So my solar powered slow cooker diet is going well, with loads and loads of stress free and delicious food experiments under way, utilising great local organic Kapiti produce. I wanted to take a further step in the sustainability direction, so I bought myself a rice cooker to work along with the solar panels.
Slow cooker meals are great, but they often aren’t self contained. You need a little something something (read: carbohydrate) to make it a filling meal. Hence the rice cooker.
In the past I’ve used the Absorption Method to cook rice. This is not super eco-friendly, because the Absorption Method requires that you heat a covered saucepan from cold to boiling, then allow it to gently simmer for 15 minutes while the liquid dissolves. Which is fine, but it results in the consumption of about 0.5 kWh in a spike of electricity, which is anathema to the “low and slow” solar powered slow cook philosophy. In effect, having a spike in electricity tied to a minor carbohydrate based side dish undoes much of the carbon efficiency that you get when you cook your main meal using a slow cooker that is powered by solar. That is particularly the case if the meal needs to be made in the early evening when solar power is unavailable and you’re on peak evening consumption time.
Not to mention that the Absorption Method requires twice as much water to cook the same amount of rice. Add that up over the eating habits of a lifetime and it’s quite a lot of water. Often, with the Absorption Method, you lose a layer of rice to the bottom of the pan, which often calls for extra washing and scrubbing and the use of more water and washing liquid to boot.
So a rice cooker is really just the logical way to go. I am totally foreign to using rice cookers, despite having grown up in Hong Kong, but the process really couldn’t be simpler. One of the first things I did was just measure the amount of energy consumption that gets used by the rice cooker. It came in at 481 W on “Cook” setting, and just 41 W on “Warm” setting. (This is a lot less than using even a small electric stove top, which could easily eat up 1000 W per hour.) Even with only 25 minutes on the boil it’s still a substantial energy saving.
More importantly, however, the lower wattage means that the rice cooking process can fit in nicely with solar power. Because our solar power system frequently produces around 300 Wh per 15 minutes (about 1.2 kilowatts per hour), the lower level of energy consumption slots nicely into our home power consumption without drawing anything from the grid.
In terms of what it will actually save me, if I don’t draw any energy from the grid for cooking rice from now on, let’s have a look:
So, for me, a saving of around 10c of power use per rice cook. Cooking rice about twice a week as I do should give me a payoff of $10.53 per annum. This amounts to an ROI of just above 25% on a $39 new rice cooker. So payoff for the investment should occur within four years.
But the bigger saving is in the time cost. Assume that it takes me even just a minute to soak and scrub a pot of Absorption Method rice, that would cost me 2 minutes per week or 104 minutes per year. If I value my time at $50 per hour, we’re up to a whopping $86.67 per year in time cost alone. Add on the savings from electricity and you’re looking at $97.20 total saving, an approximate ROI of 249% annually.
So once again, solar panels give you tremendous leverage in the kitchen when it comes to not only saving money but freeing up your time. The “low and slow” philosophy of cooking can partner well with various kitchen appliances that draw a steady flow of energy consumption. All it takes is a little bit of initiative and planning once the panels have been installed.
