this post was submitted on 27 Aug 2023
172 points (99.4% liked)

Australia

3587 readers
78 users here now

A place to discuss Australia and important Australian issues.

Before you post:

If you're posting anything related to:

If you're posting Australian News (not opinion or discussion pieces) post it to Australian News

Rules

This community is run under the rules of aussie.zone. In addition to those rules:

Banner Photo

Congratulations to @Tau@aussie.zone who had the most upvoted submission to our banner photo competition

Recommended and Related Communities

Be sure to check out and subscribe to our related communities on aussie.zone:

Plus other communities for sport and major cities.

https://aussie.zone/communities

Moderation

Since Kbin doesn't show Lemmy Moderators, I'll list them here. Also note that Kbin does not distinguish moderator comments.

Additionally, we have our instance admins: @lodion@aussie.zone and @Nath@aussie.zone

founded 1 year ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
[–] Edgelord_Of_Tomorrow@lemmy.world 9 points 1 year ago* (last edited 1 year ago) (2 children)

Check this out: https://raygen.com/projects/raygen-power-plant#resources

Batteries were a stopgap until we worked out something better. This plant gets 70% efficiency and more than enough energy storage by refrigerating a cold block, then using stored waste heat + the cold block to create a temperature differential, creating steam (in a closed loop, don't need a big water supply) to spin a turbine that generates power when the sun goes down. Absolutely genius, already deployed and operating and yet nobody is talking about it.

[–] IndefiniteBen@feddit.nl 2 points 1 year ago (1 children)

What's the advantage of that solution over existing solutions like heating molten salts?

[–] Edgelord_Of_Tomorrow@lemmy.world 1 points 1 year ago (3 children)

Efficiency. You're collecting 70% (potentially 80%) of the available energy. The best PV is below 30% and the best molten salts are 35% max.

[–] IndefiniteBen@feddit.nl 1 points 1 year ago (1 children)

I thought molten salt storage gets like 90% efficiency. What's the advantage of storing energy by cooling blocks?

[–] Edgelord_Of_Tomorrow@lemmy.world 1 points 1 year ago (1 children)

To run a heat engine you need a temperature difference in order to generate work. When your system generates heat as a byproduct you can amplify the amount of work by increasing the temperature difference. This is how the cold block "stores" energy.

What's your source on 90% efficiency? Here it's stated 35% max.

[–] IndefiniteBen@feddit.nl 1 points 1 year ago

I'm just talking about storage. Molten salt energy storage is mentioned here: https://en.wikipedia.org/wiki/Thermal_energy_storage

[–] palitu@aussie.zone 1 points 1 year ago (1 children)

I am listening to a The Solar Insiders Podcast, which is interviewing the CEO of RayGen (thanks for intoducing it to me, really cool).

the 70% is the efificency of the energy storage, which is similar to pumped hydro. ie, they put in 1MWh to the chiller, and will recover 0.7MWh from the organic rankin cycle turbine.

so, they get the 30% of the solar (or whatever it is), plus the recovery of the heat. They were saying that for 1 tower, they get 1MW of solar and 2MW of heat. but they never said how much of the 2MW of heat gets converted to electricity, or what the efficiency is, but it sounds like they need to consume electricity to use the ORC (ie for the chiller).

one other thing is that they ORCs can provide grid inertia which is a cool outcome too.

[–] Edgelord_Of_Tomorrow@lemmy.world 1 points 1 year ago* (last edited 1 year ago) (1 children)

Hi mate, I think you misunderstood me.

It captures 30% of energy as PV and 60% as heat energy. The whole system itself is about 80% efficiency in terms of the energy captured from the sun, not the PV itself.

This makes it more effective than if you somehow had a molten salt and a normal PV plant in superposition on the same site.

[–] palitu@aussie.zone 1 points 1 year ago (1 children)

i haven't been able to find the actual insolation to electricity efficiency anywhere. Do you have a link that shows the incoming energy to output electricity?

[–] palitu@aussie.zone 1 points 1 year ago

I could not see where the 70% comes from, apart from the round trip efficiency of the heat capture. I dont know if that is what you are referring to. Do they have a input v output energy comparison somewhere?

[–] palitu@aussie.zone 1 points 1 year ago

i haven't read about your link yet, but as for storage, the study states

82% of demand was directly powered by wind and solar without having to pass through storage or be curtailed

so the majority of the energy is used without being stored, and having the round trip losses.

... now back to reading ray-gen