=== Voltij Stroomprijs ===
Contributors: voltij
Tags: stroomprijs, electricity price, energy, dynamic tariff, netherlands
Requires at least: 6.3
Tested up to: 7.1
Requires PHP: 7.4
Stable tag: 1.0.0
License: GPLv2 or later
License URI: https://www.gnu.org/licenses/gpl-2.0.html

Today's Dutch electricity price per hour (stroomprijs vandaag) with the cheapest block. As a block, shortcode or widget. Free, no account.

== Description ==

Show your visitors what electricity costs today, hour by hour, on the Dutch day-ahead market. The cheapest two-hour block is highlighted, so people with a dynamic contract, solar panels, a heat pump or an electric car can see when to run the washing machine or charge the car.

* **Block:** add "Electricity price today" in the block editor (category Widgets).
* **Shortcode:** `[voltij_stroomprijs]`, or `[voltij_stroomprijs theme="dark"]` for a dark background.
* **Widget:** "Electricity price today (Voltij)" for a sidebar or footer.

The image is updated every night shortly after midnight (Amsterdam time). If today's prices are not available yet, the image says so. It never shows an invented number.

The prices are wholesale day-ahead prices for the Netherlands (source: ENTSO-E), without energy tax, VAT and supplier mark-up.

Good to know:

* No JavaScript and no cookies on your public site: it is a plain image.
* Your site does not fetch or store anything; your visitors' browsers load the image from voltij.nl.
* Optionally link the image to voltij.nl, where visitors see all hourly prices of today and tomorrow. This is off by default; switch it on in the block or widget settings, or with `link="yes"` in the shortcode.

The plugin interface is in English and can be translated on translate.wordpress.org.

== External services ==

This plugin shows an image that is hosted by Voltij (voltij.nl), a free Dutch electricity price service by Xaven BV.

* **What:** the image `https://voltij.nl/widget/vandaag.svg` (or `vandaag-donker.svg` for the dark version) with today's hourly electricity prices.
* **When:** each time a page with the block, shortcode or widget is viewed, and in the block editor.
* **What is sent:** the visitor's browser requests the image directly from voltij.nl. Like any image request, this includes the visitor's IP address, browser user agent and, depending on the browser, the referring page. The plugin itself sends no data and sets no cookies. Voltij does not use this request to track visitors.
* **Privacy policy:** https://voltij.nl/privacy
* **About the widget:** https://voltij.nl/widget

== Installation ==

1. Install the plugin from Plugins > Add New (search for "Voltij Stroomprijs"), or upload the zip file via Plugins > Add New > Upload Plugin.
2. Activate it.
3. Add the block "Electricity price today", the shortcode `[voltij_stroomprijs]` or the widget "Electricity price today (Voltij)".

== Frequently Asked Questions ==

= Does this cost anything? =

No. The plugin and the image are free. You do not need an account or an API key.

= How often are the prices updated? =

Every night shortly after midnight, Amsterdam time. Browsers keep the image for at most half an hour.

= Which prices are shown? =

The day-ahead wholesale price per hour for the Netherlands, as published by ENTSO-E. Without energy tax, VAT and the mark-up of your supplier. With a dynamic contract you pay this price plus those costs.

= Can I change the size? =

The image is 480 by 260 pixels and scales down on small screens. Use the block's alignment to place it left, centred or right.

= Does it work with page caching? =

Yes. The page only contains a link to the image; the image itself changes every night.

== Screenshots ==

1. The image on a light background, with the cheapest block highlighted.
2. The dark version.
3. Block settings: colour scheme and the optional link to voltij.nl.

== Changelog ==

= 1.0.0 =
* First version: block, shortcode and widget.
