CAISO is the California Independent System Operator, who operates the main transmission system for electricity in California. It's a big grid, reaching from the Oregon border all the way to Mexico, and powers the country's most populous state with a bit more than 38 million people. The grid demand (today's information) was a low of 21,000 MW at about 3 a.m., and peaked at just more than 30,000 MW at 6 p.m. The grid reaches a summer maximum of approximately 50,000 MW. The grid is currently supplied by a mix of generation technologies, nuclear (two reactors that provide 2,100 MW - when they are running), natural gas (a combination of steam plants, combined-cycle plants, plus a few peaking gas turbines), hydroelectric (from in-state dams), and imported power from other states (a mix of coal-based power from Utah, nuclear from Arizona, hydroelectric from Hoover Dam in Nevada/Arizona border, and wind energy from northern states), and finally the renewable energy sources. These include wind turbines, solar both PV and thermal, geothermal, bio-gas, bio-mass, and small hydroelectric. It is notable that for California, only the wind and solar are intermittent while the other renewables are remarkably steady in output.
Therefore, it is quite obvious that California, despite being completely backwards in many ways, has managed to integrate wind and solar power into the grid at the 30 percent penetration level with few, if any, adverse effects.
It is notable that other grid operators, particularly the German grid, seem to have troubles with their renewables and their grid. Perhaps that is a function of the wind turbines, or the grid design, or other issues. However, to make blanket statements that renewables ruin a grid is simply not true.
In fact, the California grid will soon have more of both wind and solar energy as inputs as new projects continue to be built and are placed in operation. I suspect that part of the California success is not having too much nuclear power on the grid, with its unyielding requirement to run at baseload (flat out at all times), whereas California has much more tolerant gas-fired power plants to slowly increase and decrease their output as the demand requires.
This is, indeed, the model for future electrical grids: (see link). As coal as baseload plants are retired (due to environmental costs and old age) and coal availability wanes, and nuclear plants are closed due to old age and bad economics, the future grids will be supplied by both natural gas and the economic form of renewables. In the US, the renewables will be wind for the most part, and solar only in the sunniest parts of the far West and Southwest (California, Arizona, New Mexico, and parts of Nevada). However, on-shore wind turbines are being built rapidly through the country's center section from Texas to North Dakota (the great wind corridor), and the first off-shore wind turbines are now under construction.
The evidence is clear: wind and solar do not crash the grid. Not at 30 percent, and not in California. As the wise-cracking pundits might say, Your Mileage May Vary. While not everything that starts in California is worth exporting to the world, in this case there is likely an exception. The lesson is pretty clear: get rid of the coal and nuclear plants, install natural gas power plants, and install wind and solar. Grid-scale storage is in the works, too.
Update 1: Note that California policy makers, in their vast "wisdom," have established a renewables target of 33 percent averaged over a one-year period, to be accomplished by 2020. The California Public Utility Commission has this to say about it (The RPS or Renewable Portfolio Standards) on their website:
"The RPS program requires investor-owned utilities (IOUs), electric service providers, and community choice aggregators to increase procurement from eligible renewable energy resources to 33% of total procurement by 2020."
This has several implications, one of which is that renewable resources are greater during some parts of the year, and less in other parts. (Sun is stronger and shines longer in the summer, wind blows strongest typically in April-May). Therefore, to achieve a 33 percent overall target, on many days in the year, more than 33 percent renewables must be achieved.
Note, though, that the total renewables in the RPS program includes the smaller renewables in the chart above, the 8 percent "Other Ren." That would mean, for that day, the total renewables reached 39 percent during those few mid-day hours from about 11 a.m. to 4 p.m. Therefore, even 39 percent is not enough, for that is not the daily average, merely the hourly average. At mid-day times, renewables will reach approximately 50 percent or even more, for the state's annual average to achieve 33 percent.
Let's hope Germany, and the other countries with grids that are struggling, are paying close attention. -- end update 1.
Roger E. Sowell, Esq.
Marina del Rey, California
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