Everything published so far
Numbered in the order it was written. The series builds, so the early ones are the place to start.
- Where to Get Your Own Half-Hourly Electricity Data (And Why It Changes Everything) 1,499 words Walks through every route to your own granular consumption data — supplier portal exports, the n3rgy DCC feed, Octopus API, IHD logging, CT clamps — and argues that until you have half-hourly data, every solar decision you make is guesswork dressed up as a calculation.
- The Five Numbers You Need Before You Model Solar At All 1,765 words Establishes the minimum viable dataset — annual kWh, daytime share, peak demand, usable roof area and roof azimuth/pitch — and shows that a model built on these five beats a slick online calculator that asks for your postcode and nothing else.
- kW vs kWh: The Unit Confusion That Quietly Ruins Solar Spreadsheets 1,800 words Diagnoses the single most common modelling error — mixing power and energy in the same column — and gives a unit-discipline convention (plus prompts that force an AI to declare units) so your spreadsheet fails loudly instead of silently being wrong by a factor of two.
- How to Measure Your Roof Without Getting on a Ladder 2,256 words A practical method for deriving pitch, azimuth and true usable area from free sources — Google Earth, LiDAR tiles, phone inclinometer, planning drawings — with an honest accuracy budget for each, so your forecast starts from real geometry rather than a guess.
- Your First Solar Model in a Spreadsheet: A 90-Minute Build 1,623 words Builds a deliberately minimal but correct model from scratch — 8,760 rows, generation, load, self-consumption, export — and argues this crude version is the artefact everything else in the year refines, so build it before touching any sophisticated tool.
- Reading a Solar Quote Line by Line 1,596 words Decomposes a real UK quote into panels, inverter, battery, scaffolding, DNO work, labour and margin, and shows which lines are genuinely fixed costs and which are the negotiable padding that varies threefold between installers.
- What Your Smart Meter Dashboard Isn't Telling You 1,562 words Explains why in-home displays and app dashboards net off, round, aggregate and lag your data, and shows how to establish what your monitoring layer can and cannot detect before you rely on it to spot a fault.
- Battery Basics for Analysts: Usable vs Nameplate Capacity 1,572 words Unpicks nameplate kWh, depth of discharge, reserve settings and continuous power limits, showing that the number on the datasheet is rarely the number your model should use — and how to find the real one.
- Annual kWh Is a Trap: Why Your Load Shape Matters More Than Your Total 1,544 words Takes two households with identical annual consumption and shows their optimal solar sizing differs by 40% purely because of when they use power — the argument for abandoning annual-total sizing entirely.
- PVGIS in 20 Minutes: Getting a Trustworthy Baseline Yield 1,610 words A guided run through PVGIS for a UK roof, explaining every input that actually changes the answer and how to export hourly output for use in your own model rather than just reading the headline annual figure.
- Writing Prompts That Don't Hallucinate Your Numbers 2,096 words Establishes prompt patterns for numerical work — supply the data, forbid estimation, demand shown arithmetic, require a stated method — and demonstrates the failure modes each pattern prevents with real solar examples.
- Self-Consumption Rate: The Metric That Decides Your Payback 1,522 words Argues self-consumption rate, not system size or yield, is the lever with the largest effect on returns, and shows how to calculate yours from half-hourly data for several candidate array sizes.
- Cheap, Mid or Overpriced: Benchmarking £/kWp Across UK Quotes 1,967 words Builds a normalisation method that makes wildly different quotes comparable on a £/kWp and £/kWh-of-storage basis, with current UK bands and the legitimate reasons a quote can sit above them.
- Shading Is Not Binary: Modelling Partial Shade Hour by Hour 1,946 words Shows how to build a horizon profile and sun-path overlay for your own roof, then translate it into hourly shading factors — replacing the installer's vague 'a bit of shading in the morning' with numbers.
- The First Month of Monitoring: Building Your Expected-vs-Actual Baseline 1,722 words A commissioning protocol for analysts: what to log in the first 30 days, how to compute a performance ratio, and how to lock down a reference baseline while the system is provably healthy.
- Agile, Go, Flux or Cosy: Matching a Tariff to Your Load Shape 1,375 words Runs the same household's real half-hourly data against each tariff's price structure to show that tariff choice is a data question with a calculable answer, not a matter of reputation or forum consensus.
- How Many Solar Panels Do You Actually Need? Three Methods Compared 1,726 words Compares rule-of-thumb sizing, roof-fill sizing and consumption-matched sizing on one real dataset, showing where each lands and why the consumption-matched answer should be your starting point and the roof-fill answer your ceiling.
- Getting Free Weather and Irradiance APIs to Agree With Each Other 1,641 words Compares Open-Meteo, CAMS, Met Office and PVGIS TMY data for the same UK location, quantifies the spread, and recommends a blending approach so your forecast isn't hostage to one provider's bias.
- Building a Repeatable Data Pipeline from the Octopus and n3rgy APIs 1,942 words A concrete, scheduled pipeline — fetch, validate, append, archive — that turns one-off CSV downloads into a growing dataset, with the authentication and pagination gotchas that break naive scripts.
- Export Payments Modelled Properly: SEG Rates vs Real Behaviour 1,700 words Shows why headline SEG p/kWh rates mislead — export timing, tariff bundling, switching penalties — and builds an export revenue model driven by your own half-hourly surplus rather than an annual average.
- Detecting a Single Failed String From Your Generation Curve 2,123 words Teaches curve-shape diagnosis: what a dead string, a failed optimiser, a tripped MPPT and new shading each look like in daily generation data, so you can name the fault before you call anyone.
- Round-Trip Efficiency and Why Your Battery Loses 12% You Didn't Budget For 1,681 words Traces every loss between surplus generation and delivered household power — inverter, conversion, standby draw, thermal — and shows how ignoring them overstates battery savings by roughly a sixth.
- East-West vs South: Modelling Orientation Against Your Own Load Curve 1,564 words Demonstrates that the orientation producing the most kWh is often not the one producing the most value, using morning-and-evening-heavy load data where a split east-west array beats a south-facing one on self-consumption.
- Roof Space Constraints: From Panel Dimensions to a Real Layout 2,039 words Converts your measured roof into an actual panel count using real module dimensions, edge setbacks, obstructions and portrait/landscape trade-offs — the step that turns a theoretical kWp target into a buildable array.
- Sanity-Checking an Installer's Yield Claim in Ten Minutes 1,764 words Provides a fast triage that catches inflated yield figures — specific yield per kWp, implied performance ratio, MCS versus marketing estimate — and shows what an optimistic-but-defensible number looks like versus an indefensible one.
- Clear-Sky Ceilings: Using Theoretical Maxima to Spot Underperformance 1,591 words Shows how to compute a clear-sky upper bound for any given day and use the gap between it and your actual output as a fault signal that works even without irradiance sensors on site.
- Arbitrage Maths: When Charging From the Grid Beats Storing Your Own Solar 1,491 words Derives the break-even condition where cheap import plus round-trip losses undercuts the opportunity cost of stored solar, and shows the counter-intuitive result that on some tariffs you should export in summer and import at night.