Power Grid: Taxes (Funkenschlag: Steuern) is a promotional card for Power Grid that was first available in October 2013 for a donation at the 2F-Spiele booth during Spiel 2013. The donation was for the children's group Knaddeldaddel, a small playgroup for 1-3 year old children in Bremen. For more infos (in German) please go to Kindergruppe Knaddeldaddel e.V..
The promo card is available via the BGG Geekstore.
Also the 2014/1 issue of "Spielbox" magazine included the card.
The Power Grid: Taxes card is shuffled into the power plant deck. If drawn in Step 1, place it below the power plant deck. If drawn in Step 2 or Step 3, all players must pay 20% (rounded down) of their money as taxes at the start of phase 5 "Bureaucracy", then remove the card from the game. After paying taxes, players receive their usual income for supplying electricity to cities.