Our journey to install renewables
Discussion
Some years ago I documented our self build (https://www.pistonheads.com/gassing/topic.asp?h=0&f=207&t=1230857&mid=49276&nmt=New+Build+Thread+-+Self+Build+in+Shropshire) and thought it might be a good idea to document our journey to install renewable energy.
Background
We have a lump of money sitting around that came from an inheritance. We have maxed out the usual things so it is sat in an account doing not a lot. As a result we have decided to "invest" it in our home. I'm therefore happy to see this as cost neutral, in so far that I hope it will effectively give me a ROI roughly 1:1 basis.
We have decided to put them on the garage for ease of maintenance, safety and aesthetics. There is a bit of shading from the house during Winter but the plan will be Octopus Go at 7p per KWH during the cheap charge time, and then export back at 15p during the day, topping up with Solar for free.
Price
We have been quoted 18k which will be 10 455w solar panels, one Tesla Powerwall and an expansion pack, plus a solar immersion heater. Total battery storage will be 27kwh.
This also includes the DNO application, all installation costs and commissioning. As part of the install they will be moling a new electrical connection from the house to our external garage as the existing 30A connection is not enough and the panels are going on the garage roof. The cost includes that plus any reinstatement of the block paving we have. I'm hoping I can get them to throw a couple of Ethernet cables down there too so I can retire the powerline adapters.
Day One
It is amazing how many companies propose simply drilling through slates to mount the panels. The company we have gone with propose properly hanging the panels using the correct brackets. This therefore wasn't the cheapest quote but I'd prefer to pay a little extra for quality.
For those following this thread and thinking the battery would be too big, the expansion pack added an extra 3k or so to the price. So without, it was under 15k. Obviously the install costs are pretty much fixed across both options.
Today I have accepted the quote and received a response that they will now draft and submit the DNO application. This will take anything from 2-6 weeks to get a response.
Background
We have a lump of money sitting around that came from an inheritance. We have maxed out the usual things so it is sat in an account doing not a lot. As a result we have decided to "invest" it in our home. I'm therefore happy to see this as cost neutral, in so far that I hope it will effectively give me a ROI roughly 1:1 basis.
We have decided to put them on the garage for ease of maintenance, safety and aesthetics. There is a bit of shading from the house during Winter but the plan will be Octopus Go at 7p per KWH during the cheap charge time, and then export back at 15p during the day, topping up with Solar for free.
Price
We have been quoted 18k which will be 10 455w solar panels, one Tesla Powerwall and an expansion pack, plus a solar immersion heater. Total battery storage will be 27kwh.
This also includes the DNO application, all installation costs and commissioning. As part of the install they will be moling a new electrical connection from the house to our external garage as the existing 30A connection is not enough and the panels are going on the garage roof. The cost includes that plus any reinstatement of the block paving we have. I'm hoping I can get them to throw a couple of Ethernet cables down there too so I can retire the powerline adapters.
Day One
It is amazing how many companies propose simply drilling through slates to mount the panels. The company we have gone with propose properly hanging the panels using the correct brackets. This therefore wasn't the cheapest quote but I'd prefer to pay a little extra for quality.
For those following this thread and thinking the battery would be too big, the expansion pack added an extra 3k or so to the price. So without, it was under 15k. Obviously the install costs are pretty much fixed across both options.
Today I have accepted the quote and received a response that they will now draft and submit the DNO application. This will take anything from 2-6 weeks to get a response.
malaccamax said:
Enjoyed the build thread so will follow this as well with interest. Sounds like a big battery! Do you have an EV as well?
Yes, well the wife does. We are heavy users as well. Daily summer usage is 16-18 KWh and winter this tops at 24 KWh. This doesn't include the car which can spike usage to 50KWh on any given day.Update today.
Local DNO have restricted the G99 app to 3.68kw. The Tesla inverter can limit the export to 3.68 but allow the house side to use 11kw. This is handy in ensuring that any big loads (induction hob, oven etc) can be serviced from the battery.
Interestingly the DNO will not allow this, but they will allow a second inverter acting as a firewall, therefore setting the external inverter to 3.68 export and have the internal set to export 0. The reason being in case the inverter was to fail.
It seems like a mad approach and ultimately it means an additional inverter cost. I can only assume that they assume the chances of two inverters failing is exponentially lower risk than having 1.
Tesla are currently offering a 750 cashback on two batteries so ultimately we will be about cost neutral. Still awaiting a date to install but looks like mid jan.
Local DNO have restricted the G99 app to 3.68kw. The Tesla inverter can limit the export to 3.68 but allow the house side to use 11kw. This is handy in ensuring that any big loads (induction hob, oven etc) can be serviced from the battery.
Interestingly the DNO will not allow this, but they will allow a second inverter acting as a firewall, therefore setting the external inverter to 3.68 export and have the internal set to export 0. The reason being in case the inverter was to fail.
It seems like a mad approach and ultimately it means an additional inverter cost. I can only assume that they assume the chances of two inverters failing is exponentially lower risk than having 1.
Tesla are currently offering a 750 cashback on two batteries so ultimately we will be about cost neutral. Still awaiting a date to install but looks like mid jan.
worsy said:
Update today.
Local DNO have restricted the G99 app to 3.68kw.
Our local DNO restricted us to 5.68KW. We could have gone up to 7KW but would have had to pay £20k to upgrade a local transformer so we said No thanks Local DNO have restricted the G99 app to 3.68kw.
.Going forwards I wonder if local DNOs will restrict install sizes even more as solar becomes more popular and local grid infrastructure struggles to cope.
With apologies for the thread crash, this may be a good place you ask a question.
We have been approved for 10kw export to grid and can fit 20kw of panels but the quote only includes one 10kw inverter. The big panels mean we would still be able to generate well on less sunny days but will obviously cap what we can produce in mid summer etc.
Is there any reason why we can’t simply use 2 10kw inverters? The added cost of a second one isn’t excessive and it seems daft to have 20kv capacity that we can only pull half that amount from.
We have been approved for 10kw export to grid and can fit 20kw of panels but the quote only includes one 10kw inverter. The big panels mean we would still be able to generate well on less sunny days but will obviously cap what we can produce in mid summer etc.
Is there any reason why we can’t simply use 2 10kw inverters? The added cost of a second one isn’t excessive and it seems daft to have 20kv capacity that we can only pull half that amount from.
Steve H said:
With apologies for the thread crash, this may be a good place you ask a question.
We have been approved for 10kw export to grid and can fit 20kw of panels but the quote only includes one 10kw inverter. The big panels mean we would still be able to generate well on less sunny days but will obviously cap what we can produce in mid summer etc.
Is there any reason why we can t simply use 2 10kw inverters? The added cost of a second one isn t excessive and it seems daft to have 20kv capacity that we can only pull half that amount from.
I have inverter envy. We have been approved for 10kw export to grid and can fit 20kw of panels but the quote only includes one 10kw inverter. The big panels mean we would still be able to generate well on less sunny days but will obviously cap what we can produce in mid summer etc.
Is there any reason why we can t simply use 2 10kw inverters? The added cost of a second one isn t excessive and it seems daft to have 20kv capacity that we can only pull half that amount from.
You could potentially have 10kw per phase and therefore a max of 30kw with 3 phase. The limit is per phase not per inverter.
gangzoom said:
worsy said:
Update today.
Local DNO have restricted the G99 app to 3.68kw.
Our local DNO restricted us to 5.68KW. We could have gone up to 7KW but would have had to pay £20k to upgrade a local transformer so we said No thanks Local DNO have restricted the G99 app to 3.68kw.
.Going forwards I wonder if local DNOs will restrict install sizes even more as solar becomes more popular and local grid infrastructure struggles to cope.
worsy said:
Steve H said:
With apologies for the thread crash, this may be a good place you ask a question.
We have been approved for 10kw export to grid and can fit 20kw of panels but the quote only includes one 10kw inverter. The big panels mean we would still be able to generate well on less sunny days but will obviously cap what we can produce in mid summer etc.
Is there any reason why we can t simply use 2 10kw inverters? The added cost of a second one isn t excessive and it seems daft to have 20kv capacity that we can only pull half that amount from.
I have inverter envy. We have been approved for 10kw export to grid and can fit 20kw of panels but the quote only includes one 10kw inverter. The big panels mean we would still be able to generate well on less sunny days but will obviously cap what we can produce in mid summer etc.
Is there any reason why we can t simply use 2 10kw inverters? The added cost of a second one isn t excessive and it seems daft to have 20kv capacity that we can only pull half that amount from.
You could potentially have 10kw per phase and therefore a max of 30kw with 3 phase. The limit is per phase not per inverter..
From doing a bit of phoning round today it seems that two inverters can be run as a master/slave setup but I am waiting for this to be confirmed.
Steve H said:
worsy said:
Steve H said:
With apologies for the thread crash, this may be a good place you ask a question.
We have been approved for 10kw export to grid and can fit 20kw of panels but the quote only includes one 10kw inverter. The big panels mean we would still be able to generate well on less sunny days but will obviously cap what we can produce in mid summer etc.
Is there any reason why we can t simply use 2 10kw inverters? The added cost of a second one isn t excessive and it seems daft to have 20kv capacity that we can only pull half that amount from.
I have inverter envy. We have been approved for 10kw export to grid and can fit 20kw of panels but the quote only includes one 10kw inverter. The big panels mean we would still be able to generate well on less sunny days but will obviously cap what we can produce in mid summer etc.
Is there any reason why we can t simply use 2 10kw inverters? The added cost of a second one isn t excessive and it seems daft to have 20kv capacity that we can only pull half that amount from.
You could potentially have 10kw per phase and therefore a max of 30kw with 3 phase. The limit is per phase not per inverter..
From doing a bit of phoning round today it seems that two inverters can be run as a master/slave setup but I am waiting for this to be confirmed.
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