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Puerto Rico's Solar Microgrids Beat Blackout

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Re: Puerto Rico's Solar Microgrids Beat Blackout

#21

Post by paranoidrobot »

dotancohen wrote: post #6

From what I understand, most homes that are connected to both solar and the grid require the grid to be active to produce solar. This is for two reasons. One, not to endanger lineman working on the grid. And two, the solar AC cycle must be synchronized with the grid AC cycle. Are these homes not also connected to the grid? Or is there some technology that addresses these two issues that are in use in Puerto Rico?

I think you're looking for the term "islanding".

It's becoming more and more common for PV systems with a battery system to be able to work in an islanded mode, and more importantly - they're legal and code compliant to do so.

When the grid goes down/out of spec, they disconnect the home from the grid and continue to power locally.

Examples of this include Tesla and Sigenergy.

Some are able to do this in very short periods and able to operate effectively as a whole-house UPS. Some will have a flickr of the lights and maybe some sensitive devices will restart. Others will take some period of time to disconnect from the grid and run in islanded mode.

Re: Puerto Rico's Solar Microgrids Beat Blackout

#22

Post by defrost »

paranoidrobot wrote: post #21
dotancohen wrote: post #6

From what I understand, most homes that are connected to both solar and the grid require the grid to be active to produce solar. This is for two reasons. One, not to endanger lineman working on the grid. And two, the solar AC cycle must be synchronized with the grid AC cycle. Are these homes not also connected to the grid? Or is there some technology that addresses these two issues that are in use in Puerto Rico?

I think you're looking for the term "islanding". It's becoming more and more common for PV systems with a battery system to be able to work in an islanded mode, and more importantly - they're legal and code compliant to do so. When the grid goes down/out of spec, they disconnect the home from the grid and continue to power locally. Examples of this include Tesla and Sigenergy. Some are able to do this in very short p…

For general interest, Western Australia's State Power company has a variety of battery application cases that it assists with; home batteries, community batteries, fully stand alone, microgrids (with batteries).

https://www.westernpower.com.au/resources-education/consumer...

https://www.wa.gov.au/organisation/energy-policy-wa/wa-resid...

West and South Australia are a fair way down the integrated renewables pathway with a high percentage of household rooftop solar, mixed rural PV farms, wind power, battery farms, etc.

Re: Puerto Rico's Solar Microgrids Beat Blackout

#23

Post by Simon_O_Rourke »

Is this more of a battery cost issue - if you owned a battery that charged off the grid and discharged during blackout periods then that might just about cover you if you budget for the expected outage duration.... And assuming you can afford said battery in the first place.

Re: Puerto Rico's Solar Microgrids Beat Blackout

#24

Post by toast0 »

amoshebb wrote: post #2

I love solar, but this "those who can afford microgrids can shield themselves from blackouts" paired with net metering where "the wealthy get paid a premium for excess generation and can buy expensive high-demand power back at a discount" probably aren't steps on the path to improved grid resiliency for any definition other than this weird "no island-wide outages" definition.

It depends on the terms of the net metering.

If it's the ancient practice of crediting on a one for one basis, yeah that doesn't help. (A look around says that's probably where PR is now). If they credit power delivered to the grid based on conditions when it was delivered, then that might help. With appropriate controls, storage can increase grid stability. It would probably be more cost effective to do utility scale storage projects, but project management is difficult in PR; letting those with personal capital hook up solar+batteries and send some of that onto the grid when demand is high seems useful?

Re: Puerto Rico's Solar Microgrids Beat Blackout

#25

Post by matthewdgreen »

amoshebb wrote: post #19
mcbishop wrote: post #13

Earlier quoted context omitted.

Net metering is gone in most of California (for new solar). I think it's going away in general. Distributed solar supports a more stable grid for everyone (per UL 1741-SB requirements).

the article is about Puerto Rico, not California, and specifically mentions net metering.

I think the poster’s point is that net metering is a tool to promote early adoption of solar, and (in at least one prominent example) when solar penetration becomes high enough for it to impact grid stability, larger grids have removed net metering. So to address GP poster’s point: net metering affecting grid stability in a substantial way is more a theoretical concern that’s already been addressed in one of the locations where it stopped being theoretical.

Re: Puerto Rico's Solar Microgrids Beat Blackout

#26

Post by fencepost »

pmontra wrote: post #20
dotancohen wrote: post #6

From what I understand, most homes that are connected to both solar and the grid require the grid to be active to produce solar. This is for two reasons. One, not to endanger lineman working on the grid. And two, the solar AC cycle must be synchronized with the grid AC cycle. Are these homes not also connected to the grid? Or is there some technology that addresses these two issues that are in use in Puerto Rico?

If your home is isolated from the grid you don't have to worry about syncing your 50/60 Hz. A UPS during a blackout is an example. I experienced it myself. I have no idea about the hurdles of keeping in sync many batteries in many homes connected together. This is not even something I thought about before the news of the blackout in Spain months ago.

Keeping in sync isn't as much of a problem as you might think, it simply requires that everything able to feed into the grid has to accept the grid as authoritative for syncing.

Relevant are some of Chris Boden's videos about bringing up a hydro power plant and his comment that you have to be in sync with the grid when you actually connect because the turbine WILL sync to the grid at connection and if it was incorrect before then there will be a lot of loud angry noises from the equipment. https://www.youtube.com/watch?v=xGQxSJmadm0

Re: Puerto Rico's Solar Microgrids Beat Blackout

#27

Post by chilldsgn »

I don't know much about electrical grids, but I'm wondering if something like this concept could help South Africa with its endlessly struggling electrical grid problems. My city constantly has power outages and the majority of people cannot afford installing solar into their homes.

Re: Puerto Rico's Solar Microgrids Beat Blackout

#28

Post by happymellon »

chilldsgn wrote: post #27

I don't know much about electrical grids, but I'm wondering if something like this concept could help South Africa with its endlessly struggling electrical grid problems. My city constantly has power outages and the majority of people cannot afford installing solar into their homes.

From what I understand, South Africa's electrical problems have been long term political.

Re: Puerto Rico's Solar Microgrids Beat Blackout

#29

Post by colechristensen »

layoric wrote: post #4
amoshebb wrote: post #2

I love solar, but this "those who can afford microgrids can shield themselves from blackouts" paired with net metering where "the wealthy get paid a premium for excess generation and can buy expensive high-demand power back at a discount" probably aren't steps on the path to improved grid resiliency for any definition other than this weird "no island-wide outages" definition.

Agreed. From first hand experience, even for regulated electricity markets, games get played to maximize profit per power generated that are directly making stability worse. Fixing these loop holes is hard for the regulator since they are instructed to encourage both increased renewable penetration and stability, despite traders/operators/producers not acting in good faith and just gaming whatever they can.

A healthy regulated will encourage maximizing profit for power and bring in competition which drives the cost down until energy is a commodity and the cost of electricity is actually based on the price of production and a small profit based on the cost of capital. Any situations that cause price spikes result in investment to harvest the difference.

The fact that you can add to the grid by installing solar and battery and connect to the grid in a single afternoon makes it pretty easy these days to have an elastic market that grows until you hit the limit of decentralized production vs. existing transmission architecture... but with the right equipment you can have community sized islands that can be much more immune to instability.

Re: Puerto Rico's Solar Microgrids Beat Blackout

#30

Post by cinntaile »

happymellon wrote: post #28
chilldsgn wrote: post #27

I don't know much about electrical grids, but I'm wondering if something like this concept could help South Africa with its endlessly struggling electrical grid problems. My city constantly has power outages and the majority of people cannot afford installing solar into their homes.

From what I understand, South Africa's electrical problems have been long term political.

That's the case everywhere in the world, it's not a tech issue. The tech exists.
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