Total Solar Eclipse 08/21/17

[jflorey2]

The morning fog may be lifting by event beginning time for me. I monitor GHI on 1 minute intervals with a Davis Pro II plus. It'll be interesting to see how the GHI will be affected as well as the PV array's output.

We saw about a minute of totality here in Pacific City, Oregon. Amazing. (And California, despite dire warnings, had no supply problems as a bonus.)

[GRickard]

Here is my SolarEdge monitoring app. Clear skies all day with a 99.96% eclipse.

IMG_1682.PNG

[SunEagle]

We saw about a minute of totality here in Pacific City, Oregon. Amazing. (And California, despite dire warnings, had no supply problems as a bonus.)

I am glad you were not affected by the eclipse.

Although I am not surprised since CA only generates about 11% of its power from instate sources that comes from solar. CA also imports about 29% of all power consumption from other states.

So what you currently get from solar is easily covered by other power sources.

[sensij]

SunEagle , I think you might be mixing up power and energy.

Here are some fun charts from CAISO

Demand at 10:30 was about 31000 MW.
Net demand shows how much power needs to be covered once variable sources (wind and solar) are subtracted out.

Net demand spiked from just over 21000 MW to a bit under 27000 MW during the eclipse, so there was about 5500 MW of solar that dropped out and needed to be made up, 17-18% of actual demand at that time. There was no visible increase in production from other renewable sources in this chart, so it looks like conventional sources (including large hydro) picked up the load.

By 1:00, solar was fully back online, producing 9600 MW of the 31000 MW demand, about 31%.

If I squint hard at it, it appears that some solar generation may have been intentionally curtailed ahead of and immediately after the eclipse, perhaps to give some runway for other sources to come online. But, I don't look at these charts enough to say that with any confidence. net demand - yesterday.JPG









renewables - yesterday.JPG

[J.P.M.]

SunEagle , I think you might be mixing up power and energy.

Here are some fun charts from CAISO

Demand at 10:30 was about 31000 MW.
Net demand shows how much power needs to be covered once variable sources (wind and solar) are subtracted out.

Net demand spiked from just over 21000 MW to a bit under 27000 MW during the eclipse, so there was about 5500 MW of solar that dropped out and needed to be made up, 17-18% of actual demand at that time. There was no visible increase in production from other renewable sources in this chart, so it looks like conventional sources (including large hydro) picked up the load.

By 1:00, solar was fully back online, producing 9600 MW of the 31000 MW demand, about 31%.

If I squint hard at it, it appears that some solar generation may have been intentionally curtailed ahead of and immediately after the eclipse, perhaps to give some runway for other sources to come online. But, I don't look at these charts enough to say that with any confidence.

I don't think the ISO has much, or at least has incomplete information about distributed (residential) PV production. I believe the 2d graph you include shows production from the big farms, etc. The demand is shown as required generation, but I don't believe residential production or behind the meter residential use is accounted for. That generation may actually show up as reduced demand on the ISO, but I don't think there's any way to quantify it.

[sensij]

I don't think the ISO has much, or at least has incomplete information about distributed (residential) PV production. I believe the 2d graph you include shows production from the big farms, etc. The demand is shown as required generation, but I don't believe residential production or behind the meter residential use is accounted for. That generation may actually show up as reduced demand on the ISO, but I don't think there's any way to quantify it.

Ah-ha moment. The actual demand increased from ~29500 MW to 31000 MW during the eclipse and dropped back down again afterwards. Might be a clue that residential solar lost about 1500 MW of generation, in addition to the 5500 MW of utility solar CAISO can account for.

[SunEagle]

SunEagle , I think you might be mixing up power and energy.

Here are some fun charts from CAISO

Demand at 10:30 was about 31000 MW.
Net demand shows how much power needs to be covered once variable sources (wind and solar) are subtracted out.

Net demand spiked from just over 21000 MW to a bit under 27000 MW during the eclipse, so there was about 5500 MW of solar that dropped out and needed to be made up, 17-18% of actual demand at that time. There was no visible increase in production from other renewable sources in this chart, so it looks like conventional sources (including large hydro) picked up the load.

By 1:00, solar was fully back online, producing 9600 MW of the 31000 MW demand, about 31%.

If I squint hard at it, it appears that some solar generation may have been intentionally curtailed ahead of and immediately after the eclipse, perhaps to give some runway for other sources to come online. But, I don't look at these charts enough to say that with any confidence.

Since the time of the eclipse and outage was early for CA I would say that helped keep the demand down. If it was later in the day (say during the afternoon) when the demand would be higher your numbers would be different.

The 11% of all power generated in state comes from a couple of websites that track fuel usage for power generation in each state as well as the US. That is also where I found that 29% of the power CA consumes is currently being imported from out of state.

All of those number are in based on MW averaged over a entire year. Each day the percentages will change but if you want to use the data from yesterday during the specific time of the eclipse then fine. But don't let a single bit of data confuse you into thinking CA will be ok during another power outage that they haven't planned on or if it is much longer in duration.

Merde happens and it usually does during the worst time frame.

[sensij]

The 11% of all power generated in state comes from a couple of websites that track fuel usage for power generation in each state as well as the US. That is also where I found that 29% of the power CA consumes is currently being imported from out of state.

All of those number are in based on MW averaged over a entire year. Each day the percentages will change but if you want to use the data from yesterday during the specific time of the eclipse then fine. But don't let a single bit of data confuse you into thinking CA will be ok during another power outage that they haven't planned on or if it is much longer in duration.

Using annual average power is the same as using energy, but that is relatively meaningless for anticipating the consequences of an eclipse.

I generally like to use energy.ca.gov for energy data... what are you looking at?

For example, here is one breakdown of the sources of energy consumed in CA in 2016. In this chart, utility scale solar contributes about 10% of in-state generated energy, and about 8.1% of overall energy, accounting for imports. Net imported energy was 31.8%, which is about average for the last 15 years. A longer data set is available here.

energy CA 2016.JPG

[SunEagle]

Using annual average power is the same as using energy, but that is relatively meaningless for anticipating the consequences of an eclipse.

I generally like to use energy.ca.gov for energy data... what are you looking at?

For example, here is one breakdown of the sources of energy consumed in CA in 2016. In this chart, utility scale solar contributes about 10% of in-state generated energy, and about 8.1% of overall energy, accounting for imports. Net imported energy was 31.8%, which is about average for the last 15 years. A longer data set is available here. energy CA 2016.JPG

That is one site that I have looked at. Most of the data I get comes from the DOE or some other similar government energy site.

I also have very large spreadsheets showing existing generating capacity from 1990 to 2013 and another up to 2015 but those are now out of date but interesting to see the changes across the fuel type per state.

I believe this is the website I found that data I made in my which was CA.GOV which showed GWH generation and MW capacity by fuel.

Like all math information, the numbers can be manipulated in just about any way and form.

[sensij]

Like all math information, the numbers can be manipulated in just about any way and form.

Sure, but it is encouraging that we are looking at the same numbers from the same source. I like that the forum is open to the different narratives that can be spun from those numbers, and am happy to be part of a moderation team that helps prevent any of those narratives from drifting too far into the realm of fantasy.

[SunEagle]

Sure, but it is encouraging that we are looking at the same numbers from the same source. I like that the forum is open to the different narratives that can be spun from those numbers, and am happy to be part of a moderation team that helps prevent any of those narratives from drifting too far into the realm of fantasy.

What I would like to see is good "current" data instead of last years. With the increase of new and bigger RE generating plants coming on line in 2017 I would say some of that data posted earlier is old news.

[J.P.M.]

Ah-ha moment. The actual demand increased from ~29500 MW to 31000 MW during the eclipse and dropped back down again afterwards. Might be a clue that residential solar lost about 1500 MW of generation, in addition to the 5500 MW of utility solar CAISO can account for.

Or, it could mean that demand from A/C etc. ramped up, or lots of stuff.