The main difference with NSIPs ( nationally significant infrastructure projects), as it explains in the consultation, is that the decision is made by the secretary of state rather than the local planning authority ( council). The council is consulted during the process, and anyone else who wants to can be involved, as per a planning appeal, I suppose, but the decision is a national rather than local one. The application isn't determined against the local development plan, but against "national policy statements", with local considerations given weight. The overall need for the project doesn't have to be determined, though, as that has already been established by the policy statement...however, a load of consideration is given to the project being in the correct location/ minimising environmental impact etc during the determination.
If granted, the project is given a "development consent order" rather than planning consent, which is structured like an act of parliament and it is a criminal offence for the development to deviate from that...so stronger than planning consents which rely on the council enforcing them. The DCO also grants various other things that would otherwise need to be agreed by the developer separately, like land agreements ( but according to the consultation, not environmental permits, which would still need to be applied for separately). I can see this being controversial, as it allows compulsory purchase of land necessary, as long as the applicant justifies its necessity.
The benefit for the developer is that there is more certainty in the determination process...once submitted, it should take just over a year to reach a decision. At present, the planning process can take much more than that, and may need an appeal process etc, which makes it difficult to predict how long determination would take. However, pre-submission there is a much longer lead-in process than for applying for a planning consent (the one I've been working on started the formal process in early 2016 and is just starting examination...). This involves a lot of consultation with various bodies and local communities/ councils to ensure their considerations are addressed in the final application. It's also veeery expensive for developers, as it is a legally- based consent, so a lot of lawyer time, especially during the 6 month examination process... There's less flexibility than a planning consent too ( I.e. it's not very easy to amend certain bits of it once granted, by providing certain additional information to the council).
From the consultation for fracking sites, it seems they are looking at this only for production wells. So the current sites ( pnr etc) wouldn't fall under it, as they are appraisal wells. I hadn't understood that previously. However, they don't know what would constitute production... presumably not just carrying on producing gas from appraisal wells, as that would be a pretty minor change...but more wells on the same pad/ more pads/ additional infrastructure etc etc. That seems to be what they were asking for opinions on in the consultation. So it's difficult to tell how it would change the process, as it is not clear how large a project would become an NSIP.
I'm still uncertain whether it would be appropriate, as I thought the point of fracking is that there needs to be flexibility to add more wells/ restore sites to agriculture etc, rather than develop fixed infrastructure...but I'm not an expert, obviously. There is also the "erosion of local democracy" aspect, which is a fair concern, though large developments like power stations and wind farms already use this process and it seems to work to balance local interest and national need... ( though there is always the question with any project, especially fracking, whether there is truly national need, which needs to be regularly revisited on a policy basis).