On stand after doors are closed the deicing trucks will come on stand and do their thing. Meanwhile you only have the APU running to provide electrics which does not require that much fuel. When they are done you pushback and start engines.
Remote deicing you pushback and start engines, taxi to the deice platform usually located close to the beginning of the runway and you stand there with running engines while you get deiced. And even at idle you burn 600kg of fuel per hour. So you need to take some extra fuel in that case, especially if there are other aircraft in the queue as well to deice at the remote platform. About 300kg extra usually covers it (depending the airport you are at etc.)