HN Gopher Feed (2017-06-29) - page 1 of 10 ___________________________________________________________________
California solar power output sometimes exceeds predictions
73 points by DINKDINK
http://www.latimes.com/projects/la-fi-electricity-solar/___________________________________________________________________
Camillo - 48 minutes ago
Reading these articles is like listening to five year olds arguing.
"These guys says it's enough!" "These other guys say it's not!"
"But what if it's cloudy?" You can picture the journalist holding a
toy microphone and nodding intently at each source, the argument
going entirely over their head.The entire argument revolves around
the distribution of power usage and of power generation throughout
the day and throughout the year. So why not explain that for your
readers? Show us charts with that information? Tell us how much
energy is produced by solar on the cloudiest days? Show us a chart
of power usage over solar power production over the last year, and
tell us the minimum and maximum percent?At least explain the
difference between minimum, maximum and average production, and
when each of those matters!But no, none of that. We get a graph
showing the increasing share of solar generation, and another with
absolute figures of the curtailed solar capacity. And a bunch of
pictures and animations, of course.This is what innumeracy looks
like.
cuckcuckspruce - 31 minutes ago
This article was produced by a newspaper for a region where butt
implants are a thing and the hottest gossip is what stars are
fucking each other.This article was not read by the majority of
its intended audience, and even if it was, was not understood by
a majority of those that read it. Asking for it to contain more
information is silly given those facts.
Brakenshire - 29 minutes ago
> This is what innumeracy looks like.I don't know whether it's
innumeracy so much as lack of time, and also the specific
expertise (not just ability to understand numbers, but expertise
in this specific area) to be able to understand the information.
For a general reporter (not an 'energy correspondent' or
something similar) the article you're proposing would take at
least a week of study and research, probably more, this 'he said,
she said' stuff can be knocked off in a few hours.
[deleted]
throwaway76543 - 21 minutes ago
It's innumeracy. I don't need to know anything about the
subject matter to understand why the concepts, numbers and
relationships mentioned above are important. In fact, I am
absolutely not a solar expert -- I have no expertise in this
specific area -- and I know that I am entirely qualified to
understand the basics of load variation over time.
andreyf - 11 minutes ago
Imagine understanding this was something you were assigned at
work. What would you ask first? I am a web programmer with no
specialty in any of this, but here's my top list: - what's min
/ max usage and production? - density plot of usage
throughout the state - density plot of usage over typical
24h? typical 356d? - what kind of special events w.r.t. usage
are there? - cost of storage, improvement over past decade?
- cost of transport, improvements? This is off the top of my
head, non-expert studied math but never professionally. How
many of these are answered in the article?
twelvechairs - 25 minutes ago
What gets me is their articles key line is 'it depends on who you
ask' then they ask you to subscribe because they are "telling
fact from fiction".I hope journalism changes soon. Id love a
higher-cost service that actually looks at the broader picture
and takes a side (edit: an informed side, clearly explained,
rather than an ideological one) rather than focussing on
headlines, 'he said she said' and too much undistilled text
a13n - 22 minutes ago
That takes a side? You mean like fox news or the New York
Times? Doesn't all media these days take a side?
twelvechairs - 19 minutes ago
Okay lets go with an informed side, not an ideological one
a13n - 18 minutes ago
Deal
EGreg - 25 minutes ago
NYTimes pioneered a lot of data visualization techniques. I think
the lead guy on the project built the now-famous d3 library.
skybrian - 1 hours ago
Seems like some local industry would be able to use this? Or maybe
turn on some air conditioning or hot water heaters.
digikata - 1 hours ago
If Tesla can really put up grid storage modules as fast as they
claim, shouldn't this just be a big opportunity to print money?
Get paid to charge the batteries on surplus surges, get paid to
supply power at night discharging them...
ChuckMcM - 47 minutes ago
Yes. The "obvious" question when reading an article like this is
"Why pay someone to take the power, why not just turn off a gas
or coal fired plant?" There are some obvious restrictions around
that (like the plant would need to be in the general area of the
grid where power was coming from of course) but the issue
according to the PUC is that "cycle time" which is the amount of
time it takes to turn off a power plant and then turn it on
again, is longer than the "event time" where you get an over
power event transient.Grid storage nicely addresses both of these
issues because it can absorb the extra energy (charging) and when
the grid storage units are charged you can safely turn off a
power plant because even if the power suddenly dips for what ever
reason the grid storage can cover that loss while the power plant
is restarting.If you reach the point where you have enough grid
storage to completely cover the variance between day time and
night time power demand, then things get even more efficient as
you switch to that storage a 'primary' and then cycle on plants
as needed to top them off.
oconnore - 36 minutes ago
But so much of the demand is flexible. For example, I get zero
benefit from heating my water tank at a particular time.
Building grid storage so I can run my heat pump when it's dark
and the air is still is inefficient and silly.
ChuckMcM - 4 minutes ago
I'm not sure what you are trying to say here. At the
individual user level energy usage may appear random and
chaotic but at the community level that is not the case. To
use your example, at any given instant in time someone in
your city is heating water (whether intentionally by
consuming water from a hot water storage facility, or
passively as that facility activates automatically to keep
the water at a given temperature). All of those usages level
out to an aggregate demand on energy to heat water over unit
time.If you think about it as a capacitor that "filters" high
frequency noise on the electrical grid it might be clearer.
tedsanders - 42 minutes ago
Printing money is not a great business if the printers cost $10M
and they print out $1,000 a day and lose the ability to print
after 1,000 printings.The economics are still not there yet for
widespread battery energy storage. Here are some real
numbers:Wholesale prices fluctuate, but are often in the range of
0 - 10 cents per kWh. Lithium ion batteries cost something like
$250/kWh. The inverting electronics cost like $100/kW. Round trip
charging efficiencies are like 80%. Battery lifetimes are like
1,000 charge cycles. So assuming a system with 10 kWh at 5 kW,
your costs will be $3,000. Or, on a per cycle basis, $3. If you
charge 10 kWh for free and then sell 8 kWh for $0.10 each, you're
making $0.80 on the transaction. Not enough to even cover your $3
in levelized costs.(Obviously the economics improve with better
assumptions. But there's still maintenance, interest rates,
hookup costs, and destruction costs to take into account.)
mtgx - 37 minutes ago
Fortunately for Tesla, it also sells a few more products that
make use of batteries.
digikata - 25 minutes ago
I don't think the charging cycles is quite as open and closed
as you represent. Its probably 1000 cycles to maintain 80%
capacity (or some such threshhold), but you can keep running
batteries in a storage-only application them far longer than
one would find acceptable for keeping in a car.But overall,
yes, there are lot of technical considerations to actually
doing it. And the article and discussions just touch the tip of
the actual complexity involved - but it seems like there are
power arbitrage opportunities of various corners of the grin in
both long and short lasting sources.
tedsanders - 17 minutes ago
I'm not an expert, but my understanding is that reduced
capacity of old batteries is a symptom, not the problem. If
reduced capacity was the only issue, then yes, it would make
total sense to run old batteries into the ground.But the
issue is that the reduced capacity is a symptom that the
battery is decaying internally, through a variety of
mechanisms (cathode/anode micro-cracking, dendrite growth,
physical leakage, who knows). Old batteries are dangerous
fire risks, exactly what you don't want in a warehouse full
of flammable batteries. For this reason, it's risky to run
old batteries into the ground. This is why there isn't a
market to turn old electric car batteries into utility-scale
storage.Then again, this doesn't seem to be an issue for
consumer electronics like laptops and phones and electric
toothbrushes, so I wonder what's different, if anything.
hobolord - 1 hours ago
seems like a good opportunity, but how much would it cost for
these storage units?
fweespeech - 51 minutes ago
If 65 days of the year you charge and 300 days you don't, it
likely isn't cost effective.Peak time is also during the daytime
which means baseload power sources like Gas/Hydro/Nuclear/etc.
are likely fulfilling demand at night just fine.Most likely you
are charging during winter and discharging during heat waves in
the summer which may not be a viable business model despite the
large delta in energy prices.At least that is my understanding,
I'm not an expert. xD
djrogers - 1 hours ago
And yet our rates keep going up, which encourages less electricity
usage and higher adoption of personal solar installations. Seems
like this is going to be a pretty rough cycle for the power
companies to navigate if they aren't allowed to change their
business models...
paulsutter - 1 hours ago
They should pump water uphill during these surges. California
hydropower is constrained by rainfall, so the dams and generators
already exist. Pumps cost less than batteries and this process has
about an 80% roundtrip efficiency
gricardo99 - 48 minutes ago
> California hydropower is constrained by rainfall, so the dams
and generators already exist.But there's nothing to pump, at
least a good part of the year. The dammed river beds are
practically dry during the summer/fall months.
redthrowaway - 1 hours ago
>this process has about an 80% roundtrip efficiencyHow is that
possible? Even if you assume frictionless pipes and lossless
power transmission, that's assuming 90% efficiency for both the
pump and the generator.
dtparr - 1 hours ago
From https://en.wikipedia.org/wiki/Pumped-
storage_hydroelectricit...> The round-trip energy efficiency of
PSH varies between 70%?80%,[4][5][6][7] with some sources
claiming up to 87%.[8]
azurezyq - 1 hours ago
Well, solar farms in CA are mostly in deserts, where hydro
reservoirs are not that feasible.
DiabloD3 - 1 hours ago
Power can be transmitted to areas inside of CA that already
have hydro reservoirs or ones at higher elevations can be
built.
rootusrootus - 1 hours ago
Since it's already wired up to the same grid, does the storage
have to be near the generating plant?
azurezyq - 59 minutes ago
I think the point of paying AZ to take excess power is to
lower the load on CA grids.So long distance transmission
cannot solve the immediate problem.
[deleted]
hkmurakami - 1 hours ago
Well we need all the reasons we can get for adding dam capacity.
oconnore - 59 minutes ago
If they priced residential power in line with real market rates
(in this case negative), I suspect this would not be a problem
for long. But we need smart meters first.I would love to be able
to have my heat pump run during steep discounts, but in Colorado
we currently have a flat 12 hour off-peak (at night -- the
opposite of this) with a mild 20% discount.
Declanomous - 50 minutes ago
It's possible to get a smart meter in Illinois, and I've
thought about rigging up appliances to run when rates are
negative. However the price feed is lagging by 15 minutes or
so. So while you can have a pretty good idea rates would be
negative, you can't actually be sure.It's not a huge deal if
you are doing something productive with the energy, but if your
goal is to make money it's probably not very effective.That
being said, it might be productive to rig up your gaming pc to
mine bitcoins or fold proteins when the price is close to zero.
Animats - 54 minutes ago
They do. Many of the reservoirs of the California Water Project
also do power storage. They usually pump up at night and generate
in the daytime. Sometimes they can't store more energy because
they're full of water, as happened at Oroville Dam this year.
Sometimes they don't have enough water. A year ago, some hydro
plants in California were down due to lack of water.There's one
big pure pumped storage plant in California - Helms, near
Fresno.[1] The geography has to be right for pumped storage. You
need a high reservoir and a low reservoir near to each other, and
since the water levels will change drastically each day, they
can't be used for boating or recreation much. Helms has about
1500 meters of elevation difference between the reservoirs.
Sites like that are hard to find.Excess solar power isn't a big
problem in areas that use air conditioning. Peak A/C load and
peak solar output tend to coincide. The big excess power
headache is wind, where output varies 4:1 over a day over wide
areas. Excess wind generation late at night is common.The best
way to understand the power business is to read PJM 101, the
introductory training material for the US's largest power grid.
Unfortunately, PJM recently put that behind a login.[1]
https://en.wikipedia.org/wiki/Helms_Pumped_Storage_Plant
paulsutter - 43 minutes ago
Well they're obviously not pumping enough. Peak power usage is
actually around 7-8PM, this discrepancy is the source of the
duck curve. More storage could allow tons more solar to be
installed.https://cleantechnica.com/2014/07/21/utilities-cry-
fowl-over...
_delirium - 39 minutes ago
7-8pm according to that link is the net peak (supply minus
demand), i.e. after solar production has canceled out the
original afternoon peak. The problem is that even though
solar supply does roughly coincide with the peak of demand,
solar production has increased enough that, since about 2013,
it's gone past the point of offsetting peak afternoon A/C
usage, to now producing an actual net trough in the afternoon
hours (you can see the afternoon extremum flips from a local
maximum to a local minimum from 2012 to 2014, and just keeps
going further down every year since, as peak afternoon solar
grows faster than peak afternoon A/C).The new net peak around
7-8pm is because demand has a long tail into the early
evening, while solar drops off sharply around 5-7pm. But yeah
the end result is that it does cause a problem for grid
management if you add more incremental solar, since the
original afternoon peak it helped smooth out has long since
been smoothed and then some.
esturk - 1 hours ago
I'm sure there's some business opportunities that can be taken to
alleviate this surplus. There's a generation of people that have
been groomed to use their electrical appliances during the night
time wether to do laundries or wash dishes because they would be
charged less from energy providers. In recent years, people are
doing their charging at home in the middle of the night.But perhaps
this can flip around. Imagine laundromats that charge cheaper for
drying or washing during the day vs during the night. Cheaper
electric car charging during the day. Business opportunities that
benefit everyone simply by changing some habits.
thephyber - 50 minutes ago
> I'm sure there's some business opportunities that can be taken
to alleviate this surplus.You need to be able to message the
energy consumers (most likely smart versions of large appliances)
within minutes notice.I think you would have to have appliances
ready when you leave home in the morning and set the power price
at which you are willing to run it. Right now, I don't think most
large appliances support such a system. Perhaps home assistants
(Amazon Alexa, Google Home, Apple HomePod, etc) would be the
right place to integrate these settings, but you would still need
the assistant to be able to interact with your dishwasher /
clotheswasher / Tesla Powerwall.At the moment, we are adding
solar to the grid faster than we are adding smart appliances that
are capable of deciding when to use power, based on the current
market price of power.
apo - 39 minutes ago
What a difference 16 years
makes:https://en.wikipedia.org/wiki/California_electricity_crisis
intopieces - 38 minutes ago
Wasn't that crises entirely manufactured though?
NicoJuicy - 31 minutes ago
This isn't abnormal, other examples.Paying the chemistry industry
for shutting down energy intensive operations during low
electricity periodsTransfers between countries in Europe and fines
when your electricity prediction is off ( it costs a lot)Useless
spending power on hot days for not blasting the net because of
solar powerLower costs at night for using electricityIt's not as
easy as it looks, solar power really puts an additional stress on
our net, definitely in the beginning of the 'electricity usage
behavior shift'. Read more about the reason why electricity is
unstable in some countries : http://infoboxdaily.com/3-african-
countries-with-erratic-pow... - didn't find anything betterSource:
done a project for 'Electricity usage prediction' in Belgium with
one of my previous employers.
sna1l - 1 hours ago
California should use the power to mine bitcoin!! :)
jessaustin - 28 minutes ago
I wondered whether TFA would ever get to the cause of this waste,
and eventually it did!Once state regulators approve new plants or
transmission lines, the cost is now built into the amount that the
utility can charge electricity users ? no matter how much or how
little it is used.Oh, so that's why they kept building natural gas
plants that don't get used most of the time! If you've ever been to
a PUC meeting, you've seen corruption at its most brazen.
"Citizens' groups" entirely funded by utilities and telcos wait
their turn to dutifully read the prepared statements, the
commissioners dutifully thank them, and then they go to work with
the rubber stamp. It doesn't actually matter that power plants get
built in a timely fashion or actually operate more than a small
percentage of the time, the rate-payers are already on the hook.
The only way a utility executive gets a bonus is by saddling the
public with CWIP charges, so that's what they scheme to do every
working day.No coal, gas, or nuclear plant should ever be built by
forcing the public to do the job of investors. If investors can't
be found to support a plant that supposedly will generate for
decades, maybe we should listen to the market?
EGreg - 26 minutes ago
Solar panels can also decentralize energy generation, letting
communities be more resilient and prevent global blackouts.
ProfessorLayton - 1 hours ago
This seems to be a temporary problem until green electricity has
the capacity and is cheap enough to be used year-round.Natural gas
is so much cheaper on a $/BTU basis, but perhaps with enough solar
capacity (or other green sources) that wont be the case much
longer. It would be great if I could keep cool and warm using
electricity alone.
mahyarm - 1 hours ago
Maybe the could make our PG&E bills not be (very quickly) .30/kwh
and instead follow the .12/kwh average of the USA during these peak
times.
jartelt - 17 minutes ago
The sad part is that many people will read the title and use the
article to say "solar power is ruining everything and is a waste of
taxpayer dollars!" But, when you actually read the article you
realize that the utilities are the issue because they keep building
natural gas plants and transmission lines rather than just
investing in storage, demand response, or other technologies that
add more flexibility to the grid.
aeturnum - 1 hours ago
Alternative title: Solar power output exceeds most optimistic
predictions.It seems like a non-story for a burst-y power source to
occasionally produce more power than we need.
mostlyskeptical - 28 minutes ago
Exact. If California had a consistent excess of solar they
wouldn't need so much from the Hoover dam.
dang - 8 minutes ago
Cool, we'll use your idea to rephrase the title above.
scribu - 49 minutes ago
Yeah, the more interesting aspect was that new traditional power
plants are still being built, despite the glut of solar.
blizkreeg - 14 minutes ago
Is this just a function of how many households in CA get 100% of
their power from solar currently? I got an email recently from PGE
where I can opt into and decide the % of my power that comes from
solar.Does the state generate enough power to move over every
household to solar?
drwl - 1 hours ago
Happened in Texas too
jalayir - 1 hours ago
Could excess power from CA be exported to Mexico or Central
America?
mullen - 1 hours ago
Transmission is an issue for that long of a distance.
iak8god - 1 hours ago
I've heard that desalination of seawater is not a practical
solution to drought because it's too energy-intensive. Does this
change when energy temporarily costs less than $0/unit?
thaumasiotes - 48 minutes ago
It's not true in the first place. Arab states, and Israel, make
heavy use of it; desalinated water is easily affordable for US
residents.What makes US desalination impractical is not the
cost of desalinating, but either or both of:- the cost of
building a plant in the first place- the availability of
cheaper fresh water
skybrian - 1 hours ago
Sort of. There are California cities that already have
desalination plants. It's okay for retail users on the coast
(who are okay paying a bit more).Agriculture is different. They
rely on much cheaper prices and besides, you'd have to
transport it uphill.
logfromblammo - 1 hours ago
That reminds me of the old engineering joke.What's the best
way to transport a million kg of water? Build a cloud.If
you're thinking statewide, you could just evaporate seawater,
and it's eventually going to rain out somewhere in the
mountains.
floatrock - 1 hours ago
It's also very capital-intensive. Ideally you would want a
useful energy-intensive process with low capital costs so
coming online during these peaks but staying idle for the other
80% of the day has minimal impacts.I wonder if hydrogen
generation would be more along the lines of what you're
thinking. Hydrogen is an energy store not an energy source --
it takes more energy to produce hydrogen than you get out. But
that just means it's a type of battery. It seems conceptually
simple to produce... if a plant can be made simple enough (low
enough capital costs that the idle time matters less), I wonder
if hydrogen generation/burning has been studied as grid-level
storage to do this kind of time-of-day energy arbitrage.(With
the amount of interest in grid-level storage and by the law of
markets-are-efficient, presumably someone has run the
numbers...)
Caveman_Coder - 1 hours ago
For a heavy price yes, but it also depends on the EHV
transmission lines going from SCE/San Diego southward.
kafkaesq - 51 minutes ago
Infrastructure issues aside -- given the current political
climate, that's highly unlikely."First they come and take our
jobs. Now they want us to give them free power!"
WalterBright - 51 minutes ago
If the consumer electricity rates were adjusted dynamically, I bet
that would soak up the extra power. For example, one could charge
one's electric car when the power cost is very low.