On Fri, 18 Sep 2009 22:43:31 +0100, Andy Furniss wrote:

It was nearly 30 years ago though, so it may be different now.

Actually it appears not.

According to the site http://home.clara.NET/darvill/altenerg/hydro.htm

QUOTE

When it was first built, the huge "Hoover Dam", on the Colorado river,
supplied much of the electricity for the city of Las Vegas; however
now Las Vegas has grown so much, the city gets most of its energy from
other sources.

UNQUOTE

See

http://en.wikipedia.org/wiki/Nevada_Power_Company

for details of the power plants that do generate power for NV Power,
the utility company that provides power to Las Vegas.

So the Hoover Dam did make the bright lights possible in Las Vegas by
first providing power to the city and fostering its growth, but by
the time of your visit, the city was no longer using Hoover Dam as
a power source.