On 2022/08/29 at 1:23 PM, Bobster. said:

The OP is somewhere in Europe. Laws RE exporting vary across the EU. I have a friend in Belgium who has a panel and inverters, no batteries, and exports and receives credit. I haven't asked him about tax implications.

I mention tax implications because recently I was in Spain, and there a householder with panels must make a declaration to the receiver. This has a chilling affect on households exporting. There is no requirement like we have that you must be a net importer, so presumably if you are making a profit on your power exports that might be deemed income.

OK. The people I spoke to in Spain were misinformed, and thus so was I. 

There WAS a so-called "sun tax" in Spain. This was to compensate the energy providers who would get less revenue but still carried the cost of providing a connection (sound familiar?). This was revoked in 2019, and Spain is now aligned with the rest of the EU. This makes the financial proposition more attractive, allows (if I understand it correctly), one consumer to supply to another with their excess PV (good for complexes and apartment blocks), and reduces red tape; and so (despite what my hosts told me), domestic PV is taking off in Spain.

Of course, in Spain the concern is one's back pocket and one's carbon footprint, they are not very concerned about outages, and so grid-tied systems are what people there are  turning to.

37 minutes ago, Bobster. said:

Of course, in Spain the concern is one's back pocket and one's carbon footprint, they are not very concerned about outages, and so grid-tied systems are what people there are  turning to.

Thanks for the detail in Spain. Here in SA we obviously have a focus on LS and power failures. To add how we are affected. In the east side of Pretoria we had a average of 1h40 without power over 3 year period during office hours per week. This stat is from the genny hour meter. It also includes the 15min we start the genny before the indicated LS event. A number of times the genny was running for 30min and we did not have the LS event.

I can live without power for say about 3hrs a week if we include after hours.

This is partly why I went for a grid tied so I just choose how I use the PV generated power. Also I have had some kind of back up inverter since 2005 so never really without power if I need it for real essentials.

Interestingly I was reading an Irish forum as they seemed to really be into diy lithium batteries and had a lot of info, but nobody talked about panels and I couldn't understand why, but then it became clear that they are using batteries to game the tariff structure. So they charge the battery from grid when the tariff is cheap and run from battery when it is expensive. It looks like the savings only support 100-200Ah of lithium, but it is interesting to see the different applications of these systems around the world.

If lithium batteries had to drop to like 50% of current prices I would seriously think of using batteries to provide a MPPT input when no sun and add another panel or 2.

2 hours ago, jumper said:

Interestingly I was reading an Irish forum as they seemed to really be into diy lithium batteries and had a lot of info, but nobody talked about panels and I couldn't understand why, but then it became clear that they are using batteries to game the tariff structure. So they charge the battery from grid when the tariff is cheap and run from battery when it is expensive. It looks like the savings only support 100-200Ah of lithium, but it is interesting to see the different applications of these systems around the world.

This still helps the energy utility, because they will impose a high tariff at time of peak demand.

Though I suppose when enough consumers do this, it will have the affect of shifting the peak demand time.

4 hours ago, Bobster. said:

Of course, in Spain the concern is one's back pocket and one's carbon footprint, they are not very concerned about outages, and so grid-tied systems are what people there are  turning to.

That said, when we were there there was an outage in Alicante. Apparently not the whole city, but when I looked out the window I couldn't see many lights burning.

I had a good laugh at that. 

Lights were out for maybe 15 minutes.

25 minutes ago, Bobster. said:

Though I suppose when enough consumers do this, it will have the affect of shifting the peak demand time.

possibly to a period where you have so much solar available, that solar rather than batteries may be more cost effective for the consumer...

2 hours ago, Kalahari Meerkat said:

possibly to a period where you have so much solar available, that solar rather than batteries may be more cost effective for the consumer...

But PV without batteries has been more effective all along. That's why 70% of the world put in grid tied unlike SA who don't want to go through 3 hrs a week without power. Actual stat I placed earlier on.

Unfortunately for them I don't think Ireland will ever have enough sun for PV to be cost effective, I may be wrong, but they are not known for good weather.

21 hours ago, Kalahari Meerkat said:

possibly to a period where you have so much solar available, that solar rather than batteries may be more cost effective for the consumer...

Well I was thinking of TOU tariffs. Say high tariff kicks in at 16:00 and lasts until 20:00. So everybody with powerwalls etc charges their batteries from 14:00 to 15:59. So the peak demand time gets moved, just not by PV.

19 hours ago, Scorp007 said:

But PV without batteries has been more effective all along. That's why 70% of the world put in grid tied unlike SA who don't want to go through 3 hrs a week without power. Actual stat I placed earlier on.

Is this within certain latitudes? Recently Indonesia revisited their subsidies and buy back tariffs for PV, but looking at it seems clear that they have a large penetration of grid-tied systems. Similar to Australia. Spain is looking to incentivise grid-tied systems.

The differentiator between SA and Spain is that here we have an expectation of load shedding, so batteries become essential. Not to play games with TOU tariffs, but just to keep the lights on.

What I find interesting in the EU is that the regulations no longer protect the service providers. The argument (in multiple territories) has been that the provider still bears the cost of providing a grid feed to your property and thus is entitled to recover some costs from you, even if you have made your own provision BUT retain a grid connection. The so-called solar tax in Spain was a way to recover the costs of providing a grid connection to properties that had PV panels and so were reducing the revenues for the utility. That law is now revoked and it's a simple sell back, with no requirement that you be a net consumer. But I wonder if the utilities haven't just reworked the tariffs to separate out the cost of electricity and the cost of providing you a connection.

 

This is not in the realm of the unthinkable in South Africa, both of these situations are a current lived reality for some. I don't think of it as gaming the system, but as smart incentives that mutually benefit the user and the grid operator.

I've previously posted about Nelson Mandela Bay where it's actually feasible to have solar grid-tie that trades power with the grid. Sunshine in the Bay is plentiful by European standards, but moderate by SA standards.For this you have to go onto a time-of-use tariff like businesses use, unlike how most residences have the Inclining-Block Tariff. You also can only offset power that is generated in one period with power that is used at the same tariff level.

It now makes complete sense to shift my usage to off-peak periods if possible. At the same time there is more value in being able to export power during peak periods, rather than to use it for purposes that can easily be shifted to the evening.

Now add in the fact that we have  load-shedding that necessitates a battery to get by. As long as the cost of lithium storage per kWh is low enough (it is), it can actually make sense to store Eskom power during off-peak times, either to self-use during peak periods, or even to export to the grid at peak time. Ditto for storing solar during the day, it's probably even possible for me to sell to Eskom at lower cost than them running OCGT at peak times. I just need them to get real about a payout rather than just trading and remaining a net consumer. But it's cheaper to use Eskom in off-peak than cycling my battery.

 

That being said, the basic firmware of the Sunsynk/Deye is not sophisticated enough to set and forget in this scenario. It would have to manage the time of import and export while accounting for tariffs on weekends and public holidays, controlling at which times I export direct solar power only and when it is viable to export power that was stored in my battery first, all while keeping an eye on loadshedding schedules and stages, weather forecasts and my usage history to ensure I keep reserves for when I need them for myself. My stats for the last week is average 4 hours per day where I needed to counteract loadshedding.

1 hour ago, GreenFields said:

This is not in the realm of the unthinkable in South Africa, both of these situations are a current lived reality for some. I don't think of it as gaming the system, but as smart incentives that mutually benefit the user and the grid operator.

I've previously posted about Nelson Mandela Bay where it's actually feasible to have solar grid-tie that trades power with the grid. Sunshine in the Bay is plentiful by European standards, but moderate by SA standards.For this you have to go onto a time-of-use tariff like businesses use, unlike how most residences have the Inclining-Block Tariff. You also can only offset power that is generated in one period with power that is used at the same tariff level.

It now makes complete sense to shift my usage to off-peak periods if possible. At the same time there is more value in being able to export power during peak periods, rather than to use it for purposes that can easily be shifted to the evening.

Now add in the fact that we have  load-shedding that necessitates a battery to get by. As long as the cost of lithium storage per kWh is low enough (it is), it can actually make sense to store Eskom power during off-peak times, either to self-use during peak periods, or even to export to the grid at peak time. Ditto for storing solar during the day, it's probably even possible for me to sell to Eskom at lower cost than them running OCGT at peak times. I just need them to get real about a payout rather than just trading and remaining a net consumer. But it's cheaper to use Eskom in off-peak than cycling my battery.

 

That being said, the basic firmware of the Sunsynk/Deye is not sophisticated enough to set and forget in this scenario. It would have to manage the time of import and export while accounting for tariffs on weekends and public holidays, controlling at which times I export direct solar power only and when it is viable to export power that was stored in my battery first, all while keeping an eye on loadshedding schedules and stages, weather forecasts and my usage history to ensure I keep reserves for when I need them for myself. My stats for the last week is average 4 hours per day where I needed to counteract loadshedding.

As much as I agree we want to counter LS of say up to 6hrs a day of which half can be when we have solar. So instead of providing for the 3hrs after dusk we started powering the full load from batteries. This is a huge expense as we still need to preserve enough in case of LS before dawn. My stats show 3hrs a week of LS over the last 3 years.

We just love to tell people how great my system is as battery is fully charged at 10h while we have the whole day to do it.

By using a system to work from batteries instead of just LS means we end with a 8+ year ROI. Pure grid tied can be less than 3 years. Much more effective. So in the end we try saving by using expensive battery instead of just as back up for LS. Yes there is a case when you have cable theft and long outings in certain areas. It comes down to design the system for what is best for each loading profile and history of power failures. My 2 longest power out over 22yrs have been 1 x 36hrs when a mini sub burnt out and the 2nd was for 12 hrs.