Here are some notes on recent changes to Chellow:

• We've begun to address the vexed question of clock-time and UTC. Clock-time is what UK clocks say the time is, and it would seem obvious that this is what Chellow should use. However, clock-time has two oddities that make it difficult to use. Firstly there's an ambiguous time when the clocks go back, and secondly there are missing times when the clocks go forward. For that reason, Chellow uses UTC internally to keep things recorded and calculated in a predictable and uniform way. However, that means that we're at odds with the rest of the world, and so for any input / output between Chellow and the user, a certain amount of mental gymnastics has to be performed to translate between clock-time and UTC. To make things easier for people, we're aiming to use clock-time for all input / output, while still using UTC internally. The first thing to transition is the Monthly Duration report. Previously this used to be specified in UTC months, but now it's in clock-time months. This move to clock-time will carry on until all input / output is in clock-time.
• We fixed a bug in the calculation of reactive power for older meters with only four channels.
• The Scenario Runner lets us run 'what if' scenarios, such as projecting the new cost if a tariff is changed. Previously we'd used Supplier Contracts for storing scenarios, but now they get their own table, and this has allowed us to make the navigation simpler, and reduce the number of fields.
• It turns out that the reading frequency is a property of a gas supply and that it affects the tariffs that apply. So reading frequency has now been added as a property of each gas era.
• There was a bit of a problem when the automatic downloader for Elexon RCRC data hung while waiting for data from a socket. A timeout has been set for this, so it shouldn't be a problem any more.
• Gas NTS commodity rates have been entered for Oct 2019 to Mar 2020.