The power station in your airing cupboard

[Tarrel]

These are not new but, as the article says, they have suffered reliability problems. They qualify for Feed-In Tariffs, like solar PV panels, so can represent a good investment. The beauty of them is that they generate electricity when you are more likely to need it (e.g. boiler is on in the evening to provide heat. Electricity also needed in the evening for lighting, TV, cooking, etc.), whereas solar PV tends to generate electricity during periods of lower demand. The big difference between MicroCHP and solar PV, is that I can't see a MicroCHP system lasting 25 years. This would need to be factored in when working out your payback period.

From a survival standpoint, they are hi-tech, rely on the gas supply continuing, and would almost certainly need electricity to start up and run, so not an ideal off-grid solution.

Now, if someone made one that would use the waste heat going up the chimney from my Rayburn, THAT would be interesting!