In article ,
Colin Wilson writes:
They can supply about 50% of a homes electricity usage, as most is below
1.1kW. If using below 1.1 kW it turns the meter backwards. Grid-tied.

This brings into question the safety of using such generation devices.

Generators should be isolated from back-feeding onto the supply network,
and afaik no meters are yet available to allow the "export" back onto the
network for a domestic customer.

They've been in use in the UK for some 10 years at least.
Maggie's conservative government forced the electricity suppliers
to buy back any excess electricity a domestic consumer manages to
generate and offer to the grid. To encourage the market to get
started, the supplier had to pay for the metering and safety
equipment required to prevent backfeeding a failed supply (I don't
know if that's still the case). Actually, because the CHP equipment
has to sychronise to the grid supply frequency, to a first approximation
it can't actually work when there is a mains supply failure. There
were some add-on optional products proposed to enable a CHP system
to operate when the mains supply has failed, but when I last looked
(some time ago), none were actually at product status, only planning.

I spotted an article about an ex-environment minister (?) Donald Dewer I
think ? - who was extolling the virtues of being the first to use a "home
generation windmill" that simply needed to be plugged into a 13A socket,
but no mention was made of a method of isolating that supply from the
network.

You get a whole replacement meter setup which does the business.
(There's no dial going backwards. You have separate digital meters
recording what you used, and what you supplied back to the grid,
as the cost per unit in each direction can be quite different.)

--
Andrew Gabriel