How does the computer lab’s new procedure save paper?

Listen to a conversation between a student (S) and a consultant (C) in a computer lab.
S: Could you check the settings on this computer?
C: Sure. What seems to be the problem?
S: I’ve clicked print like four times, but nothing is happening!
C: Oh, this will be an easy fix. Today must be the first time you have been in the computer lab this month, right?
S: Yeah, that’s right.
C: All right. Well, on the first of this month we started something new. Ok, so you already know how to send something to the printer.
S: Right. That is what I tried.
C: So after that, we added a new step, printing stations.
S: What are those?
C: There is a station, well, a computer actually next to every printer now. You’ll need to go to the printing station and you’ll see a list of all the documents that people have sent to the printer. You’ll need to find your document on the list, and click on it.
S: Ok.
C: In the past, we had a lot of documents getting sent to the printer by mistake, so we ended up wasting a lot of paper. Hopefully, with this new system this won’t happen as much. Somebody might click print by mistake, but they are not gonna get up and walk to the printing station by mistake, too.
S: I see, thanks!
C: No problem. You’ll also see your printing allocation at the station, so you’ll know how many pages you have left for this term.
S: Oh, good. Last term my roommate ran out and had to pay for printing.
C: Yeah. It’s an issue. I couldn’t help but notice you are printing an application for the Green House?
S: Yeah. An internship, through the biology department.
C: Oh. Are you majoring in biology?
S: Engineering, actually. The internship is not really related to my studies, but it sounded interesting, and it’s good to branch out—learn about new things in different areas.
C: Oh, I ask only because I have a friend, someone I graduated with, who works in the Green House. He says it’s a great place to work.
S: Cool! Is your friend involved in their summer youth program at all? That is what the internship is for— helping run that program. I think a lot of people will apply for this internship. It’d be great to know somebody on the inside!
C: I don’t know exactly what he does there. I didn’t even know there was a youth program.
S: Oh. I heard about it on the radio, the participants are gonna be planting grasses and flowers and stuff for the new green roofs on campus.
C: Green roofs?
S: Yeah. They are basically gardens on the tops of buildings.
C: Why? So students here can study plant growth or something?
S: That is not what they said on the radio. They said that green roofs can lower the temperature inside the building, so you don’t have to spend as much on air-conditioning.
C: That’s a good idea!
S: Yeah! Also in the city, storm water runoffs, you know, rainwater that runs into sewers and local lakes and rivers. This runoff apparently picks up a lot of pollution from the pavement, Green roofs absorb some of that rain, which reduces runoff, which in turn helps the water quality.