Verified answer

It's not dissimilar to how it works in humans. When the platypus eats, the various sugars enter its cells. The cells then convert this into a chemical called ATP - essentially molecular energy. They then use it up as needed.

Just as with all animals, platypus don't really produce energy. They are consumers, and get their energy by eating other organisms.

Biologists typically only consider plants to be producers - but even these really consume energy from the sun and convert it to chemicals that store energy in a fashion usable by other organisms.

First, they build energy efficient power plants that are carbon neutral. After that, they exercise a strong plant employee program to ensure proper safety and operational training. Once the plants go online, the platypuses (or platypi) run their plants, producing energy for their platypus communities.

Real answer: they don't produce energy themselves; they consume plants which in turn supplies energy to them for sustainable use. If a platypus is eaten, then it supplies energy to the predator that consumed it.

I rather like the first part of the answer myself though. Could you imagine a miniature nuclear power plant run by the platypus?