The original (very generic) title):
Government to go “further and faster” in becoming energy secure
The Energy Secretary outlines measures to protect consumers and make Britain energy secure.
They are speaking of panels in the 800W range which you can just buy , mount in front of your balcony or on top of your carport, and plug into a wall socket.
These things are wildly popular in Germany. The do not generate a lot of power, but armotize in about three years and save real money. (Depending on how old the metering technology is, they can also make the power meter spin backwards, which I think is only fair considering how much households pay for kWh, compared to energy-hungry companies, which get most of the the massive cost savings from renewables but don’t pay for the necessary upgrade of the grid).
Whether current is flowing into an appliance or into the grid depends on which of the two has the highest voltage at any given time. Current is the result of a voltage difference in a closed loop.
These batteries have a built-in inverter. The inverter can produce an output voltage. The electricity grid uses AC which means the voltage is not constant but rather always changing in a sine pattern. To control the current, the inverter can follow the sine pattern and increase amplitude to control an outgoing current, or decrease it to control an incoming current.
By the way, in many cases you don’t want to power the grid. So these batteries usually work together with a sensor placed at your electricity meter. That way they can induce just the right amount of current to power your home appliances without sending something back to the grid.