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Ethanol power generation calculator

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I've seen a lot of discussions around ethanol power lately and wanted to share my ethanol power calculator to maybe show people that ethanol is not as bad as a power source as they think.

Here's a spreadsheet link:

You can copy it to your new document to change values, right now it has numbers from my current base as an example.

How to use?

Just fill in numbers in "Main Questions" section. If you want some water and ethanol balance numbers, also fill in "Extra questions", otherwise change those numbers to zeros.

The panel on the right is just calculations, your main answers are in the answers section.

Below is a little FAQ with some confusions I often see around.

What do you do with so much CO2?


Vent it to space or just collect it infinitely in a sealed room and ignore it. I see so many people that just need to deal with CO2 and call just ignoring it wasteful. No, it is a waste to keep it around. Your dupes don't ever need to go into your generator room, so seal it, open it to space and forget about it.


How do you calculate sweeper power consumption?


In my tests, I've seen that a loader needs 100J to load 20kg of lumber. Sweeper needs 480J for one haul, and it takes either 20 or 60 kg per haul on the loading side, which averages to 40kg. On the unloading side, sweeper usually takes ~80kg per haul.

So, we need 480J to sweep 40kg lumber from the ground, 200J to load it onto the rail and 240J to unload it into the distiller, which gives us 920J per 40kg of delivered lumber.

Each distiller needs 600kg of lumber per cycle: 600/40*920=13800J per cycle per distiller or 55.2kJ per one generator.

55.2kJ / 600s = 92W.

What is a "seconds to gather a branch" value?


I don't know if there's a way to automatically harvest plants. If there's no such way, it means that actual time to produce 1 branch of lumber is more than 4.5 cycles. I add that amount of seconds to the lifecycle of an Arbor tree to simulate the time it takes for dupes to get to the tree and harvest it. As you can see, I've given it a generous 2 minutes as a default.


Your setup will overheat in time and would not work sustainably.


You are constantly supplying wood into the generator room, which is below 40C. It means that ethanol from the distillers is always 73.4C and it also cools down all the buildings in the room. Combined with the hot CO2 constantly being vented to space, it means the room will not overheat with time.

It's wrong! Everybody knows that after all the infrastructure ethanol generator only produces 137W!


An effective way to use it is to ignore or vent CO2. If you feel you have to use it in some way - you can't complain it's not as effective for you as for others. If you are using the extra power to feed it to your slicksters, you should also count the power that you can produce by using the oil they give you back. If you are using the extra power to skim the CO2... Well, don't! Why would you do that?


Why don't you count the extra power wasted on extra distillers for nosh sprouts or electrolyzer?


Because it's a different industry and I added those calculations just to show the balance of ethanol and water on my base. The tool primarily calculates the net power of a power plant, not oxygen or food industries.

It's wasteful to have a powerplant with more than half of its produced power used on its own infrastructure!


There's absolutely no difference between generator that has no infrastructure and produces 1kW and a generator that produces 2kW and has a 1kW infrastructure. The net power gain from 1 generator is almost 1kW and it takes literally 1 manual generator and 60 seconds to kickstart it and make it power itself. And most power generators in ONI produce 800W and have infrastructure too.


Any screenshots from such powerplant?


Here is an older screenshot of my unfinished powerplant with just 2 generators up. It is near the border of the map to reduce the heat exchange. Later I've added more generators in pairs just like these above, with the water just falling down in the same reservoir.



Please correct me If you find any mistakes either in this post or in the spreadsheet, I'll try to fix and edit it.


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24 minutes ago, blash365 said:

Please also add a layout of your tree farm.


And add some calculations about the temperature of your room. I dont see why it shouldnt overheat. Because lumber has a high heat capacity?

My tree farm is a simple _T_T__T_T__T_T_ layout with alternating 1 or 2 spaces between the trees. I can't make screenshots right now sadly.

I feel like proper heat calculations would be too complex, but for ~100-150 cycles of my power plant functioning I haven't seen any increase in temperature, distillers are at stable 52-55C.

The temperature of ethanol is always minimum because it only depends on lumber temperature. It actually leaves my distillers at 60-63C (I think the distiller cools it down, which is, in turn, cooled down by lumber?

The heat produced by 1 generator and 4 distillers is 38kDTU/s and they consume 4000g/s of lumber. With specific heat capacity of 3.47 it means that if lumber heats up 2.73 degrees on its way to distillers, it negates the generated heat, right? 38000 / 4000 / 3.47 = 2.73.
Even if the system will start heating up, I can easily add some tempshift plates to heat the lumber 2.73 degrees on its way.

The temperature of all of the outputs of distillers and generators are irrelevant because it only depends on building or lumber temperature and will stabilize around given output's minimum value.

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