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Rooftop solar power may be flooding the grid

smh.com.au

51–60 of 99 posts

Re: Rooftop solar power may be flooding the grid

#51
post #21

"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.

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.

Re: Rooftop solar power may be flooding the grid

#52
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.

Re: Rooftop solar power may be flooding the grid

#53
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.

Re: Rooftop solar power may be flooding the grid

#54

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). T…

> 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...

Re: Rooftop solar power may be flooding the grid

#55
post #39

Earlier quoted context omitted.

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?

Re: Rooftop solar power may be flooding the grid

#56
post #41

Earlier quoted context omitted.

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).

Re: Rooftop solar power may be flooding the grid

#57

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.

Re: Rooftop solar power may be flooding the grid

#58

Earlier quoted context omitted.

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.

Re: Rooftop solar power may be flooding the grid

#59
post #35
post #26

Earlier quoted context omitted.

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 fo…

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.

Re: Rooftop solar power may be flooding the grid

#60
post #33

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...

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?

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