School's ICT energy consumption - Room 25


Room 25, where I sit now, is one of my school's computer rooms and has been since 1976; we go back a long way. Once it was a geography classroom and once I was a young teacher and once we hadn't thought about global warming.

The story starts not so long ago, but before Windows, before HIV-AIDS, before RM, before mobile phones....

Have you ever wondered what the power consumption of a 12” green-on-black cathode ray tube monitor in 1975 was? I thought not. How about a 1980's Neon striplight's power/lumen ratio?.. still no? Sadly I do know this kind of thing so read now the brief history of Room 25 and it's growing appetite for electricity and be very afraid.

Room 25 in its 'geography' time and since time began it felt, had, and seemingly always had, four 50 watt neon strip lights (the sort that have the uncanny knack of adding gloom when switched on), desks, chairs, a full-wall blackboard, some books, a book cupboard and that was it. High tech it wasn't.

Total power consumption max 200 watts (0.2 kilowatts)

It's the end of the 1970's, meet our mini-computer; the famed PDP 11 to be exact, plus ten terminals with green text on black screens. The every epitome of modernity we were where IT was at. The PDP had a 400 watt power supply and those black monitors drew 28 watts each. We had arrived! power consumption of Room 25 is now about a kilowatt (an electric kettle's worth).

The 1980's are well under way and thanks to Apple and IBM the Personal Computer is everywhere; it's time to buy into this revolution. Dazzled, we dumped the faithful PDP and bought twenty BBC Master Series PCs made by Acorn Computers, complete with monitors and external floppy drives (the big disks, 5.25” across and really floppy). 180 watts per workstation (in case you had hoped I might forget why I started this essay).

Room 25 now uses 3.8kw

These were good times but Apple's Mac had shown us.. well, shown us mice, actually; just how cool was that? Mice! We could not afford Apples and loved our Acorns (we ignored Apricot's products...what was it with fruit in that time?) so we bought twenty-five rodent-equipped Acorn RISC computers ending with the 7000 series, which, ultimately we networked together. Thus was the modern network room born.

It had bright white screens, mice, colour graphics and a 'server'. Health and Safety arrived at much the same time: twenty, 35 watt warm-light fluorescent tubes replaced the cheerless tubes and the dusty blackboard was replaced by a whiteboard complete with solvent-sniffing pens.

The Acorns were very power efficient (even if the monitors were not), the progeny of its ARM CPU found their way into millions of low powered devices such as mobile phones; allow about 220 watts per workstation (150 from the monitor).

Room 25 can now draw 6 kilowatts on full power (a washing machine + electric oven + iron + kettle)

As the 90's wore on into the new millennium, money was poured into schools for IT and it became clear that Microsoft, the Web and Interactive Whiteboards were to be our future. IT became ICT and now, as I survey my Room I see we still have 25 computers, but now I can hear the air conditioning softly running as it always does, day and night, and accompanying it the resonant hum from three gently cooled 'servers' settled the old stationery cupboard.

Glancing up, I look admiringly at the eye-wateringly bright ceiling-mounted projector and to the Interactive Whiteboard where I can watch YouTube clips streaming from the Web over our filtered and firewalled broadband link.

The air-conditioning uses 5kw; the projector 1kw; the servers 2.1kw; the computers 0.5kw each.

Room 25 really rocks now, running full-on, it draws 26 kilowatts of power.

We have two more 'Room 25's somewhere else in the school but I rarely leave this room; I hear they are nice - full of geographers no doubt. What next? Our computers do really need upgrading if we want the latest 3D desktops or to take full advantage of the multimedia and virtual learning environments (VLE).

We'll have to get another server at least for the VLE...Hmm... let me see, in this brochure you can get some decent computers for not very much money, ... 1000 watt power supplies, impressive.., and,gosh, that 'graphics' computer even has a 120watt graphics, well ok then, not cool, hot. But hang on a minute did I just say 26 kilowatts in the last paragraph, isn't that a lot?

* Let's check the figures. Room 25 has increased its power consumption from 0.2kw ...1kw...3.8kw...6kw...26kw, My next Room 25 though looks like being 37kw (the air conditioning needed increasing for the new PCs mentioned above) that's much the same power as my car.

I can see a problem looming here. Room 25 may start to figure on the Bursar's radar... especially If we keep having those power outages and the cost of energy keeps going up. . Worse, Room 25s are multiplying, everywhere. We have three at this school, and we also have Interactive Whiteboards in every classroom..50 in total at the last count.

I can do sums, let me see, the UK has about 5000 secondary schools and the pupil to PC ratio has dropped from 7.6 to 3.9 in the last 5 years, most classrooms will have a Interactive Whiteboards and all schools will have a VLE. My goodness...UK school computing is now using as much power as an entire coal fired power station can really it is: we're toast.

Is it necessary to use so much power? No of course not. We just think it is. Let's redraw my plans for Room 25. I can do all that I do in Room 25 for a fraction of the energy consumption. 90% less to be precise.

Room 25 ... rehab program

  • All workstations will be 6 watt (max) They will have embedded open source operating systems like the new Linux laptops and we'll either use them as personal computers or dock them to our existing monitors and keyboards.
  • All 150w CRT and old 50w LCD monitors will be replaced by 17" 20 watt LCD panels.
  • Power will be supplied by a 12v rail (because ordinary transformers waste 35% of the power delivered to them as heat).
  • The projector and Interactive Whiteboard will go and be replaced by a nematic light-reflective display which uses very little power indeed.
  • Three servers will be 'virtualised' into one server and we'll turn that horrible air conditioning off for good, thank you very much.
  • Each of the lights will be swapped for 4 watt white LED clusters.

Jump forward a few years: 2015: Room 25 Total power draw 2 kilowatts...planet saved. We are back to the power use of the early 1980's. Room 25 will have just as many programs; facilities and will be just as bright; air will be fresh.

Is this fantasy? No. I will still be able to run as much software. Can I do this now? Yes. Why aren't I then?