Energy Efficiency Question?

[OperationDx]

As most of you are very aware as you play the game you unlock more powerful reactors. So I was thinking does the higher output reactors act more efficiently? Does a power pack last longer in a large reactor then a small one?

[[WDR] DrDeve]

Yes and no.

Fuel consumption is not a linear function of power produced.

Rather it's a curve based off %power used.

Since larger generators = lower % power used, the fuel consumption CAN be Michael less, or pretty much the same depending where on the curve you are.

But generslly, yes larger gens use less fuel.

[OperationDx]

Thanks

[ArnMan]

DrDeve is correct that larger generators give you more bang for the amount of tonnage they add to your build. This is the only efficiency difference for the different size generators.

small gen = 1MW power per ton (mass of the generator itself)
Large gen T1 = 10MW per ton
Large gen T2 = 33MW per ton


Since a generatoi itself does not use energy, a fuel cell produces its energy no matter what the generator configuration as long as there is enough capacity. A promethium fuel cell gives you 30 energy no matter what.

The % of power used indicator is an indication of capacity and not efficiency. If you use 1% of power when everything is running, then that means you could produce 100 times more power if you needed it. If you use 50% of power when everything is running, then you could produce double that if you needed it. In both cases the amount of fuel you burn is the same. The configuration that shows you 50% power usage is more efficient.

A general rule of thumb is that if you build a CV and apply thrust in three directions at once (forward, up, and left for example) you should hit about 70% power consumption. Anything less and you have more mass in generators than you will ever use. Now if you use the rule of thumb that every 5 tons of mass per RCS, then if you could get say 40% power usage with a T1 generator but 2% with a T2 generator, you should use the T1 generator. The T2 generator requires 3 RCS and the T1 generator only requires 1 RCS. Either way you get plenty of power but the T1 is more efficient in that scenario.

[times05]

More energy efficient generators is a nice thought for future upgrades/tech and rare rewards.

As of right now, doesn't matter what generator you use, amount of fuel used is only dependant on number of devices that draw it.

Think of generator as the size of pipe that funnels water (energy) to your house's kitchen/bathtub faucets. You can have a small one that will let through limited amount of water, or a big one that lets a larger amount through. But how much water you actually use depends on how much your faucet is turned up (faucet being the devices that draw power, not the pipe that brings it to the faucet).

So essentially you only need larger generator if you plan on using a lot of power overall, it doesn't make it any more efficient though.

[[WDR] DrDeve]

With respect times05, when generators are using 80%+ power, it's quite obvious the fuel goes faster than "the energy of all the devices installed that required at say 60% or less.

Yes device liad is the primary contributor, but with a nonlinear efficiency curve, and thruster nonlinearity, careful analysis will show that the total fuel used does indeed change depending on the %used figure as well, take some tests, and chart the results, it's pretty clear there are multiple contributing factors to fuel use which you can use to your advantage, or get burned by.

Especially on large ships that need hundreds of large generators to drive hundreds of thrusters, less obvious on small ships unless you take careful measurements.

[times05]

Originally posted by WDR DrDeve:

With respect times05, when generators are using 80%+ power, it's quite obvious the fuel goes faster than "the energy of all the devices installed.

Yes that's the primary contributor, but with a nonlinear efficiency curve, a careful analysis will show that the total fuel used does indeed change depending on the %used figure as well, take some tests, and chart the results, it's pretty clear there are multiple contributing factors to fuel use which you can use to your advantage, or get burned by.

Especially on large ships that need hundreds of large generators to drive hundreds of thrusters, less obvious on small ships unless you take careful measurements.

You might be right, my info could be outdated, I haven't tested it or heard about it. It definitely wansn't like that before.

PS: We're not talking about going over 100% power usage, just to be clear, right?

[[WDR] DrDeve]

No, I'm keeping the discussion under 99%

[times05]

Originally posted by WDR DrDeve:

No, I'm keeping the discussion under 99%

I have no reason not to believe you, at the same time I'm skeptical. It would have been said somewhere in patch notes of some sort. % usage has always been linear.

It's a good idea for it not to be, don't get me wrong. That's like the added benefit to higher tier tech, it would be awesome.

There's a way to test it. Make a base or a ship, let it sit there stationary, so it has a set specific unchanging fuel consumption. It somehow has to have a constant fuel draw, the only way I know to do this is lights, lots of lights. Put in a specific number of fuel packs (lets say 10).

Test it with small generators, medium (t2), and large T3. Don't have to wait, just have to look at how much fuel will last (there's an indicator in minutes, even seconds).

When I get the time I can test this, has anyone honestly done that before? I'm genuinely curious.

[BuffHamster]

uh oh, sounds like we need a Guide with charts and graphs, it would be a really helpful tool for good vessel design, ... or is it too soon yet?

[Caley Bannen]

Hi, I don't know how late I am to this discussion, but I just tried swapping out the generators in my mobile base, and there was no difference in the numbers (power used or power left) between the three different generators. So I guess right now, use the lowest mass generator for your power needs. My base was stationary at the time, so I'm not sure if the numbers would change in flight, but I doubt it would make a difference.

[VulcanTourist]

This is as it should be. A generator should respond to demand and only use the fuel required to generate the demanded output. Any excess output generated, and the fuel used to generate it, would otherwise be wasted. Not at all Energy Star compliant.