The demandshaper module is not currently installed by default on the existing emonSD-30Oct18 image or earlier. We are including it by default on the new image that is currently going through testing emonSD-17Oct19 (original beta testing thread).
Im just in the process of doing another run through the image build with a couple of things fixed since the 02Oct19 version, it would be worth you using the new version. Im also going to write a guide on the DemandShaper module for https://guide.openenergymonitor.org that will hopefully help with using it.