Is this hydroelectric pumped storage being used in any coastal cities without rivers? What do they use?

  Maybe. Power from any of the usual generation sources.

Explanation:

As a rule, coastal cities are located near rivers, which facilitate the movement of goods to and from inland areas. Most coastal cities without rivers are of relatively small size, having economies based on local land or sea resources, rather than commerce.

Many coastal areas have a relatively flat topography. Hydroelectric pumped storage requires a difference in elevation between two pools of water. Such facilities are generally found in areas with mountains or high hills. The nature of the facility is that the water is retained for re-use. A river may be useful for initially charging the storage reservoir, and for a source of water to replace any losses.

The pumped storage facility acts as a source or sink of power from the local electric grid, so the power it supplies can be used almost anywhere, coastal cities or elsewhere.

In general, pumped storage acts to smooth peaks in supply and/or demand so that less stress is placed on the other sources of generation in use: nuclear, coal, gas, hydro, wind, solar, geothermal, tidal. Any given city will be powered by some combination of these.

oh it is true if thats what you are asking