[HN Gopher] How the electricity markets respond to a nuclear trip
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How the electricity markets respond to a nuclear trip
Author : kmax12
Score : 71 points
Date : 2024-07-30 17:56 UTC (5 hours ago)
(HTM) web link (blog.gridstatus.io)
(TXT) w3m dump (blog.gridstatus.io)
| toomuchtodo wrote:
| Something interesting is that with substantial solar and
| batteries being deployed in the ERCOT market (in scope grid
| operator for this piece), solar generation in excess of what the
| grid can consume with load combined with grid forming inverters
| (vs traditional grid following) can step in when called upon if a
| traditionally firmer generator (coal or nuclear) trips out. The
| potential is already there (photons hitting panels), simply
| turned down to align with grid demand (curtailment), but if the
| sun is shining and PV is called upon, curtailment can quickly
| turn into emergency grid support as long as the sun is shining (I
| am not familiar how long it takes from ISO signal to inverter
| command).
|
| It would be cool if individual generators shared this curtailment
| status/reserve in realtime publicly similar to how ERCOT reports
| real time generation mix data.
|
| Citations:
|
| https://news.ycombinator.com/item?id=40908526
|
| https://news.ycombinator.com/item?id=38848989
| kccqzy wrote:
| Most curtailment IIRC is due to insufficient transmission
| capacity. I doubt curtailed solar can be called upon in an
| emergency unless the emergency is located very close to the
| curtailed solar.
| toomuchtodo wrote:
| It's a fair point (why curtailment is in effect), and I think
| speaks to the fact that more granular and timely data is
| needed wrt all nodes and transmission segment within the
| system. Also a call for more batteries everywhere between
| generation and load.
|
| With regards to transmission congestion, that is easily fixed
| with installing batteries at currently storageless renewable
| generation facilities (the batteries then charge with excess
| solar, and can continue to discharge after the sun sets or
| the wind dies down, maximizing transmission utilization
| temporally). The Inflation Reduction Act also enables those
| batteries to charge from utility side if needed, whereas
| before they could only charge from the renewable generation
| (AC vs DC coupling).
| gunapologist99 wrote:
| Batteries are extremely expensive per megawatt, not very
| durable, require carefully controlled temperatures, and
| their manufacturer and recycling extract a tremendous cost
| from the environment. For non-mobile usage, batteries
| shouldn't be seen as any kind of viable solution at scale.
|
| However, there are other ways to store energy;
| unfortunately, most involve converting electricity to
| another form of energy such as potential (gravitational)
| energy, like pumping water uphill or lifting heavy weights.
| These also have relatively little long-term environmental
| cost. Unfortunately, they're a bit more inefficient (but so
| are batteries, relative to some other forms of stored
| energy such as fossil fuels).
|
| It'd be interesting if we could find some ways to convert
| landfills or other urban blight issues into a durable
| energy store without poisoning the environment.
| toomuchtodo wrote:
| > Batteries are extremely expensive per megawatt, not
| very durable, require carefully controlled temperatures,
| and their manufacturer and recycling extract a tremendous
| cost from the environment. For non-mobile usage,
| batteries shouldn't be seen as any kind of viable
| solution at scale.
|
| None of this is accurate. I encourage you to update your
| mental model with recent data. Citations below for your
| convenience. AMA, global energy transition is my passion.
|
| https://www.utilitydive.com/news/batteries-texas-
| consumers-6... ("Utility Dive: Batteries saved Texas
| consumers $683M during 2-day January freeze: Aurora
| Energy Research")
|
| https://news.ycombinator.com/item?id=40919052 ("HN:
| China's Batteries Are Now Cheap Enough to Power Huge
| Shifts")
|
| https://news.ycombinator.com/item?id=40601878 ("Lazard:
| IRA brings LCOS of 100MW, 4hr standalone BESS down as low
| as US$124/MWh"
|
| https://news.ycombinator.com/item?id=35513612 ("HN: The
| biggest EV battery recycling plant in the US is open for
| business")
|
| https://www.bloomberg.com/news/articles/2024-04-24/batter
| y-r... | https://archive.today/OjA91 ("Bloomberg: Battery
| Recycling Shatters the Myth of Electric Vehicle Waste")
|
| https://www.lazard.com/research-insights/2023-levelized-
| cost... ("Lazard: 2023 Levelized Cost Of Energy+")
|
| https://raokonidena.substack.com/p/history-
| of-10000-cycles-o... ("History of 10,000 cycles or 10
| year warranty for Battery Energy Storage System (BESS)")
|
| https://www.nrel.gov/docs/fy23osti/85332.pdf ("NREL data
| shows BESS asset life is 15-20 years.")
|
| https://web.archive.org/web/20240728011101/https://www.ei
| a.g... (US EIA; gray installations are new battery
| storage planned for deployment over the next 12 months,
| June 2024 through May 2025)
|
| https://www.eia.gov/todayinenergy/detail.php?id=61202
| ("US EIA: U.S. battery storage capacity expected to
| nearly double in 2024")
|
| https://www.eia.gov/todayinenergy/detail.php?id=61424
| ("US EIA: Solar and battery storage to make up 81% of new
| U.S. electric-generating capacity in 2024")
|
| https://www.woodmac.com/blogs/energy-pulse/battery-
| storage-b... ("Wood Mackenzie: Battery storage begins to
| play a key role for US grids")
|
| https://www.nytimes.com/interactive/2024/05/07/climate/ba
| tte... ("NY Times: Giant Batteries Are Transforming the
| Way the U.S. Uses Electricity")
| floatrock wrote:
| > For non-mobile usage, batteries shouldn't be seen as
| any kind of viable solution at scale.
|
| Lithium-ion, sure, but aren't there a whole host of other
| battery chemistries that are basically too big / too
| heavy to put on vehicles but a lot cheaper so well suited
| for stationary storage?
|
| Are they _all_ still at the research phase and so
| currently more expensive than the decades-of-learning-
| curve lithium-ion?
| shagie wrote:
| The vanadium redox flow battery.
| https://en.wikipedia.org/wiki/Vanadium_redox_battery
|
| > For several reasons, including their relative
| bulkiness, vanadium batteries are typically used for grid
| energy storage, i.e., attached to power plants/electrical
| grids. VRFBs' main advantages over
| other types of battery: no limit on energy
| capacity can remain discharged indefinitely
| without damage ... wide operating
| temperature range including passive cooling long
| charge/discharge cycle lives: 15,000-20,000 cycles and
| 10-20 years. low levelized cost: (a few tens of
| cents), approaching the 2016 $0.05 target stated by the
| United States Department of Energy and the European
| Commission Strategic Energy Technology Plan EUR0.05
| target
|
| (and yes, there are disadvantages too)
|
| See also NPR's story: The U.S. made a breakthrough
| battery discovery -- then gave the technology to China
| https://www.npr.org/2022/08/03/1114964240/new-battery-
| techno...
| bboygravity wrote:
| How is 10 - 20 years "sustainable"?
| toomuchtodo wrote:
| We're currently experiencing a Cambrian explosion in
| battery tech. As the technology matures, and we establish
| a closed loop ecosystem to build and then recycle these
| systems, longevity can improve over time. To get better
| at something, you must first suck at it, and 10-20 years
| is not an immaterial service life for an asset that just
| sits and hums with no moving parts.
| gunapologist99 wrote:
| I agree if we were talking about a motor or a pump, but
| it seems like batteries basically devastate the
| environment every time we make one, and doing that
| millions of times every ten years is probably not great.
| (But I don't know anything about that specific battery
| technology.. perhaps it's just saltwater and two
| dissimilar metals.)
| toomuchtodo wrote:
| https://sustainability.stackexchange.com/questions/9866/i
| s-l...
| energy123 wrote:
| Lithium-ion is the cheapest form of stationary storage
| for the sub-8 hour duration niche. The vast majority of
| battery storage being deployed is lithium-ion.
|
| Sodium-ion is the second largest contender, with a few
| pilot facilities opening in China recently, but it will
| be a few years before it eclipses lithium-ion.
| megaman821 wrote:
| Not a single thing you said about batteries is true.
| Pumped hydro is in no way competitive with batteries for
| most locations. In the future it is likely they won't be
| competitive in any location.
| jillesvangurp wrote:
| Better still; the amount of deployed batteries world wide
| is projected to overtake the amount of deployed hydro
| this year. Pumped hydro is barely growing. Battery
| capacity is growing exponentially to eclipse it this
| year. That's driven by pure economics. Cheaper, better,
| faster, etc.
| ZeroGravitas wrote:
| A recent article asks:
|
| "Why did the U.S. miss the battery revolution?"
|
| https://www.noahpinion.blog/p/why-did-the-us-miss-the-
| batter...
|
| About half the comments on the article were Americans
| saying very similar things to your comment and denying
| there was a revolution to have missed, which kind of
| answers the question posed.
| energy123 wrote:
| They're the cheapest form of storage after recent price
| declines, even cheaper than pumped hydro and compressed
| air.
| galangalalgol wrote:
| The secure authentication of all those nodes concerns me.
| Are these old scada systems coommunicating over plaintext
| rs232 or similar? Is it something running crowdstrike?
| rtkwe wrote:
| The transmission lines run to solar farms should be able to
| take 100% of the output of the farm and then some otherwise
| the farm was over built and wasted money.
| kccqzy wrote:
| I agree with your use of the word "should" here. But that
| unfortunately is not what happens in reality.
| adrianmonk wrote:
| At short distances from the solar farm, yes. But it's not
| 100% in every direction for arbitrarily long distance. At
| some point, you assume the energy will be tend to be used
| sort of near where it's generated.
|
| To put it another way, if you build solar between city A
| and city B, would you build it so it can still be fully
| utilized even if city A stops using any power and city B
| wants all of it? No, you assume city A is always going to
| need some power.
| callalex wrote:
| By this definition all reserve capacity is wasted money.
| That is clearly false, as demonstrated by the event in this
| article _not_ leading to failure and harm.
| rtkwe wrote:
| I'm not talking about reserve capacity at the grid level.
| I'm talking about excess capacity at the individual
| generation plant level that exceeds the grids capacity to
| take in. If you can't output the energy onto the grid the
| only benefit is for local maintenance and you don't need
| huge amounts of excess capacity to solve that and that
| excess doesn't help in the event of a large base producer
| like a nuclear plant going offline because it can't get
| onto the grid!
| energy123 wrote:
| That's not necessarily optimal. For home installs, you can
| overbuild panels because they're cheap compared to the
| inverter. Then you curtail sometimes at midday and have
| extra energy on cloudy days and in the morning/afternoon.
| Turns out that's more cost effective than sizing the panels
| perfectly. The same logic could apply to utility farms,
| because transmission lines can be expensive. I don't really
| know myself since I don't work in the industry, but I would
| not be surprised if this were the case.
| huijzer wrote:
| An individual inverter can usually switch in about 4 ms. A
| Tesla Megapack can go from 0% output to max output in 100 ms.
| Conversely, gas turbines (the fastest type of traditional power
| plant) takes about a minute to go from say 40% to 60%. Even in
| the fastest possible design, there is a mechanical rotor
| (kinetic energy) that has to change speed.
|
| What I mean to say is that solar and batteries are likely an
| order of magnitude faster to respond to sudden demand changes.
| So I would expect a more reliable system when more solar and
| especially batteries are being added.
| bell-cot wrote:
| IANAEE (not an electrical engineer), but doesn't a gas
| turbine spin at a constant speed to drive a 60Hz generator,
| regardless of whether it's running at 20%, 60%, or 100% of
| capacity?
| markus92 wrote:
| When there's a load imbalance on the grid (more load than
| capacity), the turbines physically slow down as inertial
| energy is extracted from them. This causes the grid
| frequency to drop. It takes some time to ramp up production
| and speed up the turbine etc.
| bell-cot wrote:
| The maximum slow-down of the turbines (before the
| generator trips off-line, removing the load on it) is far
| less than you seem to assume. The article's graph shows
| the 60.00Hz grid frequency dropping...all the way to
| 59.92Hz. That's 0.1333%.
|
| For an on-line gas turbine, the time to ramp up
| production is the second or few needed for the automated
| controls to open the throttle on the "Gas IN" pipe. It's
| basically a natural gas-burning turboprop jet engine,
| with the propeller replaced by a generator. (Yes, this
| can be less efficient in a combined cycle plant.)
| jeffbee wrote:
| The more interesting thing about rotating power plants is
| that they are routinely destroyed by transmission
| outages, because when a rotating generator is suddenly
| disconnected from its load, there are infinity terms in
| the equations that govern its motion and infinity isn't a
| thing you can resist. For steam turbines the control
| system has to slam the valve shut on the steam, otherwise
| the machine would overspeed, and closing that valve
| destroys some sacrificial part of the steam plumbing
| (hopefully). Steam power plants have to be inspected and
| repaired after disconnects and this is one of the
| numerous reasons why fission kinda sucks on the
| reliability front.
| leymed wrote:
| I think you're missing the point how turbine-generator works.
| The rpm speed has to stay the same, meaning the rotor speed
| doesn't change. As long as you don't have closed circuit
| you'll waste that mechanical energy. If you meant starting
| from stand still position, then you're right it takes couple
| minutes to pick up the load.
|
| With that said, turbines responding in couple minutes are
| more reliable as a baseline when you're planning load flow of
| as big as country or wider area. The basic reason is that you
| have source of energy under your control such as nuclear,
| water, gas, coal. You cannot have solar, wind as your
| baseline, I don't want sound dramatic, but it's kind of
| suicidal to do that. Solar's ramping is not a win when you
| consider greater scale.
| ViewTrick1002 wrote:
| Reliable until it isn't.
|
| The entire grid is a statistical system where we define the
| acceptable uptime.
|
| Renewables are as good as any other energy source bringing
| its own fuel, just need to take the variability into
| account.
|
| https://www.nytimes.com/2022/11/15/business/nuclear-power-
| fr...
| leymed wrote:
| You're correct that the system is statistical, and it's
| planned accordingly. However, we cannot omit the fact
| that it's the running turbine that responds faster to the
| unpredictable nature of the grid. The backbone of the
| grid, aka the baseline plants, are extremely responsive
| to unpredictable nature of the grid at a greater scale,
| with enough amount of safety margins to bring into
| service under unusual circumstances. I really don't see,
| at least what we have in hand rn, that happening with
| solar or wind. Without strong baseline you'd experience
| supply demand imbalance, in engineering terms frequency
| decay, voltage collapse.
| quickthrowman wrote:
| > An individual inverter can usually switch in about 4 ms.
|
| A quarter of a 60 hz cycle or a fifth of a 50 hz cycle is
| _really_ fast. For comparison, it takes a current limiting
| fuse around a half cycle to clear a short circuit current and
| a GFCI takes around two cycles to clear a ground fault.
| Reason077 wrote:
| > _" (I am not familiar how long it takes from ISO signal to
| inverter command)."_
|
| The grid frequency itself functions as a signal: a deviation
| below 50/60 Hz indicates support is needed, and a deviation
| above means curtailment is needed (or load added).
|
| Instant frequency-response assets such as batteries typically
| monitor the frequency independently and respond as required.
| They don't need to wait for explicit signals from the ISO.
| toomuchtodo wrote:
| True! But this signal is typically locally monitored and
| responded to by individual assets ("frequency response"
| ancillary services). That is distinct from a grid operator,
| ISO, whomever is orchestrating grid health to call on
| generating units due to a supply crunch. Tesla Megapacks can
| respond within milliseconds to frequency and voltage sags
| (when configured to provide these services), but Autobidder
| is what orchestrates and pushes out overarching power control
| strategy to individual assets (for example) [1] [2] [3].
|
| [1] https://www.tesla.com/support/energy/tesla-
| software/autobidd...
|
| [2] https://www.tesla.com/support/energy/tesla-software
|
| [3] https://electrek.co/2023/09/15/tesla-autobidder-
| product-330-...
| sunshinesnacks wrote:
| Grid following inverters can do something similar, although
| their response time is usually limited to the grid operator's
| automatic generation control (AGC) communication cycle, which
| is typically on the order of 4 to 6 seconds. And this requires
| plant controllers, and markets/contracts, to be setup for it.
|
| See https://www.nrel.gov/docs/fy24osti/86932.pdf. It deals with
| estimating reserves from these types of resources, but also
| talks a bit about general considerations, and references other
| good papers and demonstrations.
| Symbiote wrote:
| Where does the 1500MW of heat the reactor is producing go,
| immediately after the generators are isolated from the grid?
| csours wrote:
| Water? Same place it was going
| Scoundreller wrote:
| I mean, at least some percentage was going down the wire.
| That's why we do it, right?
| csours wrote:
| It would be funny if we were doing the whole song and dance
| just to amuse the electrons.
|
| If the turbines are 50% efficient, then the heat load on
| the cooling towers would double, which I have to assume is
| WELL within design limits.
|
| You have made me wonder about turbine overspeed and steam
| bypass.
| rtkwe wrote:
| The reactor is turned down and rapidly stops producing that
| much heat. On site backups keep the pumps running to continue
| cooling the residual heat. There's a long slow tail as lower
| energy fusion chains tail off towards lead but the vast
| majority of the power comes down quickly.
| pstrateman wrote:
| Enthalpy of vaporization for water is very very large.
|
| The amount of heat that can be dissipated by evaporating water
| is kind of incredible.
| theideaofcoffee wrote:
| Instead of that energy being directed to the turbines to
| convert the thermal energy into rotational energy (and thus it
| to electricity), the reactor begins cooling from the primary
| reactions (but not completely since secondary reactions/decay
| still are going) since there is no reaction heat (reactor
| idled). All of that excess residual heat contained in the mass
| of the fuel and reactor water is carried away by the cooling
| water loop, and either out to the cooling tower where it
| evaporates and releases its energy, or through the next stages
| of the loop into the cooling supply, most likely a neighboring
| river or lake.
| gunapologist99 wrote:
| It seems like you might really be asking about a meltdown
| scenario.
|
| The reaction can be slowed with control rods, which
| stops/minimizes the heat from being generated. The previously
| generated heat still needs to be handled, however (by
| evaporation).
|
| https://en.wikipedia.org/wiki/Nuclear_reactor
|
| A meltdown occurs when the reaction can't be slowed down
| through normal means because the safety systems fail.
|
| For example, Fukushima and Chernobyl:
|
| https://en.wikipedia.org/wiki/Fukushima_nuclear_accident
|
| https://en.wikipedia.org/wiki/Chernobyl_disaster
|
| However, those safety systems are obviously designed expressly
| to prevent such a disaster. For example, control rod systems
| are often designed to be fall (via gravity) into the reactor in
| the event power fails. These failsafe systems are typically
| very reliable, in the absence of other external events (such as
| the flooding and earthquake that took place in Fukashima.)
| thijson wrote:
| The control rods don't stop decay heat from being produced.
| That's what happened with Fukushima.
|
| Also, nuclear poisons (neutron absorbers) build up after the
| reactor is shut down. After the control rods are withdrawn it
| takes a few days for the poisons to be burned up and the
| reactor can resume power production. I think they call that
| poisoning out the reactor.
|
| https://en.wikipedia.org/wiki/Neutron_poison
| thijson wrote:
| When the Northeast power grid went down down in 2003, the
| Bruce Nuclear Power Development was almost entirely kicked
| off the grid. It was able to keep ticking over at a few
| percent of power output though because of a feeder line
| that went North. This prevented the reactors from poisoning
| out, and allowed them to come back faster than if they had
| poisoned out.
| bell-cot wrote:
| In general, any sort of "boil water to steam, use steam to
| drive turbines" system can vent the hot steam from the boilers
| to the atmosphere. There's a big reserve tank of cold boiler
| feed water, to replace the water you're no longer getting back
| from the steam condensers (attached to the "OUT" steam pipe on
| the turbine). So the boilers will keep soaking up just as much
| heat, while the engineers scramble to reduce the heat coming in
| from the burning wood, or burning coal, or burning oil, or
| fissioning atoms, or whatever.
| quickthrowman wrote:
| I would assume the cooling loop is still running, so the heat
| from the reactor would go into the water of the cooling loop,
| and then the heat would be rejected into the atmosphere when
| the cooling loop water evaporates in the cooling towers, just
| like it does when its generating power.
| konschubert wrote:
| I think the nodal pricing structure in the Texas grid is
| extremely conductive to an efficient electricity market.
|
| It incentivises the grid-stabilizing deployment of batteries.
|
| Texas is really the market to watch and learn from.
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