Tidal power generation station is a movement of seawater during tidal cycles have the potential to generate large amounts of electricity. Each area with significant rising and falling tides is a potential candidate for this technology. Large banners or screw type propellers are located below the water level at low tide. As the tide comes in or goes out of power from shifting water turns the propeller that drives a generator. Such power generation systems are very expensive offshore construction is never easy and salt water itself is corrosive to metal components. Moreover, distribute and transport the power generated is difficult because most of the potential locations for a tidal power generation system is far enough offshore to high voltage lines is the only viable method for conducting electricity. However, there is no fuel to consume and generators operate on an easy - predicted cycle.
Shimana is only one of several similar-sized urban areas on Hidoma. Road and rail networks connected planets towns and traces of these transport systems can still be found and followed. Given that Shimana's power generation system still works, it is reasonable to assume other cities have available power networks and is supplied by tidal generation or more "conventional" settings such as fusion or Naquadah reactors. What may lie within their borders, including human societies is anyone's guess . (RPG: "First Steps: The Stargate Unexplored Worlds Roleplaying Sourcebook")