9000KWh reliance on grid is no good; how to avoid?

[billt1827]

I can build a second array with similar size elsewhere on the land.

I went through the steps involved to be allowed grid feeding my surplus power.

Especially for winter times, when having 88 panels would also not be enough, especially without a good power storage I am dabbling with

Cheap chinese horizontal wind turbine, an in depth exploration.

--- Begin edit Please do not reference to unproven products. A proven product should at least have an rpm vs some kind of output graph with warranties. for the building of a DIY alternator that actually works please see...

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I can install up to 5 of them on my main roof and a couple more elsewhere on my land.

Then I think I am out of options in terms of power generation other than inventing a fusion reactor

Your graph proves my point about not generating enough. For instance, November last year generated 114kWh which is 3.8kWh per day. Even if you double that it's only 7.6kWh per day. That's nowhere near enough even for our consumption, yours will almost certainly be much higher than ours. Just like here you have 4 winter months of inadequate generation.

If you pursue this you will need to completely rebuild your system. At the moment your PV inverters are directly coupled to the grid. If you were to go for an AC coupled system like the Sunny Islands you cannot connect your existing inverters to the grid. The Sunny Island system controls the output of the PV inverters by changing the system frequency, you can't do that while grid connected. this mean that you will use different equipment for your grid connection, not the equipment for which you have permission. DC coupled systems will likely also require getting new connection permission.

I refer you to this concise explanation of why small wind turbines aren't worth it.

Climate change mitigation strategies

Climate change mitigation strategies

forum.mrmoneymustache.com

Small scale wind: Almost, but not entirely, worthless. Small scale wind you don't build yourself: Entirely worthless, unless you're selling the gizmos.

Literally everything is working against you. Wind power is proportional to swept area (so square of the diameter), and a cube factor of wind speed (double the wind speed, you get 8x the power). Small turbines have swept area working against them, and you'll find that their rated power comes at some speed you only get for dozens of hours a year, if that. Usually by the time you put them up, hanging in the trees/roofs/etc, you don't even get that speed for long. And with a cube factor working against you, they'll spend most of the year producing next to nothing, and being vibrating pains in the rear in the bargain.

On top of that, you need a lot more complexity in the system than you do for solar. If solar panels aren't having the energy pulled out, they just... sit there. So if the battery bank is full, or the grid is offline, a solar panel needs nothing added - just disconnect it from the inverters and it can hang there all year long, if you let it. Wind can't. You have to have a diversion load that can take the full output of the turbine, otherwise it will overspeed. You might be able to do some tricks with shorting the windings and trying to brake the blades that way, but what you've mostly done is use the coils as the blade brake, and that works... until you burn them up, and the turbine overspeeds and is on fire. So you need a diversion load. Plus, perhaps, a mechanical blade brake. It adds substantial cost to the project.

 

[mrzed001]

Currently I draw +- 9000 KWh more from the mains grid than I supply to it in one year.

Earlier I posted this thread

scalability of LifePO4, an insane® battery pack.

I am not sure if I am going completely off the rails with what I would like to do and if at all possible or sane and what not. But essentially I would like a battery pack that I can run heavy load appliances with like 11kw (3 phase) EV charging and 3KW electric cooking and 3KW (single phase)...

diysolarforum.com

That started it all

TL;DR
I have an 11kw 3 phase EV charge, I 3KW single phase heat pump, a 15KW 3 phase electric heater and several kitchen appliances that draw +- 3KW to run.

I'd ideally go off grid once I have demonstrated it can be done for a year or 2.

What configuration of 3.2v 280AH LifePO4 cells would you recommend?

EDIT
Please ask for more details so I can help you guys help. I am far too inexperienced to think of a better way of explaining myself at this point in time.

Why go completely off-grid ?

You can have off-grid or hybrid inverter with grid support and a 280Ah EVE cell battery.
Like you can make your own power but when it is not enough (and there will be times it is not .... like 1 week rain) then you have to start a generator to charge the battery.

If you use a hybrid inverter then:
- you are still connected to grid, so no need to a generator (loud, smelly, and environment unfriendly)
- you produce a lot of extra power that can be sold to the grid. So you earn money :D
- and have almost zero power bill

And here are the calculations (EU give us a very good tool to do it):


So if you put down a 40kWp solar panel array and 6x16 EVE cells (86,4 kWh) ... and you have only 30kWh consumption a day, then
8,28% of days battery will be empty.
30 day you have to use a generator to charge your battery.
Also in the summer you do not generate (loose) daily 100 kWh power ... that you could sell to grid.

(calculation is not perfect because in the winter you will have more than 30kWh usage with electric heater .... waaaay more)

 

[brandnewb]

I just figured I can hook up a threadmil to a generator and get in the best shape of my life. I am actually going to do that now I think of it because then finally i'd have a real good incentive to be more active.

By the looks of it I wont survive it due to physical stress

 

[brandnewb]

for all the ones nearby enough of me please see

[SOLVED]Looking for a Netherlands based electrician that can go slow

My current breaker panel is in disarray. https://diysolarforum.com/threads/cheap-chinese-wind-turbine-an-in-depth-exploration.30146/post-364197 It is the result of hastily adding new components over time during house construction without reevaluating the layout before each new addition. So...

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[DJSmiley]

Winter is going to be a PITA. It's unrealistic to get 100% coverage, unless you're spending a huge amount in solar panels (at least double your capacity). But that's going to be costly, no guarantee, and you're ending up with sooo much unused PV power during summer (which you can't backfeed to the grid due to your 3x25A max)

Another option: Some EV's do have a schuko outlet. If you're daily drive doesn't require all your battery capacity, you might use your EV as backup source during winter time. If the shuko is allowing discharge with the doors locked, you can use that to compensate for the lack of capacity during the night. With a simple 48V 3-4A charger you're only drawing 150-200W from the car, which generally isn't a problem, but still can charge 24-32Ah overnight.
If you're charging at eg a office, it might be a cheaper option than paying your own kWh. (At our company we use >10000kWh/year, and with these amounts, kWh price is cheaper, thus if you can make a deal with your job, you can get power for cheap and use it at home)

 

[brandnewb]

@DJSmiley I hear ya! Your input if much appreciated.
Although a great suggestion for owners of multiple EV's I can't go that route. 1st my renault zoe does not offer that and 2nd I am not sure my next car will as well.

How about thermal storage?

I have the means, will, space and ability to actually create a 10000 liters or more heat storage buffer tank with an insane insulation level of how ever much RD we want it to have.

I am worried that this will only lessen the load from my heat pump yet we have a lot of non heat related loads to think about as well.

Granted, the heat pump is the only big (not sure if one single phase 16A load can ever be called big) load that run 24/7 during winter times, so perhaps it is a good way to go.

Edit; Let's not forget the power hungry kitchen appliances. I'd like to be able to still be ale to cook the best Christmas dinner ever, so that means like 10KW for a couple of hours load while there is no sun,

Simple meals are nothing like this excessive Christmas meals demand. A few minutes of a low setting of heating the stove and we can eat.

 

[billt1827]

Thermal storage has similar problems to battery storage; in the winter when you need the heat there's not much solar energy available in northern latitudes. (That's why it's cold!)

What you would need is an inter-seasonal thermal store. A few people have tried to make these, but they are very large and difficult. Although you can put lots of insulation on the store itself, there are lots of opportunities for parasitic losses in the connecting pipework.

In my last house I had a 2,500l thermal store whose primary function was to accept the full output of a log boiler so the boiler could run at maximum output with the highest efficiency and lowest pollution, but it also had input from 120 evacuated tube solar collectors and an immersion heater. In the late spring/summer/early autumn the solar collectors would provide enough hot water but in the winter they gave very little. Also, on cold days the heat demand from the house would completely empty the store, so the log boiler had to be run for a 10 hour burn every day.

FYI a 10,000l store will store about 11 kWhr per degree C rise in temperature, so if you can use a 40C temperature range it would store about 460kWhr. One of the issues with thermal storage is the range of useful temperatures that you can store. Ours would be heated up to 80C or so and was usable down to 40C. If you want it to supply hot water that's pretty much as low as you can go without complaints about tepid water. For heating the range may be lower. if you are using a heat pump with a well insulated house presumably the flow temperatures are quite low so you would be able to use more of the heat in the store.

Another issue is that the energy you are storing is low grade; it can only be used as heat. Energy stored in batteries is high grade and has many uses apart from heating.

I wouldn't worry about Christmas dinner. Cooking appliances have very high diversity - they don't draw their peak power for very long.

We've just replaced a horrible dual fuel gas range cooker with 2 of 4 ring induction hobs and 2 ovens. The hobs are nominally 7.6kW each and the ovens 3kW, giving a total nominal load of 21kW but we haven't had any problems with the6 kW SI8.0.

This is this evenings use. You can see the oven element switching on and off. The hob uses 2500W for less than 2 minutes to bring water to the boil, then drops to less than 500W. There's a few seconds of a 5kW peak then


Here's another sample with both ovens working. This time there's a 2 minute peak of 6.5kW as one ring runs on boost and both ovens were heating.



The rings average about 500W when not on boost, so the total demand if they were all on and the ovens as well would be about 7kW, but you would be very unlikely to use all 8 rings at the same time.

Note that just over an hours use of 2 ovens used 1.6kWh, so 2 hours would be around 3 kWhr. One of the ovens was at 270C, so the worst possible consumption.

 

[brandnewb]

The short answer is - forget it.

I would like to rephrase that. Short answer being not very likely.
How about I am going to actually really try and do it?
I think I want it and there are options to explore

 

[brandnewb]

Nah, F98k it. If we all, with our combined brain power just try and make it happen.
Interesting formula would be;
EDIT:
(avg human minds) = (einstein mind)
Many minds combined could do Tesla/Einstein levels of greatness

 

[brandnewb]

Ok guys, I have an update. I managed to install a dedicated power socket for the max 2.4KW EV charger. My first attempt on doing electrical work.

It worked and now the 11KW EV charger is hopefully obsolete, only occasional use at day time during summer. Anyway this will lessen the load considerably.
I am happy

 

[brandnewb]

For heat storage: I don't see the benefits. 200-300L is generally sufficient for normal purposes.

You clearly have not met my wife yet. Let alone her family. She showers for ages and when the extended family comes my 500l boiler is 'cold' in like 20 minutes.

Nah, better to go for 10k l + if one has the space and will.

Perhaps calculating the heating demand during our winter time could help size the thermal buffer

 

[DJSmiley]

Replacing / downsizing the demands of the wife is probaly cheaper

You might look into heatpump boilers. Those are much more efficient compared to regular ones with just a heating element. Also, when using solar collectors is more efficient than using electricity.

As for the EV: There are also chargers which allow up to 16A charging. Your current 'granny' charger is probably maxed at 10A, since thats about the best you can get from a decent Schuko socket.
I have for example one which also can be set to 16A. If you hardwire it, I don't see any issues (Or replace the Schuko with a 16A CEE plug).

Depending on your daily drive (thus the amount of kWh you need to charge) this might be a faster charge option, without having to upgrade to 3-phase

 

[brandnewb]

You might look into heatpump boilers. Those are much more efficient compared to regular ones with just a heating element.

I must apologize for unclear wording. I do not have a boiler. I have a thermally insulated cylindrical shaped object with a 500l water content capacity that is being heated by a solar collector, a heat pump and a hybrid pellet stove. The hybrid aspect about the stove is that it is in our living room and can also enhance the mood by burning wood rather than pellets. I am not sure how long we can keep using the fireplace though given the ruckus about it here in NL before corona muted any debate about any other topic

 

[12VoltInstalls]

Many minds combined could do Tesla/Einstein levels of greatness

showers for ages and when the extended family comes my 500l boiler is 'cold' in like 20 minutes.

I would so-fast have a propane tankless demand water heater. Never out of hot water, relatively low cost fuel. That eliminates one very strong intermittent load that would be mind-bending annoying. Running water and hot water are two modern ‘conveniences’ I really wouldn’t want to forego. Other things you can choose how to use but hot water is wanted when it’s wanted.

Einstein levels of greatness. Not even close to Tesla and not collectively possible. Einstein envisioned how his observances were possible at an ethereal level and then figured out the math to get there.

What you’re trying to do doesn’t take genius. Just like Tesla you are trying to take existing technology and do new or possibly better things with it. No new wheels are required for you to do that- just scale and engineering.

 

[brandnewb]

I would so-fast have a propane tankless demand water heater. Never out of hot water, relatively low cost fuel

let's go for hydrogen. so we can make it our selfs