The Solar House Experiment: An Overview

If I had the space, I would definitely install something this size! (credit)

I am a tech geek at heart. New graphics cards and processors? Tell me more! There’s a new version of Windows 10 coming out, tell me all the new features I can play with! There’s a new phone out that has built-in radar components and can map a room?! Awesome (if horribly impractical and battery hungry)!

My wife and I moved into our semi-detached house in 2017, selling both our flats at the time. Now while I loved my flat very much, it was missing a couple of things that bugged me. It didn’t have a roof I had sole access to, and it didn’t have a drive (it did have a parking space – a rarity in some parts of where I lived!). That meant my “super green solar” plans were never going to happen there. But now I was free of those restrictions, I had the opportunity to experiment with all that cool tech!

The key part – solar panels

None of the below would be possible without solar panels. 95% of people in the UK get their energy for their home via the national grid (electricity), gas and/or oil. You are completely at the whim of your energy supplier for whatever they charge to supply and meter you. You can move supplier (and I fully encourage you to check you’re on the best deal for yourself!) but at the end of the day, you have zero control where your energy comes from.

The reduction in cost of solar panels ($/watt) since 1977

I’ve wanted solar panels since I realised they were a thing and the price has been steadily dropping even over the past few years. I got my 3.6 kW array installed in November 2018 and therefore have over a full year’s data which I plan on sharing in a future post for this series. This post will detail the plans and achievements of The Solar House Experiment (TSHE) so far, with more detail for each component in their own post. I’ll also include the financials and maths that went into deciding whether each component was worth it or not and hopefully save you some hassle in each post!

The grand plan

The Solar House Experiment plan currently consists of the following parts:

  • Solar Panels – required to generate the “off-grid” carbon-free electricity in the first place. I was fortunate to get in before the Feed-in-Tariffs disappeared.
  • Smart Meter – required to get the best tariffs for solar batteries and EV charging at the moment.
  • Solar Diverter – these take excess solar energy from the panels and dumps it into your hot water tank, providing free hot water!
  • Electric Car – put “fuel” in your car with the excess energy off your solar panels! They are also exceptionally cheap to run on a day to day basis, but not really “part of the house” per se.
  • EV Charger – required with the electric car, in order to charge it at a rate measured shorter than “days”.
  • Solar Battery – stores excess solar generation for use when needed, such as when its dark or cloudy and the panels can’t supply the house fully. Arbitrage opportunities may be possible with selling stored electricity to grid in the future.
  • Smart Thermostat – heats the house / hot water at low carbon / low price hours.

The fantastic thing about this plan is that everything is quite modular, once you have the solar panels anyway. I’ve been slowly adding new pieces to the house system over the past year and a bit and they all work pretty effortlessly together after the software is setup correctly.

The only things I don’t have installed yet are the solar battery and the smart thermostat, but the reasons for this will be discussed in the relevant articles.

What did it cost and why on earth go to all that hassle?

Amazingly, once I researched and decided what products I wanted and got a few quotes for the installations I couldn’t do on my own, it’s only taken about a week’s worth of time to get everything installed and setup. Here’s an actual price guide for each part of the system so far:

TSHE ComponentPrice (£)Installation TimeNotes
Solar Panels,
Micro-Inverters,
Monitoring Software,
Installation
7,5662 days1. My wife and I split this cost 50/50 between us (because she’s awesome).
2. I went for top spec panels and micro-inverters due to space constraints and plans to expand the array at a later date.
Smart Meter02 hoursInstalled for free by my energy supplier: Octopus Energy.
Solar Diverter
(MyEnergi Eddi)
3652 hoursSpent an afternoon with my Dad installing this together. Pretty easy! The price appears to have increased since I bought mine though.
EV Charger
(MyEnergi Zappi)
6001 dayI had to use an OLEV approved installer to get a £500 grant from the government. You also have to have an electric car first to be eligible.
Misc. add-ons
(MyEnergi add-ons)
50 + 852 hoursThese optional extras allowed me to have internet connectivity for the EV Charger and Solar Diverter and I didn’t have to drill holes around the house to run extra cables to them.
Smart Thermostat
(Nest Thermostats)
199 / 219 + installation1 dayI have not bought or installed this, and may not ever have one.
Electric Car
(Nissan Leaf / Tesla Model 3 / Renault Zoe / etc.)
8000+1 day
(pickup)
An electric car isn’t needed for the house, but including for completeness.
Total:8,885 (no car)
16,885+ (with car)
The costs to buy and install the various parts of the solar house experiment so far

So as you can see from the above, I have a top-spec solar setup for just under £9,000. I tend to buy the more expensive models/variants of the various categories because they offer extra features I find worthwhile. For example, I fully believe you could get the same number of panels (I have 11 on my house) that produce ~15% less power for nearly two-thirds the price. The micro-inverters could also be replaced by one main inverter and you’d save about another £500 on the above – but your panels may suffer some efficiency loss – do your own research. My panels and micro-inverters carry a 25-year manufacturers warranty and are made by very reputable companies so I’m not concerned about panel failure.

There are also much cheaper EV chargers, solar diverters and smart thermostats. I bought and installed the ones I have because they can communicate with each other and provide additional features to maximise my solar usage. For example, with this setup my house will divert solar power in the following priority:

Normal Electrical Loads (Kettle/Oven) -> EV Charger (Car) -> Solar Diverter (Hot Water)

We’ll get to the elephant in the room in a later post, I promise (credit)

That means that when it’s bright and sunny outside and we’re not using anything particularly electrically heavy in the house (like boiling the kettle), the car’s battery is slowly being topped up. At max output in summer, the car could be gaining nearly 12 miles of range an hour! If the car is full or unplugged then the rest is dumped into the hot water tank, saving us money as instead of the gas boiler heating the water, the immersion heater is activated and draws as much power as there is excess solar power.

If there’s minimal load in the house, the car is full/unplugged and the hot water has reached temperature, then it is passed out to the national grid where it is hopefully off-setting someone else’s coal/gas/nuclear powered consumption.

That’s great and all… but why?!

Did you know that the UK has 40% of Europe’s wind reserves in its borders? (credit)

A few reasons, but let’s do them from most important to least:

  • Global Warming – I think this is the biggest threat to our planet, unless someone gets nuke-happy, in which case we’re screwed either way. I have the means to reduce my fossil fuel use considerably and for a pretty minimal cost. Every step we collectively take to reduce carbon emissions as whole is a win. And I don’t care what other countries are doing – do your bit if possible. I’m putting my money where my mouth is with this experiment.
  • Lower on-going costs – Having solar panels and all the fun toys will (eventually) lower my on-going day to day costs. I need to tally up all the sums first, but I’m fairly sure after Year 11 of installation the panels will have paid for themselves and every-thing after that is just gravy. I’m deferring saving the cash now for the possibility of lower costs in the future (bit like saving in a pension, no?).
  • Regain control of production – I have essentially bought ~15 years of electricity up front and the means to use it. How high do you think electricity prices will be in the next 5 / 10 / 20 years? I know my own electricity rate has jumped from 11p to 15p a kilowatt in the past 5 years. Perhaps solar panels are a good inflation hedge? Eventually they may reach the point where I will install a solar battery and be as grid-free as possible and laugh at their price increases?
  • It’s just really cool! – This is a big one for me, but it’s a purely emotional thing. When the sun is out and bright – I know I’m slowly saving money. I get to have a hot shower in the morning and it was heated and powered by sunlight. When I get in my car and drive to work, I know at least a bit of the energy I’m using came from the sun. I’m not polluting the city streets with exhaust fumes. Imagine if everyone did this, what an awesome place the UK would be! (Obligatory comic link as well)

Anyway, that’s the basics of The Solar House Experiment. In future articles (they probably won’t be sequential this time) I will dive into the details of each part of the system. Why I picked the part I did, what other alternatives there are, expected payback times, dealing with the variability of the seasons. Oh, and a big article on just how much all this stuff is saving my wife and I in our day to day lives.

Stay tuned!


7 thoughts on “The Solar House Experiment: An Overview

  1. A fascinating post and experiment – I can see how all this gives you great satisfaction in helping with global warming and just being self-sufficient and not having to rely on the grid.

    Nice if you live somewhere where you are likely to get a lot of sunshine – not a lot of that in Manchester however, otherwise I’d consider solar panels!

    Liked by 1 person

    • Thank you weenie! I’m still typing up the ‘return on investment’ post for the panels, but amazingly by my calculations, even having a couple of panels and a small battery (maybe 2-3 kW) has a big impact on your carbon footprint. But that’s for a future post 🙂 Scotland apparently only gets about 60% of the sun’s energy as Cornwall, so Manchester probably isn’t too bad from a solar perspective. The nearer the equator you are the better though, you’re right.

      Liked by 1 person

  2. I’d love a set up like this, I’m a big Tesla fan. Although, I’d argue that the only benefit is for saving the planet or being off-grid, not for saving money.

    This is due to the fact that the money spent (£9k in your case) could have been invested. Earning an average return, I’d be really surprised if the solar panels give you a greater return over 25 years.

    I could be wrong though! I’d love to see the Maths 🙂

    Like

    • Thanks Mr. Ninja. If you’d like to see the maths on the first year, it’s in my follow up post here:
      https://igniting-fire.com/2020/01/19/tshe-solar-panels-1-year-review/

      I would indeed have made more dumping it into index funds but I’m very happy with the panels. With inflation on energy bills being about 3-4%, it may actually save me more money in the long term, plus the FiT is inflation linked too. I wouldn’t be surprised if the panels last 30+ years. The ‘major’ savings should start now I can charge my car off the excess solar in spring/summer/autumn. No £2k a year of petrol bills for me! 😀

      Like

  3. May I simply just say what a relief to discover somebody who actually understands what they’re discussing on the web. You certainly understand how to bring a problem to light and make it important. A lot more people ought to check this out and understand this side of the story. I was surprised that you are not more popular since you definitely have the gift.

    Like

  4. So glad I stumbled across this post – I’ve recently just purchased an electric van (nissan e-nv200 24kwh battery) and have been considering solar panels on the house.

    Problem on my side is that we live in a historic house and plonking some PV panels on the top might not go down well with the partner / bit of a dent on the village. So I’m looking for the ‘PV tiles’ type arrangement (but still technology is quite new / to make it look like part of the roof structure) – plus as well, efficiency / energy gain is significantly reduced.

    Like

    • Hi Jase, thanks for your comment. I’ve only just started using my solar panels with my car and the savings aren’t there… yet. I think it will be a very different situation in summer. In winter, the panels can’t always cover the house’s needs, never mind an electric car/van on top. PV Tiles are far more expensive than PV Panels – on a purely financial basis I would not recommend them until prices drop significantly.

      How are you finding your electric van though? Any issues?

      Like

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