Power Grid: Theme Park (Funkenschlag: Freizeitpark) is a promotional card for Power Grid that was available for a donation at the 2F-Spiele booth during Spiel 2011. This card was also previously sold here at the BGG Store as part of the larger promo card set for Power Grid. However, this listing is for a single card only.
The card is auctioned to the players immediately after it has been drawn. It counts as an additional city for its owner and not as a power plant.
For more information, please refer to the BGG listing.