I have just finished detailed documentation of an OpenEnergyMonitor Solar PV Monitor system see: http://openenergymonitor.org/emon/applications/solarpv
The system monitors both generation and consumption and gives the user a clear indication of when their household electricity demands are being met by their solar PV array (green light on display) or when their not (red light on display). The display also shows how much electricity is currently being exported or imported.
The system is web connected, posting data to emoncms for logging and historical visualisation.
It has been suggested that installing a solar PV system results in decreased energy consumption and consumption pattern changes due to increased awareness of energy consumption verses generation. To enable these effects to take place the home owner needs generation level put into context with consumption level, in real-time. The OpenEnergyMonitor Solar PV monitoring system does just this, by simultaneously monitoring and displaying both generation and consumption. Most energy monitors currently available either monitor generation or consumption, not both.
The system is based on the emonTx, emonGLCD, emonBase and emoncms. All hardware and software are open-source and have been developed by OpenEnergyMonitor and contributors.
We would like to be able to offer the system pre-assembled in the future.
Please use the forums for discussion.
Here's a bit of background to solar PV monitoring in the UK:
The Feed in Tariff scheme (FIT)currently running in the UK pays the home owner a fixed amount per kWh generated, the home owner also gets paid a much smaller amount per kWh exported. At the moment (Dec 2011) most homes in the UK don't have export or smart meters fitted, utility companies assume, for calculation purposes that the home owner exports half of the power they generate. The cost of importing power from the grid is higher than the amount paid per unit of exported electricity. Therefore it makes financial sense for the home owner to use as much of their generated power as is possible.
A monitoring system with a real-time living room display indicating the amount of power being imported/exported allows the home owner to attempt to match their power consumption to the power being generated. I.e. make tea when the sun is shining! Financial benefits aside it can be very interesting and satisfying to monitor the yield of your solar PV system. To engage in discussion regarding this post, please post on our Community Forum.