To recap, we have 5,040W of solar panels, with a 3.6kW inverter, and a 4.8kWh battery. That's a lot of (expensive) gear! What does it mean in terms of energy savings? Over the last 12 months we have: 4,000 kWh generated by the solar panels. 1,200 kWh purchased from the grid. 1,200 kWh sold to the grid. 1,300 kWh discharged from the battery. (Data taken from various APIs and rounded to make life easier). It's important to note that the battery doesn't only charge from the panels. Because…
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Less than a year ago, in August 2023, we installed a 4.8kWh Solar Battery at a cost of £2,900. Whenever I talk about the upfront capital costs of solar power, people rightly want to know what the payback period is. Well, after less than 10 months, the battery has given us 1MWh. To put that in to context, the average UK household uses about 3MWh per year. So (again, very roughly) over a third of our electricity use this year has come from the battery. But where does the battery get its …
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Just as the UK was entering the first COVID19 lockdown, we got solar panels installed on our roof. Four years later and our generation meter shows they have produced 15,480kWh of electricity. That's a rather impressive 3,870kWh per year. This is what the average UK household uses in electricity: Our roof is non-optimal. We have an East/West split rather than the more usual South-facing panels. We have some big trees near us. And we live in a rainy, cloudy, overcast region of London. We…
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I love my solar panels. But the solar panels don't love the British midwinter. Most of the year, my panels produce more electricity than I can use. But in winter we're lucky if they produce 3kWh per day - and most of the time it is considerably less. So our winter electricity bills must be massive, right? Nope. The normal cost per kWh is 28.5p (including VAT). We're paying less than half that - 12.4p per kWh. This is thanks to two things - a smart tariff and a home battery. The Octopus…
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Nuclear power was sold to the world as a safe, clean, and economically viable source of electricity. We were told that it would be "too cheap to meter". Even the most ardent proponent of nuclear power will have to admit that hasn't come to pass. Construction costs for nuclear power stations are dwarfed only by their decommissioning costs. Yes, politics and regulation conspire to increase the price - but nuclear hasn't made electricity particularly cheap. Indeed, we mostly seem to be paying…
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I'm a little bit obsessed with building eInk displays. They're pretty cheap second hand. They're low energy, passive displays, with good-enough performance for occasional updates. Here's a new one which shows me what the current cost of my electricity is: Background After installing solar panels, a smart electricity meter, and a solar battery - the next obvious step was a smart energy tariff. Octopus (join and we both get £50) have an "Agile" tariff. Unlike a normal tariff - with a set …
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August is meant to be full of gloriously hot days. An endless parade of sunshine and drinks in the park. This year it seemed mostly grey, miserable, and prone to pissing it down at a moment's notice. We all know that solar panels' efficiency wilts in the heat, but do they get a tan work standing in the English rain? At the beginning of August we installed a 4.8kWh solar battery to supplement our 5kW of solar panels. The battery provides a CSV of readings taken every 15 minutes. It measures…
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Please imagine I have an extreme-YouTube-shocked-face as this post's thumbnail image. We recently got a 4.8kWh solar battery installed. Batteries are still somewhat complex beasties. In order to prevent damage to the internal structure, a BMS (Battery Management System) ensures that each cell in the battery gets a fair share of wear and tear. One side effect of this is that our battery never dips below 10% charge. So our usable capacity is 90% of 4.8kWh - which is 4.32kWh. The other day my…
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We recently upgraded our home solar storage to 4.8kWh. The battery has sensors to detect how much solar power we're generating, and how much electricity we're buying from (or selling to) the grid. That means... GRAPHS AND STATISTICS! Our battery was commissioned just after midday. This graph shows: 1630 - it was fully charged. 2000 - the sun had set and the battery started discharging into our home. 0700 the next day - the sun rose and started generating electricity, so the battery stopped…
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I have upgradeitis. If something newer and shinier comes out, my stupid monkey-brain compels me to buy it. Seven years ago, we installed a solar battery. It was part of an experimental project which looked at creating a community power-grid, so it came at a subsidised price. As I explained to BBC Click, the 2kWh capacity was reasonable - but I expected the future would bring higher capacity, cheaper costs, and smaller sizes. But, after 7 years the battery was starting to show its age.…
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After 3 full years of having solar panels on our London roof, they've generated 11,950kWh of electricity. Nice! Here's how those three years look, according to our smart meter. kWh Solar Generation 11,950 Solar Export 7,346 Grid Import 7,521 Quick maths! The difference between the generation and the export is our solar consumption: 4,604kWh over 3 years. So we directly use about 38% of the solar we generate. The remaining 62% gets sold back to the grid. I…
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Electricity demand varies throughout the day. When demand is higher, electricity prices go up. Most UK consumers are insulated from this variability - we pay a fixed price per kWh no matter what the actual wholesale cost. But it doesn't need to be this way. Exposing users to the immense variability in pricing is probably too dangerous - as seen in Texas recently. Imagine if your electricity provider could say "hey, prices are going to be high tonight. We'll pay you to use less electricity!" …
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