First of all a little disclaimer, for user mrvn, he thought it was impossible to make a power plant without using storage tank, and when i did a nuclear power plant using fluid wagons : viewtopic.php?f=208&t=100376 he very honnestly answered like he often does :
so here is another one i had fun making that has:
0 train signal
And some water-containing-stackable-cylinder, which to some may be another form of tank.
This power plant uses train loaded with water barrel. Each train carries 100K water ( 40 stack filled with barrel ). On a 3 core power plant ( 280MW) everytime 3 fuel cell are burnt, there is enough energy for roughly 577K steam. ( 280MW for 200 second = 56 000 MJ, and 1 steam representing 0.097MJ). This is how the refuel timer is counted. Every 5 train 3 fuel are inserter simultaneously. This is quite imprecise, some fuel is wasted you can say. This keeps the reactor core always hot, 999° hot. Because it's only a 3 core, the temperature doesn't reach 1000°, the speed at which temperature increase is higher when adjacency bonuses are higher but 3 core is not enough to have the temperature reaching 1000° when overheating interestingly.
I also added a utility factory next to it because why not. It does recycle the used fuel cell, does all the steps for uranium enrichment and kovarex process and provide trains with nuclear fuel. I used the editor to place the oil there it's not a real map as there are no biters and no ressources but the map uses only 1 item from the editor mode now, it's an infinity chest used to destroy some item to create fluctuation in electricity demand.
The train counter is made using inserter passing a fish one side when a train is present, the other side when train is absent.
When the fish is present on the right side, the power for the assembly is activated. Then when the fish pass on the other side, it triggers a pulse to move an item on the circular 4 belt loop. Those activate 1 tick and deactivate, this means the item only move for 1 tick. If you use a blue corner belt, and place the item on the inside lane, then 5 ticks is all it takes to move pass the activating corner. Every time the item on the circular loop does a lap, it means 5 train passed, and there is a belt reading and sending the message to the fueling inserters, simple. ( but messy when i build ok ok ).
What is this mess ?
it's belt logic math and overkill safety !!!
The uranium enrichment is made thinking that uranium 238 ( the bad one) coming from recycling should have highest priority then the 238 coming from kovarex process, then the new 238 from the outpost. The belts are sideloading to obey those priority.
The U-235 from the centrifuge is overfed, they hold a lot if it, and they output in a loop. Everytime they ouput the loop gets loose, the extra U-235 is pushed thanks to the splitter onto the right toward the nuclear fuel cell assembly and the nuclear train fuel.
Oil is transformed into rocket fuel without cracking due to perfect ratios in game and not using prod module. The belt logic here is used to give priority to the solid fuel made from heavy oil ( 5 every 4 cycle) then the solid fuel made from petroleum ( 11 every 4 cycle ) then we're left with 180 Light oil, ( 160 used to transform the previous solid fuel in rocket fuel 10 light oil transformed into solid fuel, and the last 10 to make this last solid fuel into rocket fuel).
There's also the sulfuric acid production for uranium mining. And some steam engines.
The accumulators are here to read the power charge. The power switch connect the 2 grid only when A=200. This means in case of brownout, the fuel production will isolate from the rest of the map and rely on its steam turbine that's why all necessary steps for fuel production are located here.
This explains where the following pictures were taken and allows to quickly hint at the fact that it's a no-signal train network. Instead of blocks that can contain only 1 train at a time, the whole network is just 1 block. This looks funny when train start moving very synced and makes the down time between 2 trains for barrel unloading as short as possible which is necessary to avoid using storage tanks while only unloading barrel from one side of the train
Trains have very long schedule with each of block/station on them.
U0 ( up) and D0 (down) are synchronized station, i used this simple mechanism that put a storage tank on each belt loop at the exact same moment: the only 2 tanks on the map! It is possible to pause the game and put the things at the exact same time, or to use circuit to trigger that and then remove the circuit, but it felt better waiting for the sun to rise.
Then everytime the storage tank is read, it triggers the circuit condition for the train waiting at U0 or D0. As they can only have departure on fix interval, this means they will always be at predictible area when crossing. Easiest to understand is at the exact mid-way you need a passing lane haha. Then I built the passing lane at the location where frontal collision happened when the 1rst train crossed the path of the 2nd coming from opposise direction. Now it look like it's very fragile and that collision may happen at everytime, but it's been at least 20hours without any ( except the first time i forgot to manually refuel the 3 nuclear thingy before automating it, it was bad, (reload-autosave bad).
For this one i needlessly complicated the task by having the machines that are solar powered turn off to minize drain. When a train arrive it turns on power, then a barrel is put on belt-loop that i manually adjusted to trigger 2 pulse in quick succession every lap takes the time for 10 barrel to be filled, this makes all inserter synchronized and reduce loading time by a lot. When a train is filled it goes the 2nd station, just next to the 1rst one, which remove the barrel from the looping belt, that turn off power and tell the train to leave.
A train can enter the 1rst station only if the power is turned off and 4 sec of inactivity, which prevent them from colliding into a train that is on the 2nd station, since there is no signal and 1rst station is free now. When water is heavily consumed, the 4sec of inactivity are not slowing down, since a train is loading at all time or almost, when water isn't heavily consumed, 4 sec lost doesn't matter.
4 switch for a single outpost it is. Because no combinators, they work in pair. One isolate the outpost from the main grid if there is a power shortage and use the steam engines reading accumulators to know when to do. The other pair is used to activate/cut power when the belt is full of uranium to minize drain. This outpost receive the utility train that carries sulfuric acid barrel for the miners, water barrel and solid fuel for the boilers. Train schedule here is wait for 10 second passed and 5 sec inactivity OR when water barrel= 0 and empty barrel = max, this means everytime the train arrive, no matter the power situation, it will leave filled with uranium ore, or at least what he could get with the steam engine time offered by water barrel.
The solar pannel is used to guarantee the steam engine is fed before the train leaves in case of total blackout on the main grid, only 1 barrel is enough, then it start loading and it prevent inactivity condition to triggers.
The 3rd and last station of the utility train, for iron plate, required to make nuclear fuel cell. In case of total blackout, one part gets isolated to rely on steam engine, one mine a 2 furnace, will be loading the train with iron plate, same logic as before, solar pannel to make sure the water barrel is unloaded, and then steam engine takes over. Same as before , 10 sec passed, 5 sec inactivty for the train or no more water and all empty barrel. The utility train has a 3 station schedule, if it ever need iron plate OR uranium, it will go to uranium outpost and THEN iron plate outpost, and then come back to utility area. No need to wire the whole map to trigger the limit, no need for chests on which to read a quantity to open a station or not.
The other switch are here to cut power to the miners if the belt is full of ore, and to cut power to the furnaces if the belt is full of steel, which makes power/consumption graph looks great:) here is my favourite from a grid that host very few machines very spiky but also very regular :
Some more technical details :
The 3 cores can only provide for 280 MW energy, however there are 30 heat exchangers, and 50 turbines. The fuel cycle is due every 5 trains, meaning 500K steam instead of 577K. This means there is a basis for only 86% maximum fuel efficiency. This means the reactor will overheat constantly. Now due to the 30 heat exchanger and 50 turbines, this power plant, when really hot, can power for 291 MW during around 1H30 before going down to a regime that average at 280MW.
When being at 100% or 110% or even 120% load thanks to test beacons, nothing that is necessary for the power plant to function is hindered, nor fuel for train, nor recycling, nor uranium, not even plate for fuel cell. Instead the 3 core will take 1H30 to go from their usual 999° to their minium temperature of functionning which will starve the furthest 2 heat exchanger from heat, causing the train to have very slightly longer unload time during which only the middle area is functionning, ( 83 MW or so) but it takes like 1 or 2 second , and then it goes back to 281 MW for the rest of the train unloading. If you consider 5 train every 200 second, that would represent 5% severe brownout time (83MW), 95% 280MW are produced.
That is until you fix the consumption/production ratio to 280MW ( max capacity) this regime of very short but heavy brown out will occur every train but without any cascade.
This allow roughly to trigger an alarm when main grid accu are <99%, and then you have 1h30 left during which you can over consume/overproduce at 291MW, before it shoud go down to 280MW, but if you don't adapt it's ok, just the intermitent brown-out no cascade death spiral or whatever and it will average at 280 MW despite the occasionnal drop due to overconsumption.
It was a lot of fun using all those weird designs i don't normally use.
EDIT : => the previous version had one 1 too many copper cable i didn't see on the utility factory between 2 large power pole. I updated and replaced the old one, now the switch functions properly.