Falling panel prices lead to global solar boom, except for the US

Has storage been solved yet? In my experience US power companies hate crediting pushback to the grid because it all happens at the same time during peak sunlight hours and then customers get to use those credits at night and during the winter which the power company thinks is unfair. In Idaho at least the power companies were able to change the laws so that you get much fewer credits for solar panels on your roof which means they aren't great unless you can figure out how to store the generated energy inexpensively.

Personally I like the idea of an electric car doubling as a house battery but so far I think only the F-150 lightning is capable of doing that.

> Has storage been solved yet?

No, but it's cheaper than it ever was and panels are so cheap that they can have ROI even without storage. That said, grid solar makes the most financial sense if you're not in an off-grid location.

> Has storage been solved yet?

In general yes, grid solar + grid batteries are cheaper than any peaking power plants. So now 24/7 batteries + wind + solar generally outcompetes nuclear, coal, or natural gas on price as long as there’s no tariffs involved.

This isn’t enough to make batteries + solar viable in Alaska but long distance transmission lines could solve that issue cost effectively.

> In my experience US power companies hate crediting pushback to the grid because it all happens at the same time during peak sunlight hours and then customers get to use those credits at night and during the winter which the power company thinks is unfair.

I'm pretty sure PG&E pays back something like only 5% of the generation of my solar panels. I'll end the year with $400 more generated than used, and I'll get a check for $20...

Carful when saying it’s not cheaper, it’s generally profitable to add some batteries to a solar power plant.

The economics on storage only kicks in after scaling the grid with a lot of solar, but adding solar to that point is itself profitable almost anywhere.

Are batteries cheaper than pumping water up hill?

*as long as there's no tariffs involved and no entrenched power monopolies taxing folks for installing solar. Looking at you, Southern Power Company.

Solar is actually viable in places like Alaska and Finland. It just isn't viable in the winter, but in the summer it is extra viable. Greenhouses (another form of solar) also work wonders in Alaska, and outside they can grow the biggest pumpkins you'll ever see anywhere.

Prius's can do it too, they are super efficient.

Do you have a place to store that water up hill already? Then no. Don't have a place to store that water already? Then yes. Pumped storage is great if you have reservoirs or a place to put them, and the water to pump between them. But those conditions don't really happen that often.

OK, but nobody has enough batteries to store enough for the winter. Overnight? Sure. Winter? That's a whole different deal.

I have seen some really shockingly cheap homemade stored water systems on YouTube (I’m into that kind of thing so there’s a lot of it in my feed) so if you own a hill and have sufficient recharge even in winter then it’s super cheap install that makes even a meagre battery seem expensive. But you have to have the terrain.

Yes. Cheap batteries distribute storage at the end user location, flattening the demand curve and stabilizing the grid at economically viable prices.

The most likely is that storage will never be "solved".

We will run with 100% renewables for years, and there will still be people asking if storage has been solved already. We will just solve every large issue, and suffer lots of small issues.

Also, if you are using your car as a battery, you can't use it as a car. It's more likely that you will have extra batteries at home so that you can charge your car when you want.

> Has storage been solved yet?

If it wasn’t, parts of the country wouldn’t be invested in adding it.

Recent discussion on HN on a similar topic: https://news.ycombinator.com/item?id=45706527

> unless you can figure out how to store the generated energy inexpensively

Like solar panels, also tariffed.

if you don't have a hill, certainly

First, the only reason solar isn't so common in Alaska is that hydro is even easier to get power from, so your outback communities will often use small scale hydro instead of solar (especially in southeast Alaska).

Communities in the north will use diesel generators in the winter (nothing else is viable). Again, I assume you are talking about off grid communities, which is basically all of them except a few cities (and most cities have their own grids disconnected from the rest, especially Southeast Alaska).

They take up less space, and can be done without the hill.

That's why you generate hydrogen during summer for gas power plants during winter.

Rooftop solar is nice for resiliency and can have its place in a grid, but it's not cost effective. Grid-scale solar is what most folks are talking about when they say solar boom. Even in the somewhat backwards US, where Solar in total is ~340TWh, the majority (~250TWh?) comes from grid-scale interconnected solar and solar+battery installations. Hopefully this gap continues to grow as the Biden-era IRA fueled grid-scale solar projects mature through their design/build/deploy pipelines in the coming years.

Thinking of national policy from a home owner perspective is expected, but it isn't always instructive.

For the latter item, my Rivian has a relatively paltry 1500W inverter with standard 110W plugs in the back seat, truck bed, and gear tunnel, but I can use a rectifier/power supply to pull a constant 1kW, step that back to DC and feed it into my home's battery backup system. My whole house tends to use ~2kW at peak, and obviously can conserve in outages. So I get my normal 4kWh battery bank with solar hookups, but can splice the 141kWh Rivian battery in, too, for a good chunk of off-grid power.

I assume that the extra regular (daily?) cycling of the battery in your car would have a notable effect on your vehicle battery's longevity. (But I'm very fuzzy on how battery improvements in the past ~decade have applied to "cycle life", or really even what the cycle life means, e.g. is end of life when it's something like 70% of total original capacity?)

What mass of hydrogen is needed per house to last a winter?

I've always been confused by the insistence on storage. Saturate 100% of the daytime loads with solar, curtail at peak, it's still cheaper than just about any other source. Save all the hydro power, gas, and other standby sources for before and after sunset.

Once you're curtailing a bunch of power during the daytime, then you can add storage as a no brainer bonus and stop curtailing.

Places in California has this problem too. Installing solar panels today could result in a larger electricity bill than not having them.

Getting solar panels forces you onto a plan in which they charge more per kwh pulled from the grid. The surplus electricity is only credited at the generation cost which is only 1/4 the total cost per kwh. (Delivery costs is 3x the price of electricity).

So if you want to go solar to save money you need both batteries and solar panels which is not an insignificant amount of money.

Cheap in terms of capital, but home hydro tends to take quite a bit of labor and maintenance over time. If you look at that stuff as a fun hobby or YouTube content it’s no big deal, but economically your labor isn’t free.

I’ve got an usually good location for small scale hydro, there was even a mill on the property, but it just doesn’t seem worth it to me.

rough math: 1000 kwh / mo / house, ~30kwh/kg hydrogen so 30kg H per mo per house. idk how long winters would be, 8 months is 240kg of hydrogen, which if compressed to 10 bar is roughly 300 cubic meters of storage. kinda a lot of space. compressed to 100 bar is like 10kg/m3 which sounds more manageable

Net metering is unrealistic.

Maybe just force grid-connected solar installations that want credit (any size) and even those that just want to be grid-tied (beyond some small size like maybe 5 panels/2kW worth of MPPT) to use a registering meter that meters net energy for each like 15 min interval (that's the granularity we use in central Europe; I assume the US would have come to a similar choice of granularity), and bills energy according to market rate and appropriately handles connection capacity/transformer capex by like taking a histogram of those individual measurements or otherwise letting a few isolated bursts through while ensuring transformer capacity is paid for by those responsible for the (hypothetical, until it's not) transformer upgrade.

Yes, and if peak solar generation exceeded demand, and were priced appropriately, I think we'd find that some workloads could be timeshifted (e.g. precooling homes).

Round trip efficiency on hydrogen is horrible. Local hydrogen production could make sense because importing fuel into remote off grid communities is extremely expensive.

Rather than building 10x as much solar in the north + battery systems + winter hydrogen storage etc long distance HVDC to cities and the surrounding grid just makes so much more sense. Even better because the state is huge and the population is tiny they can go nearly 100% hydro.

Where batteries could be useful is operating those long distance power lines at nearly 100% 24/7 then load shifting via batteries to match local demand.

You can just put solar fences in Alaska....

Half of Germany is north of the straight part of the US/Canada border...

Hydrogen containment isn't long term, every atom we use to make hydrogen tanks are much larger than hydrogen, so they leak no matter what.

In the lower 48 you'd just size the solar to handle winter and find a way to use summer electricity, like electro winning metal from ore or running low-capex high-power chemical synthesis steps like making ammonia without natural gas.

Having energy cost related scheduled (winter) downtime gives the plants proper maintenance windows.

With free power but only during surplus peaks in summer when the grid can't transmit a large utility solar farm's entire production, and the day/night/weekday time shifting batteries are also already fully active, you could (looks like the math checks out) electrolytically refine iron ore into iron metal (for later smelting in an arc furnace) just about cost-competitively with (coal-fired) blast furnace operation. The key is to skip most overhead by operating them only to eat otherwise-curtailed production and connecting them to the DC bus between the MPPT and the grid inverter (same as the day/night shifting battery).

I used to think hydrogen was the front runner for this storage use case, but as I've pointed out previously on HN it's looking like ultra low capex thermal storage will be superior.

https://www.orcasciences.com/articles/standard-thermal-copy

It would be stored underground at scale, not in tanks.

Yeah different perspectives. Some people find diy easy and are quite happy to tinker with things. Where I live is currently suffering a wild boar infestation and I’m happily setting up an electric fence system for basically no money at all whilst a neighbour just paid a lot of money for someone to install it for them. I wish I had a good property for hydro or stored water batteries!

Ketchikan is about the same latitude as Copenhagen. You actually have enough easy to access hydro on the panhandle that solar isn't going to be very competitive. Fairbanks and up is where solar is viable in the summer and not in the winter.

You always combine solar power with wind power, that already solves more than 90% of the storage problem. In places like Europe the darker winter is usually quite windy.

For example, last Sunday Germany covered more than 100% of its own power load with renewables even though winter is approaching. Only a small part of that was solar power, most electricity was generated by wind turbines: https://www.energy-charts.info/charts/power/chart.htm?l=en&c...

> *which the power company thinks is unfair"

The way you worded this implies that you disagree. Are you aware of why wholesale prices aren't constant?

> Round trip efficiency on hydrogen is horrible.

For seasonal storage, round trip efficiency is mostly irrelevant; the relevant metric is capex per unit of stored energy.

Usually that works, but not always. It's the last part that's the killer. When you optimize against historical weather data in Europe to produce steady power at minimum cost, a wind/solar/battery/hydrogen system cuts the cost in half compared to wind/solar/battery.

As I said elsewhere I'm thinking ultra low capex thermal storage will edge out hydrogen here, though.

That could be generally true, but it’s not true in this specific instance.

A panel in Alaska only collects so much sunlight over the summer before considering efficiency losses from Hydrogen. It would require buying panels that effectively get ~1 month of use over the entire year due to efficiency losses + limited gathering period, and solar isn’t that cheap.

So in Alaska you’re just better off only using panels directly in the summer which at least provide several months of electricity per year. In say Texas on the other hand you get energy from a panel year round so a marginal panel purchased to generate hydrogen at say 20% round trip efficiency gets 30% * 9 months + say 70% of average production for the 3 winter months = 4.8 months of winter electricity per year. Of course you also need to pay for the hydrogen generating machine and the hydrogen burning device, but that’s not necessarily problematic.

If the alternative were, say, diesel, I think a RTE of 40% (which you might get with hydrogen) would be fine in this case, if the capex of the storage system is low enough.

It is certainly the case that hydrogen would be better than batteries for this storage use case in Alaska.

And tell me again what the ground is made of

If the baseline is ~2c/kWh solar in a good location and they are forced to buy 10x as much solar panels to cover winter use they are now spending ~20c/kWh on solar panels but on top of that they also need to pay for hydrogen generating equipment which only gets used for a few months a year, hydrogen storage equipment, and hydrogen specific generators plus presumably a backup diesel or gas based generator + storage system.

In 20 years it might make sense but today green hydrogen is several times more expensive than gas even when you can use cheaper electricity, can make use of the equipment year round, and have the benefit of larger economies of scale. Even if the goal is completely about climate change locating that same equipment in the lower 48 states is just a much better idea.

Saturation of daytime loads with solar kills nuclear by lowering its capacity factor or daytime pricing, which some people object to.

It’s clearly a net win environmentally and economically, but for anyone who sees nuclear as part of a green future storage in some form is a massive requirement.

> Saturation of daytime loads with solar kills nuclear

If you exclude China, effectively no nuclear plants have been built in the last decade, and the existing fleet is aging out. "We shouldn't do this thing, because it might threaten that other thing that we don't do anymore" is a weird argument.

Ideally, salt. Deeply underground, solution mined to make large cavities. This is a preferred method for storing natural gas. Failing that, deep aquifers (not potable ones; saline water is fine).

If the basement rock is close to the surface and is crystalline, it probably involves deep mining to form cavities, which would raise the capex by maybe an order of magnitude. Other options could become cheaper then, say storing ammonia.

This is for large scale storage, of course, not for individual residences.

It’s not quite that extreme: https://www.worldnuclearreport.org/reactors.html

But yea building nuclear is all about forecasting the future so most of the damage has already occurred here, still advocates are going to advocate even if what they say doesn’t make sense.