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This article contains outdated information that is inaccurate for the current version. It was last updated for LU-356355. Unreflected changes in the discussed game mechanics are detailed here: CS-442154
This article contains outdated information that is inaccurate for the current version. It was last updated for LU-356355. Unreflected changes in the discussed game mechanics are detailed here: CS-442154

Petroleum Generator uses Petroleum or Ethanol to produce electricity, and emits Polluted Water and Carbon Dioxide in the vicinity.

Polluted water and carbon dioxide are output with a minimum temperature of 40 °C and 110 °C respectively. The temperature may be higher if the building temperature is above the outputs' minimum temperature. Polluted water is emitted from the bottom-right tile of the generator (Tile of interest).

Efficiency[]

Water-fuel[]

Since sustainable crude oil production requires water, water can be considered the base fuel for Petroleum Generator, which in turn begs for a comparison with Hydrogen Generator. However, the comparison does not turn into Hydrogen Generators' favor.

The details can be found at Hydrogen Generator#Water-fuel

Petroleum[]

Comparison with Natural Gas Generator, which uses the same fuel source, and has the same by-products:

Natural Gas Generator NGG, Power matched (x2.5) Petrol Generator PG/NGGm ratio
Petroleum (g/s) 134.33 335.82 2000 5.9(5)
Power (W) 800 2000 2000 1
Polluted Water 67.5 168.75 750 4.(44)
Carbon Dioxide 22.5 56.25 500 8.(89)
Heat (kDTU/s) 10 25 20 0.8
  • Note, that fuel consumption should be scaled to account for the loss of mass from Sour Gas to Methane transition, thus the Natural Gas Generator uses (90 / 0.67 = ~134.33).
  • Heat does not take into account temperatures and rates of outputted products.

When compared to a Natural Gas Generator scaled up for equivalent output, The Petroleum Generator uses six times more fuel and produces far more byproducts, including heat-bearing.

This does not mean that the Petroleum Generator is a bad option, though, since this comparison assumes no loss of energy from petroleum heating, cooling and re-heating. Meanwhile, a Petroleum Generator can burn cold petroleum and produce energy without further processing of the fuel, which makes it much easier to set up. Still, it is a good nudge to start sinking any excess heat energy into Crude and Petroleum.

Besides that, Petroleum Generator's ability to produce germ free polluted water is not bad. The Pincha Pepper plant requires 35 kg/cycle which is roughly 58 g/s so one Petroleum Generator can supply 12 plants.

The carbon dioxide can be traditionally fed to slicksters to regain some fuel, but it is far from sustainable (see recycling section).

Ethanol[]

Comparison with Wood Burner, which uses the same fuel source, and has similar by-products:

Wood
Burner
WB, Power
matched
(x3.4(6))
Petrol Generator +
4 Ethanol Distillers
PG/WBm
ratio
Lumber (kg/s) 1.2 4.16 4 ~0.96
Power (W) 300 1040 1040 1.00
Carbon Dioxide (g/s) 170 589.33 1166.67 ~1.98
Heat (kDTU/s) 9 31.2 38 ~1.22
Polluted Water (g/s) 0 0 750 N/A
Polluted Dirt (g/s) 0 0 1333.3 N/A

The fuel-efficiency is comparable, although Petroleum Generator still generates more heat and by-products (which might be desirable). 4 Ethanol Distillers per Generator also take a lot of space, which is a main drawback of this setup and it keeps increasing with deeper processing steps.

Sustainability notes:

  • 1 Petrol Generator requires 7.2 domesticated Arbor Trees to run constantly
    • Or 28.8 wild ones.
    • 6 domesticated trees with 6 wild trees creates a balanced symmetry that is water positive without Slicksters.
  • 1 Petrol Generator produces 450 Polluted Water kg/c cycle, which is enough to feed ~6.42 domesticated trees, the 7.2 trees requires 504kg/c
    • Each Wild Arbor tree essentially produces 15.6 kg/c of polluted water, ~3.5 Wild Arbor trees will cancel out the water loss.
    • If Water is still a concern. The polluted dirt from the 4 Distillers can be used to run 1.33 Sublimation Stations for Oxygen instead of Electrolyzers. Saving 600kg/c of Water per Cycle.
  • 4 Ethanol Distillers provide over 1300 kg of dirt per cycle, enough to feed 80 domesticated Arbor Trees.
    • It will keep 13.3 Compost piles occupied.

Thus, the setup requires input of around 56 kg/cycle of polluted water if only domesticated Arbor Trees are used, and generates excess renewable dirt with any ratio. With supplemental wild trees it is possible to generate renewable polluted water too (although this will likely start generating heat also, if not balanced for that).

Note, however, that if the Carbon Dioxide output from the distillers and generator are fed to Molten Slicksters, and the resulting Petroleum used to run a separate generator (fuels cannot be mixed in the same generator), only 3 distillers and 5.4 domesticated trees are needed to run the two generators a total of 100% of the time (75% of the time the ethanol generator can run, 25% of the time the petroleum generator can run). This reduces the Polluted Water input required, resulting in a net excess of 72 kg/cycle Polluted Water. This setup requires 30 happy (groomed) Molten Slicksters (4 stables), or 120 glum ones (no stables needed).

Heat Economy[]

The SHC output/input ratio for petroleum and ethanol is 1.01 and 0.72 respectively. However, as the output temperature is depending on the building temperature, it is possible to use hot input fuel hotter than 40 °C but still output 40 °C polluted water, assuming the engine can be sufficient cooling capacity to maintain 40 °C. Conversely, it is possible for the petroleum generator to become heat multiplying if you were to input low temperature fuel into a hot petroleum engine.

For the process to be heat negative, the petroleum input must be at least 56 °C, assuming that the building temperature remains at 40 °C. Whereas when burning ethanol, the ethanol input must be at least -44 °C to be heat negative. This is calculated by comparing the enthalpy of the input and output materials i.e. the total thermal energy of the input and output. This is given by the following equation, where is mass, is specific heat capacity, and is temperature:

Note that temperature must be in kelvin.

Assuming that the engine outputs the materials at its' minimum temperature the total enthalpy output is:

For the machine to be heat negative, the enthalpy of the system input must be less than the sum of the outputs' enthapy and machine heat generation. Hence the minimum input temperature is given by:

Carbon Dioxide recycling[]

Slicksters convert Carbon Dioxide to either Crude Oil or Petroleum at a rate of 2:1 depending on the variety.

If you use the Slickster then the 500 g/s of CO2 will be converted into 250 g/s of crude oil. Using an Oil Refinery will consume 5 kg/s of crude Oil, and produce 2.5 kg/s of petroleum and 90 g/s of Natural Gas. This means that for every second that you run the Petroleum Generator you will get enough by-products to produce another 40 W from the Natural Gas Generator and 125 W from the Petroleum Generator for a total of 165 W, a 8.25% return.

If you use the Molten Slickster then the carbon dioxide will be converted 2:1 into petroleum that can be fed right back into the generator. Every second 500 g of CO2 becomes 250 g of petroleum that can produce 250 W of power. This is a 12.5% return without the 480 W of power consumption by the Oil Refinery and the hassle of having dupes operate it.

Without Slicksters, you will need a 1.66 Carbon Skimmers to remove the Carbon Dioxide from a Generator. With the Ethanol Route, as each Distiller also makes Carbon Dioxide, the number rises to 3.88 Skimmers.

History[]

  • LU-356355: Petroleum Generator no longer requires Plastic to build.
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