Automated export based on average Agile slot price

nbullus

There are times when it is cost effective to export your battery under Agile just before the next schedule window starts, but the decision is based on how much you paid for the electricity in the first place. No point selling surplus electricity back to the grid at a lower rate than what you bought it for, so you may as well keep it in your battery.

A nice feature for the export schedule is to have a user defined Agile export threshold which determines whether he export schedule runs that day or not (assuming the export schedule is Enabled). For example, if you are on the 15p fixed export rate you could set the threshold at 12p and the export schedule would then only run if the average price of your selected Agile slots that day was less than the 12p threshold. On days you pay more than your threshold you don't export, and on the days you pay less than your threshold, you trigger your schedule export as normal.

A set and forget feature that avoids having to make this decision manually each day.

kerregan

nbullus The price you paid for import is a historic sunk cost, so the criterion is whether you can use it yourself at a time in the near future when the import price is higher than the best export price in the near future.

kerregan

nbullus

nbullus There are times when it is cost effective to export your battery under Agile just before the next schedule window starts, but the decision is based on how much you paid for the electricity in the first place. No point selling surplus electricity back to the grid at a lower rate than what you bought it for, so you may as well keep it in your battery.

Imagine that in the period leading up to next window the export price is down to 8p, so you don’t sell. But in the next window you can import at 6p.

You would be better off selling for 8p the units you bought at 9p, rather than consuming them at a time when they are only worth 6p.

The price you paid is irrelevant. What matters is the best price you can get when you sell.

nbullus

kerregan Not sure I understand your point. A sunk cost is one you cannot change or influence. Its not a sunk cost If I buy 10kWh @ 9p at the start of the day and then decide to sell 5 kWh surplus back at the end of the day at 15p, as I reduce the overall cost for the day for the 5kWh I did use by 33%, from 9p/kWh to 3p/kWh.

This is what I and others do, but would have to make this decision manually every single day and wait till last thing to activate the export schedule accordingly. Its a simple switch (sell or don't sell) based on the cost of my slots in a rolling 24hr schedule compared with my chosen export limit.

kerregan

nbullus The 9p cost is fixed. There is nothing you can do to change this after the fact. It is a sunk cost.

Your objective is to get the maximum price for the unit you bought regardless of the price you paid. Some days this may mean selling it or using it at less than 9p.

nbullus

kerregan Still disagree.

What's important is the net price I actually pay for it on my bill. The net price varies depending on how much of it use, how much I export back and the price difference, i.e. it becomes a variable cost depending on the decisions I make.

If I only need 10 kWh to meet my home demand and I buy just 10kWh at 9p, cost is fixed £0.90 on my bill. If I buy 20 kWh and sell half back at 15p, cost is £0.30p for consuming the same 10 kWh, so not a fixed cost.

Only a fixed sunk cost if you import it and use it.

nbullus

Depends on how much of it you export, the time frame between your export and re-charge windows, the home demand in this period and the price in between that you might be forced to import at before you even get to the cheaper slot price. I suspect there would be far too many variables to think about and suspect a very complex solution trying to automate export based on future variable prices, but I may be told differently.

Be interesting to see whether others think and whether they would see any benefit from automating export. More importantly whether WW think its a non-starter or not, or even if it is doable.

admin

nbullus

More importantly whether WW think its a non-starter or not, or even if it is doable.

Leaving aside that we don't currently store agile export prices - why would someone even want to if you can get a fixed 15p/kWh? And with Flux even better during the peak period, but again, it's a fixed window too.

And knowing that, I don't really see the need or understand the requirement to assess this on an ongoing basis (every 30 mins) and dynamically schedule this.

Besides, without really having a good handle on the home's usage patterns during the seasons and the week, we'd be guaranteed to get it wrong in a lot of cases, and get swamped with requests of users asking why WW did what it did given effectively rough estimated information.

And even with all the usage detail recorded, which we have no intention of collecting, it would be incredibly difficult to get right most of the time IMO.

nbullus

admin I agree.