Random Renewables Thread

Dtp1979

https://www.boards.ie/discussion/comment/119891281#Comment_119891281

Yea. Why only Luke warm?

Fantana2

https://www.google.com/amp/s/www.smart-energy.com/storage/first-commercial-scale-sand-battery-goes-online-in-finland/%3Famp%3D1

Any reason why this couldn’t be used in a domestic setting? Say 5 tonnes of sand in a a drum in the back garden. It wouldn’t take up much space and you would effectively have a large thermal battery you can charge off excess solar in the summer for very cheap. Once the heat in the house needs to go on you draw from here first. According to their numbers at 500 degrees you get 80 kWh of storage per mt of sand.

the_amazing_raisin

Someone did something similar as a research project

https://www.scanhome.ie/research/solarseasonal.php

Uses a big water tank instead of sand but the principle is similar, and domestic scale

Probably easier to just heat the medium in the tank to a more modest 70C or so, unless you want superheated steam going through your radiators

It would dry the towels quickly though 😁

unkel

https://www.boards.ie/discussion/comment/119892807#Comment_119892807

For long term heat retention, I'd imagine you would need an expensive insulation setup. But the principle of course can be used and implemented very cheaply for short term heat retention. Immersion diverter + old skool storage heater with concrete blocks and basic insulation. You can pick these up for free. Total cost of the system: about €500. The bigger heaters store about 15kWh.

silver_sky

ESBN's data portal is now up. You can sign up to view historic meter reads and if you have a smart meter the import and export data. Mine is off, everything doubled up and the time is out. I'll get on to them I guess...

https://www.esbnetworks.ie/existing-connections/meters-and-readings/my-smart-data

graememk

https://www.boards.ie/discussion/comment/119892807#Comment_119892807

Yeah like this ?

https://youtu.be/NOUDbx1tX-A

(Tepeo boiler)

But old tech like storage heaters etc work in the same way.

Sillybody ABC

Hi ELM327

Did you find anyone who has used carbonfreeheat wind turbine? I've been looking at this one also to improve solar in the winter. Can't find a single small wind turbine with a good review.

bullit_dodger

https://www.boards.ie/discussion/comment/119955821#Comment_119955821

Can't find a single small wind turbine with a good review.

LOL - That's cause they are all muck! Love wind power me, but small wind turbines (<500w) aren't a runner for domestic use. You need to be going lower medium scale 1-5Kw costing ~€10K and then you'll get a solid production

unkel

https://www.boards.ie/discussion/comment/119956308#Comment_119956308

But only in the right location. Which is what at least 95% of houses in Ireland are not.

ELM327

And youd get much more value for that 5-10k putting it toward PV

graememk

https://www.boards.ie/discussion/comment/119958138#Comment_119958138

Thats the kicker. 95% of the time, just putting in more solar (and maybe storage) is way more cost effective, than trying to eliminate a bit of import on the really bad days.

Been doing the sums on 2022, Im on the EV tariff ( 20.27/5.83 until end july, then 27.8/7.9 until next july)

I have most things accounted for and any diverts counted as Night rate. And I'm a high user of electric. I am on track to save 1200 this year.

If I take this years use and put in next years unit rates. (47.77/13.75 from Aug on) I'm at 1800. Thats not taking into account the recent upgrade.(eg the extra 20kwh of batteries)

A whole year at the 47/13c things just get a bit silly! (2500ish!!)

This is EXCLUDING any FIT i'm due.. (about 320/yr)

bullit_dodger

https://www.boards.ie/discussion/comment/119958431#Comment_119958431

I recently passed the 1yr mark (end of Oct) and I worked out that the value of electricity that I "saved" via generation and load shifting via my battery was €1,244. This also doesn't include FIT, which incidentally moving from SSE -> Energia looks like I've lost from Feb to Sept. (There's always SOMETHING when I switch providers, hence my reluctance in swapping providers - they invariably find a way to SHAFT me!) I also have reduced gas consumption from the heating as i use the bitcoin miners for heating for many of the milder days, so not included that reduction either. Others use infrared heaters, or electric oil radiators, I use GPUs :-)

The big issue of course with adding more solar to an installation is that while generally it's a positive thing, the law of diminishing returns kicks in. Sure doubling panels does help on the VAST majority of days, but on the dark, crappy days.... twice feck-all is still pretty close to feck-all :-)

Take today, right now in an overcast day in Dublin, my 5.3Kwp is producing ~300watts. Doubling this to 10Kwp would give me 600w at a cost of €5k. Then it's a question of could I spend €5k and get 300watts via another medium. I guess it's doable, but not in a residential housing estate in Dublin 16! LOL

Solar though would on 70%+ days be the way to go, but for solving the Nov-Feb issue....wind might be a worthwhile investment over 20 years.

I still like that idea of the lads in Wales (or was it Scotland?) who have with the megawatt sized wind turbine where you buy shares. Wish we had something similar in Ireland.

unkel

I use GPUs, infra red panels and battery charging and discharging for most of my heat 😁

You won't have lost your FIT from Feb to Sept. You'll get it eventually. There is no legal way your previous provider can avoid paying it.

ELM327

https://www.boards.ie/discussion/comment/119958670#Comment_119958670

Today I was getting 2kW on my 8kWp system, but the general peak is 800w-1.2kW. If I was to quintuple that, from 8kWp to 40kWp, that would be more than enough to run the house even in the depths of winter. There's always a way with solar and thats the way I'm going. There are diminishing returns but have you looked at the cost of any wind turbine with real power (like 4-5kW). That's the equivalent of one of my solar strings. It then would need maintenance, not to mention mounting, and also to have a burn off. I investigated the wind option but I think it ranks behind hydro, let alone PV.

bullit_dodger

https://www.boards.ie/discussion/comment/119958993#Comment_119958993

I raised a complaint already unkel about that, fell on deaf ears. I don't know if you remember it from the other thread, but they were saying that

"Sure, we'll pay that, but you MUST move to a smart meter going forward for us to do that"

I found this somewhat insulting as they were in effect asking me to move to a smart meter now (when I'm with Energia) in order for them to pay me for deemed export when i was with them. I was like WTF? It sounds arrogant, but life's too short to spend hours on the phone and raised stress levels with Terry-Feckwit's .... so I've given up on it and will just accept the FIT from Energia from Sept onwards and just chalk it down as "another reason to minimise supplier moves" in future. Had I stayed with SSE, I'd have had the FIT - but then again......I'd not have had the excellent €0.08/unit rate, so overall I'm still happy I moved.

unkel

You really can't scale PV to fully cover your electricity needs, @ELM327. Unless you not only have a huge PV setup but also a huge battery. To give you an example, my 11kwp fully south facing arrays generate close to 100kWh on the best day of the year, but just 1kWh on the worst day of the year. And the trouble is you could have a few of those worst days of the year in a row, typically in December.

bullit_dodger

https://www.boards.ie/discussion/comment/119959014#Comment_119959014

I guess it's not so much about the peak power but really how much you get in total for a day. Take yesterday (another poor day) here in Dublin.

Doubling this from 5.3Kwp to 10.6Kwp would mean I go from 1.1kwhr generated for the day to 2.2Kwhr generated for the day. So I would (in effect) have spent €5K for boosting the production by 1.1Kwhr. Saturday last, a better but similar story.

2.7Kwhr generated on Sat. So doubling the panels would bring me to 5.4Kwhr, still way off what I'd need to run the house (20Kwhr/day)

Don't get me wrong - in general I'm 100% of the opinion that all things being equal increasing your solar panels is generally a good thing. I installed 6 panels myself (2.3Kwp) there last summer on the shed for exactly that reason - but there comes a time that it's no longer feasible when the days are short, cloudy (dark) and the sun angle is very low. 16degree at noon in Dec means many trees and houses shade panels.

Extra panels only really help the "edge" months and extend your self consumption timeline from 7-8 months to maybe 8-9 months. Outside of that your looking at wind as a cost effective alternative. Gut feeling tells me about 12-15Kwp is that magic number, but of course it's dependent on the household consumption.

(Assuming you have the land/space/location for a decent wind turbine of course)

ELM327

Yes I concur with both of you. But as long as you are generating something, there is a mathematical point where you can generate enough for the day.

Today's peak for me was 2kW on an 8kWp system. Now I can have another 4kWp on that same roof without issue and probably another 8kWp ground mounted facing similar direction. If you extrapolate that 2:8 ration out to 20kWp you get 5kW peak, maybe 3kW constant baseline for 5-6 hours.

So it's clear that I would need more than 20kWp to make running the house on solar in winter feasible. I'm aiming for that, I know I may need 30+kWp and I'm not going to get it this year or next but I will have the house off grid if it kills me!

There's some key points to note:

not every day is good, not every day is bad, theres no point planning based on summer and theres no point planning based on zero. You need to build a system that, in addition to generation on a daily basis, can store 2-4 days of use.

If you're using 15kWh per day and your generation is 5kWh, 10kWh,20kWh,0kWh , 15kWh for a mon-fri week in december, you need to have buffer to cover that.

unkel

So if you are using 15kWh per day and your generation of the worst mon-fri week of the year is about 7.5kWh per 10kwp (for the total of the 5 days), you would install 100kwp in panels? 😁

the_amazing_raisin

https://www.boards.ie/discussion/comment/119959455#Comment_119959455

You know you've hit the big time when you've too many panels to be covered by an NC7 form 😁

the_amazing_raisin

https://www.boards.ie/discussion/comment/119959014#Comment_119959014

Well you'd also need to factor in the field you need to buy to put all those panels on

Unfortunately for us living in the suburbs we're stuck with what roof space we've got. I'm getting 6kWp installed next year and that'll max out my current roof space.

I reckon if I built an extension and log cabin and put panels on them I could get to around 15kWp but that's all I'll ever manage, unless I put panels on the north facing side

Some quick calculations tells me that I'll probably be almost cost neutral for energy between export and savings. But that's different from true grid independence

unkel

That's what I did. The 14 panel install on my new shed has just about paid for itself already and now the panels are actually starting to pay for the shed itself 😁

ELM327

https://www.boards.ie/discussion/comment/119959455#Comment_119959455

Not saying I will/would, no. But I could.

There would have to be a balance of storage (ie to keep energy stored from the prior week or something) and generation. I can't afford to spend 100k on a vanity project. However in bits and pieces I reckon I can get to a point where I am off grid (regular use of a generator doesnt count either) and not spend 100k or anywhere near it. If we didnt have an EV it would be a lot easier!

https://www.boards.ie/discussion/comment/119959570#Comment_119959570

We are thankfully rural and surrounded by fields and cows, so no one to complain about excessive panels (once herself is on side!). Our site is slanted and we have a water drain from the main road so the option for hydro is also there. Without going ground mounted or pure north facing, I reckon I could get to 20kWp. I've a large 6 car garage, a pumphouse, and a 2 bed granny flat which we use as office space in addition to the main house. You may have seen my posts in the facebook group of my 8.2kWp install by Solarplus.

unkel

I don't really do FB, but I'll go over to have a look 😁

bullit_dodger

It's an interesting problem and this thread is perfect for discussing as it touches on a variety of different aspects of solar. ROI cost, generation capacity, actual physical space for said panels, limits by ESB, etc etc.

ELM you mentioned above that you were getting 2Kw off 8Kwp, since it's nearly dark out now.....how much did you get for today in total? The peak is useful, but really it's the overall what we care about of course.

You see, I do believe that it's possible to get yourself 100% self-sufficient for 8-9 months of the year with solar, but to get to 100% all year round requires a huge capital investment....to the point of being insane. Taking myself as an example again, so far in December I have used 72 units (low for me) and I've generated 11.5Kwhr. So I'd have needed need 6x times what I have in panels or 33Kwp to cover what I used.

Taking Dec '21 figures (I was mining more back then).....Imported from the grid was 1008 units for December. Generated by solar 58.4Kwhr. So i'd have needed 18x times the panels I have. Granted they are in E/W aspect, so not great in winter, but needing 95.4Kwp in panels isn't a feasible option. That's like 250 panels. Sure, people will say

"Ohh but you were mining....if you weren't mining you'd need less".

True, but I don't have an EV, or heat pump, which could easily push a household consumption to 1000+kwhr/month in Dec/Jan. So (if you had the land and a good wind resource), rather than buying 200 panels.....I'd hazzard that it would be much more economical to have a 5Kw turbine. Course I'm only speculating as it's an interesting scenario.

Me - I'll get my own overall system up to 8.8Kwp (currently 5.3Kwp on main roof and 2.3Kwp on the shed) but at that, adding 3 more panels would mean that I'm totally out of space. If I'd more space I'd probably go to 12Kwp or there about and call it a day.

the_amazing_raisin

https://www.boards.ie/discussion/comment/119959888#Comment_119959888

Ah that's a good way to justify the man cave/home office/mini spa to the missus 😂

Punchin A Keyboard

Now if you have a nice big field and don't want to export, you probably could put in a nice big hydrogen tank and use excess solar for hydrolysis.

You could have a glut of roast beef if it goes the way of the Hindenburg

the_amazing_raisin

https://www.boards.ie/discussion/comment/119960845#Comment_119960845

Nah you'd need something that burns longer for roast beef, like napalm

Hydrogen explosion is more concussive so would probably be more like beef puree or just liquified cow

And on that note I think I'm going to become a veterinarian now after that horrifying mental image 🤢

redmagic68

https://www.boards.ie/discussion/comment/119960845#Comment_119960845

Solar barbecue, proper global warming. Wind supplementing solar would seem sensible where you have the space and right location on the wind map. However you have issues such as turbulence, maintenance, cost, lifespan to factor in. This on top of not knowing exactly how revenue and providers will treat your units going back to the grid it seems just too risky for the investment. Or go off grid with a tonne of batteries, 5 days minimum and with a 3 day factor of safety I would say.

A community owned large scale turbine could be a much more appealing way to go but then Karen and her friends will show up and…..

bullit_dodger

https://www.boards.ie/discussion/comment/119961716#Comment_119961716

You may have missed this over in another thread RedMagic , but there are companies over in the UK, who build community funded wind turbines (the big jobbies) and then for say €5k, you get a share of the electricity generated. This wasn't the one that we were talking about previously, but it's on the same lines. Home - Baywind Energy Co-op

So effectively you could "invest" in a large wind turbine, which are WAAY better than your local domestic ones and reap the rewards - albeit you would need a grid connection of course. Your account with your supplier would take away your usage from what your share of the turbine created. Clever idea. No Karen's to bitch about.... :-)

As for hydrogen, there's a good "test house" in Sweden that's quite famous.

Hydrogen house in Gothenburg, Sweden - BBC Teach