There are several ways you may want to install and use emoncms. You can install it on say a raspberrypi based home server or your own remote server, or on your computer as a backup client for data logged on say emoncms.org.
Setup a raspberrypi to simply forward data to remote emoncms server such as emoncms.org
Setup a full web server using the raspberrypi and an external harddrive.
This is no longer a recommended option due to the limited number of writes available on SD Cards causing data corruption after a short period.