Power, Energy and the Pursuit of the Perfect Piece of (Off Grid) Toast
By Cam Mather
I love toast. I eat a lot of it. There was a great song from 1978 by the Streetband called “Toast” that hailed the merits of toast and it still plays on a continuous loop in my head.
Toast is the most versatile food in the world and you can do so much with it. I have it for breakfast. And often for lunch. And once in a while if we have “breakfast for dinner” I’ll even have some then. It’s an Atkins Diet nightmare but I know that toast is a staple of my 99-year-old grandmother’s diet, so I’m sticking with it. In fact I can remember being at my Great Grandmother’s house one day as she was enjoying a peanut butter and banana sandwich. She lived on them. Apparently my love for bread is in my DNA and I’m not going to fight it.
Most people don’t think much about toast, certainly not how you make it, but I do. It’s pretty basic, you put the bread in the toaster, and it pops up a few minutes later toasted. If you wanted to criticize someone’s cooking ability, you could suggest that they can’t even make toast (or boil water.) But living in an off-grid house, toast isn’t quite so simple for me.
Being electrically challenged (as I am) and having a friend who is an electrical engineer is a great test of a friendship. In the case of my friend Bill Kemp, the good news is that much of what Bill knows is self-taught. So when you ask him a question he doesn’t rub your nose in the fact that he knows something that you don’t. Bill just has a genuine love of sharing what he’s learned. I think this is what makes his book The Renewable Energy Handbook so successful. People can sense from reading the book that he genuinely enjoys sharing information.
My great challenge with moving off the grid has been learning the difference between power and energy, and believe or not, there is one. Bill has been persistent in his attempts to teach me the difference. When we moved off grid we got rid of all of our electrical appliances. I figured there was no way we could use an electric kettle or waffle maker, so we gave them all away before we moved in to our off-grid home. And quite honestly, back then, with just 480 watts of PV and a battery bank nearing the end of its natural life, it wasn’t too far from the truth.
A toaster uses a lot of power. Power is measured in Watts and our toaster draws 1200 watts. I have a 2500-watt inverter, so when my toaster is on it sucks up almost half of the inverter’s potential output. “Power” over a period of time is measured as “energy.” So if I run the toaster for 1 hour it would use 1200 Watts x 1 hour or 1200 watt-hours (1.2 kilowatt hours.) That’s a fair amount of energy. When we first moved to this off-grid house that would have been about 30% or more of our energy consumption for the day.
But of course your toaster isn’t on for an hour. It’s only on for a few minutes. If I made the mistake of saying that I didn’t use a toaster because it required too much “power,” Bill would quickly remind me that it was irrelevant because a toaster doesn’t use a lot of “energy.” It used a lot of power but only for a short period of time, so it wasn’t that big a deal.
I’m not sure why, but this concept took a really long time to sink in. If I had $10 for every time Bill said to me “Remind me to explain the difference between power and energy to you, Cam,” I’d be a rich man! And if I had $10 for every time that I’ve had to refer to Bill’s book to figure out stuff in my off-grid home, I’d be even richer. I used to try to sneak a question past Bill at one of our lunch meetings, but eventually he got to the point where he would say “That’s in Chapter 7 Cam” and I’d be forced to re-read the book to figure it out myself.
All this is to say that moving off-grid doesn’t mean you’ll have to give these things up. When we first moved to this off-grid house, we “grilled” our toast on the cookstove in a cast iron pan. In the winter we’d use the cast iron pan on the woodstove. But when the woodstove wasn’t on we used propane. Now I think of that as cheating. I moved off grid to reduce my impact on the planet so to shift a heat load from electricity like an electric toaster, to propane, isn’t doing the atmosphere any favors. In my province where more than 60% of the grid electricity comes from nuclear and hydro-electric with no CO2 produced, if I were on grid it would actually be even worse to use propane for this purpose.
Eventually we were able to buy an electric toaster to use here at Sunflower Farm. We continued to upgrade and add more solar panels and we got to the point where on many days the batteries are fully charged shortly after the sun comes up. So electric appliances started creeping back into the kitchen. Eating toast from a toaster was like being served the finest food in the finest restaurant. Toaster toast! What luxury! During a sunny spell I’d eat electric toast until I was sick of it.
Even now I’m still partial to grilling toast. I find an electric toaster dries out the bread more than grilling it. But Michelle prefers the real toaster. Last summer we replaced our batteries and we’re finally living the way we should have been all along. Previously in the dark months (November and December) I’d convince Michelle to grill our bread, but this fall I officially declared that Michelle could use the electric toaster whenever she wants. I remind myself that the toaster really doesn’t use that much energy. And if the batteries get drawn down during a cloudy period in November, we’re going to have to run the generator eventually anyway, so the additional energy used by the toaster is marginal. And so far this fall with our upgraded solar panels, 1 kilowatt Bergey wind turbine and new batteries we have only had to run our generator 3 times. This is fantastic!
Right now we have some Montreal style wood-oven baked sesame bagels in the breadbox. We also have some insanely healthy sour dough bread from Little Stream Bakery and some Stonemill Muesli bread in the freezer. I have a cornucopia of bread ready for toasting today. My heart is all aflutter! Fire up the toaster!