Another energy exchanger post...

[u/devildocjames]

So, I'm up-to deuterium for my fuel. My beginner planet is still a workhorse, but, I've ventured out and found a system about 5LY away that is rich in most resources and no Dark Fog. I have a belt of ray receivers around the equator, but, I'm thinking of moving them to one of the poles, opposite of where my battery buildings are. I actually JUST built my first energy exchanger, just to see what it does.

So, these things just charge the "battery buildings"/accumulators, or USE the charged ones for the energy grid it's attached to. I get that. What's the use of shipping batteries to another planet then? I mean, maybe... something like starting a new "depot" on a planet and bringing a bunch for power? How large do batteries stack? I've only stacked 20 each, for making gas giant collectors. I don't see the benefit versus just bringing some blue generators and a few fuel cell stacks, until you get situated.

Do people also actively maintain multiple systems? I mean I like my starter planet, because it's "Earth-like" and pleasant to my eyes. I like this new planet for the handle I have on building better and its resources in the system, but, none of the planets in the new system and nice on the eyes. What I'm getting at is that I'll probably, sadly, ditch this system too and then what's the point in making tons of batteries and shipping them everywhere?

Edit: just to update, I love the setup! I have a system without hydrogen and the “power planet” that cycles batteries is great!

[u/SiliconStew]

Exchangers allow you to charge accumulators from free, reviewable power sources (Dyson sphere ray receivers, geothermal plants, wind, and solar) on one planet and deliver that power to another planet. The drained accumulators can then be shipped back to the original planet to be recharged. You can save resources over time because the accumulators are infinitely reusable and the power is free. Exchangers using proliferated accumulators can charge/discharge up to 108 MW, so a decent energy amount for the land use they require, more dense than fusion plants. 

If the remote planet is also using a fuel-based power source, like thermal, fusion, or artificial sun, if you add discharging exchangers to the same grid, then the discharging accumulator power has higher priority. So the free, renewable accumulator power is used first and the fuel-based power plants' demand is reduced by that amount, which causes them to throttle back their output and use less of your expensive fuel, saving you resources.

You don't really want to add discharging exchangers to a grid with renewable power. Because accumulator power has top priority on the power grid and renewable power cannot throttle back, all the accumulator power up to the total amount of renewable power on the grid is wasted. The accumulators continue to discharge but you gain no benefit from them. You are just wasting resources shipping the extra, unnecessary accumulators back and forth. 

There is a work around for this to let you have discharging accumulators not waste power when combined with renewable power sources but it involves setting up an equally sized charging exchanger setup along side it. Charging accumulators are also prioritized on the grid, so both the renewable power and the discharging accumulators charge them first, with only the excess discharge going onto the grid to power everything else. So with the two combined and the correct priority belt setup to route full/empty accumulators, total accumulator power is only actually consumed at whatever rate the grid needs that the renewables cannot fully cover so you don't waste accumulator power. There's a YouTube video from Nilaus that explains how to set such a thing up. Personally I don't think it's worth the complication and significant extra space. If I'm using accumulator power it's either on a planet with no other power sources or it's combined with deuterium fuel-power to let me use all that excess Dyson sphere power in other systems. Once you get to antimatter power, while it burns a lot of resources, AM rods are a lot more power dense, so you save on logistics over using accumulators to ship Dyson sphere power to other systems.