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By Sherry Listgarten

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About this blog: Climate change, despite its outsized impact on the planet, is still an abstract concept to many of us. That needs to change. My hope is that readers of this blog will develop a better understanding of how our climate is evolving a...  (More)

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The Emissions Intensity of California's Electricity Grid

Uploaded: Jul 24, 2022
Sometimes California’s electricity is powered almost entirely by gas turbines. Below is an example from January 12 of this year at 6 pm, when there was little sun or wind. At that moment, 60-70% of the grid was gas, including much of the imports. (1) Small amounts of renewables, nuclear, and large hydropower supplied lower-emission energy. (Data is from CAISO.)

On the other hand, sometimes the grid has very little gas on it. Below is an example from April 27 of this year at 1:15 pm, when there was not only a lot of sun, but also a lot of wind, reducing gas to just 15% of the grid.

We all get this sometimes-clean, sometimes-dirty power. (2) Even though Bay Area power providers largely purchase low-emission electricity, that energy goes into a big puddle of grid electricity. We then consume from that puddle, getting a blend of what everyone has purchased, not just “our own” power. So we can reduce our own emissions by choosing to use electricity at cleaner times. (3)

I like to think about a metric called the “emissions intensity” of the grid, namely the amount of emissions produced for every unit of electricity being generated. When the grid is powered entirely by efficient gas plants, the emissions intensity would be about 0.4 mTCO2/MWh. (4) When there are more low-emission sources of energy, the emissions intensity is lower, in theory as low as 0. The grid is usually somewhere between those two values.

Emissions intensity is for me a useful metric for understanding “how much gas is on the grid”. CAISO publishes the current value on their Emissions page, calling it “emissions rate”. Take a look and see what it is as you are reading this. Then look at the Supply page showing the current grid mix. Do they match up? A number around 0.2 would mean that only about half of the electricity is coming from gas turbines.

Unfortunately none of the California Energy Commission (CEC), the California Independent System Operator (CAISO), or the California Air Resources Board (CARB) publishes historic emissions intensity numbers. The CEC does have access to the data for modeling purposes, but Michael Nyberg of the CEC told me that “all hourly generation data collected by the Energy Commission is automatically confidential and cannot be released,” adding that “The data we use for … modeling is obtained from the California ISO under subpoena.”

The staff at CAISO suggested dividing their historic “demand” data by their “emissions” data to get unofficial historic values for emissions intensity. The charts below show that calculation, with some additional caveats because of my limited skills downloading and processing the CAISO data. But I think they are illustrative nevertheless.

The graph below shows the (unofficial) emissions intensity of California’s grid for a recent temperate week in July. (5) You can see that it is regularly around 0.3 from evening to morning, and dips below 0.2 midday.

Another way to look at this is using a heat map, where times with higher emissions intensity are redder, and lower emissions intensity are greener. The colored bar below shows data for Tuesday, July 12 2022, with hours going from midnight on the left to 11 pm on the right. (6)

Staff at the CEC urge caution about using a chart like this to conclude that midday EV charging (for example) is better than midnight EV charging. “Using system average numbers to estimate the impacts of specific changes in load, such as load shifting, … can easily result in misleading results. In reality, (such a change) would result in a complex response from electricity supply that will have emissions impacts that may be counter to past system wide averages, or any overall changes in system-wide averages.”

What does that mean? To give one example, a hot summer afternoon may have greenish emissions intensity because of all the sun still available, but that might obscure the fact that solar is max’d out and any new demand would be covered by gas. When you add demand to a hot summer afternoon, you are likely triggering a gas plant to run (the plant that is “on the margin”). Evenings are especially problematic. Electricity supply has to ramp up as the sun goes down, so gas plants operate inefficiently as they quickly start producing more power. That results in any additional load producing even higher emissions.

So the emissions intensity metric doesn’t tell the whole story. If you are trying to decide when to schedule an electric load, it is probably better to look at the general trend in emissions intensity and choose times when it is decreasing or flat and avoid times when it is increasing. More precisely, what you want to know is, if you were to increase electricity demand at a given time, what power plant would service it and at what emissions intensity? I have written about this concept of marginal emissions before.

Unfortunately, I can find no public source of marginal emissions data to share with you either! (7) The best freely available proxy for marginal emissions that I can find is the grid’s battery charging and discharging curves. Batteries charge when marginal electricity is cheap (and clean) and discharge when it is expensive (and dirty). You can see an example below, showing how 2 GW of batteries was deployed on July 22 to help clean up our electricity during the 4-9 pm interval. If you can use electricity when the grid’s batteries are charging, and avoid using much at times when the grid’s batteries are discharging, you can further help to reduce your own emissions and the cost of operating the grid.

On July 22, 2022, batteries charged midday when energy was cheaper and cleaner, and then discharged during the dirty and expensive evening interval. Source: CAISO

EV owners, do you see that discharge spike at midnight and a smaller one at 1 am? Lots of EVs start charging at those times, and I expect that spikes in EV charging demand are behind these bumps in grid battery deployment. In the chart below for the following day, July 23, you can again see a spike at both midnight and 1pm. If you can’t charge your EV during the day, then a simple thing you can do to help the grid is to move your charging start time to something like 2:15 am.

On July 23, 2022, batteries discharge at midnight and again at 1 am, perhaps to handle steep ramps due to scheduled EV charging. Source: CAISO

Your best bet, when possible, is to use electricity between 9 am and 2 pm. It is generally cleaner and cheaper then, even for new loads. This is likely to be true well into the future as the grid continues to add massive amounts of inexpensive solar. Consider setting a schedule for your pool pump, heat pump water heater, or electric vehicle charger.

Not all electricity demand is flexible. Stoves are always going to operate in the evening. Lights go on at night. Home heaters often work in the early morning. I have a heat pump to heat my home, and I don’t want to wake up to a cold house. It runs a lot on early winter mornings. What is the grid like then? You can get a sense in this graph, which shows a sampling of emissions intensity data from 2022. (8)

Emissions intensity, in mTCO2/MWh, at a point in time for every hour of every Wednesday to date in 2022. Data source: CAISO

This chart and the battery charts indicate that the grid has a lot of gas on it during winter mornings, but gas that is running pretty efficiently. That may change as more people adopt heat pumps, but at least for now these are pretty efficient gas plants running at steady state. The heat pump is also efficient, using only one-third the energy that a gas boiler would use. If the grid were a full 70% gas with turbines operating at a reasonable 45% efficiency, the heat pump still reduces emissions by about 50% on winter mornings (0.7 / (0.45 * 3)), and more at other times. That’s not too bad! Plus the grid is only getting cleaner. The chart below shows all of the low-emission power California is investing in that will operate at all hours of the day.

Planned resource buildout for California’s power grid. Source: California Public Utilities Commission, December 2021

The grid is a complicated system. To keep things simple while still helping people to save money and reduce emissions, most of our local utilities have rolled out time-of-use rates. They are designed to encourage people to use electricity at the “right” times. But those rates are a coarse tool that do not reflect the full complexity of the system. The grid is dynamic -- demand ramps up and down, different types of power plants go online and offline, weather changes affect solar and wind power, and transmission lines get congested. Time of use rates cannot begin to approximate all of that. We could save money and address global warming by better aligning electricity prices with costs and emissions. With that aim in mind, California’s Public Utilities Commission is looking at offering real-time electricity prices that would incorporate the ever-changing costs of generating and delivering electricity. Smart electric appliances (chargers, thermostats, pumps) could read those prices and adjust their operation, within constraints, to reduce emissions and help customers save money. I will write more about that in an upcoming blog post. It would be a massive change with many implications.

For now, I hope you have a better sense of how emissions intensity varies on our grid, by the hour and by the month, and a better idea of how you might reduce your own footprint by shifting when you use electricity. I’d love to hear any questions or observations you have.

P.S. If you want to understand emissions intensities a little more, this interactive map shows (somewhat delayed) emissions intensities in electric grids around the world. The units are different from what is used in this blog post, so divide by 1000 to match the units shown by CAISO. (Instead of 0.3 you will see 300.) You can see that our grid is pretty good compared to much of the world, and certainly compared to much of the US. You can navigate around to see what types of plants are running. Look at all the coal being burned in Indonesia and Poland, for example.

Notes and References
1. California’s imports are often from low-emission sources such as hydropower or wind, but in this case the emissions data indicate that imports were mostly gas.

2. By “all of us”, I mean those of us in California, and more specifically in the 80% of California that CAISO covers.

3. This is a somewhat subtle point. Our power providers are not required to align their generation curve with our demand curve. When there is a mismatch, as there almost always is, the “clean power” utilities effectively rely on other utilities to provide (dirtier) power for their customers when their clean power is inadequate (e.g., 4-9pm or night). So even customers with “clean power” utilities can reduce their emissions by shifting more of their electricity use to times when the grid has more clean capacity. That will mean that dirtier gas plants will run less.

4. mT = metric ton, MWh = megawatt hour. These efficient gas plants are assumed to be running in steady state, not ramping up or down, which increases their emissions. Less efficient gas plants, like “peaker plants” that run only as a last resort, have even higher emissions intensity. The 0.4 value also ignores any reserve requirements the grid has.

5. The graph shows one value at the top of the hour, for every hour during the week.

6. Each square shows only a single measurement taken during the hour. Measurements within each hour were not averaged.

7. The CEC has recently published an API called MIDAS that makes this information and more available to developers. The CPUC's Self-Generated Incentive Program (SGIP) also makes available an API with real-time marginal emissions data provided by WattTime that is used to ensure that participating storage is used for more than just backup emergency purposes.

8. Specifically, one measurement from every hour from every Wednesday was averaged to make this chart. Measurements within each hour were not averaged.

9. The electric system has “distribution losses”, where transmission lines and the distribution network lose some amount of electricity as it moves from the power plant to the home. These losses effectively increase the emissions intensity of an electrified system. The gas system has methane leaks, both in production and in distribution. These leaks also effectively increase the emissions intensity of a gas-based system system. I am ignoring both in this post.

Current Climate Data (June 2022)
Global impacts, US impacts, CO2 metric, Climate dashboard

On the good news front (ICE stands for Internal Combustion Engine, i.e., a gas car) ... (source):

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Posted by West Menlo Mom, a resident of Menlo Park: University Heights,
on Jul 24, 2022 at 7:37 am

West Menlo Mom is a registered user.

I have an EV and a grandfathered EV-A rate structure. Why does PG&E still encourage off-peak (after 11 pm) charging when there is an abundance of solar flooding the grid from 9-2?

Posted by Eric Muller, a resident of Los Altos,
on Jul 24, 2022 at 8:20 am

Eric Muller is a registered user.

You may want to check, they try to tell you how clean the grid is at any time. Their CEO, Gavin McCormick, was interviewed by The Interchange Recharged podcast Web Link

As you noted, what we buy (where our money goes) and what we get are two different things. For the later, we have no choice but aggregate the grid. CAISO is too small, you need to look at the Western Interconnect. Using the EIA data for the 11 western states is the best approximation I have found (and unlike CEC/CARB, they offer 2021 data, and machine readable data).

Posted by Mondoman, a resident of Green Acres,
on Jul 24, 2022 at 9:55 am

Mondoman is a registered user.

It's nice to see that battery storage is intended to quadruple over the next 3 years - it'll be interesting to find out how much of an effect that has.

Posted by Jake Waters, a resident of Birdland,
on Jul 24, 2022 at 10:48 am

Jake Waters is a registered user.

First, I am for innovation and very much a fan of the accomplishments in this field, but I also know that we are in no way at a point in time to cut the cord of fossil fuels- and the Biden administration has been Mach 3 since he sat behind the desk in the Oval Office to do just that. His foot on the brakes of our oil industry for the purposes of pushing his Green agenda can't be any more obvious. Who does that? Who tinkers with a country that was practically energy independent when you first pulled back the shades in the White House? Who tells citizens to go out and buy electric cars when they are struggling to pay the mortgage, the rent, food? Energy is everything to a ‘first world' country and helps sustain our freedom, which is fading rapidly day-by-day.

Energy storage, mentioned above, is vital to the whole innovation, but we are nowhere near capturing this capacity in the near future. Look outside our boarders and see what is happening in France, Germany, Argentina, and others regarding their forceful hand upon their citizenry to bear the problems of their ideology. Secondly, open your eyes at the caustic and dangerous byproducts of the Green New Deal: solar panels, Wind machines, and batteries will and are becoming an issues for disposal. They create some serious chemicals. Anyone who has attempted the slightest bit of reading knows that Nuclear has a smaller footprint to the environment and greater and consistent output for our community. The Green New Deal is for the donors who have everything invested in this new industry.

Lastly, I'm not a fan of ‘brown outs,' and I particularly don't care for having to consults time charts as to when you can turn your A/C on or run your washing machine. EV cars are exciting, but again, we are not at a point to rely totally on these products. I feel much more confident knowing that my car can travel to its destination without 3 stops to charge it back up.

Just my thoughts. Thank you.

Posted by Local Resident, a resident of Community Center,
on Jul 24, 2022 at 10:51 am

Local Resident is a registered user.

I noticed you did not include residential solar, only grid scale solar. However, residential solar is very valuable in combating global warming. It increases the total supply of clean energy (thus reducing burning gas) while being privately financed (by home owners). When combined with a home battery (like Tesla Powerwall) it allows you to shift the excess solar collected to lower the times when gas burns and recharge your electric car at night. While Solar pays for itself, the electric storage does not currently and should be partially subsidized going forward. Regardless, I think your negativity towards residential solar is misplaced and harmful to our planet.

Posted by Ronen, a resident of Menlo Park: Suburban Park/Lorelei Manor/Flood Park Triangle,
on Jul 24, 2022 at 11:04 am

Ronen is a registered user.

Sherry - as always an informative, well-sourced article. Thank you.

Jake - we're in a planetary emergency. You clearly don't get that and neither does the republican party or Joe Manchin. Unfortunately, our kids and theirs (and many generations to come) will be paying a very steep price for this ignorance and complacency.

Green New Deal? What Green New Deal are you talking about? Are you under the impression that this has become law or even government policy? And the Fox News sourced garbage on environmental problems caused by green tech? There might be some issues to deal with but can you honestly compare any such issues to the millions dying from air pollution from fossil fuels or the land, rivers and oceans being polluted by massive spills and pipes bursting?

[Portion removed.]

Posted by MichaelB, a resident of Pleasanton Meadows,
on Jul 24, 2022 at 11:55 am

MichaelB is a registered user.

"Jake - we're in a planetary emergency. You clearly don't get that and neither does the republican party or Joe Manchin. Unfortunately, our kids and theirs (and many generations to come) will be paying a very steep price for this ignorance and complacency."

Who's "we"? The "emergency" is too many (ignorant) people thinking the world is going to end if we don't do what they want, when they want it.

You clearly do not get that crippling our current energy production/supply capabilities (while other nations will not) to "save the planet" has both economic and national security implications. Negative ones, that is. Manchin "got it". The average person/family would have been paying a steeper price - just to make ends meet. Inflation would be much worse than it is now if Biden's trillion-dollar climate spending bill was enacted.

Posted by Sherry Listgarten, a Palo Alto Online blogger,
on Jul 24, 2022 at 6:59 pm

Sherry Listgarten is a registered user.

Terrific comments, thanks! I can tell that you read and understood this post, which I worried was a little wonky… I have a lot of thoughts, so I will break them up into smaller posts.

@WestMenloMom: I do not know exactly what went into crafting the time-of-use rates that the utilities have today. They are all different (for different utilities), and as you said they have changed over time. I am pretty sure that the utilities optimized for cost rather than for emissions. (The two are generally aligned but not completely aligned.) That is what the utilities have to do, in fact. PG&E's portfolio is mostly nuclear, with some gas and solar and hydro, plus a smaller amount of wind. Since nuclear and some gas plants run much better/cheaper when at a steady state, it could well cost PG&E less to satisfy demand from midnight to 5am than from 10am to 2pm, at least on weekdays.

One of the points of discussion with the real-time pricing they are considering is whether the prices should take emissions into account or just the cost of producing the energy (assuming cost of emissions is zero). That will be an interesting discussion.

Posted by Sherry Listgarten, a Palo Alto Online blogger,
on Jul 24, 2022 at 7:00 pm

Sherry Listgarten is a registered user.

@Eric: Thanks for the pointers! I omitted WattTime from this post because they charge for the data. The Western Interconnect doesn’t represent the electricity that we use. Any electricity we get from outside of CAISO is counted as an import. So I think looking at CAISO is the correct representation of what is coming into our homes and businesses. It is great that we have this large interconnect, though, that allows us to exchange electricity easily. It reduces cost and increases reliability for all of us.

Posted by Sherry Listgarten, a Palo Alto Online blogger,
on Jul 24, 2022 at 7:01 pm

Sherry Listgarten is a registered user.

@Mondoman: I've already seen a huge change in how batteries are used in the last few years. Just two years ago they were mainly used for frequency adjustments on the grid, basically ensuring that power stays at the right frequency. Now there is enough of it to really make a difference in shaving the peaks down, reducing our emissions and costs. I think the new batteries will have a great effect if we can actually build it all. It is an enormous amount. Then imagine on top of that if we get EVs contributing at times of critical summer peaks (for example). There is a gigantic amount of storage in EV batteries already, and even more in 5-10 years.

Posted by Sherry Listgarten, a Palo Alto Online blogger,
on Jul 24, 2022 at 7:08 pm

Sherry Listgarten is a registered user.

@Jake: I so appreciate you weighing in, and I agree with many of your points. We are not in a position today to cut ourselves off from gas. We clearly need some gas on the grid now, and we will for a while. We also need some gas for buildings, industrial processes, transportation, etc, and we will for a while. As you say, gas and energy more generally have been critical to our development, and will continue to be. We can’t be careless with them. I also agree that energy independence is important. I also agree that brownouts are not great, that NO ONE wants to consult time charts in order to use their appliances (some may do it to save money, but no one wants to), and that EV cars are still not a good choice for everyone. I appreciate the thought you’ve given to all of this, and the many sensible points you make.

I’ll add a few things, which you may already be aware of…

Although we will absolutely need gas for many things for many years, I would say that it is really important that we start using less of it right now. That is because it will save us a lot of money in the long run. The more gas we use now, the more emissions “debt” we are taking on, and the more it will cost us to clean up. If anything, I wish we had started 20 years ago. I wrote about that some here, if you didn’t see it. And as you know, as someone who likes and appreciates innovation, we have lots of ways to reduce our gas use, safely and reliably and cost-effectively, and will have even more soon. I love that, and it’s a really exciting time right now, though as you also say sometimes we don’t get everything exactly right. That’s what innovation is about, right? (*)

Because of that, I do NOT think we should be growing the gas industry. In fact, I’m not sure even the gas industry thinks we should be growing the gas industry at this point. New oil wells are 30-year investments, which is just not a good use of money given our need to reduce emissions. Our job as a first-world country is to invent and move to the better option -- cleaner energy -- and then bring the rest of the world along. Solar and wind and geothermal development make us more energy independent, and we are working on more domestic battery materials and development. So I am 100% in favor of stopping new domestic oil exploration. It makes no financial sense and it just entrenches old ways of doing things instead of moving forwards.

I worry more about things in the other direction, honestly. Young people coming out of college want to be part of exciting and growing industries. So they are not interested in oil and gas, even though as you say we rely on that industry and we need people to keep efficient plants running, reducing methane leaks and improving efficiency, and so on. Carbon capture and storage will hopefully be a way to attract young people.

Re nuclear, FWIW, if it were cheaper to build I think we would use it more. I worry also here that since we are building so little, we are losing our expertise in this area. So I hope we keep innovating here as well. But right now it is just far too expensive, even with its high capacity factor. We’ll see what comes down the pike.

Finally, re needing to read time charts, here is some hope for you. My EV is plugged in right now, but I have no idea if it’s charging or not. (I just checked and it’s not, it’s waiting for cleaner power.) So, no time chart! If I did want it to charge right now, or be charged by a certain time, I can use settings for that. The idea is just that more appliances could work this way. You probably don’t care when your hot water heater or pool pump are running as long as you get hot water when you need it and a clean pool when you need it.

Anyway, I just want to thank you again for reading and chiming in, and I hope you continue to do so.

(*) There are limits to this though, and especially when the risk falls primarily on the disadvantaged. The terrible ERCOT failure in Texas last winter comes to mind.

Posted by Sherry Listgarten, a Palo Alto Online blogger,
on Jul 24, 2022 at 7:10 pm

Sherry Listgarten is a registered user.

@LocalResident: The table you refer to is just straight from the CPUC document. It is about utility buildout, so it didn’t include “behind the meter” tech like rooftop solar or home batteries. No editing on my part :) FWIW, I have no beef with rooftop solar or with the many homeowners and businesses that have invested in it. My only beef is with the pricing, which is patently unfair. Non-solar utility customers are paying far too much for energy that has far too little value. It’s been a great deal for adopters but a terrible deal for non-adopters. California is appropriately addressing that. I think we will continue to have lots of rooftop solar because it will still be a good deal, if not a screaming deal, especially with batteries. But hopefully we see it more equitably deployed and with more storage. That's my 2c anyway.

Posted by Sherry Listgarten, a Palo Alto Online blogger,
on Jul 24, 2022 at 7:12 pm

Sherry Listgarten is a registered user.

@Ronen/MichaelB: I think the planet is in bad shape and getting worse. The evidence is all around us, and I’m not sure any political party is disputing that any longer. So that is something. It is fair to weigh short-term benefits vs long-term pain and short-term pain vs long-term benefits. We people tend to be pretty short-term focused, and climate-change is (or at least has been) a long-term problem. It is also very much an equity problem, as MichaelB alludes to. My concern is that Manchin’s policies have not been good for the people of West Virginia, where GDP has gone up just 4% since 2010 compared to 80% for California, and I don’t think they will be good for the country either. We need to be looking towards the future, not looking to the past. We can do that with a focus on equity and affordability. I actually think Biden has that focus, and you can see much more climate-forward policies in other countries where there is good GDP growth and much more equity than we have here.

But I get that these can be difficult discussions, and I appreciate your weighing in respectfully and thoughtfully.

Again, thanks for all the interesting and helpful comments. There are just so many fairly straight-forward ways -- and even more innovative ways -- that we can be reducing our emissions, and every day I appreciate California’s leadership on this, the dedication of many minds working on technical and social solutions, and all of you who are interested in learning more, discussing the topic, and trying things out. It all makes a difference!

Posted by Kevin, a resident of Castlewood,
on Jul 25, 2022 at 6:33 pm

Kevin is a registered user.

I have installed solar and 2 Tesla batteries. They went into production in April and I am very happy with the way they are working. We have had a couple of power outages because of accidents on the road. The only thing I noticed was my wifi dropped for about a minute until it came back on. It was just a PG&E outage so everything was working fine. I highly recommend to folks who can afford it.

Posted by SRB, a resident of St. Francis Acres,
on Jul 26, 2022 at 2:57 pm

SRB is a registered user.

Thanks for another informative blog.

It shows that when a city like Mountain view switches to Silicon Valley Clean Energy, the electricity it purchases might be clean but the electricity it uses not so much or at least not 24x7.

The switch to SVCE is a great first step but quite a bit of work left to fully green the electricity we use.

Posted by Menlo+Voter., a resident of Menlo Park: other,
on Jul 27, 2022 at 7:49 am

Menlo+Voter. is a registered user.

Destroying our economy while China and India continue to spew insane amounts of carbon is not going to help the planet. Until the world starts to deal with this problem our efforts will only hurt the US. The goals are laudable, but I am not in favor of killing our economy to do something that will have very little effect on the world due to other countries' lack of action.

Posted by Raymond , a resident of Monta Loma,
on Jul 27, 2022 at 3:58 pm

Raymond is a registered user.

For reliable energy, nukes are the way to allow wind & solar to make their contributions. Without nuclear backup, wind & solar set us up for interruptions in supply.

Posted by SRB, a resident of Mountain View,
on Jul 28, 2022 at 9:04 am

SRB is a registered user.

Regarding nuclear energy reliability, it's also subject to climate change. France has had to curtail its production during the reccent heat wave(s) : Web Link

Posted by BobB, a resident of Another Pleasanton neighborhood,
on Jul 28, 2022 at 10:57 am

BobB is a registered user.

Sherry makes a good point that with nuclear we may be losing our expertise in this country because we are building so little. It would be a terrible shame to shut down Diablo Canyon early, and I really hope efforts to keep it open longer succeed.


Note that even with restrictions in France they are far better off with their nuclear power then Germany which tried to switch to solar and wind and are now facing a crisis in which they are burning more coal and gas. France has also realized that they were neglecting nuclear and have now pivoted back toward it.

Nuclear is reliable safe and cheap. Much of the expense of building new nuclear in the US is due to inefficient bureaucracy and older non-standard designs.

Posted by Sherry Listgarten, a Palo Alto Online blogger,
on Jul 28, 2022 at 1:30 pm

Sherry Listgarten is a registered user.

@Kevin, your setup sounds great, and it’s exactly what the state and utilities love to see, especially in the areas that are targeted by the public-safety power shutoffs (due to fire risk). Your energy is cleaner and more reliable than the grid! Soon there will be some ways for you to get money back by donating your battery energy at critical times (e.g., when demand is high and you don’t need it all).

@SRB: Exactly!! Everyone should be asking their “clean” utility when they will be zero emissions on a time-coincident basis, or at least where they are now. Peninsula Clean Energy is on top of this. Palo Alto is on top of this, but they are prioritizing electricity costs over truly net-zero power right now. I don’t know what Silicon Valley Clean Energy or East Bay Community Energy are doing on this. Let me know if you find out! It is easier in areas with a lot of businesses, since their load is often largest during the day when solar energy is available and inexpensive. That is the case for Palo Alto. Not sure about these other, larger, areas.

@Raymond and others: One of the big problems with existing nuclear plants is that they are largely inflexible. That means they have to run even when there is cheaper energy available. In the recent Diablo Canyon report by Stanford and MIT researchers, they acknowledged that if Diablo Canyon were flexible, it would run as little as 12% of the time by 2045. Instead, it runs almost 24x7, displacing cheaper energy. If the plant were flexible, then its maintenance costs would need to be spread over many fewer hours, which is also difficult. There is some discussion on how flexible existing plants can be, but this is generally acknowledged to be a major problem. Utilities are not using nuclear to complement solar and wind, they are using it in addition to or instead of solar and wind. Same with geothermal. Only more flexible resources like gas and batteries can be used to complement solar and wind.

If the newly proposed Inflation Reduction Act passes, it will provide tax breaks to keep existing nuclear reactors running, while also providing tax credits for development of new designs that might be more flexible and lower-cost to build. There are many risks involved with nuclear energy, but I think these are reasonable compromises.

Thanks again for weighing in!

Posted by Local Resident, a resident of Community Center,
on Jul 29, 2022 at 9:37 am

Local Resident is a registered user.

Sheryl, you wrote, "My only beef (with rooftop solar) is with the pricing, which is patently unfair."

This is because you count the cost of the grid but at the same time assume the residents investment in solar is not part of the grid and does not count. In fact, when a resident adds rooftop solar they are adding to the grid and also paying for its ongoing maintenance. Furthermore, they are increasing the total amount of renewable energy produced, something PG&E has been very reluctant to do and does not appear to have any motivation to do.

The problem with Palo Alto's electrification plan based on their 100% renewable energy, is that energy was taken from a fixed amount available to all of California. Thus we have more but other cities have less and it did not increase the overall total renewable energy supply for all California customers, whereas each time a new rooftop solar installation occurs, it increases the total amount of renewable energy. Thus every time a resident adds rooftop solar it is a step forward in fighting climate change.

You also previously stated "Palo Alto switched years ago to using 'avoided cost' for solar exports. " which means the city buys electricity from solar providers at the same rate it buys it from PG&E and its other outside folks to deliver it to the city boundaries. Thus we should not be lowering that rate further.

Furthermore, NEMS 3.0 is adding a $0.05 per kWH tax for each kWH generated by the residents solar. This is ridiculous and should be removed since the resident paid for their solar system.

I hope you revisit your stance on residential roof top and your desire to reduce financial incentives to residents to fund and increase the total amount of renewable energy.

There are two policy changes that I believe we both support that would move things forward, which are batteries & time of use billing. However, all customers should pay time of use, not just solar customers.

Posted by BobB, a resident of Vintage Hills,
on Jul 31, 2022 at 5:52 pm

BobB is a registered user.

Using nuclear instead of solar and wind sounds like the right way to go for a large portion of electrical power. The way the French are doing.

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