Couldn't find the info on Telecity's website, so contacted them. Just got a reply:
"Thank you for question through our website.
We do have a mix of renewable energy, but this is only applicable when customers explicitly ask for. I can only answer you that Digital Ocean is a customer of us in our Amsterdam's site. For more information I would like to refer you to Digital Ocean.
I'm going round in circles on this one. Does anyone have a definitive answer?