It's not always about the ratios. Sometimes you only need a trickle.
For example, a miner directly against a boiler hooked up to a steam turbine connected to a solar panel with a small power pole. The offshore pump needs no power. The single miner can feed the boiler fine, but the steam turbine will never reach full power output. But you have power that will trickle through a general power grid failure, and it takes up minimal space.
If you are playing with Wormmus Config;
mods.factorio.com/mods/wormmus/wormmus-config
and you are set to 10 plate per 1 ore, then a mini-miner directly against a mini-furnace is all you need.
Wherever the Alt-Info shows a yellow out-arrow you can put that directly against whatever takes it to just skip the belts and inserters.
This pic is 50mw anywhere I wanna put it;
forums.factorio.com/download/file.php?id=28605
It's from a thread I'm toying with. I'd like to see a persistent multiplayer environment set up along the lines of MineCrack. My direction is towards a base that the player can pick up and put in their backpack before logging off, so that they are safe from attack while off-line. PvP or PvE, I think that Factorio can be modded into a reasonable persistent map with the right mod mix. Ideally with as many mods as possible condensed into as few mods as possible. So I am experimenting with a variety of mods and shift my install base frequently.
The thread is dated, and I am now encouraged to update it, but feel free to have a read;
forums.factorio.com/viewtopic.php?f=33&t=51093