George Cave Gets on Top of Solar Generation and an "Agile" Energy Tariff with This ePaper Dashboard
With supply pricing changing on a half-hour basis, solar panels, and a whole-home battery, this dashboard keeps an eye on a lot.
Maker George Cave has home solar and an experimental demand-based energy tariff — and to keep a track on what exactly that means for cost and consumption at any given time, built a slick energy dashboard on an ePaper display linked to an Adafruit ESP32 Feather V2 board.
"I live in a house with solar power, battery storage and an experimental energy tariff that adjusts with national demand," Cave explains of the project. "The hardware and data are awesome, but most smart meters and apps do a terrible job at explaining what’s actually happening behind the scenes. So I built [my own]. Every fifteen minutes, this ePaper dashboard updates with real time data from our household energy flow."
Cave's energy supplier offers what it dubs the "Agile" tariff, which sets pricing 24 hours in advance in half-hour blocks based on projected supply and demand — incentivizing, the theory goes, usage at times of peak supply and conservation at times of peak demand. When low demand and high supply, driven by an excess of renewables including solar and wind, overlap, prices can even go negative, paying the user to relieve some of the oversupply on the grid.
To keep track of everything — the current and future Agile pricing, energy usage, local solar generation, and house-level battery storage — Cave built a dashboard that combines an 800×480 tri-color ePaper display, requiring energy only when it changes state, with an Adafruit ESP32 Feather V2 development board, based on Espressif's popular microcontroller of the same name. Scripts pull the pricing data from the energy supply and solar harvesting data from a cloud service at regular intervals; this is then stored in a database and used by a private application programming interface (API) to render the graphical dashboard itself.
"I'm particularly proud of the peek-behind solar graph," Cave writes of the dashboard's appearance, developed after several months' of data had already been gathered, "which renders the hidden outline of the solar in yellow on top of the daily load in red, to maximize the information density in only two-bit color."
The project is documented in full on Cave's website.