Geothermal may beat batteries for energy storage • Hacker News Board

Re: Geothermal may beat batteries for energy storage

#281

Post by cupofpython » Wed, Oct 12, 2022, 9:51 PM UTC

Schroedingersat wrote: post #277

cupofpython wrote: post #275

Earlier quoted context omitted.

Completely agree with the hybrid approach wrt reducing emissions. I am talking more towards work that would be done concurrently with that. > During this build all storage technologies where they make the most sense so that when that last 10% is needed, prices will have dropped this is kind of the point of what I'm getting at. Without any investment, none of the storage technologies are going to make much progress. I…

In terms of promising technologies, they're broadly categorisable as thermal, kinetic, battery/fuel cell, and thermochemical. Most of the promising ones are far enough along the learning curve that other markets (such as green hydrogen/ammonia for fertiliser driving electrolysers and small scale/more efficient chemical reactors) will drive the learning curve. Thermal storage concepts include: Molten salt thermal. sho…

What a great read. Saving this for additional research later. I also saw something related to harvesting some energy from the tides, which I think would fall under lifting or sinking stuff and virtual batteries. I wasn't convinced on being able to scale it, or get too much of significance out of it, so i didnt read too much into what the exact technical implementation was.

Re: Geothermal may beat batteries for energy storage

#282

Post by Schroedingersat » Thu, Oct 13, 2022, 2:54 AM UTC

cupofpython wrote: post #281

Schroedingersat wrote: post #277

Earlier quoted context omitted.

In terms of promising technologies, they're broadly categorisable as thermal, kinetic, battery/fuel cell, and thermochemical. Most of the promising ones are far enough along the learning curve that other markets (such as green hydrogen/ammonia for fertiliser driving electrolysers and small scale/more efficient chemical reactors) will drive the learning curve. Thermal storage concepts include: Molten salt thermal. sho…

What a great read. Saving this for additional research later. I also saw something related to harvesting some energy from the tides, which I think would fall under lifting or sinking stuff and virtual batteries. I wasn't convinced on being able to scale it, or get too much of significance out of it, so i didnt read too much into what the exact technical implementation was.

If you're letting the ocean move it, it's generally known as tidal or wave power. It's appealing because it's very predictable and the variability is not correlated* with wind or solar. Afaik cost and placement of suitable sites is a dealbreaker.

One potential technogy https://www.abc.net.au/news/2022-07-31/wave-power-generator-...

New thing I just learned. The tidal stream industry seem confident they can beat nuclear at shockingly low investment. https://interregtiger.com/understanding-tidal-stream-energy/

If they're not lying, that's your high return investment for the future (if you're a policy maker...if you are a private investor then what happened to the solar industry when panels got cheap could happen again).

* uncorrellated variable sources need less storage when combined There are already regions that can work on wind, solar, and a small percentage of existing hydro with no storage for this reason. Tidal isn't completely uncorrelated -- roughly once a month your peaks will line up with solar peak production, and the trough will line up with peak demand for a few days -- but attaching two systems at distance will help with this and it reduces the load on hydro.

Re: Geothermal may beat batteries for energy storage

#283

Post by jonstewart » Thu, Oct 13, 2022, 4:01 AM UTC

mderazon wrote: post #279

jonstewart wrote: post #253

Earlier quoted context omitted.

Basically. There are all sorts of neat DIY examples of people using large solarthermal arrays and big storage tanks to provide adequate heat, but they’re major projects and custom. For your system, what I’d potentially recommend is looking at a heat pump that can provide both domestic hot water -and- hot water for your radiators. They exist! Then, explain to your vendor/installer that you want a second heat exchanger…

Thanks a lot for the detailed reply. Old radiators operate in high temperature but from what I understand, the fan coil heaters operate in lower temperature more equivalent to radiant floor heating. For cost reasons, installing undefloor heating is not an option, that's why I opted for low temp radiators on top of floor. However, it sounds like the heat pump system will not be cheap either. According to BTU calculato…

Daikin makes air source heat pumps with water storage, and that can be paired with solarthermal: - https://www.daikin.com/products/ac/lineup/heat_pump - https://airconditionerlab.com/daikin-heat-pump/

A "variable speed compressor" is what you want in a heat pump, as these modulate their speed (and electricity usage) to produce a constant amount of heat. You might be okay with a 24K BTU system, especially when coupled with the thermosiphon and then some effort spent on insulation & air-sealing?

Here in the US the base system would be about $3K USD, but with installation costs on top of that.

Re: Geothermal may beat batteries for energy storage

#284

Post by Mrdarknezz » Thu, Oct 13, 2022, 9:09 AM UTC

pfdietz wrote: post #254

Mrdarknezz wrote: post #251

Earlier quoted context omitted.

Battery costs are literally rising

Short term rise due to commodity prices, but shifts to LFP and other cheaper approaches will allow the dramatic long term price trend to continue. https://about.bnef.com/blog/battery-pack-prices-fall-to-an-a... If you look at PV there were similar "ah ha, costs have stopped falling!" moments in the past (mid 2000s, for example), but they didn't last long and were followed by even more dramatic cost declines. It's imp…

Well it doesn't really change the fact that batteries: 1. Doesn't scale to grid level 2. Isn't interchangeable with firm energy sources

Re: Geothermal may beat batteries for energy storage

#285

Post by pfdietz » Thu, Oct 13, 2022, 10:10 AM UTC

Mrdarknezz wrote: post #284

pfdietz wrote: post #254

Earlier quoted context omitted.

Short term rise due to commodity prices, but shifts to LFP and other cheaper approaches will allow the dramatic long term price trend to continue. https://about.bnef.com/blog/battery-pack-prices-fall-to-an-a... If you look at PV there were similar "ah ha, costs have stopped falling!" moments in the past (mid 2000s, for example), but they didn't last long and were followed by even more dramatic cost declines. It's imp…

Well it doesn't really change the fact that batteries: 1. Doesn't scale to grid level 2. Isn't interchangeable with firm energy sources

Why don't batteries scale to grid level? I don't see how this assertion could be justified. Do you mean a specific KIND of battery?

Renewables + storage certainly could provide 100% of the needs for the grid, in a properly designed system. At this point it's just a matter of quibbling over cost. Since the world could be spending upwards of a quadrillion current dollars on energy in the next century there's a hell of a lot of financial headroom to scale things up.

Re: Geothermal may beat batteries for energy storage

#286

Post by Mrdarknezz » Thu, Oct 13, 2022, 12:23 PM UTC

pfdietz wrote: post #285

Mrdarknezz wrote: post #284

Earlier quoted context omitted.

Well it doesn't really change the fact that batteries: 1. Doesn't scale to grid level 2. Isn't interchangeable with firm energy sources

Why don't batteries scale to grid level? I don't see how this assertion could be justified. Do you mean a specific KIND of battery? Renewables + storage certainly could provide 100% of the needs for the grid, in a properly designed system. At this point it's just a matter of quibbling over cost. Since the world could be spending upwards of a quadrillion current dollars on energy in the next century there's a hell of…

So far there is no proven technology that scales to grid level? We are closer to achieving fusion than large scale energy storage.

Re: Geothermal may beat batteries for energy storage

#287

Post by jonstewart » Thu, Oct 13, 2022, 3:03 PM UTC

2Gkashmiri wrote: post #256

jonstewart wrote: post #255

Earlier quoted context omitted.

I don’t have intuition for how large a 300L solar water heater would be — you mean the solar array on the roof, right? If you have infloor radiant heat with concrete floors, then you might not need much water storage — the concrete provides heat mass. I would look more at deploying PV arrays for offsetting the electricity usage of the heat pump than adding more water storage and solarthermal. Solarthermal is technica…

yeah, the problem with infloor is that the floor is already laid down so i would have to redo the flooring for all rooms. my use case is winter nov-feb which occasionally has snow, some year there is 0 snow, some year there is 12 inches, usually inbetween. electricity from the grid is often down during this time period but when it does come, we could use the heat pump to heat up the "storage". 300L water heater in th…

Ok, you're in Kashmir and don't have a reliable grid. I'm not sure it would make sense to spend the money on a heat pump if you didn't have reliable electricity to operate it (if you had sufficient PV panels, then it might be worth it).

Build It Solar has a ton of DIY projects for improving efficiency and using solar energy in various ways. You might find inspiration there: https://www.builditsolar.com/. In particular, they have plans for a solar collector that's a wood frame box with clear plastic sheeting and window screen material — extremely cheap and simple to build. It provides hot air, and it's best if you can fit a few cheap fans (like 120mm 5v PC fans) into it, powered by a small PV panel. I want to build one of these to heat my garage.

Some of the nice things about air-based solar collectors is that they're cheap, low maintenance, can't leak, and can't freeze. The downside is that storage is harder. If you have enough heat mass inside the house it might not matter, though.

Re: Geothermal may beat batteries for energy storage

#288

Post by pfdietz » Thu, Oct 13, 2022, 8:19 PM UTC

Mrdarknezz wrote: post #286

pfdietz wrote: post #285

Earlier quoted context omitted.

Why don't batteries scale to grid level? I don't see how this assertion could be justified. Do you mean a specific KIND of battery? Renewables + storage certainly could provide 100% of the needs for the grid, in a properly designed system. At this point it's just a matter of quibbling over cost. Since the world could be spending upwards of a quadrillion current dollars on energy in the next century there's a hell of…

So far there is no proven technology that scales to grid level? We are closer to achieving fusion than large scale energy storage.

There's no proven nuclear technology that scales to power the world either. Do you accept that as an argument that nuclear should be disregarded?

It's entirely reasonable to assume that some storage technologies will survive being rolled out to the scale needed to allow renewables to reach 100% penetration. After all, there are thousands of different battery chemistries, and many other non-battery storage technologies, including ones using 19th century levels of science (pumped thermal storage, for example). Your negativity requires that all fail. I think you doth whine too much.

Re: Geothermal may beat batteries for energy storage

#289

Post by Schroedingersat » Fri, Oct 14, 2022, 2:44 AM UTC

kragen wrote: post #264

Schroedingersat wrote: post #262

Earlier quoted context omitted.

Are those prices up to date? There are several shops in Brisbane AU that will sell drop in 12V batteris retail for 350USD per nominal kWh (about $320 per real kWh at 0.1C) including taxes. The occasional special is in the 250-300 range. Ebike batteries with higher current are in the 300-500 range. They're highly unsuitable for an engine starter at that price though (1C BMS) and have no built in low-temperature monito…

It's possible they're not! But I'm suspicious of this notion that prices have dropped by a factor of 5 since last year, and have reached Australia but not Just Catamarans in Florida; maybe they're doing the calculation differently than you are. Or maybe there's a fraud going on. FWIW your US$320/kWh works out to US$89/MJ. (I try to use SI units when I can; it saves a lot of hassle.) I think it's fair to exclude taxes…

Are you correcting for usable capacity in your prices? 50% DoD was typical for lead acid last I checked vs 85% for LiFePO4 (or 100% if you're happy with it lasting as long as lead acid at 50%)

As to fraud, I've seen at least four batteries perform as advertised. Also a 5x disparity in prices between different shops is entirely consistent. Prices have been dropping rapidly and there are enough people who go 'oh yeah, that was about right 3 years ago'. Plus retailers may have paid several times current retail for their stock if it's a year or two old and was bought at prices that hadn't been updated for a year.

Re: Geothermal may beat batteries for energy storage

#290

Post by kragen » Fri, Oct 14, 2022, 7:43 PM UTC

Schroedingersat wrote: post #289

kragen wrote: post #264

Earlier quoted context omitted.

It's possible they're not! But I'm suspicious of this notion that prices have dropped by a factor of 5 since last year, and have reached Australia but not Just Catamarans in Florida; maybe they're doing the calculation differently than you are. Or maybe there's a fraud going on. FWIW your US$320/kWh works out to US$89/MJ. (I try to use SI units when I can; it saves a lot of hassle.) I think it's fair to exclude taxes…

Are you correcting for usable capacity in your prices? 50% DoD was typical for lead acid last I checked vs 85% for LiFePO4 (or 100% if you're happy with it lasting as long as lead acid at 50%) As to fraud, I've seen at least four batteries perform as advertised. Also a 5x disparity in prices between different shops is entirely consistent. Prices have been dropping rapidly and there are enough people who go 'oh yeah,…

Thanks, that's very interesting!

The price I gave in the comment you're replying to is just a literal unit conversion of the price you gave.