@Cable idea: Would require more rewrite then implementing flat panels+solar generators.
@Lightcheck: Nope.
If only "one sinle" block is checking for light, people WILL start stacking multiple layers of solars above each other.
If only "a single block of all" gets covered and is meant to blackout the system, it would still require all bocks to check for light > no gain.
Picking a random block of a system and asking it to do a lightcheck could work. But as mentioned alreaydy, lightchecks don't use CPU anymore, but are static calls upon a simple array provided by the base engine.