In Mindcrack, to move up to the Medium Voltage Tier is as simple as upgrading your power generation and switching from the basic machines to their advanced versions. In vanilla IC2, this is where solar power begins to become a realistic, although expensive and unwieldy, option. In Mindcrack? Keep dreaming. You're still unable to get anywhere near making them viable. This is the point where you should begin crafting the
Nano Suit, which is an excellent, unbreaking suit of armor that is powered by electricity. It's much weaker than it used to be but even nerfed is much better than iron armor and arguably diamond armor as well.
GregTech's
Industrial Centrifuge and
Industrial Electrolyzer are introduced in this tier and allow you to start properly experimenting with GregTech's features. You will need a minimum of one of each. The Electrolyzer in particular is power-hungry and you will need high quality power generation to operate it properly. This should be quite possible at the MV level.
As for upgrading your existing infrastructure, you will need a
Low Voltage (LV) Transformer, an
MFE, a
Rotary Macerator, an
Induction Furnace, a
Singularity Compressor and a
Centrifuge Extractor, in that order.
The
LV Transformer steps the MV current output by an MFE down to the safe LV current that the vast majority of your machines can take safely. If you accidentally overvolt a machine it will explode, so this is why having this transformer is an essential first step. The
MFE itself is simply the MV version of the BatBox with superior storage and power output.
To complicate matters, the Induction Furnace and Industrial Electrolyzer both take MV. They'll try to run on LV but your success rate will be mixed. This is the point where you will need to consider the long-term design of your power grid. You will eventually need power "rails" for LV, MV and High Voltage (HV). A select few machines benefit from even greater voltages but still run happily on HV so keep this in mind.
The advanced versions of the other core machines are actually part of an addon for IC2, not GregTech, that adds these special machines which have unusual behaviour: they suck huge amounts of power to start running, similar to the Induction Furnace. Once running at maximum speed, the power draw from the machines drops even lower than the basic machines whilst the speed they run at is enormously faster than the basic machines. The power draw at max speed is to maintain that speed,
not to actually perform tasks, although there is a very slight jump in power draw when they're actually in use. You have the option of applying a redstone signal to these machines to leave them permanently on, but this will very gradually drain your power reserves. How useful these machines actually are is debatable but I adore them and highly recommend them. They absolutely are better than the basic machines unless you almost never use them, and you should be using your IC2 machine bank heavily.
For actual power generation, solar power trumps absolutely everything else except GregTech's fusion power. Getting fusion power running will probably be the absolute last thing you ever do so in the meantime solar power is a superb choice. Once you have a Centrifuge it should become possible to build the basic solar panels. However, individual basic solar panels are
very weak. What makes them so powerful and valuable is the fact that they don't require any fuel, ever. This fact alone makes them the supreme power source in the long term. If anything they're
too good.
Right now, though, if you want to use solar power you're stuck with the basic versions which need to be produced in mass quantities to start producing decent amounts of power and so take up huge amounts of space. You will eventually be able to upgrade your solar panels into much more compact, high-performance arrays, but in the Mindcrack this is a major task that will require you to already have an excellent power supply before this becomes realistic. That said, however, a set of 8 basic solar panels attached to an MFE are enough to keep your Advanced Machines running indefinitely. Solar power will
not be your primary source for a long time yet, though.
A distant yet still potent second in power generation systems is the almost-as-cheaty
Geothermal Generator, which runs on lava. If you try running one of these in the Overworld alone, you'll find it's actually quite a challenge tracking down lava pools and connecting them to the generator. What makes the GG so ridiculous is that you have access to a functionally infinite lava source: the Nether. If you make the effort to pump lava from the Nether into your power grid, you'll be set for a
very long time. Worse, once you have a single Geothermal running fine, it's trivial to produce extras and massively boost your power output. It only takes 30 Geothermal Generators to start rivalling a high-end nuclear reactor and they're much much safer. Only solar power is more ridiculous than geothermal energy; the difference is that GGs are viable to use in mass quantities the second you can make them and fuel them. They are the supreme MV Tier power supply.
GregTech adds a multitude of potent alternatives to lava power and they are worth investigating but none of them will be as consistently reliable as the humble GG, or at least not until equally ridiculous giant pools of alternative liquids become available, which is actually on the cards for Mystcraft in the future. Unfortunately that mod is not in Mindcrack, but the point is important all the same. Only the Thermal Generator from GregTech trumps the GG as it is a literal upgrade to the GG.
If you get far enough to graduate out of the MV Tier you should already have a very good idea of where you want to go from there and this post is long enough already. Here's a hint: matter fabrication.
tl;dr: Lava power will have you set well into the late-game of GregTech. As soon as it becomes viable,
Solar Power beats nuclear power totally and utterly, and only Fusion Power can trump Solar for sheer performance. It's a shame that nuclear power is so consistently rendered obsolete by other mods and IC2's own addons, but that's the case.
