The goal of Power Grid is to have the most number of cities and be able to provide power to the most number of cities.
The game has a unique system of going first -- players are ranked by how many cities they have, then their greatest-numbered power plant. In some phases, whoever is ranked first gets to act first; in other phases, they will be last to act. This gives the person who is ranked the lowest a chance to catch up.
Each turn, players will have the option of bidding on power plants; after the initial standard plants have been bid on, other plants will be randomly turned over each turn, with the highest-ranked person bidding first. These plants can be either coal, oil, trash, nuclear or green plants.
After buying plants, starting with the lowest-ranked player, each player has the option of buying resources for their plants. Resources are replenished each turn, but it is possible to collectively buy more resources than will be replenished, cause the price of these resources to increase. Resources will replenish at different rates depending on the number of players and the current phase of the game.
Once resources have been bought, starting with the lowest-ranked player, each player has the option of buying into cities by paying the cost of buying into the city plus any connection costs necessary to connect to another city of yours. As the game progresses into later phases, more people will be able to buy into the same city.
Finally, players use resources to power their power plants, and gain money based on how many cities they can power.
The first person to reach a pre-determined number of cities (based on the number of players) will trigger the end-phase of the game. Whoever can power the most number of cities once the end-phase of the game has been triggered is the winner, with excess money being the tie-breaker.
There are a number of expansions for the game, each providing new rules and a double-sided board with a different country on each side.
- Power Grid core game (company web site)
- Central Europe/Benelux expansion
- Italy/France expansion
- Brazil/Iberia expansion w/box to hold the other expansions
- Korea/China expansion
- Russia/Japan expansion
In addition, a new set of power plants is available as an expansion deck.