Friday, October 29, 2021

Decarbonizing California's Grid

This is a follow-on to Rooftop Solar Inequity or Net Metering Goes Grrr.  It was brought on by this hilarious inside joke Tweeted out by @BPBartholomew

I had to ask him what "Gas plants running through negative spark spreads" meant. He clarified with another Tweet explaining how gas power plants can be ramped down to only the minimal amount needed to stay stable without shutting down. This costs them some gas and causes them to run temporarily at a loss.  Or they can be shut down completely, which reduces gas costs, but increases other costs. It's not an easy call. He and others coined the term "negative spark spread" to describe when plants run at a loss. 

Why would a plant operator run at a loss?  It can make sense if the cost of restarting from a shutdown is too high in terms of money or time.  The entire system has to ramp up for California's evening peak demand.  If you don't, the grid frequency slows down and may even crash*. 

For instance, the system had to add 13,671 MW over 3 hours to meet electricity demand the evening of Oct 12, 2021. That's a large amount to add over such a short time and California does this nearly every day!

First, some background on CAISO (California Independent System Operator) and the Duck Curve.  CAISO oversees the operation of California's bulk electric power system, transmission lines, and electricity market generated and transmitted by its member utilities. 

Net load is the difference between forecasted load and expected electricity production from variable generation resources. In certain times of the year, these curves produce a “belly” appearance in the mid-afternoon that quickly ramps up to produce an “arch” similar to the neck of a duck—hence the industry moniker of “The Duck Chart”.
Here's another plot from @BPBartholomew of the net load.  

At midday, California electricity is mostly renewables, mainly from solar.  It doesn't matter who your electricity provider is or which energy plan you are on; we share the same grid.  In most of the state, including all the urban areas**; you are using mostly renewables at midday and mostly gas at night. The different energy plans that customers sign up for at the retail level is about shuffling paper Renewable Energy Credits (REC). That's a gross simplification but I'll explain that later in another post. 

Don't take my word for it, stalk the CAISO supply website. Here's yesterday, October 12, 2021. The tall Green Hump is Renewables.  The Orange Duck is gas plants (of all types). The smaller Brown Duck is energy imports from other states. (Imports can be Solar from the east in the early morning, hydropower from the north, or wind power from the east in the evening.  Or it can be gas or coal from power plants east of us. 

Note that large hydropower is not considered renewable for regulatory purposes (meeting California's Renewable Energy Portfolio Standard), but it is low carbon.  Nuclear is also low carbon but not considered renewable. CA only has ~2,000 megaWatts of nuclear power capacity since the San Onofre plant closed in 2012. 

Renewables are further broken out on a separate plot.  Note that the day started out windy and then calmed down. Some clouds also rolled in. Geothermal is like nuclear, it hums along at a constant rate. 

There are "Climate Warriors" that oppose interconnecting California's grid to those of other states because they have use fossil fuels than CA. That would mean losing access to hydropower from the Pacific Northwest, wind power from the Intermountain Region, and solar power from Nevada and Arizona.  The grids serving the western states are getting greener and an important driver is that new investments have a big market for new power coming online.

Anyway, micro-grids are important for resilience, but not feasible for year-round decarbonizing. There simply aren't enough batteries. We are building a great deal, but winter nights are long, the wind is intermittent (and NIMBYs prevent us from building it), and batteries rely on rare earth minerals that are rare and environmentally costly. Read Batteries don't grow on trees for more about that.

Decarbonizing the grid while keeping it running is so hard for many reasons, big and small.  I'm in awe that it works at all, much less works so reliably that we take it for granted.

A couple of years ago, the leader of the League of Women Voters of California's Natural Resources Committee asked me to serve as the Energy Team leader. That's why I've been reading so much about energy.  I've learned so much and still have so much more to learn. Should I blog more often about electricity? I'm not an expert.  Although I took graduate Electricity and Magnetism and passed my qualifying exams in E&M, it was my weakest subject in both undergrad and grad school. 

* Remember when large parts of Texas lost electricity for days in February 2021? I read many accounts by industry professionals about how they narrowly averted a disaster that could have kept the state off-line for months.  AC, alternating current, has to be kept in a stable range of 60 Hertz. Texas' current dropped to 59.4 Hertz at 1:51 AM on Feb 15, 2021. This can damage equipment, which would take months to repair.

You don't start up a bunch of power plants and then blithely add them to the grid.  AC stands for alternating current.  You have to carefully hook up each generator to the grid such that their frequencies and phases are perfectly matched to the grids'. This is one of those invisible *very hard things* that get done all the time to bring us our comfortable lives.  

** There are pockets of rural California near the Nevada border that are more tied to the Nevada/Reno grid and parts of far northern California that are better connected to Oregon. But we're all part of WECC, The Western Interconnection and shift energy to each other as needed. 

Wednesday, October 13, 2021

Rooftop Solar Inequity or Net Metering Goes Grrr

Brian Bartholomew tweeted this out around 3 pm on a sunny autumn afternoon (October 13, 2021) along with the message, "CAISO right now"

I ran over to CAISO's real-time prices page and saw this:

If you were buying or selling electricity then, you would have paid $0.41 per megaWatt hour, or $0.041 per kWh.  

Under Net Metering, owners of rooftop solar panels who are producing more than can use can put it on the grid and be credited against their electricity use from the grid for anytime between 7AM and 5 PM.  The problem is that electricity prices fluctuate quite a bit. Here's another graph from @BPBartholomew

Say your panels are on the west-facing side of your roof and don't generate any electricity in the early morning hours you are getting ready for work/school.  You use your credited kWh banked during midday and don't have to pay for the energy.  Say you (or your kids) come home after school and turn on the air conditioning; you can crank away between 4:00 and 5:00 PM against your credits. 

A Southern California Edison (SCE) customer under the Time of Use (TOU) Prime plan, users without credits would pay 48 cents (Jun-Sep) or 45 cents (Oct-May) for that electricity.

Sometimes, net electricity costs can be negative.  You can be paid to take electricity and move it out of a congested grid. Do you have a big bank of batteries near Los Banos?  If so, you can be paid to charge your batteries tomorrow and then sell them during the evening duck curve.  It's called Energy Arbitrage. 

Meanwhile, in Los Angeles, the owners of rooftop solar panels selling electricity to SCE (which is forced by the CPUC (California Public Utilities Commission) to take it (even if they don't want/need it), can feed electricity into the grid worth 41 cents/megaWatt-hour or 0.041 cents/kWh, get credit for it, and use that 1 for 1 to offset electricity use in the evening, when it's worth 1000x that.

There is no point in me belaboring this; just read Severin Borenstein's Rooftop Solar Inequity.

I wrote a Net Metering Fact Sheet after reading lots of books, reports and government documents about how electricity is generated, moved around, regulated, purchased and used. I'm sure it will get angry comments from the people who are benefiting the most from California's current Net Metering policies. It's important to know that academics, government scientists and CPUC agree that overall, people with rooftop solar are benefitting at the expense of those without.

This "Energy Waterfall" plot showing the different 2019 costs for the three largest electricity providers in California from Ensuring Equity in California’s Energy Transition was very convincing. Look at the right-most column of Public Purpose Programs.  The thin green slice is aid for low-income customers under the CARE program. The fat brown slice is payment to PV owners (solar rooftop) under the current net metering scheme. 

Here's the detail of CARE and PV subsidies. We spend more subsidizing rooftop solar owners than low-income electricity users.  A lot more.

Who benefits from rooftop solar?  People who own their own homes and don't need to obtain HOA approval. That's basically people who live in Single Family Homes and have enough cash or home equity to purchase solar systems. They tend to be much wealthier than those who subsidize them.  (I know that lower income people have been growing among the rooftop solar owners, but that is largely because they were pushed out to live in new homes built in the deserts.)

That cost-shift from rooftop solar owners to those without is about $2 billion in 2019 and growing.

This post grew too long, so I split it up into another one explaining the Duck Curve and California's renewable energy portfolio. Stay tuned. 

Speed Kills (& doesn't get you there any faster)

Getting data out of some public agencies is so hard.  But, Redondo Beach Policy Department Tweeted this out today. It shows the traffic count at all hours of the day for a 15 day period between September 23 and October 7, 2021 at 1700 Artesia Blvd (just west of the intersection with Aviation Blvd).

On the top left plot of traffic counts:

  • Green is Compliant
  • Yellow is Inside Threshold
  • Red is Violators
There doesn't seem to be any violators so that looks great, right? 

Notice that the Threshold is set for 5-10 miles per hour above the 35-40 mph speed limit (which was ratcheted up from 35 to 40 mph by speeders due to the 85 percentile rule.) So you can speed up to 50 mph near an intersection of two busy arterials and not get a speeding ticket.

This should concern all of us because speed is the overwhelming determinant of whether a pedestrian or cyclist will die when hit by a motorist. CalBike showed this in yesterday's webinar, summed up by Warren Wells in a Tweet thread

Killing 40,000 people per year in the name of economic efficiency is worth it, right? (Sarcasm light flashing)

The dirty little secret is that it doesn't even get us there any faster. 

I found this nugget from A Century of Fighting Traffic Congestion in Los Angeles. The faster vehicles go, the more following distance they consume. (The same goes for taller vehicles like trucks/SUVs, which are much more to blame for traffic congestion than bike and bus lanes.) Road occupancy (space covered by a car) goes down with speed. 

The sweet spot for moving the most vehicles in a limited area and time is around 20-25 mph. Above that, you don't move any more people, but you make the roads more deadly. 

To quote the UCLA report:
  1. When cars are traveling at free flow speed and more cars are added the flow increases. 
  2. Flow continues to increase until the critical density. 
  3. Every additional car now lowers speed on the roadway. 
  4. Since cars are traveling slowly when traffic is dense, fewer cars overall are passing a given point on the roadway. 
  5. The relationship between density of traffic and speed is non-linear. 
  6. Figure 2 shows the relationship between speed and flow. As described above, flow increases until the roadway reaches capacity then begins to decline.
So why are we allowing people to speed up to 50 mph near a high school, two daycare centers/nursery schools, an elementary school and two senior housing complexes?

It's time to lower the speed limits on both residential streets and arterials.  

It's time to build out the South Bay Bicycle Master Plan (passed in 2011), and put *Protected* bike lanes on arterials.  Paint is not protection as the evidence and the bodies mount up. 

Both Artesia and Aviation Boulevards are supposed to get bike lanes whenever the roads were getting work done.  In the last decade, very little of the promised *Connected* network has been built.  What was built, is sadly disconnected and often in door zones next to fast-moving traffic.

Redondo Beach is using eminent domain to obtain land to build a right turn lane on Northbound Aviation, also without building a bike lane. 

Take a look at the graphic up at the top again.  The median and average speeds at most hours of the day and evening is 20 mph.  It's only higher around 2am, bar closing time.  What if we just made that the speed limit?  

Traffic flow would remain the same, but lower speeds would reduce road noise, making walking on the street more pleasant and welcoming. See also, Road noise and what we can do about it.

I've written letters.  I've gotten nowhere.  I need others to help apply political heat so that we see meaningful change on our streets.  Please.  Let's build streets where high school students can safely ride their bikes to school and our seniors can walk to senior fitness classes at the HS pool.