Going Green

Energy Savings

Did you know that MSU’s electricity bill was over $1.8 million last year? In a time where everyone is looks for ways to cut costs, save money, reduce carbon footprint, and preserve the environment, there are things YOU can do to help cut our energy bill and go green too.

Some ideas are obvious – like turnoff lights when no one is in the room or when you leave the office/classroom (you do this at home, right?)

Another way you can save money is to turn off your computer when you leave work. People occasionally ask if it’s better to leave a computer on or shut it off. The answer in most cases is to shut it off when it’s not in use. This will both save energy and extend the life of the hard drive and monitor.

How significant are the savings? Our own Dave Esping measured the power use of several different types of computers and monitors. What he found was that leaving your computer idle was like leaving a 40-88 watt light bulb burning 24x7. Turning your computer off, putting it to sleep or hibernating it when you leave will reduce energy consumption by about 73%.

LCD and LED computer monitors use very little power and only consume about 1 watt in energy saving mode.

But some of you know that it may take a long time to start up your computer in the morning – which might be the reason why you don’t want to shut down your computer at night.  PCs and Macs have two alternatives for you to use to cut power and get to work faster in the morning.

Sleeping and Hibernating

Both modes freeze the current state your computer is currently in. Say for example you have web browsers open to where you are doing research, you have e-mail open, you’re working on a Word document and trying to correct an Excel formula. When you sleep or hibernate your computer in the afternoon, then power it back up in the morning, all of your programs are where you left them the afternoon before. You just log in after a very quick boot-up and you’re ready to continue working.

But there is a slight a difference between sleep and hibernate. Sleep freezes the programs and goes into a low power state, so there still is some ‘brain activity’ since the computer’s memory is still being powered and refreshed while the hard drive and other devices are powered off.  In contrast, during hibernation the computer’s state is frozen, memory contents are copied to the hard drive and then everything is powered down. So although sleeping reduces power consumption, hibernation eliminates power consumption. Now, if your computer is asleep and there is a power outage, your computer will have to do a full system boot-up and unsaved work may be lost. (The exception is with Vista which uses a hybrid sleep so if there is a power interruption Vista will recover as if it were hibernated) Hibernation will bring everything back regardless if power was removed. So hibernation offers added benefits of lower power consumption and more reliable recoverability of your work.

Another difference between hibernation and sleep is the time it takes for your computer to ‘wake up.’ In sleep mode, some computer bypass power on tests and your computer will be up and ready to log in within 5 seconds. Hibernation may take 15 to 30 seconds to be ready to login on some computers since it has to copy the contents of memory from the hard drive to memory first. (your mileage may vary)

Have a laptop? Hibernation is the way to go since while it’s hibernating it will not use battery power. If you sleep a laptop, eventually the battery will drain and you’ll be back to a full system boot with a dead battery when you go to use it. So not only will your boot up time be reduced, but your laptop will be ready to go much more quickly and your battery live will be preserved.

Here’s the link to the results https://mavdisk.mnsu.edu/bryan/Esping_Powerstudy.pdf. Some interesting results are that laptops use much less power (20-30 watts less power than desktops), and Macs use much more power when sleeping than Dells.

Introducing Problems?

There is a possibility that sleeping or hibernating will result in some computer issues – like sound not working or you may find your computer does a full system reboot rather than waking up quickly. The ability for a computer to successfully sleep or hibernate will depend on the devices in it and the software and driver’s ability to recover gracefully from a sleep or hibernation state.

You may find that your computer doesn’t have a sleep or hibernate option. You can call the Help Desk at 389-5993 for assistance in enabling these options.

Terms:

Shutdown

saves files and closes running applications and then powers down your computer. When you power on your computer, the computer does a health check, checks files the hard drive for functionality, boots up the operating system, checks for devices connected to the computer, loads drivers, loads other programs that need to be ready for you to log in, and finally presents you with a login prompt. After logging in, you must open applications to begin working or communicating.

Sleep

keeps applications open and running in memory, but stops hardware devices and enters a low power state. Power keeps memory running an monitors keyboard or mouse activity. When the power button is pushed again, hardware devices are started and all running programs are still open and ready to use just as when the computer was put to sleep. Time to start up is a matter of seconds versus tens of seconds booting from shutdown. (NOTE: that if a computer is sleeping and power is disconnected, any program data that is in memory may be lost and the computer resumes just as if it were completely shut down.

Hibernate

hardware devices are stopped, and the contents of memory are written to disk and then power is shut down. When the computer is powered back on, memory is copied back from disk and then hardware devices are restarted. All programs that were running are still open and ready to be used just like when the computer was hibernated.

Hybrid

Windows 7 introduced hybrid sleep that puts the computer to sleep, but it also copies memory to the hard disk. In case of no power interruption, the computer wakes from sleep instantly. If power is interrupted while asleep, it wakes up from hibernate.

The difference between hibernate and sleep is that in sleep although power is reduced, it must still be maintained to successfully return from sleep. In hibernate, the computer powers down and power to the computer may be disconnected and all programs and settings will be ready to use. Vista uses a combination of hibernate and sleep.

So what is best option to use?

• Laptops - The best option is hibernate because no battery is drained while the laptop is not in use. Mac laptops will sleep until the battery is depleted and then it will hibernate.
• Desktops - Windows 7 hybrid sleep will go into low-power sleep as it also hibernates. In case of power interruption during sleep, all programs, data apps will always be ready to go in seconds. Macintosh desktop's sleep mode will greatly reduce power when not in use and will wake up in seconds so you can get to work quickly. For Windows XP, either sleep or hibernation is the best option depending on how long it takes to wake up from hibernation.

Pass on your ides to save energy to Bryan Schneider, Office of Information Technology Services.