Solar & Powerwall 2

[Embattle]

So here are the impact figures for each month:






We use an induction hob, the gas is only for the boiler which provides heat for both rads and water.

As I've said before getting solar is a good thing and still will save you money, at least if you stick to the standard size of installation.

We ultimately don't live in a part of the world that can do solar power all year round, but often when there is low levels of solar there are higher levels of wind this is why a combination of the two along with a mixed base load is ideal. You can't live the lifestyle you want off grid, there just isn't the solar available or the battery capacity to store it long term, which means you are tied to the grid.

There are more and more developments in panels with higher power levels, improved efficiencies and lighter panels but even then you still can't escape a winter in the UK meaning a lot less solar power.

 

[Scouse]

We use an induction hob, the gas is only for the boiler which provides heat for both rads and water.

Judging from the data you kindly provided, I potentially un fully solar for about 7 months of the year - for everything. Heating, water, everything.

Then we'd have to fall back on LPG for heating and the grid for about 50% of electricity demand for 5 months of the year. That sticks in my craw like you'd never believe - more the fact that we'd have to fall back on LPG - as I want to put my hard-earned against getting us off fossil fuels completely.

Yes, it would mean that in 20 years my bills would be significantly reduced (for a large initial capital outlay) but it's not really the point

 

[Embattle]

Well you could use electricity for heating as well during the winter, this makes sense in the end as the grid becomes more renewable based.

 

[Scouse]

Well you could use electricity for heating as well during the winter, this makes sense in the end as the grid becomes more renewable based.

At the price of electricity - it would bankrupt me.

I'm willing to put (significant) money where my mouth is. But I can't afford to run central heating on electricity if that investment isn't covering the cost. With the price cap as it is right now electricity is 3.5x the price of gas. Average use is about a £2500/year bill for the cheapest sources (and some people are saying that'll be £5400 next April).

As soon as they decouple renewables from the wholesale gas price, I'd be right there.

 

[Embattle]

Electricity is undeniably expensive at the moment, but I suspect no matter the cost on the market the price of fossil fuels will generally go up.

Well a heat pump provides a ratio of 1kw electricity to 4kw of heat, but depending on possible energy storage systems you get you could take a low night rate and fill them to use during the day.

 

[DaGaffer]

Judging from the data you kindly provided, I potentially un fully solar for about 7 months of the year - for everything. Heating, water, everything.

Then we'd have to fall back on LPG for heating and the grid for about 50% of electricity demand for 5 months of the year. That sticks in my craw like you'd never believe - more the fact that we'd have to fall back on LPG - as I want to put my hard-earned against getting us off fossil fuels completely.

Yes, it would mean that in 20 years my bills would be significantly reduced (for a large initial capital outlay) but it's not really the point

Dude, you live at 53 degrees latitude, why is any of this surprising to you?

 

[Raven]

At the price of electricity - it would bankrupt me.

I'm willing to put (significant) money where my mouth is. But I can't afford to run central heating on electricity if that investment isn't covering the cost. With the price cap as it is right now electricity is 3.5x the price of gas. Average use is about a £2500/year bill for the cheapest sources (and some people are saying that'll be £5400 next April).

As soon as they decouple renewables from the wholesale gas price, I'd be right there.

Have you not thought about wind turbines?

Brutally expensive by the looks of things

Wind turbines

Wind turbines harness the power of the wind and use it to generate renewable electricity, reducing your carbon emissions.

energysavingtrust.org.uk

 

[DaGaffer]

Have you not thought about wind turbines?

Brutally expensive by the looks of things

Wind turbines

Wind turbines harness the power of the wind and use it to generate renewable electricity, reducing your carbon emissions.

energysavingtrust.org.uk

Seems a bit rich for domestic use; you can buy a 5KW turbine for a couple of grand. Bet there's all kinds of planning shite to deal with though.

 

[Embattle]

Planning on the domestic side of Wind is probably more of a ball ache than going above the standard 3.7kw solar array, even that won't be easy considering where Scouse lives.

 

[Scouse]

Dude, you live at 53 degrees latitude, why is any of this surprising to you?

I figured a 15kw array would be such overkill that it would make up for any shortfall during the colder months - but this:

was really very shocking.

I've not ever had access to an actual real-life dataset before. Now I do it's forcing a rethink. A 15kw array is way overkill but solar still makes all of the sense because for a significant portion of the year I'd be completely bill-free (apart from the now ridiculous 50p/day "standing charge" for the grid).

Have you not thought about wind turbines?

Brutally expensive by the looks of things

I have. And after yesterday's data, I looked again just to make sure. It's pointless - because if I get the solar array then for 7 months of the year it'd a complete waste of time (I'd have to ditch the energy) and for the time I want it it's too unreliable - and topology here (never mind the planning) makes it not worth it.

 

[Embattle]

In May, June, August and September we suffered from over 1000+ events Tesla, with that start of this month bad as well, the average per day can be from 20-60 a day with the occasional 0. So in practical terms what is happening is the Tesla Gateway believes that a power cut is incoming and switches from the mains to the Powerwall, now as quick as this is to switch things like lights flicker and TVs turn off thus if we are watching football on Now TV this becomes a ball ache and sometimes other stuff turns off as well such as cookers etc.

I've been busy discussing this issue with Western Power Distribution (WPD) because this was becoming majorly annoying, I also contacted Tesla who looked at the issue, and in June WPD installed a voltage monitor for 7 days. Below are the results, the first graph shows the readings from the whole week with the second a close up on one of the events:





This next graph is from Tesla:



In the first two graphs from WPD you can see massive spikes in demand/supply or supply/demand, with the first one giving you that overview for the week and that it happens a lot and the second giving you a close up view of those spikes lasting 1 second. The Tesla graph shows you a similar image to the first WPD graph but also the oddity that towards the end of Jun and whole of July everything went back to normal.

After the voltage monitor WPD thought it might be something in the house, because they had no other reports near where we live of any issues, thus we developed a plan to use the trip switches to find out if it was something inside the house however this hit a problem since the issue vanished at the end of June for over a month. When the issue came back in August I tested each trip switch and both RCDs to see if it stopped happening but no joy thus talking to the gentleman at WPD he agreed they would put a voltage monitor on the substation I was connected to, so after just over a week and his holiday he came back but told me the first monitor failed thus they would put on another one in the next week or so.

I received a phone call a few weeks ago from the guy I've been dealing with at WPD who had some good news for me, some other people in the local area have had issues as well which has lead them to find out what they believe may well of been causing my issue. They've picked up a disturbance on one of the 11Kv cables, which is happening a lot more than it ever should but they also had an idea who might be responsible for it but they needed another week or so to pinpoint it with some more monitors. At the end of last week I got another call from WPD and he confirmed it was who they thought, not he was allowed to tell me who, but in essence WPD believe they are outside agreed connection conditions and he sort of gave away it might be something to do with a renewable etc by mentioning outgoing power. A sort of stroke of luck had also happened because a 33Kv had an issue and the company was knocked off the grid and the disturbance on the 11Kv disappeared at the beginning of last week, I was able to confirm with him that the issues with the Tesla had also stopped during those 2 days as well.

So because of the seriousness of the issue it isn't something that the guy I've been dealing with can resolve himself, in fact he said after his planning boss does his bit it'll probably make it's way up the chain to their HO where the lawyers etc can look over the detail but he will keep me informed on the outcome and after it is all sorted they might install another voltage monitor at our house just to check.

So fingers crossed this really annoying issue will finally be resolved.

On to future plans, I might take advantage of this during the winter:

National Grid raises discounts for off-peak electricity use

Households will get a discount of £3 per kWh instead of 52p off bills, National Grid says.

www.bbc.co.uk

In essence I'll load up the Powerwall during the early morning (off-peak) then use it in the evening.

 

[Embattle]

Yeah sorry about the jumbled sentences to start with, seems my thought process and editing went awry

 

[Embattle]

I signed us up to the Octopus Saving Sessions, in essence we will get a warning up to a day ahead of when to save energy and will get paid for doing so.

Due to low levels of solar this time of year I've upped the backup to 80% and 20% self use. I'll use this backup reserve whenever a saving session is active.

 

[Embattle]

First Saving session is tonight from 17:00 to 18:00.

 

[Embattle]

So that 1 hour saving session earned us £2.18.

 

[Embattle]

Over the assorted saving sessions we made about £24.

The longer sunnier days are here providing some nice power.

 

[Embattle]

Nice sunny period at the moment, 192.7 kWh solar last week with 70 kWh exported.

 

[Embattle]

Small lifetime update:

 

[caLLous]

Marques Brownlee did a good video on this a few weeks ago after having a 100% Tesla system (Powerwall, Solar Roof with the solar tiles) for a year. He was principally happy with it although had doubts about the difference normal solar panels would've made because of the smaller surface area.

 

[Embattle]

Marques Brownlee did a good video on this a few weeks ago after having a 100% Tesla system (Powerwall, Solar Roof with the solar tiles) for a year. He was principally happy with it although had doubts about the difference normal solar panels would've made because of the smaller surface area.

Yeah saw that a couple of weeks ago, it was impressive. In general the more aesthetic you make solar roof generation the higher the cost and the slightly lower the return, for example in roof panels are more expensive but aren't as efficient as on roof because solar panels never perform there best when too hot and on roof get the advantage of allowing air to reach the back of the panel thus the efficiency doesn't drop quite as much, some research in this area is being looked at such as water cooling on the panels etc.

 

[Embattle]

We are currently investigating the possibilities and costs involved with going over 3.6kw.

 

[Embattle]

As you may know from previous information we have 8 panels facing East and 8 facing West, all the panels are rated at 315w thus you end up with 2.52kw facing each direction.

My idea is to hopefully move at least 6 of the current panels from the East side to the West side thus giving a total of 14 315w panels for a combined 4.41kw facing West. Due to the roof design there can only be 8 panels facing East so we would consider getting panels capable of at least 410w resulting in 3.28kw facing East.

The total system power would be over 7.5kw with an actual peak of around 6kw during the summer I reckon.

 

[Embattle]

So early plans sent to us are to add a small array on the empty part of the west roof, in essence adding another 2kw array using a mini inverter which would cost under £5000 and give a better payback time. Although it all depends on the outcome of the G99 application.

 

[Embattle]

So part one is for the application to the DNO to check what the power limits are on the export side, this can take up to 3 months.

 

[Deebs]

So I take it you have a surplus?

 

[Embattle]

So I take it you have a surplus?

The majority of solar systems will export to the grid at some point, thus the grid must be able handle that exported power.

The grid wasn't originally designed for many small generators thus if your system is capped at 3.7kw then that is little more than informing the local DNO and a little paperwork. When you want to go over 3.7kw you start into the realm of needing a G99 application which gives the DNO more information and in essence requests them to investigate the maximum export allowable from our house, so they need to check what their equipment can handle from our house.

 

[Embattle]

So below is the updated diagram with the additional planned work such as adding another 2kW Inverter, this along with other documents have been sent to the National Grid:

 

[Deebs]

That makes my head hurt just looking at it.

 

[Embattle]

That makes my head hurt just looking at it.

Fairly simple once you break it down into basic areas:

• Lower Left - Solar Panels & 2 Inverters
• Middle Left - Household Trip Switches
• Middle (Inside Dash Line) - Tesla Gateway
• Lower Middle - Tesla Power wall
• Middle Right - Mains