Seedling · Rough notes and first results
An Android app for RCE energy prices
Under Polish net-billing, energy exported around midday is often worth pennies – 10 grosz per kWh is not unusual. Little money, but room to optimise. If you have a battery, that is when you charge it. If you only have panels, you can run the washing machine, dishwasher or dryer in those hours, top up the heating or the water in the boiler – and use energy you would otherwise give away.
Those hours show up in the RCE report on the PSE website, but it is hard to read, and I like minimal interfaces. So I wrote a simple Android app.
What it does
- connects to the API published by PSE (the Polish transmission system operator) and fetches today’s prices,
- shows the current price,
- tells you when the low-price period starts (or ends) and how many hours away that is.
In the morning, before leaving for work, I can see what time to set the dishwasher to. For the rest of the family it suggests when to wash and dry. The washing machine does not have to run every day, so it often pays to wait a day or two and save 1–2 PLN per cycle.
The app is free and has no ads – I do not like ads myself, so there will not be any.
Publishing on Google Play
New personal developer accounts on Google Play must run a closed test with at least 12 testers before publishing. I looked for them on the elektroda.pl forum – ideally among people who would actually use the app.
To check
The first feedback showed that RCE prices are only useful where the energy seller settles exported energy with them. Energa, my supplier, does. I do not know yet how other sellers calculate it, or whether it depends on the tariff. I do not want to overcomplicate the app, but I would like it to be useful to more people.
Plans
- a chart of the day’s prices,
- a look at the next day’s prices.
Why I shift consumption instead of buying a battery: How much power a hybrid inverter burns while doing nothing.
Source: my thread on elektroda.pl (in Polish) – Aplikacja Android do monitorowania cen prądu PSE – szukam testerów (net-billing) (September 2025).