California's annual energy consumption was  250,384 million KW-hrs in 2010, or 250.384 TeraWatt-hours/year. We require 10 cubic KM of fresh water per year, or 10x10⁹ cubic meters. At 5 KW-Hr per cubic meter that would be 50x10¹² Watt-hrs or 50 TeraWatt-hours/year, ~ 20% of present annual consumption, if my math is correct.

The levelized cost of wind power in 2010 dollars was $90/megawatt-hr. 50TW-Hrs would cost $4.5 billion/year. Note that intermittentcy is not a problem for desalinization unless underestimated. Overestimated, the system could load balance the western grid. In 2012 the value of California agricultural production was $45 billion, so getting the irrigation water from desalinization instead of ground water would add about 10% to the cost. And average wind speed is only going to increase.

"It is not necessary to have hope in order to persevere."