My electronic "smart" meter sends out a bunch of data every second by flashing an infrared LED and transmitting UART compatible data. To log this data (in conjunction with data my photovoltaic system provides via json) the following components are necessary:
Hardware: just add an infrared diode/transistor and connect to esp8266. Add housing and power supply.
Software: brew up a webserver that spits out json and maybe a web page based on spriteTMs http server for esp8266. Plug it into already existing logging software (e.g. cacti). Maybe add local cache/fifo buffer for raw data.
Future expansion might be possible by integrating esp8266s into the dish washer or other household devices to trigger them to run based on consumption/solar power generation. Another possible idea is to wire an esp8266 to an spi speaking display and show some stats etc.