Generating your own energy

Talldave

Ectophile wrote: »

I have a solar PV system, and an old spinning disc meter. But this one is designed not to run backwards. It won't rotate back more than one revolution before it hits an end stop and sits there making grinding noises.


One approach that is currently just barely financially viable is a combination of solar photovoltaic and lithium ion batteries.


When my original solar inverter failed a couple of years back, I was persuaded to buy a new one with a small battery attached. I am not sure I will ever get my money back on the extra cost of the installation, but it is nice to be running the house on free electricity long after the sun has set. My usage over the summer was less than 1kWh per day of grid electricity.


The down side is that in cloudy weather (including most of the last week), the system is not a lot of use. As a rule of thumb, even a light cloud blocking the sun will reduce the power to about 1/10 of the maximum. If it's heavy cloud, this may go down to 1/100 of the maximum. At that sort of power levels, it will barely cover the background load in the house, and won't even make a start on charging the battery.

Thanks for the informative post. I like the battery idea and if I owned a house I would probably go that route simply because of the freedom it gives you:
- you can use energy from your panels in the event of a power cut
- you're as energy self-sufficient as is possible
- when time of use tariffs become mainstream, you can top up the batteries on cheap energy when the panels won't fully charge them up (e.g winter). The storage heater model applied to electricity, not heat.

Uxb1

Grid tie inverters are required by law to disconnect the panels from the mains in the event of mains failure.
This is to safeguard those trying to mend the fault from reverse power being generated by solar panels feeding into the fault backwards.
So if you want a battery system capable of running yourself offline you will need to check out the precise details of how to arrange a changeover type arrangement such that if the mains fails the battery/solar panel/inverter can continue to supply/generate for you and you are totally isolated from the grid.
Now it is not as easy as it looks as once you are disconnected and running/generating on your own in "island mode" as it is called your frequency will drift away from the grid frequency. This means that you cannot simply reconnect your supply to the mains when you want at the push of a button but will need to re-sync your supply frequency to the grids's frequency such that they are both at the same rate and equally that they are both in the same point of the cycle of the 50 Hz waveform.
Even mega large generators in power stations have to do this synchronizing before they are connected to the grid to make sure they are running in sync.

Talldave

Uxb1 wrote: »

Grid tie inverters are required by law to disconnect the panels from the mains in the event of mains failure.
This is to safeguard those trying to mend the fault from reverse power being generated by solar panels feeding into the fault backwards.
So if you want a battery system capable of running yourself offline you will need to check out the precise details of how to arrange a changeover type arrangement such that if the mains fails the battery/solar panel/inverter can continue to supply/generate for you and you are totally isolated from the grid.......

I know, but a lot of solar panel owners seem quite surprised that their panels would be useless during a power cut, even though the reasoning is quite sensible once it's explained to them.


There are off the shelf solutions to handle the switching.

sevenhills

Ectophile wrote: »

The down side is that in cloudy weather (including most of the last week), the system is not a lot of use. As a rule of thumb, even a light cloud blocking the sun will reduce the power to about 1/10 of the maximum. If it's heavy cloud, this may go down to 1/100 of the maximum. At that sort of power levels, it will barely cover the background load in the house, and won't even make a start on charging the battery.

Not sure how much the seasons affect the solar panels, my Feb payment was £38, May - £32, Sept - £84


I only have 8 panels, installed in 2015

Ectophile

Talldave wrote: »

I know, but a lot of solar panel owners seem quite surprised that their panels would be useless during a power cut, even though the reasoning is quite sensible once it's explained to them.


There are off the shelf solutions to handle the switching.

The solution on my install is somewhat clunky. If everything goes dark, I have to crawl into the meter cupboard and turn a big switch to disconnect the house from the grid and tell the inverter to go into islanded mode.


I can then run on solar and battery until I try to use too much power, or the battery goes flat.


Rather surprisingly, when the mains comes back on again, the inverter will switch off islanded mode and everything will go dark again. So I have to go back into the meter cupboard to go back to grid-tied mode. I guess I could effectively disable that by turning off the breaker that feeds the inverter, so it never knows when the mains comes back on.

spiro

matelodave wrote: »

the benefits of the feed in tariff and selling excess leccy back to the grid ceased about 18months ago and there's not much hope that it will ever get re-instated. Even in the last few years of the FIT it wasn't really giving much of a return so the payback period was getting a lot longer than the original 8-10 years. I'm afraid that you've missed the boat

In the new year FIT will be replaced by SEG (Smart Export Guarantee), where every supplier will be required to offer an export tariff. You will be required to have a smart meter which will register exactly what you export and that is what you will be paid for.

sevenhills

spiro wrote: »

In the new year FIT will be replaced by SEG (Smart Export Guarantee), where every supplier will be required to offer an export tariff. You will be required to have a smart meter which will register exactly what you export and that is what you will be paid for.

https://www.ofgem.gov.uk/environmental-programmes/smart-export-guarantee-seg/about-smart-export-guarantee-seg


Not too far away, people will switch to those offering the best price.


The details of SEG payments, including the amount of money received and the length of the contract, will be determined by the supplier you apply to. However, whilst wholesale electricity prices can sometimes fall below zero, SEG licensees must always offer a tariff that remains above zero. Generators are also entitled to payments based upon actual meter readings, even if some suppliers offer deals with alternative payment models.
Generators should shop around to find the best deal for them.



How will that compare to the previous FIT rates, in relation to what is the rate paid.
My rate from 2015 is 13.47 kwh

VfM4meplse

spiro wrote: »

In the new year FIT will be replaced by SEG (Smart Export Guarantee), where every supplier will be required to offer an export tariff. You will be required to have a smart meter which will register exactly what you export and that is what you will be paid for.

I'd like a smart meter, but apparently they are not compatible with gas meters in brown triangles.




As I have no plans to change this - I wouldn't know where to start! - I think the short answer is I can forget it.