I think all versions of Espace after 1999 are fitted with a 12V power outlet in the centre console behind the hand brake. It's located so it's easily accessible from the rear seats: Perfect for powering verious accessories. Earlier models has only a cigarette lighter in the ash tray under the compartment in the It's a nice outlet with a lid on, but ours stopped working years ago: It overheated, corroded etc.
A replacement socket costs a fortune, but I've managed to fit a (cheap) 12V socket - this one is from Biltema, p/n 43328 http://www.biltema.dk/da/Bil---MC/Bil-tilbehor/Bil-el/12-Volt/Cigartanderstik-43228/
. It comes complete with a rectangular cover plate which I have cut to fit the console:
This makes us ready to drive to France in about 2 weeks time with DVD's, phone chargers and cooler box well powered!