The California ISO is the manager of California’s “grid” and keeps track of the quantity of electrical energy contributed to the “grid” by each category of alternative energy, and started reporting solar-thermal separate from solar (photovoltaic) in late 2012. From that time, solar-thermal has been dwarfed by the much more robust solar PV generation. As well, solar PV generation has exploded, with the price of rooftop systems falling so rapidly that utilities are starting to notice decreases in demand.
The data allows us to get a feel for how the Ivanpah Solar Electric Generating System is coming along getting integrated into the grid, because Ivanpah is so much larger than all the rest of the existing solar-thermal production entering California’s grid. The company hasn’t updated its progress reports online for many months, so the production data is helpful gauging its technical success.
Here’s raw production of solar thermal, three-day average for smoothing, since the shortest day of the winter…
My amateur’s reading of this data starts with an assumption that the half-gigawatt/hr fairly consistent production at the end of December is the “background” non-Ivanpah sources of solar thermal, and that it’s reasonable to double that for the May background activity due to longer days. The rest must be Ivanpah.
The detail data shows that the background level was consistent through the new year, then on January 2 the background level was joined by an extra two and a half gigawatts of solar thermal, for a total of three gigawatts produced that day. Here’s the Cal ISO Daily Watch for that day. There may be some year-end New Years Weekend accounting anomaly at play, because it shows ST producing far into the winter darkness, a rare event. It did happen on January 2, 2013 as well.
Then, radio silence. ST production plummets and stays down for a while. Perhaps bringing the first 2.5 gigawatt/h per day broke the ST connections to the grid.
The world got back to normal around Feb 1. Halfway through the month, they brought another big burst online each day for a week or so, took a week off to assess how everything performed (PV numbers dipped hard at the point too), then ran between 1 and 1.5 GW/hr per day more or less permanently. Around the beginning of May, and again in the middle of May, output increased to 4.5 GW/hr per day – more Ivanpah?
The loudest voices in the fray seem to be nailing down solar-thermal’s coffin. They say Chinese engineering and manufacturing advances have caused photovoltaic costs to fall rapidly. Large scale PV is now almost 20-percent cheaper than solar-thermal, and does less environmental damage.
There’s some question about the wisdom of large scale energy generation in general, even aside from the man-made-climate-change conclusion that has been driving the discussion.