Farce
The use of 2G / 3G by smart meters, and indeed the installation of smart meters is beginning to reach astonishing levels of farce.
There's no great argument in favour of smart meters in the first place. The fact that they're now going to have to be swapped out is ridiculous. What a ****ing waste.
If the government wants us all to have smart meters and to have the control / influence over how much energy people use, then it's going to have to act seriously to bring that about. That means thinking about the entire ecosystem. Either one builds a dedicated network for the data link, or one obliges the telcos to provide it. One does not let two entirely separate markets act independently. It's notable that the energy supply market is regulated by one government department, and the telecoms market is regulated by another.
We've not been very good at building dedicated network infrastructure in this country (harrumph harrumph Tetra / Emergency Services Network replacement), so it's perhaps no surprise that this is turning into a major cock up.
The problem with "the market will provide", or the "use commercial services" mantra for what is essentially critical national infrastructure is that there is no commercial incentive on commercial suppliers to provide a level of service adequate to meet the "Critical National Infrastructure" needs. It takes either law, or government ownership to make this happen. Some industries have been regulated to drive behaviours towards particular national goals - e.g. TV and public service broadcasters (not that there's many of them), and the BT and the core telephone network. If Government has similar requirements for, say, telecomms in support of, say, smart meters, there is no reason why it couldn't have similar laws / regulations for the same effect.
The problem of not having thought about the requirements in advance of an industry coming into being (e.g. the mobile telecoms industry) is that, once established, if government then moves the goal posts government then has to pay for doing so. Having said that, I think it would have taken quite a leap of imagination to realise back in the early 1990s when mobile phone networks first got going that there were going to be use cases like smart meters. Having not thought about it, the damage is done, and the only way to fix it is to take a deep breath and pay for someone to alter their network to become something different to what it is today.
Here's a Thought
If we really do need a national network adequate for things like smart meters, how about the following.
1) Build a proper network for the emergency services - I don't care what, so long as it's heavily government controlled (that being the only way to ensure it ticks the "Critical National Infrastructure" box) and actually does the job.
2) Tetra, which has been blooming marvellous as a voice-only / small data network for the emergency services for decades, could get repurposed for a smart meter data network. This would re-use the Tetra infrastructure, probably reach to a load more places than mobile phone networks do.
LORA
This is probably a reasonably good candidate for building an entirely fresh, Smart meter dedicated network. It would be madness if there were more than one network; it needs someone to build a common network that all suppliers / consumers use.
Multiple Suppliers is Part of the Problem
The use of 2G / 3G by smart meters rather highlights the lunacy of "multiple suppliers" for things supplied by utilities. A really good reason to use 2G / 3G or any cellular standard for utility metering is that 1) the modems are cheap, and 2) there's already an existing network to hook into. So, if you're an electricity retailer obliged to supply a smart meter option, the cheap / fast way of doing so is to use what's already there. It's not economically feasible to expect all the energy retailers to independently build their own smart meter data network.
Yet, if they were to all get together to build one that they all share, then really that's just highlighting the lunacy of there being more than 1 energy retailer in the first place. It's probably not politic to suggest in government (of any flavour) that the whole energy supply utilities thing should be forcibly coalesced back into just one organisation; that'd be tantamount to re-nationalisation.