alt Hacker NewsIn the UK as a consumer you can (always AFAIK) get a smart meter for free, and your retail supplier is required to offer you a non-zero rate (the "Smart Export Guarantee") for what you export back to the grid. That can be as high as about half the rate to import.
To get paid for export you will nearly always need an MCS number to show it was installed by accredited professionals. Doing it yourself, or by your local electrician or plug in solar is not something they accept. It's a bit of a racket, but in practice pay up for the professional install or no export payments.