Renewably

The cheapest (or lowest-carbon) run of `duration_hours` starting from the next half hour and finishing by the next `finish_by` – when to set a washing machine or dishwasher's delay timer.

When the grid operator, NESO, is asking homes in a region to use less electricity (often the evening peak) or more (often in Scotland, when there's more wind than the grid can carry south), through its Demand Flexibility Service: live events from now to the end of tomorrow, usually announced the same morning. Households can sometimes get paid for taking part – but only if they've signed up to a scheme with their energy supplier or another provider (eg Octopus's Saving Sessions), and that provider is taking part in the event; it tells them and says what it pays. These are NESO's requests to such providers. Without a scheme, shifting use still helps the grid but isn't paid.

For a typical weekday and weekend day at this time of year (on a fixed-window or flat tariff, today's rates): the cheapest time to reheat hot water (and the cheapest ready by 07:00), and the cost of each kWh of heat by hour – price divided by a generic air-source heat pump's efficiency at that hour's typical temperature.

For a typical weekday and weekend day at this time of year (on a fixed-window or flat tariff, today's rates): the cheapest charge slot to fill a home battery before the 16:00 peak, an optional afternoon top-up, and what it saves a home using `usage` kWh a year – the battery runs the house after its charge until it's empty, through a typical day's use. No export, and not counting the battery's wear; with `solar_kwp`, also how full to charge overnight for the next day's sun.

Half-hourly prices for a region from midnight today, up to five days (`days`) - Renewably's own format, and the one to use unless your software was built for Octopus's API (then /unit-rates). On Agile (the default), Agile Outgoing, FreePhase Dynamic and Shape Shifters: Agile, each is published by the supplier or estimated by Renewably (flagged `estimate`), with how good the estimate has been for each day ahead (`estimate_accuracy`); other tariffs show only their supplier's published prices. An export tariff's are what it pays for export (and take no panels). Cached to the next half hour (five minutes from 15:55 to 16:45, when tomorrow's come out).

The 14 Agile regions (GSP groups), each with well-known places in it - to place a home by its town. The regions are the local electricity networks' areas, not counties, so some places surprise (Milton Keynes and Coventry are in the East Midlands, Croydon in South East England, York in North East England). The surest way: the first two digits of the 13-digit MPAN on the home's electricity bill (`mpan_prefix`).

The time-of-use and standard tariffs from Octopus, EDF and E.ON Next that the `tariff` parameter accepts – or, with `direction=export`, their export tariffs (for get_prices and `export`), each saying which homes can have it.

The cheapest or greenest half hours to charge an electric car by a ready-by time up to four days ahead.

A home's past year on every tariff in list_tariffs and at Ofgem's price cap – and what switching tariff, an electric car, a heat pump, solar panels or a battery would save, each added to everything before it (tariff, car, heating, solar, battery). Each of car, heating, solar and battery is something the home has (it explains the bill) or is considering. Totals are electricity, gas at the price cap and petrol or diesel – only what changes.

A home battery's plan from the half hour under way to the end of tomorrow, on the tariff's real prices (Agile's, and Agile Outgoing's, estimated beyond what Octopus has published), half hour by half hour: charge from the grid, hold, run the house (self-use), export, or send the sun to the grid – the cheapest way through, counting the battery's losses and wear. Exporting follows what the export tariff pays for – everything on Octopus's, only what the panels put in on the others – unless `battery_export=all` says the home is paid for what the battery charged from the grid too. A battery without panels gives `export` (Octopus's `outgoing`, `agile-outgoing` or `prime-outgoing`, `eon-next-export-premium` for a battery E.ON fitted, or `fixed` with `export_rate`) and trades on the grid: charging cheap, exporting at the peak. Smart Export Guarantee tariffs pay only for what panels made, so not a battery on its own. `now` is what to set this half hour; `settings` the few changes worth typing into the inverter's app. For a typical home of `usage`; give `soc` (the battery's charge now) for a plan from where it is. Advice and data for the owner's own automation – Renewably never controls a battery.