This webpage displays some rough forecasts of hourly electricty prices for the next week, based on expected demand, wind and solar generation. I have also included the day ahead half-hourly prices (averaged to hourly) once these are known and have been imported.
The prices are essentially estimates of day ahead hourly auction results in £/MWh.
If you want to know how historic forecasts performed, you can see the latest forecast before a past datetime, eg http://energy.guylipman.com/forecasts?before=2020-12-31T12:00
It should be noted that future wind generation and resulting prices are likely to be significantly different than those forecast.
I have described the methodology used in a bit more detail in this blog post. You can also see the code for this model on github