Many shortwave relay stations are directly or indirectly powered by oil.
In some places (ALLOIS, ISSODUN; France) -- atomic power is available.
In other places coal is available (Hawaii).
Hydro power probably powers only 33% of shortwave relay stations (globally)
with 4+ shortwave transmitters 50kw.

Due to jamming disappearing, 500 kw output power is for the most part not
needed (with some notable exceptions).
However, due to the geopolitical importance of SW it is very hard to place a
SW relay station into another country.

However, with a demand of 33 billion barrels of oil per year -- and most
nations not exporting their oil production (if they still have any) ...
conflict over the remaining amounts will notch up. Shortwave will come back,
because the expensive TV and Sat -TV infrastrure may not necessarily last
(or be fully viable) during a global recession that runs for 30 or 40 years.

33 billion barrels per year equals (1 km x 1 km x 1400 stories) of volume
area (ignoring compression issues due to depth of the oil).

What will bring Shortwave broadcasting back from a post Cold War
backwater
... PEAK OIL

Large oil provinces are no longer being discovered.

The kinds of geopolitical empires that can be built with a ready supply
of
cheap oil -- will no longer be viable.
Nations without oil will soon (over many decades) be equal as there will
be
no oil.

Relay stations shut down for PEAK OIL reasons
-- Caribbean Relay Station, Antigua (BBC-DW, direct cause)
-- Tangier 3, VOA-BBG (direct)
-- Delano, CA US, VOA-BBG (indirect, funding)

In risk
-- Relay Stations on: GUAM, SIPAN, ...
===============================================
What?

Ever read "Over a Barrel..." ? (
http://www.amazon.com/Over-Barrel-Br.../dp/1595550364
)

Your logic is flawed. Do you think that the discontinuance of "morse
code" on the high seas in favor of satellite communications is also
due to "PEAK OIL"?

Stations have given up on shortwave radio for other reasons more
trackable. (High operating and maintenance costs, budget cuts, votes
for other ways to spend money, and so forth).