Call me crazy, but Helios are even more important on cold planets, if the intent was to colonize a planet for the sake of hydrogen production.
Most people will get to a level 22 Solar Array and 11 Nuclear Power Plant before they start considering their options and thinking their upgrades are limited due to the large amount of resources needed to build the next level of either.
If you have the defenses to protect them, build a metric tonne of helios. You're going to save 314 Hydrogen per hour, on a planet you build to produce more hydrogen in the first place, which is already most likely producing 300-500 more hydrogen per hour, depending on the temperature difference and level of mine. The only upkeep to a Helios is the potential ability for destruction. But, if you leave enough defenses behind, you'll likely not run into problems.
At 7 energy per helios, it'll take roughly 242 Satellites to make up for the energy production of a level 11 Nuclear Power Plant. Already, it's cheaper to build, but then you figure the 314 Hydrogen/hr decrease, and you'll find that those NPP's are quite taxing, to the point where they are not worth it to have operating. If you have the extra fields, go ahead and build the sats and turn the NPP's off.