Thinking about solar cells and powerwall.

[Dilly]

That's a real challenge! I've heard of houses being devalued by having solar panel installations, and have a feeling they add no value to most properties for many prospective purchasers. This seems bizarre on the face of it, but I know of a couple of people who removed their PV systems when they sold their homes because they found that buyers weren't keen on having them.

As another data point, when we completed our self build in 2016, we had it valued, really just so we had an idea as to whether self-build had saved us much money (they answer was "not a lot"). The valuer we had around (a RICS chap) reduced his value by 5% because it was a passive house (i.e. very well insulated, air tight and effectively zero energy over the course of a year). I challenged him on this, and his reply was that "eco houses" were a niche market, and because of that there were fewer buyers prepared to purchase one, and fewer interested buyers meant reducing the value.

This may change as people start to place a higher value on house running costs and damage to the environment, but right now I suspect it's still the case that things like solar panels and battery storage systems are seen as a liability, rather than a benefit, by many. It's still the "bling" that sells houses and makes them more valuable, stuff like decent kitchens and bathrooms are much higher on the value scale than anything that reduces running costs.

I’ve heard this too. Attitudes will change as the younger generations enter the housing chain. That’s assuming that they will be able to in the foreseeable future. Sadly the pandemic may have scuppered their chances for now as we’ll be paying it off for some while to come.

 

[sliyk]

Wow so much discussion and valuable points to ponder
I live in an area where we have not had a power cut so far since this house was built in December 2017. This is a 4 bedroom detached property.
I understand that the financial outlay might never pay for itself completely but as everybody mentioned there are other Avenues of personal satisfaction with having your own power generation system.
I am thinking of putting about 5k down myself and financing the rest via a home improvement loan, they come to about 2 percent interest over 5 years. Still in the contacting and requesting quotes phase.

As we only bought this new build property in 2017 late and it is 4 bedroom and we are 4 people living in it I can and also cannot see this being our forever home

 

[Gatsojon]

I have a 5 kWp solar system split between SE and SW and one Powerwall 2. Total cost about £13.5k. I'm not expecting to get much of it back, perhaps half. The other half I'm happy to pay for the 'project' and the perverse enjoyment I get from it. If you are considering the outlay as purely a financial investment, then it's unlikely to work now. That lucrative FIT ship has sailed.

With solar, a Powerwall and a Tesla, the Octopus Tesla Tarif is worth looking at for times when the solar production is higher than now. It's currently 8p in and out with no daily charge. You forgo your 'control' over the Powerwall but in reality, mine is cycling once a day as I charge each night on 'Go' and use it during the day.

 

[KennethS]

Not sure anyone has posted it, but I'm about to pull the trigger on Powerwall + Tesla Energy Plan. I have an existing (2013) solar array, which has just about paid for itself.

The Tesla Energy Plan actually looks like saving us ~£500/yr as it's a flat 8p/kWh rate, with no standing charge - a huge saving. If that stays true, that's a 20-year payback window, but as others have said, there's more to it than just the financials

We did just that in July (2019). Already had a 3.5kWp system installed in December 2011. When I ordered the Powerwall they had an offer of a £500 credit with Octopus energy and threw in a free Tesla WC. We use an embarrassingly high amount of electricity in our home, despite my reasonable efforts to reduce it. The Tesla Energy Plan estimate was for annual savings of over £1,000 per year, which we are on target to hit. Calculating the break even date is always a guess with the main factor being how energy pricing moves in the future, but so far the system has exceeded our expectations and for us it wasn't too difficult to decide to redeploy capital sitting in a zero interest rate environment. Of course our electric use is far above typical and that was the main driver in our decision.

 

[SpareHeadOne]

I had ~3kW of solar installed in 2015 - all I can fit on my roof - and followed that up in 2019 with a PowerWall.

Savings are marginal because I can't get enough generation, but I use roughly around £400/year less electricity from the solar and save another £2-300 from the PW operating in cost-saving mode - so at this time of year we run cheap rate electricity more or less around the clock and in the summer it's almost entirely self-generated solar. (These are actual savings without taking increased electricity prices into consideration.)

On top of that we have quite regular power outages where we live (in a town centre too!) so the ability to keep running has been very useful. I only knew about our outages because of an alert from the Tesla app telling me the grid was off, we didn't even lose internet connectivity and during lockdown that meant we could continue working at home instead of having to make our way into our offices.

So while the energy savings aren't big enough to have the system pay for itself in a reasonable time, I get it back by not wasting my time going around and turning everything back on 3-4 times a year, losing productivity for sometimes hours at a go and not paying to replace electrical items that get killed by regular power cycling that they're not designed for - I estimate around £4k of stuff has been killed by our ropey electricity supply in the last 10 years.

 

[Obliter8]

I looked into this recently and the fact that you have to give up the deemed 50% export payment from the PV system pretty much scuppered it making sense financially.

If you have PV, a PW and Agile your pretty much able to run off the lowest carbon electricity possible and do not impose a drain on the grid at peak times as it is.

Remember, the Deemed Export portion is by far and away the smallest proportion of the FiT - we make ~80% of our return from the actual generation. Add on to that, if you are a low electricity user (which sadly, I am not), you will get paid what you actually provide to the grid, rather than the deemed 50%.

 

[sliyk]

I'm currently on octopus agile and seems that this is the first time go is cheaper than agile.

 

[Fly.guy]

Let’s face it, if your seriously considering installing a PW then your not going to be driven to destitution by a few of pounds a week higher electricity bill.

Another consideration is the ability of a PW at this time of year to charge from off peak electricity and then run the house for most of the day. Possibly more important than the financial benefit ( from a global perspective) is therefore the potential for CO2 savings.

This morning around 4am the 14kWh that went into our PW was associated with around 115g CO2 / kWh. This has now run the house (plus a whole extra 1.3kWh of PV ) all day and will keep us going till 1am. This has offset grid electricity that was consistently above 200g /kWh since 08:00, over 230g/kWh at 10:00 and is still over 220g/kWh now at 19:00.

That’s well over one kg of CO2 saved today by time shifting our entire days consumption to the small hours of this morning. Repeat that every winters day and we are saving over a hundred kg of CO2 per year just like that....

 

[Glan gluaisne]

There are better ways of reducing CO2, though, like simple improvements to house design and construction. Obviously not an option for existing housing stock, but I designed our passive house self-build back in 2012, using what was available then, and it cost about the same to build as a conventional house. According to the EPC issued in 2014, it has a CO2 emissions rating of -900kg of CO2 per year (a negative figure), and an energy efficiency of 107 (100 is notionally a zero energy house). Just living here has the same environmental impact, in terms of CO2, as a plantation of around 42 mature trees. Not hard to make all new build houses perform like this, the additional build cost was negligible, a bit more for materials, but a lot less for things like the heating system.

 

[Fly.guy]

Agreed, the biggest CO2 saving bang for the buck is to first implement things like super insulation, LED bulbs, class A+ appliances, installing PV, air drying clothes, driving an EV, holidaying without air travel, minimising eating meat etc etc.

But once you’ve done that then the additional savings of time shifting electric through a battery is a welcome extra....

 

[ACarneiro]

There are better ways of reducing CO2, though, like simple improvements to house design and construction. Obviously not an option for existing housing stock, but I designed our passive house self-build back in 2012, using what was available then, and it cost about the same to build as a conventional house. According to the EPC issued in 2014, it has a CO2 emissions rating of -900kg of CO2 per year (a negative figure), and an energy efficiency of 107 (100 is notionally a zero energy house). Just living here has the same environmental impact, in terms of CO2, as a plantation of around 42 mature trees. Not hard to make all new build houses perform like this, the additional build cost was negligible, a bit more for materials, but a lot less for things like the heating system.

The big thing is that you know how to make all that happen.
Most people haven’t the knowledge and wouldn’t even know how to find someone who does, let alone it becoming commonplace with mainstream builders.

 

[sliyk]

The offset of co2 is definitely something that is important to me. Probably the most important thing to me is to become self sufficient in terms of energy generation and consumption.
Having a Tesla as well and being able to charge it in the day (we have just gone into lockdown) and using it when required (key worker so seeing a lot of patients in ane and community) will definitely be a plus.

 

[ACarneiro]

You will find that you’ll only be self sufficient for small number of days in the summer.
Turns out a car actually uses quite a lot of electricity.
I can produce up to, say, 70Kwh in the middle of summer at the very best. My daily commute uses about 30kWh so not problems there.
In the winter I’ll be lucky to generate 3kWh.

 

[Glan gluaisne]

The big thing is that you know how to make all that happen.
Most people haven’t the knowledge and wouldn’t even know how to find someone who does, let alone it becoming commonplace with mainstream builders.

True, but I only started learning about house design and energy efficiency in 2008, and knew nothing at all about house construction, architecture, or passive house technology when we started looking for a plot of land to build a house, when I retired in 2010.

If I could go from knowing nothing at all about house design and construction, to designing and building a passive house, in just a few years, it should be easy for the big building companies to do it right now.

 

[ACarneiro]

True, but I only started learning about house design and energy efficiency in 2008, and knew nothing at all about house construction, architecture, or passive house technology when we started looking for a plot of land to build a house, when I retired in 2010.

If I could go from knowing nothing at all about house design and construction, to designing and building a passive house, in just a few years, it should be easy for the big building companies to do it right now.

It means change and they’re dinosaurs.
They’ll have to be legislated into efficiency, unfortunately.

 

[Daverh]

it should be easy for the big building companies to do it right now.

It should be but they don't seem to want to make it easy.

We were interested in a new estate being built near us. I mentioned to the sales rep that I liked plot x vs plot y because it would be better for solar. She informed me that there were covenents forbidding solar panels on the development and tried to explain that the council required houses to be built as per the granted planning application.
I pointed out that a) their affordable housing has solarpower/water heating and b) surely the developer's responsibility for planning ends once the houses are built and it would then be up to the council to agree on the solar. Her response was that I would have to pay a deposit and have our respective solicitors continue the discussion

 

[kuruma]

love the power backup when we lose power...working flawless.

As a caveat on the backup capabilities... it isn't flawless. We had the grid drop very low immediately before a complete power cut, the backup didn't work because of the very low grid reading just prior and we lost power. After investigating this with Tesla, they told me that this was to be expected. So, the backup gateway is not a foolproof power supply like a UPS is just in case you, like us, were relying on it to be so. I'll not make that mistake again.

For those contemplating an entire system, do buy it all at once. If you do, 5% VAT will apply to the whole system (currently). If you add a battery later on to a PV system, you'll pay 20% VAT on the battery and installation.

 

[sliyk]

What do you guys think of the following;

Green Homes Grant extended for extra year

I think it also applies to solar PV installation.

 

[browellm]

What do you guys think of the following;

Green Homes Grant extended for extra year

I think it also applies to solar PV installation.

It only includes solar thermal iirc, which makes it a bit pants. Also a friend who looked into it quite a lot said it was nigh on impossible to get installers interested in doing jobs within the timescales that the scheme was running.

 

[sliyk]

It only includes solar thermal iirc, which makes it a bit pants. Also a friend who looked into it quite a lot said it was nigh on impossible to get installers interested in doing jobs within the timescales that the scheme was running.

Got this in an email today;

Happy New Year.


Without a site visit you would be looking at a budget of £6,000 plus vat for 4Kws of solar and £9,500 for the Tesla Powerwall 2. I've attached the latest Tesla brochure for you. This is budget figure which we could firm up to a quote after a site visit.


Solar has recently been included in the new Government grant scheme and you might be eligible for it. Here's the link, it doesn’t include the battery but it is for the solar. We are just completing our Trustmark enrolment so we are eligible to quote for the works.


Let me know what you think of our quote and how you would like to proceed.