These kinds of questions are dumb af. Why? What do you think would reasonably happen if half the population disappeared in an instant? You don’t know when they’re coming back you just know they’re gone.
Yeah most people would survive but the electricity grid would probably go down, roads and airports would be shut down due to a instantaneous huge number of crashes, fires started might not be able to be put out due to lack of firefighters and no way to transport their equipment, etc. So not quite apocalyptic but probably comparable to a natural disaster or war across the entire earth.
Okay, all electricity goes out, planes start falling, sewage gets clogged, no more coal for heating so that goes away as well, no plumbers and repair men to fix shit. So, I'd assume a chaos.
Electricity would probably work for a day. Sewage plants have backup generators and can usually last a while even without them. It's mostly a gravity feed process. Except the wet well but they are always oversized.
Grid is constantly adjusted by adding and removing power plants from the system to meet the demand. This process is not always automated because frequency needs to be synced and sometimes that's really hard to do automatically. For solar it shouldn't be a problem, wind, steam and hydro are different beasts. Here's a nice video showing the process of connecting hydroelectric power plant.
Edit: Here's another video on the subject. Worth the watch.