Hi there …
We regularly camp on the island … in fact is has no residents from Monday to Friday anymore… not even the two policemen stay there. The elders told us that it was electricity supply .. pure and simple … there is none .. people use generators at the weekend when they get the ferry across to open up and trade with the walkers and school parties.
BTW .. Tung Ping Chau must be one of the best places for camping in Hong Kong … a great weekend away where you really do feel as though you have been away. Some great walks and some fascinating rock structures along the coast. A MUST if you’re into camping in Hong Kong …and you should be! But be prepared to be woken up by the anti-smuggling boats floodlighting the coast! If you’d like information then get in touch … but the pitch near the entrance to the site is reserved! 
One villager told us that the island actually has Hong Kong’s only genuine nuclear bunker, which I’m assuming would be under the police post there. Martin .. can you shed any light on this?
Regards
Tom