Export Tariff - "Opting Out" - Can I keep my own energy please?

Cardew

I think you have underestimated the technical difficulties(and costs) of having banks of batteries capable of being charged with the excess power your panels are likely to produce.

Where do you propose to house these batteries? What about ventilation?

ClaimYourEnergy

Cardew wrote: »

I think you have underestimated the technical difficulties(and costs) of having banks of batteries capable of being charged with the excess power your panels are likely to produce.

Where do you propose to house these batteries? What about ventilation?

Hi Cardew,

From the research I have done to date, I have been led to believe that some batteries that can be recommended for PV systems do not emit fumes and are maintenance free. E.g. AGM batteries. These could be housed under the stairs near the inverter and electrics to the grid.

This is all new to me at the moment and so if you have any reliable feedback that can help me decide, then please do let me know.

From what I have learned so far, it is best to use true Deep-Cycle batteries (are these also available maintenance free?) that have as high AH rating as possible. I have seen some AGM batteries rated at 12v 200 AH (weighing nearly 70 kgs!) for £280. These are the equivilent of 2.4 KWh if I understand the working correctly. So, two of these would give me 4.8 KWh "backup", which would be more than enough to cover the evening hours until grid cheap rate energy begins. (Also made me wonder if storing energy for day use with night time cost energy was a good way to save money if you could set the system up in such a way. But, I don't know how long it takes to charge a battery. Anyway, I am getting distracted here ... )

That said, I also found some "Stinger" batteries (unfortunately, I cannot find the link now - they were bright yellow batteries), but I am fairly certain they said they were 600 AH and even 1000 AH, which would be the equivilent of being able to store 7.2 KWh and 12 KWh in a single battery and I know one of these was around £400. There size and weight I do not recall, as I was not taking many notes on this initial search.

I also found a gadget called a Power Streamer that looked like it may be something that I might need to help sort out all the procedure of battery storage and priority usage, etc.

The bottom line, however, is I only need something that will store around 12 KWh that I can use before I have to rely on energy provided by the grid. Actual logistics of whether this will work and if it is even worth it will depend on the final cost of the batteries, installation and if they require maintenance or if they are any risk to the property (such as fumes as you mention). If they are too expensive, I would consider the 4.8 KWh option above, if fitting costs are not prohibitive.

Ideally, all I want is a battery that can charge with excess energy throughout the day, that will be at maximum of 12 KWh fully charged, which I can then use to power my devices throughout the day and evening before relying on the grid. Of course, during a good summer, there is likely to be some excess energy that I cannot store if I do not use it in some way ... most likely would heat the water during the day in these circumstances, just to make use of it. And in winter, when the battery will only be partially charged by the solar panels, I will rely on the night time energy from the grid (which is cheaper) to top up the battery for the follwoing day.

Being able to switch the charging from the grid on or off would be a factor I needed to include in the build, which I would use according to daylight hours charging and usage throughout the year.

CYE

Cardew

None of the above is allowed to be a DIY task these days.

I would get a quote for the work.


Also see if they will agree that batteries handling that sort of power can be stored under the stairs.

ClaimYourEnergy

Cardew wrote: »

None of the above is allowed to be a DIY task these days.

I would get a quote for the work.


Also see if they will agree that batteries handling that sort of power can be stored under the stairs.

Hi Cardew,

I agree ... I would not dream of touching that stuff. I will definitely be getting a quote. And as you say, if it can't be installed under the stairs, then it will be a no-starter anyway, as I don't have anywhere else to put them.

I am waiting for some people to call me back. The best person to talk to appears to be on holiday at the moment for a few weeks and so I may not have any more updates for a while. One guy I did manage to get through to (sold batteries) tried to do some calculations with me and found it quite hard to work out what is actually needed as well, due to what seems to be more complicated than one first thinks.

He agreed that at least two batteries (storing 4.8 KWh in total) would be the least I would need, but there are other factors like switching between the sources subject to amount generated and that being used to take into account. I really need to talk to an installer who does this sort of thing for a living. I found another site, but both of their installation models that included batteries were not quite what I was after. Unfortunatel, I did not note their site and cannot find it again, which is a shame because I have not yet found another site with similar installations that are available to talk to over the phone. Even my own PV installers did not have the information I needed, and appeared not to know about this side as much. Lastly, I read about some "new" Li-Ion batteries that are being designed for just this sort of thing. The article was a year old and I have not found anything more on them yet. These might be a solution.

QUOTE FROM THE SITE ABOVE: Li-ion battery technology

In grid-connected energy storage applications, the newest practical battery technology, lithium-ion (Li-ion), offers the potential for significant improvements in terms of performance and service life over conventional storage batteries, and it is also zero-maintenance. However, although Li-ion batteries are very well established in consumer applications, the more rigorous demands of PV applications means ordinary consumer cells are not suitable. Instead, a new generation of Li-ion battery systems designed specifically for industrial applications is under development, with the first systems already on field test.

The initial indications are Li-ion technology will offer both very high efficiency, of around 95%, combined with a long calendar and cycle life - 20 years at 60 percent DOD (depth of discharge)/day.

The compact, sealed for life design of Li-ion batteries also offers considerable advantages. Considering a minimum capacity of 5kWh, then using Li-ion batteries it would be possible for a compact domestic battery to only take up 50 litres or so of space - similar to the footprint of a fridge-freezer.

Maybe if anybody reading this has any experience with battery backups, they might post. Or perhaps I should start another thread on the subject?

CYE

DVardysShadow

grahamc2003 wrote: »

This only happens if the station is operating in frequency sensitive mode, so supplying primary reserve. It helps maintain grid stability over a short timeframe, up to about 4 or 5 minutes. After that, it's up to the grid engineers to instruct stations on five minute reserve to sync.

It makes no difference to my point whether the frequency regulation is done at a high MW/Hz figure at a few stations or at a lower MW/Hz over all stations. It is enough thta there ai a certain MW/Hz regulation somewhere on the grid.

ClaimYourEnergy

Just a quick update to say that initial investigations are tending to suggest that the vost of a battery storage system may be prohibitive. I am waiting for a call back before making any final decisions, but that won't be for a week or two yet.

CYE

penrhyn

Here is an idea!

http://www.extremetech.com/extreme/92314-nissan-leaf-can-power-your-house-for-a-day-or-two

Cardew

penrhyn wrote: »

Here is an idea!

http://www.extremetech.com/extreme/92314-nissan-leaf-can-power-your-house-for-a-day-or-two

Wouldn't it be cheaper to buy a £100 petrol generator than a £24,000 car;)

penrhyn

Good point but petrol is the devils urine.:D