Here I want to talk about another infinite source of energy: Oil -> Solid Fuel -> Boilers -> Steam Engine cycle
Definitions
Now we will calculate everything and find the perfect set up.
Axioms:
1. You never run out of oil.
2. 0.1 oil/s per pumpjack is the production limit of "depleted" oil spawn.
3. Boilers have 50% efficiency. Solid fuel power value is assumed to be 12.5 MJ per unit.
We assume:
0. "Depleted oil spawn" is an oil spawn that yields 0.1 crude oil a second.
1. Only depleted oil spawns are used.
2. No pipes are used, all machines are connected directly to each other
3. Vanilla
1. You never run out of oil.
2. 0.1 oil/s per pumpjack is the production limit of "depleted" oil spawn.
3. Boilers have 50% efficiency. Solid fuel power value is assumed to be 12.5 MJ per unit.
We assume:
0. "Depleted oil spawn" is an oil spawn that yields 0.1 crude oil a second.
1. Only depleted oil spawns are used.
2. No pipes are used, all machines are connected directly to each other
3. Vanilla
Crude Oil, energy cost
Let's first calculate the energy cost for a unit of crude oil. Fortunately this is easy. Regular pumpjack consumes 90 kW a second and produces 0.1 units of oil a second, so 900 kJ of energy is spent to produce one unit of crude oil.
Adding 1 speed module 1 to the pumpjack increases oil production to 0.12 oil a second and energy consumption to 135 kW, which translates to 1125 kJ of energy. Speed Modules 1 are useless here.
1 speed module 2 makes it ~1108 kJ/unit of crude oil, still not good.
1 speed modules 3 gives 1020 kJ/unit of crude oil.
So the most efficient approach is actually having pumpacks with no speed modules.
Using efficiency modules is a must to increase our, well, efficiency.
The limit is 20% of initial consumption. If we are to use only efficiency modules in the pumpjack, we will get 180 kJ/unit of crude oil, which is almost ridiculous.
If we try to use 1 speed module 1 and 1 efficiency module 3, then we get a flat increase of 20% in oil production for the same price of 900 kJ of energy, but that's still only 750 kJ of energy per unit of crude oil. Not efficient.
Therefore we conclude that we have to use 1 pumpjack with two efficiency modules 2 or 1 efficiency module 3 and 1 efficiency module 1. That gives us 180 kJ / unit of crude oil.
Adding 1 speed module 1 to the pumpjack increases oil production to 0.12 oil a second and energy consumption to 135 kW, which translates to 1125 kJ of energy. Speed Modules 1 are useless here.
1 speed module 2 makes it ~1108 kJ/unit of crude oil, still not good.
1 speed modules 3 gives 1020 kJ/unit of crude oil.
So the most efficient approach is actually having pumpacks with no speed modules.
Using efficiency modules is a must to increase our, well, efficiency.
The limit is 20% of initial consumption. If we are to use only efficiency modules in the pumpjack, we will get 180 kJ/unit of crude oil, which is almost ridiculous.
If we try to use 1 speed module 1 and 1 efficiency module 3, then we get a flat increase of 20% in oil production for the same price of 900 kJ of energy, but that's still only 750 kJ of energy per unit of crude oil. Not efficient.
Therefore we conclude that we have to use 1 pumpjack with two efficiency modules 2 or 1 efficiency module 3 and 1 efficiency module 1. That gives us 180 kJ / unit of crude oil.
Oil processing cost
Moving on to processing crude oil. Here we hit a branch: should we use advanced oil processing or basic?
We'll deal with both cases.
Let's break it down first.
Basic oil processing consumes 10 units of crude oil, takes 5 seconds and produces 3 units of heavy oil, 3 units of light oil, 4 units of petroleum gas.
Advanced oil processing consumes 10 units of crude oil and 5 units of water, takes, again, 5 seconds and produces 1 unit of heavy oil, 4.5 units of light oil, 5.5 units of petroleum gas.
Oil refinery consumes 420 kW. Efficiency -80% brings it down to 84 kW.
Since both methods of processing take 5 seconds and take 10 units of crude oil, our energy consumption is constant: 420 [5 seconds of 84 kW] + 1800 [10 units of crude oil] = 2220 kJ of energy for each oil processing step.
We'll deal with both cases.
Let's break it down first.
Basic oil processing consumes 10 units of crude oil, takes 5 seconds and produces 3 units of heavy oil, 3 units of light oil, 4 units of petroleum gas.
Advanced oil processing consumes 10 units of crude oil and 5 units of water, takes, again, 5 seconds and produces 1 unit of heavy oil, 4.5 units of light oil, 5.5 units of petroleum gas.
Oil refinery consumes 420 kW. Efficiency -80% brings it down to 84 kW.
Since both methods of processing take 5 seconds and take 10 units of crude oil, our energy consumption is constant: 420 [5 seconds of 84 kW] + 1800 [10 units of crude oil] = 2220 kJ of energy for each oil processing step.
To crack or not to crack
Should we go ahead and convert all of this into solid fuel or further process it?
Fortunately for us, cracking takes constant amount of energy: 168 kJ of energy per cracking cycle (assuming full efficiency).
Note that heavy oil -> light oil converts 4 units of heavy oil [which is 2 units of solid fuel] to 3 units of light oil [which makes 3 units of solid fuel] and consumes 168 kJ units of energy. You gain 12.332 MJ of energy for converting heavy oil to light oil. So yes, go ahead.
Light oil -> petroleum gas converts 3 units of light oil [3 units of solid fuel] to 2 units of petroleum gas [1 unit of solid fuel!] and consumes 168 kJ units of energy. You lose whopping 25.168 MJ of energy for doing that.
Therefore we are going to convert heavy oil to light oil, light oil to solid fuel and petroleum gas to solid fuel. That's the plan.
Fortunately for us, cracking takes constant amount of energy: 168 kJ of energy per cracking cycle (assuming full efficiency).
Note that heavy oil -> light oil converts 4 units of heavy oil [which is 2 units of solid fuel] to 3 units of light oil [which makes 3 units of solid fuel] and consumes 168 kJ units of energy. You gain 12.332 MJ of energy for converting heavy oil to light oil. So yes, go ahead.
Light oil -> petroleum gas converts 3 units of light oil [3 units of solid fuel] to 2 units of petroleum gas [1 unit of solid fuel!] and consumes 168 kJ units of energy. You lose whopping 25.168 MJ of energy for doing that.
Therefore we are going to convert heavy oil to light oil, light oil to solid fuel and petroleum gas to solid fuel. That's the plan.
Best Oil Processing Way
So which method is more efficient here?
Basic oil processing will lead us to 5.25 units of light oil and 4 units of petroleum gas, which transform to 7.25 units of solid fuel. 7.25 units of solid fuel is 90.625 MJ of energy. We spend 2220 + 126 = 2346 kJ of energy at this point (not including assemblers yet).
Advanced oil processing leads to 5.25 units of light oil (again) and 5.5 units of petroleum gas. That means 8 units of solid fuel for us. 100 MJ for 2220 + 42 = 2262 kJ of energy, which means 282.75 kJ/solid fuel ingredient. Not bad.
Therefore we choose "Advanced Oil Processing".
Basic oil processing will lead us to 5.25 units of light oil and 4 units of petroleum gas, which transform to 7.25 units of solid fuel. 7.25 units of solid fuel is 90.625 MJ of energy. We spend 2220 + 126 = 2346 kJ of energy at this point (not including assemblers yet).
Advanced oil processing leads to 5.25 units of light oil (again) and 5.5 units of petroleum gas. That means 8 units of solid fuel for us. 100 MJ for 2220 + 42 = 2262 kJ of energy, which means 282.75 kJ/solid fuel ingredient. Not bad.
Therefore we choose "Advanced Oil Processing".
Solid fuel cost
Finally, solid fuel production.
This one is easy.
Solid fuel takes 3 seconds to produce.
Chemical plant will only need 2.4 seconds for 1 unit of solid fuel for 100.8 kJ of energy.
This one is easy.
Solid fuel takes 3 seconds to produce.
Chemical plant will only need 2.4 seconds for 1 unit of solid fuel for 100.8 kJ of energy.
Results
Final cost is therefore 282.75 + 100.8 = 383.55 kJ of energy per 1 unit of solid fuel. That yields net potential energy of +12.11645 MJ per solid fuel block.
Our perfect configuration is as follows: everything must have efficiency of 80%, oil refineries are to use "Advanced Oil Processing", all heavy oil is to be cracked to light oil, light oil is to be completely converted to solid fuel and so is petroleum gas.
Our perfect configuration is as follows: everything must have efficiency of 80%, oil refineries are to use "Advanced Oil Processing", all heavy oil is to be cracked to light oil, light oil is to be completely converted to solid fuel and so is petroleum gas.
Perfect ratio
Now let's make a balanced minimal system out of this all.
Thanks to the power of Foreman we can easily calculate required ratios for the best system possible.
Pumpjacks : Oil Refineries : Chemical Plants
100000 : 5000 : ~20200 -> 1000 : 50 : 202 -> 500 : 25 : 101 -> 20 : 1 : ~4.
A setup of 20:1:4 will produce 1+2/3 units of solid fuel a second which means 20 + 5/6 MW
Thanks to the power of Foreman we can easily calculate required ratios for the best system possible.
Pumpjacks : Oil Refineries : Chemical Plants
100000 : 5000 : ~20200 -> 1000 : 50 : 202 -> 500 : 25 : 101 -> 20 : 1 : ~4.
A setup of 20:1:4 will produce 1+2/3 units of solid fuel a second which means 20 + 5/6 MW
Overall efficiency in comparison to other power sources
Make your choice.PowerGen/Area is going to be horrible though.
Excluding pipes and the water pump we will need at least 241 tiles of space to accommodate a 20:1:4 setup.
Additionally we will need to install boilers and steam engines.
We will use the usual 1:14:10 ratio.
One energy block takes at least 179 tiles of space (including inserters near each boiler) and produces 5.1 MW assuming full capacity.
We will need ~4.085 of them for each solid fuel production block, which means that we need no less than 732 tiles to contain this whole setup.
This finally converts to ~21.4 kW per tile. Realistically it's much less due to pipes involved.
For comparison, solar panels have flat efficiency of 6+2/3 kW per tile during daylight and 0 at night.
Interestingly enough this setup is not all that far away by efficiency to a coal-powered steam engine setup. Its max efficiency is close to 25.3 kW per tile (excluding belts and power taken by mining drills themselves, it's just slightly less efficient than this). And unlike coal-powered generation, you will never run out of oil.
Excluding pipes and the water pump we will need at least 241 tiles of space to accommodate a 20:1:4 setup.
Additionally we will need to install boilers and steam engines.
We will use the usual 1:14:10 ratio.
One energy block takes at least 179 tiles of space (including inserters near each boiler) and produces 5.1 MW assuming full capacity.
We will need ~4.085 of them for each solid fuel production block, which means that we need no less than 732 tiles to contain this whole setup.
This finally converts to ~21.4 kW per tile. Realistically it's much less due to pipes involved.
For comparison, solar panels have flat efficiency of 6+2/3 kW per tile during daylight and 0 at night.
Interestingly enough this setup is not all that far away by efficiency to a coal-powered steam engine setup. Its max efficiency is close to 25.3 kW per tile (excluding belts and power taken by mining drills themselves, it's just slightly less efficient than this). And unlike coal-powered generation, you will never run out of oil.