The above post is correct in a way, you would need a step-up transformer,
they cab be expensive.
BUT that isnt your main problem, the US Wii runs on NTSC standard, if trying to use it in Europe, it has to be PAL standard, the NTSC standard is ONLY compatible with the US, Japan and a few other countries.
unless you are going to ONLY play US & Japanese imported games in Europe, your best bet is to try selling it on Ebay US or Japan. then trying to sniff out one from Europe. (and good luck on that, they are like hen's teeth here in the UK already).