into them but also take fuel out of them. So make a series of boiler rows with an inserter inbetween each row. You need belts for the first boiler row so fill it and then the inserters move the fuel from one to the next. I think the inserters even hand off the fuel from one to the other without it ever entering the boiler at the start. Means that at the start all the fuel is passed down to the last row till that boiler is full. Then the second last row gets some fuel till it is full and so on. Makes it harder to start up after a fuel outage.

Without the extra belt between boiler rows you get a more compact design.

Homework: Figure out how many rows of boilers can be chained together with inserters, fast inserters, stack inserters before the first row never gets any fuel.

BlakeMW wrote:Except I find the savings from using a dedicated day-store design to be significant. When you consider a 1/14/10 the "1" is fiddly and the "14" is parts intensive, the 14 is actually 14 boilers, 14 inserters and (perhaps) 14 belts. The 10 is just 10 steam engines. So if you can cut down the fiddly 1 and parts-intensive 14 the thing becomes quite a bit more convenient to build, even accounting for the need for a few tanks.

This.... is a really good reason to use water storage over just placing more 1/14/10 groups. Thanks for an awesome post.


Btw. I tried another design. To save valuable shoreline space.

Started with a normal 1/14/10. Then added a tank every three engines, repeating. Total 8 tanks, 33 engines. No pipes in between, so it would be massively annoying to try to run past. Haven't tried adding any underground pipes to actually let you run past, afraid it'll reduce performance.

I did a test with one of these with 33 steam engines, 280 solar, 56 radars and... it worked. It dips to 90% for a few seconds each morning. So doesn't reach full theoretical output but close.

33 steam engines in a row are normally a terribly bad idea. But it works here. During the day there's only the water flow from one shore pump, and sustaining that over a long-ish pipe is no problem. At night the first ten steam engines are supplied as normal, and for the other ones the water only has to flow 1.5 steam engines from a tank. There's never a need for high throughput.



Here's a screenshot with two of the setups side by side; notice that the two lines are not connected at all. The 14 boilers are technically in a line; I just like to shape the line as a snake to save width if I'm going to have a free space between each steam engine anyway. If it weren't for power poles you could stack them side by side; they wont accidentally link up.

I notice you have the first tank after the 10th engine and then every 3. Shouldn't the tank be after the 11th or even later?

Here is my reasoning:

Firstly during the day the hot watter just passes through since the engine are only partly used. So it doesn't matter. Most water just ends up in all the tanks. During night the first 9 engines get water from the pump. For the 10th engnine the remaining low pressure from the pump competes against the high pressure in the tank. I bet tank water gets used there.

Secondly each tank is supposed to drive 3 engines except one engine is missing. So center the tanks between the engines as best as possible. Since 3 isn't divisible by two we can't do it perfect. So put 1 engine before the first tank, 1.5 after the first tank. Then 1.5 before and after each tank until the last gets 1.5 before and only 1 engine after. Note: The 1.5 after one tank plus the 1.5 before the next make up a whole 3 engines, so no cutting in half here.

Alternatively put the tanks even later so they compete even less with the pump. Would make things less centered though.


Question: Did you put the additional engines after the 10th (or even all) on a separate power circuit and disconnect that during daytime (or when an accumulator is full)?

On the long and compact design, is it viable to add offshore pumps and then extend the engine/storage tank pattern further? Or has it already become water-throughput limited at it's current stage? I ask because the shoreline use is technically not 100% optimal, and you could easily fit more pumps, either by switching to a 3 pump->2 lines setup, or simply 2 pumps for each individual line, with an extra space gap between each line.

Not very good at this kind of fluid theory-crafting, not sure what to look for if I tested this myself.

Using landfill I made two parallel channels of water (to get 2 coastlines) and placed pumps alternating on each coastline to get one pump per tile. Then lengthening the lines with rounded pipes I interspaced the lines to get one line of boilers and steam engines per tile too. One pump, one line of boilers and one line of steam engines really is the best setup. But boy does that get long.

On the other hand I tried combining pumps into a longer line of boilers and steam engines (just minim pipes between the pumps and boilers). With 2 pumps per line, 28 boilers and 20 steam engines only 17 get full water. Using 3 pumps makes that 18. So yes, there seems to be a throughput limit.

I tried using small pumps to help the water flow with very limited success. It might help a bit. Usually what happens when I test this is that I draw too much power, the pumps don't get enough electricity, slow down and you get a catastrophic downward spiral ending in a total blackout within seconds. Seems the only way you can use small pumps with steam engines is if you put them on a separate power network that is free of small pumps and that is just to hard to build.

Well, my complements to the long and compact design. It took awhile to paste everything, but I now have a 2GW steam complex where I had original been expecting to settle for only 600MW. Based on calculations, 4 blue belts of coal should fully supply all the boilers even at max load. Just need to get caught up on my solar panel count now...