Nomad Lore v1.31, page 35 Wrote:Empowered with various advanced artifacts the Advisors [one of the nomad castes, not in a nomad ship form] are capable of rendering themselves invisible to visual detection in a similar way ship forms were able to. They can remain invisible for days if necessary and up to a month in dormant state to preserve energy necessary to maintain cloaking artifacts working, and even more when very near strong energy sources.
Nomad Lore v1.31, page 47 Wrote:Nomad vessels are covered with special skin layer allowing very efficient photosynthesis process to accumulate energy for internal organs including self-propelling systems, weapons and neural system. Beneath it is a special membrane layer that reflects the light that has passed through the skin, this gives the Nomad ships' surfaces a reflective look.
I think the use of fuel for cloaks is a way very typical for humans of supplying their own manufactured devices that are based on nomad technology with energy.
Space-faring nomads however gain their energy from photosynthesis, so I think it would be reasonable to assume they use the same energy for cloaking.
Rather than coming up with some sort of fuel for nomads, I think it would be a better idea to include the cloak commands by default for nomad ships, even without a cloaking device (since those are made by humans) - possibly with a time limit based either on their powercore, or simply a fixed time limit.