The site’s been kind of dark lately. I’ve been playing UFO: Afterlight after reading a review on the mods available for it. The mods make the game 2-3 times as good as the original. If I’m not doing that I’m researching solar. My electric bill for last month was 719 kW or about 1 kW-hr. This kind of solar array is $5-$10k. It adds value to the home w/o raising property taxes (in Texas). The house seems built for it with a low angle, wide, south facing roof.
Anyhoo, I saw an interesting article on Ars and a blog post from someone who went solar. At something like $10/kW-hr for wind/solar vs $1/kW-hr for fossil fuels, renewables are very expensive. The first step in gauging the size of an installation is to . It’s very eye-opening. The blog poster claimed to have lowered his usage by %20. Energy efficiency is free. Renewable electricity is expensive. You do the math.
The easiest things to do are using power saving features in computers, buy energy efficient appliances and HVAC when you need new ones, insulating your home in the attic, with a new garage door, windows, doors, etc., putting wall warts on a power strip to turn them off when not in use, putting microwaves and TVs on a power stip to turn them off when not in use, etc.
The computer power saving features are in all operating systems. They were originally intended for laptops to extend battery life. At the beginning, ~1995, these features were really buggy. However, with Vista and up they seem exceedingly stable. I have begun using them on XP, Mac, and Vista and really appreciate them. Some features save power will the computer is running. Things like turning off the monitor when not in use or turning off the hard drives.
Other features control how the computer “turns off”. There are three ways to power down or off. One is the power switch or Shut Down. This turns the computer completely off. It no longer uses electricity. Sometimes if you’re like me you have many things open and it would take 15-20 minutes to reopen them all. There are 2 modes for this. Sleep turns off everything except the computer memory. This typically lowers usage from ~100 W to ~2 W. If someone unplugs your computer while it is in this state everything will be lost. The other mode is Hibernate. Hibernate happens when the laptop battery is about to go out and the computer is already in Sleep mode. Everything in memory is saved to one huge file on the hard drive. You may have seen hibernate.sys in c:\ at around ~2 gig. Hibernate takes no power and when you turn the computer on all the programs are still running.
So what’s the difference between Hibernate and Sleep? Why risk losing everything because the power might go out? First of all, use the Save feature on your programms before doing either either one of these. You’ll save yourself from heartache along with your files. Power saving features are still not 100% reliable, especially on Windows XP and older systems. Hibernate takes longer to come out of than Sleep. If a computer is Sleeping and you tap the keyboard or move the mouse it is instantly on. In Hibernate, the computer is off and it has to boot up and the load the 2 gig hibernat.sys file. This takes a couple of minutes.
Computers are getting much better at conserving power. Laptops with limited batteries were a start. Today, huge, hot server rooms that house Google, Microsoft, and Yahoo servers are continueing this drive. In the past two years, Intel and AMD have agreed to maximize chips on instructions per Watt instead of fastest computer possible. AMD has a line of Energy Efficient CPUs introduced this year that use 45 W instead of 65 W. 3-4 years ago that was up to 95 and 105 W. Still, CPUs continue to get faster.
In addition, hard drive manufacturers are coming out with a line of energy efficient hard drives. Western Digital was the first to offer a 1 TB drive that use half the electricity of regular drives. ~6 W instead of ~12. If you’re interested in what the other components might use, Tom’s Hardware has a great article about running a regular computer on solar and auditing the components that went into it.
There are still challenges. The typical power supply is 250 W. You can buy them in excess of 2 kW. That’s right, the computer can use twice as much electricity as the whole rest of my house. The real travesty is that most power supplies are 65-75% efficient. I use a high efficiency on the XP box and it is 85%. The lost power goes into heat. In the summer you will be doubly charged, for the excess heat and the extra air conditioning.