Thursday, November 01, 2007

Ahead of the (energy) curve

Mark has this annoying habit of taking the food out of the microwave when there is 1 second left on the timer. Because the microwave faces a window, it is hard to see the display. Thus, the next person who uses the microwave oven will enter in the time, wonder why it isn't working, realize why, then hit clear and reenter the time. This makes that person (usually me) very cranky. He couldn't wait one more second?

It turns out that there is method in his madness; even he was not aware of his brilliance. According to Action Earth, "The average microwave oven uses more energy powering its digital clock than it does cooking food."

When Mark leaves the oven at 1 second left on the timer, he is leaving it in the most energy conserving state, short of unplugging it. Think about it. 3 or 4 numerals to display the time or a single digit? And it's the one formed out of the fewest light bars!

Thanks to Bek's Friday enviropostings for the heads up. See more tips at Action Earth.

I have one more tip that Action Earth omitted. The energy usage on refrigerators is just an estimate, based upon typical usage. You can improve the energy efficiency of any refrigerator by keeping it full.

Why? Because, when you open the door, the cold air spills out and warmer air from the kitchen flows in. After you close the door, the refrigerator has to cool all that air down. Empty refrigerators use more energy than full ones. (Unless you keep nothing in your fridge and never open it. In that case, maybe you should unplug it altogether.)

As you use up the food in your refrigerator, put bottles of water to displace air. This is akin to placing a brick in your toilet tank to conserve water when you flush. While you are at it, fill your freezer with containers of water, too. As a bonus, all that ice and cold water will minimize food spoilage during power outages.

While I am enviroblogging, I might as well add a link to the story about the Great Plastic Garbage Patch aka the North Pacific Gyre.
Charles Moore, the marine researcher at the Algalita Marina Research Foundation in Long Beach who has been studying and publicizing the patch for the past 10 years, said the debris - which he estimates weighs 3 million tons and covers an area twice the size of Texas - is made up mostly of fine plastic chips and is impossible to skim out of the ocean.
Thanks to Here in Malibu for the heads up. Also, read more about the Great Plastic Garbage Patch in the Synthetic Sea. They find 6 pounds of plastic for each pound of zooplankton in the North Pacific Gyre. See the pictures of the junk on the Algalita website.

Aside: They do the analysis in Redondo Beach's very own SEA Lab (a good place to tour with your kids).


  1. Maybe he just doesn't like the bell? My toaster "ding" turns Waldo into a whimpering, quivering mess. Not that I'm comparing Mark with a dog, mind you.

  2. Anonymous07:40

    Thank you for that tip! I keep my freezer full of water jugs in late winter & early spring when it's mostly empty. I never thought about that for the fridge.

  3. Anonymous08:05

    I have considered (but never actually gotten around to) buying a bunch of timers to use around the house. The microwave, modem, VCR, etc. all use a lot of power when they are not being used. I could turn them all off during the night and save some power that way.

    There are products like the "Kill-a-Watt Electricity Usage Monitor" to help find the worst offenders.

  4. Anonymous12:32

    If you find yourself frequently taking bottles of water in and out of your fridge to make room for a new batch of groceries, then this probably isn't a net-win strategy. It takes a lot more energy to cool a litre of water from room temp to fridge temp than it does to cool a litre of air. --Eric
    (ps, seems to me you could address my objection by swapping _empty_ water bottles in and out.)

  5. No, Mark doesn't notice the ding.

    In response to Eric, that's a good idea. If you shop often, use EMPTY water bottles so your fridge doesn't have to struggle to re-cool the water in the bottles. Sadly, we shop only once a week so our veggies don't look or taste too good by the time we get around to eating them.

  6. In response to my buddy mimi -

    It's probably not too helpful to use a timer to shut the devices off, since the timer itself draws energy to run -- Probably a level of energy draw comparable to the clock on a microwave, for example.

    About that microwave -
    I wasn't convinced in my heart of hearts that it was a good calculation but then I made the following estimate:

    1300W microwave running 10 minutes a day = 130 watt-hours in a day.

    digital clock drawing 0.1A at 120V for a day = 288 watt-hours in a day.

  7. Grace,

    Eric's argument is true if you're frequently taking the water bottles in and out. If they are going to be in a long time, and you're opening the fridge a lot it could still be worth it.

    I also now have a good reason to leave spoiled and inedible food in the refrigerator until it absolutely has to be removed to make room for fresh groceries. And you thought I was just lazy.


  8. No, you don't want to leave spoiled food in the fridge because they outgas ethylene, speeding up spoilage of everything else in the fridge. You should know that.

    Bek put a power strip between the wall outlet and her microwave, which she turned off when she was done with the microwave. I wish more appliances had a totally off or "vacation" switch.

  9. Anonymous15:39

    Well, our fridge is bursting-full all summer when our farm share is coming every week faster than we can eat it, and mostly-empty all winter while we eat canned & dried foods and not much fresh. Same with the freezer, pretty much - it's chock-full now, but in a few months it will be mostly empty and probably stay that way until corn gets ripe in August.

    Plus, in Minnesota in the winter time, we can just put the filled water jugs outside for a while if we need to fill the fridge with beer or leftovers.

  10. Anonymous22:07

    Grace, have you tried those green Evert Fresh produce bags that supposedly keep produce fresher longer? I've been using them for years and maybe it's my imagination, but I think they do keep produce fresher longer than regular plastic or string mesh bags.

  11. No, I haven't used those bags. But I sometimes use those green disks that suck up (adsorb) ethylene. I do notice a difference when the disks are fresh.

    We are not the most organized household. Someone actually has to note when the disks have expired and remember to buy more before the one in the fridge stops working. But, if we had someone that organized in our household, maybe menus would be planned (and executed) so that the veggies get eaten in time.

  12. I realized that I confused 10 minutes with a 0.1 hour in my calculation above. If you use a 1300W microwave for six minutes a day then it's 130W-hours in day. 10 minutes of usage is 216W.

    Meals are often catch as catch can in our household too. I consider a bit of spoilage part of the cost of keeping enough stuff on hand so that I have at least two meal options. We compost, so anything that doesn't go rancid or have lots of seeds does go back to the garden.


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