Rooftop solar power may be flooding the grid | Hacker News Reader

Rooftop solar power may be flooding the grid

smh.com.au

55 pointslxm95 comments

Renewable energy is quite predictable: there is sun during the day, and no sun during the night. Wind is a bit less but could be too.

Why not organise accordingly?

First, there are batteries: solar roofs should come with batteries, than will power the house during the night. Authorities could enforce that, and could also build larger energy storages with batteries at a region level (see recent examples from Tesla).

Then, this is mostly communication: why not make the grid and the roof "talk" to each other and the roof be turned off from the grid when there is no need for it? Is it because subsidies or some kind of mandatory buy from the grid that this could be an issue? otherwise there could be incentive to have this better integration with the whole system.

Otherwise, use bitcoin miners, during the day!

We're trying to fit square peg into round hole - after 50 years of centralized grid with one type of predictable demand curve now we got all those people that dare to install their own solar.

I'd wish that utilities would stop fighting and accept inevitable.

What's the inevitable?

I would think move to renewables and more decentralization (more choices for individual consumers, as it happened with almost any other industry).

Decentralized is not really the problem here: it's more about the links between each installation and the surplus. It's harder to see it with electricity, but think as if it was water for example: if people were pumping water at home and pushing it into pipes to others, and not that many water was actually needed, where would it go?

By decentralization I mean something different, decentralization of energy production. The fact that, say, a village can decide to install a solar panel array to satisfy some of their energy demands, and they don't have to rely on powerful (and often global) energy companies who mine coal or process oil, is an important game changer in terms of power relations between people.

You just have to buy the solar panels from a global megacorp instead.

Don't get me wrong, this kind of decentralisation can be very effective in small isolated communities such as the Scottish islands, but for most places doing it locally is both more difficult and more expensive.

> You just have to buy the solar panels from a global megacorp instead.

That's still a massive improvement in competition. But I'm pretty sure it's also not true and tons of companies make solar panels.

The service utilities provide changes from energy production to energy storage, distribution, and management.

Your question about the grid and the roof "talking" is exactly what was described in the article about "curtailment".

The problems with curtailment are:

1) The management of roof solar output is currently in the hands of solar roof owners, not grid operators, so the grid operators cannot easily "reject" the produced electricity. 2) Solar installations are often financed with expectations of savings and/or revenue, so if the grid operators curtail the solar generation, do the solar roof owners have a right to be compensated for their lost revenue? How is this compensation managed fairly across all solar roof owners?

> solar roofs should come with batteries

This is a good way to kill new installations by making them needlessly expensive.

Demand is typically higher during the day, because that's when people are working and running their aircon.

You do get a "duck curve" https://en.wikipedia.org/wiki/Duck_curve but that's best dealt with by gas peaker plants. It's just that Australia is in a stupid situation on the gas "markets": https://theconversation.com/gas-crisis-or-glut-why-japan-pay...

This is the part where someone points out why I'm completely wrong:

> solar roofs should come with batteries

The way I understand it, batteries tend to be bad for the environment if/when they need to be replaced, because often they are improperly recycled and/or there are no adequate facilities for that.

If this is correct, do we really want to have more of them around? Wouldn't an environmentally-friendly(ish) central plant be better in the long run?

Lead acid batteries are pretty easy to recycle. We already do this for car batteries. Lithium batteries are currently not as easily recycled, but that seems to be because there is little demand for recycled Lithium and they're not very toxic in landfills.

Stationary batteries have fewer constraints wrt to energy density, because they don't move.

Well, it really depends on the kind of battery.

I don't understand why these utilities are not creating a centralized battery in the form of, for example, pumped water. Use excess energy in the day to pump the water up, and let it down when the current energy demand exceeds standard production rates.

Pumped water is not the only possibility either, there are plenty of alternatives which are not terrible for the environment. See: https://en.wikipedia.org/wiki/Energy_storage

Pumped storage relies on having a suitable natural basin, building one is far too expensive.

Quick googling suggests that Australia is already looking at this: http://www.abc.net.au/news/2018-06-06/tasmanian-pump-hydro-s...

This is a tough and awkward problem, because accounting for the externalities of a "good thing" would curtail progress towards a good thing. Meanwhile, the externalities of bad things get a free pass. Ouch.

The solutions are either very expensive, very counterproductive, or very unfair.

The expensive solution is grid energy storage, where the utility installs a bunch of storage to time-shift some of the generation to better match the demand. The unfortunate aspect is that this is capital intensive, and most utilities are already loaded full of debt to pay for capex. This will probably result in the increase of rates billed to consumers, which is ironic, even if the grid is now providing a more complex service.

The unfair solution is to legislate that onsite storage must accompany all residential distributed solar generation. This pushes the costs significantly higher, and forces homeowners to locally account for the added complexities of their green energy generation. But full suite of complications around other energy sources isn't priced into their cost.

One counterproductive solution is to force market pricing on all consumption and generation. The revenue on residential solar generation would free-fall, because all of it in a particular area gets generated at a time when it's most plentiful. It wouldn't be worthwhile for a small player to generate it anymore.

Another counterproductive, but simple solution, is to dump excess solar at the inverters at peak time, then run a bunch of natgas peakers in the evening once solar drops off. This is an environmentalist's nightmare, but takes no effort to execute.

I am in my 5th year of a 9.8MW system. I have generated about 45MW of power and approximately 1/3 stays in my home and the rest is sold to local power company.

A couple of years after installation I started to see negative press for solar and eventually some action by my local power company. "Solar is no use to me", to quote the manager. Their actions finally killed new solar in our town. They used arguments like this, but we all suspected they were worried about revenue protection. There are 7 solar customers, a gnat's cock, so-to-speak, but they are/were scared. Local newspapers echo sentiments that solar customers have their hands in the pockets of non-solar and provide no balance.

My goal is to get a 10-15kWh storage (Tesla Powerwall probably) and then keep most or all of my power and pay the grid like a very low usage customer. I believed we could do better, but I don't see it happening.

> I am in my 5th year of a 9.8MW system

Do you run a power plant?

The same thing is happening in Europe. Energy markets need large reorganization for the transition and energy grid and storage technology needs to catch up big time. This takes lots of money.

Wind and solar turn spot prices negative when it's sunny and windy. Existing nuclear, coal can't be easily turned off for just a part of day. In free spot energy markets, the price of electricity must jump sky-high during low supply to pay for the rest of the time.

What is needed is load following power plants and large scale energy storage (flywheels and lithium ion are only solutions for very short fluctuations). In the North Europe there is possibility of using Norvegian hydropower to compensate for wind power as long as the grid capacity keeps up.

Just pass those negative prices to customers and they will solve the problem.

Your solution would require massive increase in carbon tax without loopholes. That would be a good and simple solution, but it's not happening.

Consumers (especially 24/7 industry) wants to solve the cost, not the problem of CO2 emissions. Steady supply contract from non-renewables is cheaper. Letting markets to decide means that industry is not going to use renewable at all.

That requires "smart" meters everywhere.

In the Netherlands smart meters are the default now.

Reading this article, the first thing I wondered was, what does Australia have in terms of peaking power plants, which can come online—and, just as important, safely go offline—quickly to stabilize grid voltage?

The second thing I was wondering is, where are the bitcoin miners? Assuming electricity prices are not being held artificially high, then when they start to come down, miners will start coming in.

In fact, I could envision a two-tier pricing model, similar to what is used for EV charging. Combine that with something like Zellweger ripple signaling, and the grid would have a way to tell miners (et al) “Hey, we have excess, were reducing the rate so start mining!”

Australia has some of the most expensive electricity in the world. There are no bitcoin miners of any size here.

The electricity problems we are facing are pure corruption and negligence. Solar isn't the problem, its the lack of funding and poorly weighted energy markets that are crippling Australia's grid.

Solar isn't the problem, but the renewables situation is related. We had a Labor government with the Greens holding a balance of power from ~2010 to ~2013. The Labor party had, I believe, been opposed to a carbon tax up until that point. Then, likely because of pressure from the Greens, introduced a carbon tax.

The lesson there will not have been lost on big investors. If anyone invests in fossil fuel generation (ie, the economic option) then the Greens will find a way to destroy their profit margins at some point in the next decade.

And so, little serious investment in the energy sector seems to be taking place. I'm not aware of any big developments planned except an interesting hydropower project by the current government and creeping smaller-scale wind and solar as prices rise and justify their existence.

Following your reasonning, there is no reason why investors should shy away from renewables. The Greens would not harm any project of additional large scale batteries, for example.

Yes but the Coalition will because solar gives you cancer.

> solar gives you cancer

Is that hyperbole or are they seriously saying that?

Hyperbole in that specific case, but they did have an enquiry into wind turbines partly examining alleged health effects...

Okay, that's not as outlandish as health hazards from solar. We have a lot of wind turbines in Northern Germany, and some people complain that they emit low-frequency sounds and thus cause noise pollution. I don't know about the research on this topic, though; I never noticed any adverse effects when staying near wind turbines.

I think there are two main reasons whu investors would shy away from renewables in Australia:

1) Firstly there are no large well-known actors, so there is uncertainty around renewable energy companies are going to "win".

2) Secondly, Australia currently has a government that is hostile towards renewables. It could at any time introduce legislation that would make renewables economically untennable.

These are both true, furthermore a lot of the bigger players became big as a result of the initial round of solar rebate schemes - where a lot of low quality solar installations were put up. Now a lot of these companies are doing much larger jobs without the necessary skillsets. There's a bit of a minefield of shoddy installers still out there - look at the Crap Solar Facebook page for an insider look (there are some horrific installations).

Despite all this, I've seen a huge amount of interest in investors wanting large scale commercial and utility scale solar projects. From what I know, solar engineering consultancies are turning jobs away due to the demand being so great.

Even with the evilest scheme, it seems unlikely to come up with something harming the rentability of renewables, or of solar in particular. It's basically free electricity from sun, which is plenty in Australian deserts. You pay only the installation, which price is determined by the tech market.

Australia is in the unique position of having abundant reserves of gas, coal and uranium but through what is probably blatant corruption the most expensive power prices in the world.

The gas is exported at a fixed cost to Japan and other countries where it can be resold to Australians at a profit.

Other issues are that no power company in Australia is willing to build a new coal power plant because the current coal subsidies are likely to go away with a change in government. The current government is very much pro coal. To illustrate how bad this is the current government Treasurer brought a lump of coal into sitting parliament and was waving it around showing how non dangerous it is. The coal lobbies are very strong and are running out of export options.

Australia is in this position due to a lack of bipartisan support towards any energy policy. Its also a problem because the power networks have been privatized and the incentives were set to guarantee returns on building infrastructure. The network as such is gold plated but the power it carries is very expensive.

While gas should be the answer to the network shortfalls there was a massive profit incentive to not do so initially wait for the spot prices to surge and then jump in and collect massive paychecks.

The result is that people installed solar. Which caused the electricity companies to raise prices which lead to more solar installs. The companies here are in a death spiral. They are insanely profitable right now, but the writing is on the wall.

However companies such as Tesla installed a massive battery to counter some of the issues and that project after 6 months is almost about to pay for itself.

Its a horrible situation to be honest, and I cannot wait for the power companies to fail due to their own hubris.

BTW if you think this is bad, do a quick check into the status of the National Broadband Network NBN in Australia. That's corruption on a whole other level and you should laugh at us Australians. No matter how bad your internet is I promise ours is worse, more expensive and despite billions of dollars not about to get better.

Australia does not need any more coal stations. Wanting to build new ones has weirdly become a strange infatuation by the conservatives, but there is absolutly no need in Australia for more baseline capacity. It's all in the peaks, which is all gas (which mostly of sets the benchmark price given where it sits in the AEMO stack).

So most of our price problems are just the price of gas, and the introduced reservation program has helped with that a little but does not go far enough. That, and the gold plating of the infrastructure (which alone is like 40% or something IIRC of the price rises over the last decade).

Most of the 'reliability problems' than the politician are on about are really just 'fears of possible future reliability problems', stirred up by the blackouts in SA that were mostly due to transmission lines being blown over in a massive storm while one of the interconnectors with Victoria was down for maintenance, and some wind turbines tripping out because of dangerously high wind speeds. There isn't really that much reliability risk apart from the fact that our coal stations are all pretty unreliable (the Australia Institute has taken to tweeting every time a generator trips out, it's pretty crazy how unreliable our coal stations are).

Perhaps we will need some more gas peaking stations but new pumped hydro and big batteries will probably take over some of that.

Sorry, should be 'baseload capacity' in the first bit.

I don’t think the economics work for mining only during power gluts. The cost of the mining equipment is high and needs to be amortized over the longest period possible.

The ABC had a story today on pumped hydro storage: http://www.abc.net.au/news/2018-06-07/how-does-pumped-hydro-...

The Snowy 2.0 scheme looks promising: 2 GW max power, 350 GWh max storage, A$3.8-4.5 billion. Online ~2024. Just approve the bloody thing already.

For comparison, Tesla's 'world biggest battery' aka the Hornsdale Power Reserve, is 100 MW max power, 129 MWh storage, and cost ~A$100 million. (cheaper per Watt, but about 60 times more expensive per Wh) Built in 4 months!

So solar power is irregular and has a peak production (mid day) far from peak consumption (start and end of business day)? News at eleven, water is wet and all that...

edit: I should have said irregular through the day.

Solar power is not irregular at all, and is entirely predictable with a weather forecast. Unless Australia has an entirely different usage pattern to the rest of the developed world- businesses are perfectly aligned to use the solar power generated during the peak.

From the article: "the growing peak demand that comes at the end of the day, as the sun sets.". So the solar production of electricity peaks earlier than the end-of-day consumption peak.

There is a company in Australia that have improved flow batteries technology to the point where it can be miniaturised down to the size of a fridge freezer (previously they were the size of shipping containers) ten shipping containers full of them are able to store 3.2 megawatt-hours of energy and discharge a megawatt of power for over three to four hours which is roughly enough to keep 500-600 average homes going for the afternoon during the end of day consumption peak.

They are perfectly suited to be paired with solar/wind/etc where they can store up the days usage and discharge at a regular rate throughout the evening peak when generation is reduced. And as for reliability, unlike lithium-ion, flow batteries can last for 20+ years with unlimited cycles.

I assume you are taking about red-flow?

I head about them several years ago but haven't seen much since. Do they have the scale/ pricing to sell to the average consumer yet?

I am indeed. I think they got some press coverage three or four years ago. I personally discovered them by watching a documentary on YouTube that featured their technology and discussed its future.

I know that they recently raised some capital to invest in increasing sales. However I think a large proportion of their target market are grid scale and remote outposts for telecommunications/industrial applications.

That could be because their residential solution still cant beat something like the Tesla powerwall on price. However, I believe when investing in something that you expect to have longevity in the 20-30 years range it's better to go with something a little more pricey that is proven to last that long without degrading of performance, so on that point the flow battery wins.

It's like with solar panels, you can pay a premium upfront and get panels that will be producing the same output in ten years time like my parents did, or skimp on price and end up with a 30-40% reduction over the same time period like their neighbour.

Sure, there is an evening peak when people get home and start cooking/turning on their homes etc- which can't really be offset with solar (without using storage, battery/hydro). Doesn't negate the fact that solar generation pretty much perfectly matches business usage.

"water is wet and all that..."

...and it's a very good energy store when much of your energy demand is for heating/cooling with target temperatures in the "habitable zone".

The only real challenge (but a big one) is getting the incentive structures right so that they are not "hacked" (e.g. pretending to be a dispatchable consumer at high supply but actually just switching to the conventionally billed socket at times of high demand) and keep inevitable oversteering/pork cycle within a reasonable margin.

Interesting. In Australia do people regularly install rooftop solar installations without also installing battery units? What's the logic there? Just selling it to the grid?

Yeah, we had extremely generous feed-in tariffs for a while. It's generally net-metering too so pretty good value, even as the prices have come down. We have no shortage of sun most places, so it's pretty easy to almost wipe out your entire bill (except for the service/distribution fees, which have gone up a lot over the last few years, I guess to combat that).

A very relevant YouTube video from Dave at EEVBlog, where he goes through the numbers for his five year old solar installation, to see whether it has paid for itself. He also does hypothetical modelling of adding a battery, which proves to not be financially compelling at all.

https://youtu.be/aQQE8V9NBXw

This is because those "environmentalist" laws weren't created to satisfying national energy demand, but only the people's desire to roleplay environment-savers and get paid for it.

Similar government schemes played out in much of Europe. Install subsidized solar panels, and the government/electricity companies have to buy your electricity at unsustainably high prices whenever you produce it, regardless if they need it/can handle it.

Obviously, as far as I know, this didn't last very long, especially in the countries with more limited budgets. Eventually the sale prices dropped close to normal wholesale electricity prices and the subsidies were dropped. Those who installed the panels late in the bubble probably got out with a loss.

It was just a terrible idea all around. The grid isn't made for distributed production, energy storage isn't solved, and solar electricity is just not sustainable as rooftop photovoltaics.

Well, grid feed-in can lead to faster repayment and smaller bills, but it's only 20-25% of the electricity price, so generating enough to be in credit relies on paying off the usage you have when the solar isn't generating enough for storage, or to offset your grid usage.

i.e. If you use 10kwh from the grid, and export 40kwh, you should get credit on your energy bill, but it's never that ideal, and some of the providers cap the export to 5kw/h for residential solar.

Most Australian energy providers have flat rate, some are on smart metering with peak/Time of Use rates;

The benefit of a battery isn't as immediate if you're not on peak rates. For those states which do have Peak/ToU rates, there are calculators that can show the amounts saved over 10-20 years, but it's still around 12 years to pay off a battery and solar install with the current pricing, not enough to cover the warranty or the useful lifespan of a battery in the same period. i.e. In 6 years, we'll have a next generation Powerwall or a competing technology, or something even cheaper, etc to store energy.

The solar rebates mean that even a smaller solar system is cost-effective in a smaller payback period.

The amount of the rebate has started to reduce, but a 4kw solar install will have a rebate around $2400 AUD ($1800 USD) off the price of the install, which usually comes to around 25-30% off the total cost of $5000 AUD, around USD $4200.

Prior to the half-price chinese panels coming into the market, the break-even was around 8-10 years, even with rebates. Cheaper panels have reduced the payback window to 4 years in some cases, even if the actual performance is not even close to the system's size,

ie. their real-world performance might only be 3.4kwh on a 4kw system, and the real-world payback might be closer to 5 years, due to changes in energy pricing affecting the returns, but also handling the problems like difficult installations, replacing/handling faulty hardware, or having to service the system if it fails in Australian weather conditions.

You can also find aggregates for these prices on sites like https://www.solarchoice.net.au/blog/residential-solar-pv-pri... which contrasts costs and pricing across states, and also accounting for variables like labour and electricity pricing, etc. Most solar systems with the rebate can be USD $3k to $5k for a smaller home install, and the system can be paid off within 4 years, 5 years if you want reliable parts.

Energy Pricing in Australia depends on state and providers, but is around USD 20c per kWh depending on state and supplier, with some areas having flat rate, others requiring net metering and peak/offpeak times

There's also a grid connection cost of USD ~70c/day, while Feed-in of solar PV generation is around USD 6c to 10c per kWh, which will probably drop to 5c/kWh in July. An earlier solar generation scheme had dual/gross metering and USD 45c/KWh feed-in rates, but this was discontinued in 2016.

Add to this, residential systems often have to get special approval from their energy company for things like 3-phase solar installs, require limiting exports to 5kwh, restricting to 90% output for Grid stability, sic. etc.

There are no rebate programs for the batteries, and there's a cost hike for importing the Tesla Powerwall 2, for no particular reason.

Compared to the AUD $9,000 to $11,000 AUD cost for the PW2 install, and despite it being better value, there are smaller, but similar LG Chem RESU batteries, which are more affordable and easier to obtain.

Why don't Australians use Solar water heaters? It's the best ROI you can get from solar, Mediterranean countries and the sunny parts of China have absolutely massive capacities installed. It's direct thermal, so it's not a cool high-tech gadget, but if you're worried about the environment, it's "better" than solar panels when applicable. It also essentially includes on-site thermal storage, so no grid instabilities.

Lots of them around (especially in my state, Queensland, which has hot summers and mostly fairly warm days in winter), but you need to use a gas or electric booster to have hot water all the time. So in a lot of places it actually turns out to be fairly similar energy use to put in a high-efficiency heat-pump hot water heater.

I've just evaluated this because I want to replace the hot water system at my house, and I was initially thinking of solar because my parents have had one for years and it generally works well but the heat pump will be cheaper and I'll eventually get some PV anyway. So all in all it should be a bit cheaper and more efficient per square metre of roof space.

Solar panels mix well with heat pumps in hot and dry climates indeed, because of the happy coincidence that peak solar radiation=peak demand for cooling. In that case it's not a bad combo, especially if you have mild winters without temps deep in the freezing (which ruins the COP for heat pumps, assuming you use them for heating too).

Please note that there are powerful lobby groups in Australia that have interests in fossil fuel businesses and promote journalism that exaggerates problems with renewable energy. Eg see this:

http://artsonline.monash.edu.au/climate-change-communication...

I thought exactly the same thing. It looks like the power companies want to have more control over individual homes’ solar panels and they are inventing a “crisis” as a way to do it.

Just as there are powerful interest in solar and wind.

Edit: To the downvoters. What are you disagreeing with? Are you claiming that the wind and solar industry doesn't have special interest and that they aren't powerful especially when you look at the support it has politically?

People are generally familiar with the self-interest of the fossil industry, but you seem to be saying that everyone who supports renewables is also in it for the money? Without evidence?

What do you want evidence for? Are you saying that those who invest in solar or wind do not have a self-interest in what they invested in. That seems to be a much bigger claim that the very obvious that any investment you make you have a self interest in.

Climate gate should have made it quite obvious that no one is excempt from bias. Thomas Kuhn wrote a whole book about it.

Much stabilization could be done by varying the price of electricity on a minute-by-minute basis according to the supply.

Then, electricity users can correspondingly adjust their usage for things like electric car battery charging and heating the hot water.

An interesting alternative to battery storage opened in the UK this week - liquified air energy storage. I wonder if this may be helpful.

https://www.theguardian.com/business/2018/jun/05/pioneering-...

There’s also places like Dinorwig: https://www.theregister.co.uk/2016/05/16/geeks_guide_electri...

Absolutely. The advantage of the liquified air approach is that you don't need a handy mountain. You could pop storage into city infrastructure quite easily.

You may have seen some of these balloons appear here and there, too: https://www.google.com/search?tbm=isch&q=Biogasanlage

Having now read the wikipedia article, I see that my answer to my youngest daughter was much too simple. "Daddy, what's that?" "That white balloon next to the barn? It's full of cow fart. The cows in the barn fart, the farmer keeps the fart in the balloon and then burns it to make electricity when people need lots of electricity". According to Wikpedia it's a little more complex. But I like the simple version better.

Whatever the source, it's gas the farmer can burn whenever the spot price for electricity is high.

>liquified air energy storage. I wonder if this may be helpful.

Let me answer this: No, it would not be helpful, because on pretty much all metrics (capital and operating costs, efficiency, flexibility, size etc) this technology is way worse than battery storage.

Unfortunately - today - a lot of money which could be sensibly used deploying cost effective technology such as solar and wind power (and to a lesser extent battery storage) is wasted pursuing fundamentally flawed concepts (such as compressed air energy storage, and now this liquified air), which have no chance of being competitive .

Horse stables were in their day a cost-effective solution to transportation, and those steam engines had no chance of ever moving a couple of meters on the rails...

I think there a physics problem there. The efficiency is way worse than charging almost any type of battery. So unless material for any type of battery becomes completely unavailable (including say Iron and sulfur or lead), the power free and you manage to build your Air Liquifier with less resources than batteries it will always be a stupid way to spend resources.

They are claiming efficiencies of 60-70% compared with batteries of nearly 90%

OK, I have thought about this a bit (I have worked on gas liquefaction plant design), and I do not believe this claim.

70% is about the maximum thermodynamic efficiency of any heat engine operating between -190 degrees and ambient. And the best efficiency you can expect in liquefaction, in a very complex and large plant, is circa 50% (1). Combined with storage losses, I think the overall cycle efficiency cannot be more than 25% or so.

Happy to review and comment on any back-up to their claim.

(1) see eg here: https://search.informit.com.au/documentSummary;dn=8933572137...

Thank you for that thoughtful and informative reply.

What do you make of the claim that this technology is better for long term storage than battery storage?

I see what they are getting at. My initial thoughts are:

1. There will be considerable losses in storage. Evaporation in LNG tankers is around 0.05-0.1% of their cargo capacity per day. This is around the same as the self discharge rate for Li ion batteries, which have higher cycle efficiencies.

2. The claim could be that the overall cost of complex liquefaction equipment to use up a little bit of energy per day over say summer months combined with large relatively simple storage tanks to hold the liquified air until say winter could be cheaper than having very large batteries. This is possible... but:

3. This would have to compete with for example production of hydrogen by hydrolysis, which would be cheaper, easier to store, and have similar cycle efficiencies.

Finally: Consider that none of the current LNG import terminals attempt to extract energy from the re-gasification of liquified gas. This seems to be the low hanging fruit of liquified air technology, but it is not economically attractive. So I sincerely doubt that the described scheme would make economic sense.

People finally starting to realise that energy systems and grids are more complex than just put a solar cell to your roof. There is minimum level of service has to be provided (even over night) and the balance of production and consumption has to be kept in balance otherwise very bad things happen.

It’s called battery storage of excess energy

Ten Years of Analyzing the Duck Chart https://www.nrel.gov/news/program/2018/10-years-duck-curve.h...

home appliances should be aware of the home's solar panels somehow.

you could fill a washing machine and have it wait a few days and turn on if the solar panels are at full usage.

other things could operate at peak hours (dishwasher)

you could also pump water into a silo when it's bright outside.

>home appliances should be aware

You mean IoT installed into wallplugs and whitegoods appliances, pool pumps, heaters, washers, heat pumps/air conditioners, hot water systems, etc.

Yeah. If there was only an IoT standard that worked to allow for usage to be monitored and devices to be switched on/off in a standard way ... sure.

There are "appliances" like HomeAssistant.io and OpenHAB and Domoticz out there to micro-manage these peripheral home devices and monitor consumption/excess/PV generation, and rulesets that can trigger responses and excess/egress of energy,

but it's too complex for the Inverter/Solar managers to take care of usually.

it's better to spend the energy directly than to sell it cheap now and buy it expensive later.

As long as feed-in tariffs are artificially high (e.g. anything not noticeably below 1:1), neither xkcd:927 nor total absence of standards are what is keeping solar-aware consumption from happening.

PS: I absolutely don't want the subsidies to go away, I want them restructured into better subsidies that do not nullify other important incentives.

Couldn't the problem be solved my publicly registering your solar panels (location and power output)?

The utilities could access that data and actual weather data and predict the demand curve in a better way.

Those on feed-in tariffs will be registered in order to pay them. Mine certainly are in the UK.

If you’re going to replace something and keep uptime then you’re going to have situations where you have more than you need.

Good opportunity to mine cryptocurrencies.

edit: https://cointelegraph.com/news/even-with-energy-surplus-cana...

Use the power for crypto mining (while it's still based on hashing), use returns for energy storage infrastructure.

Better just to use it for aluminium smelting or some other productive purpose instead...

"Monitor electricity 3600 times a second" in the video seem wrong, as AC is usually 50 to 60 HZ that would be measuring the consumption 60 to 72 times per period which does not really make sens. It's likely 3600/hour or 1/seconds. Immediately make me doubt the quality of the research.

Edit: DC -> AC. was tired.

*AC is 50 to 60Hz (DC does not alternate). Also I can see how it's possible that electrical fluctuations could happen at a higher rate than the utility frequency. 3600 Hz does seem like a lot though.

Oops. Fixed AC/DC. I know better. 3600Hz seem also quite a weird number while 3600 time an hour ends up being exactly once a second.

> DC is usually 50 to 60 HZ

Immediately make me doubt the quality of the comment

Sorry meant AC, got things mixed up in my head with solar beeing DC.

3600 times a second is reasonable if you want to calculate true RMS values at 50/60Hz. This is almost required as well as most inverter and supply waveforms are far from sinusoids.

If you have distorted currents and voltages, you need to do this. 3.6kHz sampling captures harmonics up to 1.8kHz, which is the 36th harmonic. Power is 1/T \int_0^T U(t)*I(t)dt for periodic signals with period T, and if current and voltage cannot be assumed to be sinusoidal, faster sampling is needed.

Standard advice for digital scopes is that you need a sample rate at least 10x the signal you're trying to look at. The main signal may be 60hz but for power quality you're interested in looking for harmonics, deformations to the waveform, current/voltage phase mismatch etc.

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