The OpenEnergyMonitor system has the capability to monitor electrical energy use / generation, temperature and humidity.
The system is made up of five main units. These can be assembled and configured to work for a variety of applications. The system is fully open-source, both hardware and software. All hardware is based on the Arduino and Raspberry Pi platforms.
See https://guide.openenergymonitor.org/setup/ 
System Overview
Getting started with OpenEnergyMonitor