So now I have a solar PV system how do I make the most of it???

orrery

Alnat1 said:

Another thing to think about is, if you're filling a DC battery overnight from the grid on the (not so) cheap Flux rate, you can lose up to 10% on the conversion. Then when you discharge the battery, you're losing out again as it converts back. Probably better to only fill it from the grid when weather is poor.

I'm not sure that is the right view now. The real crime here is to import peak rate units (typically at 25 to 30p/kWh), so that must be avoided at all costs.

If you have a decent export deal*, then ignore unintended exporting and use every opportunity to get the batteries to 100% and keep them there. By all means kick off (low rate) EV charging, washing machines, wishdashers (serially, of course, never at the same time) etc to make best use of it. You can't afford to come out of the overnight period with much less than 100% battery and find it overcast and pouring with rain all day.

* I don't, as I'm on an old FIT with assumed export so I do have to fiddle around with battery charge levels on a day-to-day basis.

Doc_N

orrery said:

Alnat1 said:

Another thing to think about is, if you're filling a DC battery overnight from the grid on the (not so) cheap Flux rate, you can lose up to 10% on the conversion. Then when you discharge the battery, you're losing out again as it converts back. Probably better to only fill it from the grid when weather is poor.

I'm not sure that is the right view now. The real crime here is to import peak rate units (typically at 25 to 30p/kWh), so that must be avoided at all costs.

If you have a decent export deal*, then ignore unintended exporting and use every opportunity to get the batteries to 100% and keep them there. By all means kick off (low rate) EV charging, washing machines, wishdashers (serially, of course, never at the same time) etc to make best use of it. You can't afford to come out of the overnight period with much less than 100% battery and find it overcast and pouring with rain all day.

* I don't, as I'm on an old FIT with assumed export so I do have to fiddle around with battery charge levels on a day-to-day basis.

You doubtless already have, but if not have you considered the Octopus Outgoing tariff?

Martyn1981

orrery said:

Alnat1 said:

Another thing to think about is, if you're filling a DC battery overnight from the grid on the (not so) cheap Flux rate, you can lose up to 10% on the conversion. Then when you discharge the battery, you're losing out again as it converts back. Probably better to only fill it from the grid when weather is poor.

I'm not sure that is the right view now. The real crime here is to import peak rate units (typically at 25 to 30p/kWh), so that must be avoided at all costs.

If you have a decent export deal*, then ignore unintended exporting and use every opportunity to get the batteries to 100% and keep them there. By all means kick off (low rate) EV charging, washing machines, wishdashers (serially, of course, never at the same time) etc to make best use of it. You can't afford to come out of the overnight period with much less than 100% battery and find it overcast and pouring with rain all day.

* I don't, as I'm on an old FIT with assumed export so I do have to fiddle around with battery charge levels on a day-to-day basis.

Yep, for a DC side battery on an early FiTs scheme, the losses from the round trip efficiency, could and probably will mean you lose more in FiT's than you gain through arbitrage.

orrery

Doc_N said:

orrery said:

* I don't, as I'm on an old FIT with assumed export so I do have to fiddle around with battery charge levels on a day-to-day basis.

You doubtless already have, but if not have you considered the Octopus Outgoing tariff?

I don't think I can have it. I have the original, very generous, Feed-in-Tariff which mainly pays me to generate (not export) power and includes a payment allowance for an assumed export level of 50% of generation, whether I export it or not. For clarity - I get paid nothing for actually exporting. In reality, with a 20kWh battery system, I export very little so being paid for an assumed 50% export is very generous. I think that trying to add an export tariff would mean I'd have to terminate my FIT contract which would cost me very dearly.

My comment was an unnecessary diversion - my point was, that if you are on a decent Smart Export Guarantee, it may be that the only sensible approach to managing a battery system is to use all means to keep it at 100% so that you avoid using high-cost peak rate units. This may mean that have to put up with exporting a lot of power, but at least you are getting a payback for the exported units.

Doc_N

orrery said:

Doc_N said:

orrery said:

* I don't, as I'm on an old FIT with assumed export so I do have to fiddle around with battery charge levels on a day-to-day basis.

You doubtless already have, but if not have you considered the Octopus Outgoing tariff?

I don't think I can have it. I have the original, very generous, Feed-in-Tariff which mainly pays me to generate (not export) power and includes a payment allowance for an assumed export level of 50% of generation, whether I export it or not. For clarity - I get paid nothing for actually exporting. In reality, with a 20kWh battery system, I export very little so being paid for an assumed 50% export is very generous. I think that trying to add an export tariff would mean I'd have to terminate my FIT contract which would cost me very dearly.

My comment was an unnecessary diversion - my point was, that if you are on a decent Smart Export Guarantee, it may be that the only sensible approach to managing a battery system is to use all means to keep it at 100% so that you avoid using high-cost peak rate units. This may mean that have to put up with exporting a lot of power, but at least you are getting a payback for the exported units.

I know very little about the battery side (it's something I'm considering though) but my system sounds similar to yours. Set up in 2010 when FiT payments were at their peak. Like you, I was getting paid for a notional 50% at very low rates indeed, but decided to switch to Octopus for a rather more generous 15p based on actual (rather than notional) exports. FiT payments continue as before, unaffected.

Not much good though to anyone not actually exporting, as you say.

KevinG

orrery said:I think that trying to add an export tariff would mean I'd have to terminate my FIT contract which would cost me very dearly.

It doesn't, I have done exactly that and my 70p+ feed-in tariff continues.

orrery

KevinG said:

orrery said:I think that trying to add an export tariff would mean I'd have to terminate my FIT contract which would cost me very dearly

It doesn't, I have done exactly that and my 70p+ feed-in tariff continues.

Interesting. Presumably without the assumed export payment?

Doc_N

orrery said:

KevinG said:

orrery said:I think that trying to add an export tariff would mean I'd have to terminate my FIT contract which would cost me very dearly

It doesn't, I have done exactly that and my 70p+ feed-in tariff continues.

Interesting. Presumably without the assumed export payment?

The assumed 50% export payment is replaced by an actual %, but at a rate of 15p per kWh.

KevinG

orrery said:

KevinG said:

orrery said:I think that trying to add an export tariff would mean I'd have to terminate my FIT contract which would cost me very dearly

It doesn't, I have done exactly that and my 70p+ feed-in tariff continues.

Interesting. Presumably without the assumed export payment?

Yes, it was a bit of a palaver, took several months with Octopus but got there in the end. Too early to tell whether I will actually benefit from it.

KevinG

orrery said:

KevinG said:

orrery said:I think that trying to add an export tariff would mean I'd have to terminate my FIT contract which would cost me very dearly

It doesn't, I have done exactly that and my 70p+ feed-in tariff continues.

Interesting. Presumably without the assumed export payment?

The assumed 50% export payment is replaced by an actual %, but at a rate of 15p per kWh.

My rate is rarely that high, apart from at times when I hardly generate anything (1600-1900).