For UK users, the "Bright" product (see app stores) - which is also part-branded "Glow", almost like they want to set themselves up to fail - from Hildebrand allows for real-time access to smart-meter data (as in minute to minute, not delayed by 24 hours or even 30 minutes) via MQTT. It's essentially a modified consumer HID for smartmeters (the now ubiquitous little screens issued by energy companies to show consumption on an LCD display). It's cheaper, as well as more accurate, than the other devices mentioned here, albeit at the expense of providing a breakdown by circuit.