Even if your energy provider offers a tariff where your costs aren't going to rise for a fixed period of time, the money to pay your energy bills still has to be found - although you have the peace of mind that some of your outgoings aren't going to increase for a while, your take home salary isn't likely to either. This is why many homeowners are looking into fitting solar panels on to their homes, not just for environmental reasons, but to ease the pressure on their income in the long-term.
However, they aren't right for every home; your immediate thought might be that the UK is too cloudy, too often for them to be effective, but if you think of how much you can catch the sun, even on an overcast day, you'll realise that they're still a good deal. The actual issue might be with your home itself. For example, if you're not a homeowner, or if you live in a leasehold property, you'll need to do some serious negotiating with the landlord or the freeholder before you can install solar panels on your roof.
Additionally, if your roof is small, or isn't south-facing, solar panels aren't likely to be efficient enough to make a sizeable impact on your energy bills. If you have large trees providing heavy shade, or if you're in a built-up area with higher structures all around, the panels won't be too effective either.
Conservation areas can also present problems; where there are strict rules on construction and alterations to residential properties, regulations can be an absolute minefield, and you may find that solar panels aren't permitted. Even in less heavily-regulated areas, panels visible from the roadside may need planning permission, so do check before you go ahead.
As with any structural alteration, going to the experts is best; if neighbours already have solar panels installed, it's unlikely there will be any planning opposition, so do get recommendations from them on who to use for your own project. Talk through options, and do your own research - smaller energy bills could be within your reach.