We have just installed solar panels on our house in London. We also had panels on our old house in Oxford. How do they compare? Oxford London Latitude 51.753738 51.486880 Panel Size 4000 Watts 5040 Watts Orientation South East/West Split Obviously, it's hard to compare exact weather conditions - lower temperature makes for more efficient generation - but I've picked a date in April where both sets of panels seemed to have an unblemished view of the sky. …
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Mostly notes to myself. My solar panels have an open API. But it's only available if I'm on the same network as the Fronius inverter. I can connect my system to https://www.solarweb.com/ so I can access it anywhere in the world - if I have the right password. SolarWeb has an (optional) guest mode. You can view the panels' performance if you know the secret URl. It looks something like this: https://www.solarweb.com/Home/GuestLogOn?pvSystemid=123-456-789 Visiting that URl sets some…
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I have solar panels! The UK mandates that my electricity supplier buys the surplus energy off me. They set a minimum price, known as the SEG (Smart Export Guarantee). My supplier - Bulb - pay me 5.38p for every kWh I export. I pay them about 13p for every kWh I import. You notice the discrepancy? When I tweeted about this, some people got angry on my behalf. How could I stand being ripped off like this? Why couldn't I sell electricity to my neighbours at full price? Personally, I'm quite…
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I'm hooking my solar panels up to the Internet! Installation Inverter API & Code My solar panels have an API! It tells me the total amount of power they've generated each day. But there's a small problem... I have panels on the East and West sides of my roof. My solar inverter has two MPPT "String" inputs. That is, East and West supply power separately. Luckily, there's an API for that! Thanks to "Grannos" on the PVOutput forum for their excellent open source code which helped get me…
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I'm hooking my solar panels up to Twitter! Installation Inverter Fronius provide a comprehensive API guide - I wish more companies did this. There are lots of unofficial libraries in a variety of different languages. I've written this code in Python3. This is a general tidy-up of the code I wrote several years ago. Here's how it works.... Every minute, the script runs from crontab. If it is after sunrise and before sunset, it takes a reading and writes it to today's CSV file. If it is…
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Having solar panels on your roof is great - but you need something to turn their wicked DC electricity into pure and godly AC. This bit of kit is called an "inverter". It's a big box which lives in your roof working magic. This is what ours looks like: We chose a Fronius Primo inverter - they're a reliable brand which we used in our previous build. I've been impressed that every few months my inverter's software was upgraded. Not bad for a 6 year old bit of kit. And, most importantly for my …
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A few years ago, we installed solar panels on our roof in Oxford - I've enjoyed blogging about them. I've released open data from them, inspected them with a drone, and measured what happened during a solar eclipse. They've even been on the BBC! But the best thing I did, was release this little Twitter bot. Edent's Solar Panels@Edent_Solar AutomatedToday I generated 17.37kWh of solar electricity & earned £3.24 pic.x.com/j7fs0ydoij❤️ 0💬 1♻️ 020:21 - Thu 11 July 2019 At sunset every day, it cre…
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Back in 2014, I set up a rather silly Twitter account - @OxfordSolarLive. The premise was simple. A camera took a photo of the sky above my house. It took a reading from my solar panels to see how much electricity they were generating. It superimposed the reading on the photo. Then posted it on Twitter. Solar Realtime Edent@OxfordSolarLive1206 watts. pic.x.com/ip2cp5rrao❤️ 0💬 0🔁 014:11 - Fri 24 August 2018 When I had a solar battery fitted, it also added that into the mix. Solar Realtime Ede…
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(Long and data-filled post ahead!) I've switched to energy provider Bulb (£50 off if you join using that link). They offer a "peak time" electricity charge which looks like this: 23:00 to 07:00 = £0.0815/kWh 07:00 to 16:00 = £0.1235/kWh 16:00 to 19:00 = £0.3263/kWh 19:00 to 23:00 = £0.1235/kWh By contrast, the standard tariff is £0.1359 per kWh. That means my electricity is 2.4x more expensive for 4 hours per day, during peak time. But cheaper the rest of the time. Let's look at a typi…
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A few weeks ago, I had a delightful chat with the BBC about our solar battery storage. You can watch it on iPlayer starting about 7m 30s in. Community battery technology is here. It is feasible. And it just works. The solar panels on our roof generate more power than we can use - so we store it and share the rest. Yes, even in rainy England, solar panels work! Storage is expensive now - but it won't be long before it is as common as loft insulation or energy efficient light-bulbs. …
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Amazon Alexa is a fun little bit of kit. But it can be tricky getting it to work with all your smart devices. Not every company has an Alexa skill - just like not every company has an app. Using Flask-Ask it is possible to bring Alexa smarts to a range of previously mute devices. Alexa coding works on "intents" - the following is a simple intent. That is, you can only ask the skill one thing. No state is maintained, no multiple commands to get right, no complexity. This gets information…
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I can now query my solar panels via my Alexa Amazon Dot Echo thingie (why so many names?). https://shkspr.mobi/blog/wp-content/uploads/2017/05/VID_20170501_161804.webm I flatter myself as a reasonably competent techie and programmer, but fuck me AWS Lambdas and Alexa skills are a right pile of shite! Sorry if that sounds a bit harsh, but they're a pain in the arse to get anything done. I wanted something simple. When I say "Solar Panels", call this API, then say this phrase. That's the…
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