I once had the idea to do something like this, though the intention was to pitch it to gas station operators as a way to keep their prices competitive (i.e. alert them when the station down the street drops their prices so that they can too and not lose business to casual price shoppers or, alternatively, when the station down the street raises their prices, so that you can too and not lose revenue needlessly) and learned that there are a couple entities, at least in the US, that have national data here. I couldn't even figure out how to contact one, and when I called the other I was essentially laughed off the phone by someone with a VERY New York accent -- it seems from context that their data is VERY expensive and used by Wall St. types, so the idea of some nobody from flyover country essentially reselling it to mom & pop gas station operators was funny, and out of the question.

Also depends on the size of your fuel tank and how full it already is. The time taken to refuel is (almost) the same regardless, but if you've got a 40l fuel tank vs a 70l one or you're only half-empty then it's going to be less worthwhile.

7p cheaper for 10 minutes works out at about minimum wage if you're buying 30 litres, but with a bigger car you could easily be buying twice that, which works out much better.

Although of course you also need to factor in how much fuel you burn driving to the cheaper place, and the extra wear and depreciation on the car. If you take the HMRC standard rate of 45p/mile (which was meant to cover all of that kind of thing, but hasn't been updated for years) then even going a few miles out of your way quickly ends up costing more than it's likely to save.

mostly such tools are useful when you go very close to a few petrol stations on your regular routes anyway. I can pretty much time topups for when the cheapest station locally is en-route to my destination

A 7p per litre difference does sound like the difference between local station and motorway prices though, and they probably will have factored in that opportunity cost of time...

    Unleaded is 131.80p (UK wide) and 156.80p (Motorway Service Area).

> Never investigated myself, but some car-knower once told me that running the tank on low always isn't good for the fuel pump, or something like that.

The main issue is that it risks pulling detritus from the very bottom of the fuel tank, usually a bigger issue in diesels and I suspect less of a problem these days.

> doesn't the fuel pump use fuel itself as a coolant or something

I know very little about these things, but my understanding was always that any form of liquid pump uses the liquid itself as coolant to some extent.

Of course. I'm not talking about lack of money though here. We've all been on our last tenner until payday and need to go somewhere.

Some people seem to think that spending less at the pump means your saving money, but to save money you need to drive less. They religiously drive on £10-20 fuel stops.

My ex wife was convinced she spends less on fuel by putting less in a time, she even earnt more than me.

> usually mandate a minimum of 2 litres

Out of curiosity how does that work (never been in a situation where I have to worry about minimal fuel purchases) - does the pump simply round up the price to the minimum when done, or did you actually have to dispense extra fuel, either into a jerrycan or donating it to someone else's car otherwise the pump would not actually finalize the transaction?

> I think it's exactly that, the UK has never had this so people there either choose by brand or just convenience.

We've had it for years (as noted in other comments there's a few different people like the RAC, AA and Petrolprices.com all maintaining their own lists - a quick check of my email has messages from the latter going back to 2011). The new part is that this is from the government and the data is freely accessible (Petrolprices in particular covered their pages in ads, so I'd be surprised if there wasn't a way to exchange money for the data).

The context to this is that, especially since the pandemic, there's been a complaint with the Competition and Markets Authority that the petrol stations were quick to raise prices, slow to lower them, and weren't competing with each other[1]:

> The CMA found that retail prices tended to "rise like a rocket, but fall like a feather" in response to increases or decreases in the cost of crude oil.

Independent petrol stations have virtually disappeared and you don't have to look too hard to see that in an area they tend to all raise or lower their prices in virtual lockstep. Gathering this data would make the case significantly easier if the next step were that some of the petrol station operators had to be broken up to encourage more competition.

1: https://www.bbc.co.uk/news/articles/cp80dpzdg37o#comments

Edit: Petrolprices was founded in 2005 (!) [2]

2: https://www.myautomateapp.co.uk/

>the UK has never had this so people there either choose by brand or just convenience

Disagree - drivers maintain a mental map of local stations and know roughly how expensive they are, and make a decision based on that. Obviously this API will help inform us better!

I don't see how that makes it uniquely viable in France. Germany has something very much like this too. And we've had it for nearly 13 years.

> Since 31 August 2013 companies which operate public petrol stations or have the power to set their prices are required to report price changes for the most commonly used types of fuel, i.e. Super E5, Super E10 and Diesel “in real time” to the Market Transparency Unit for Fuels. This then passes on the incoming price data to consumer information service providers, which in turn pass it on to the consumer.

As a consumer, there is no direct API by the MTS-K that you can use, but there are some services like Tankerkoenig which pass this data on to you. I have used their API in Home Assistant before I switched to an EV.

https://www.bundeskartellamt.de/EN/Tasks/markettransparencyu...

So no petrol is permitted to be higher quality (for the same octane rating)?

ie you're asserting there is zero variance in quality?

OP wrote lower quality, not low quality

Thanks.

Looking at that document, this regulation is dead on arrival. Enforcement is contingent on the aggregator noticing the price discrepancy, giving the seller many opportunities to rectify the situation without a penalty (if we assume every step gives them 30 days to respond, we're looking at ~5 months before a financial penalty becomes possible), and even then, the regulatory "may" impose a financial penalty, meaning it isn't even guaranteed.

You know what would immediately resolve this problem and prevent non-compliance? A reporting system where any citizen can submit evidence of a price discrepancy and upon validation gets a 1k payout from the government who then recovers it via a fine. This would make it sustainable for anyone to act as an "auditor" or even do this as a business.

Of course, the reason it isn't done this way is because it would be too effective, where as this current iteration gives the appearance that something is being done while having no impact in practice.