San Onofre shutdown will mean tight electricity supplies

[kristopher]

112. If nuclear is reliable why are we having this conversation?

That deals with your snarky comment at the end of your OP. Now let's dispose of the false claims in the OP itself.

Without SONGS, California still has more than enough capacity to meet their needs:

In order to keep the lights on, the ISO needs to have more generation available than consumers are expected to use. This is known as a “reserve margin,” and the California Public Utilities Commission requires the utilities to plan for a 15% cushion. And the state already has more power plants than we need to pass that test. This summer, the ISO expects to easily exceed that margin under normal conditions, and to still avoid rolling blackouts even under extreme conditions (like if a lot of power plants go down unexpectedly at the same time customers’ demand is unusually high).




Source: ISO (Note: SP 26 and NP 26 are roughly Southern and Northern California, respectively)

As you can see the problem presented by the shutdown isn't having enough capacity to meet demand.

So why, in 2012 when SO shut down, did they need to pull 2 retired natgas generators (450MW) out of retirement in nearby Huntington Beach?

Blame it on a grid designed around centralized generation. The gaping hole in the system left by the shutdown of a large centralized source of generation causes a lot of problems besides the loss of ability to meet demand.

...the grid needs the “voltage support” SONGS used to provide.

Since a major part of the Southern California electric grid was built around SONGS, it is a lot harder for the transmission grid to remain stable without the plant operating and providing that voltage support. This all gets very technical fast, but the important thing to know is that there are different ways to provide voltage support (and they don’t all require burning fossil fuels at a power plant). So even though one might expect the state to fill the hole left by SONGS with more dirty power plants, this year the state is taking a better and cleaner approach.

So what happens now?

...(Huntington Beach - k) is instead being converted into “synchronous condensers,” which provide voltage support without onsite emissions. (The synchronous condensers operate like electric motors and use a small amount of energy from the grid in the process.) Other emissions-free efforts to fill the hole left by SONGS include installation of capacitors and upgrades to a local transmission line so that if the line has a problem, only part of it goes down instead of the whole thing.

<snip>

The Public Utilities Commission should continue to build on the great start made this year by requiring utilities to fill the gap with efficient and clean resources by:

making the electric grid more resilient through transmission system upgrades;
adding renewable resources in different geographic regions to take advantage of the different times when they’re available; and
avoiding new generation through more aggressive efforts to help customers:
improve the efficiency of their homes and businesses;
reduce consumption during costly “peak” periods; and
use clean on-site generation like solar panels.

Information courtesy of the wonderful folks at the Natural Resources Defense Council.
http://switchboard.nrdc.org/blogs/dwang/replacing_songs.html