Category: Home Economics

One of the great strengths of the slow carb keto diet that I am currently on is that for the first time in my life, I have actually been able to fast successfully. In the past, many of my attempts at fasting have resulted in rapid drops in blood sugar, in turn leading to a partial loss of vision that has cost me the better part of the day.

Now that I have successfully adapted to the slow carb keto diet, this is no longer such a problem. While fasting is still occasionally difficult, I can make it through the day with a reduced food intake.

The slow carb keto diet has also led to a reduction in the total number of meals I take per week. From having three square meals a day, I have shot down to just two meals, lunch and dinner, with the obligatory butter-coffee in the morning to get me started.

In the spirit of one thing leading to another, it came as quite a surprise to find that I had reached the end of a batch cooking day and had managed a successful fast. One would think that being in front of food all day would have tempted one to hunger – but no, the concentration and rapid motions involved in batch cooking a week’s worth of meals led to a fast that happened virtually automatically.

I love to tease out the subtle benefits of things, and this particular benefit is as perverse and as subtle as it gets. The health benefits of fasting are well-reported, and while I never set out with this objective, it neatly folds into the nexus of keto-solar-batch cook activities that seem to be absorbing a chunk of my weekend.

I’ve recently been on a mission to rearrange my home cooking and energy utilisation around days of concentrated sunlight, so as to maximise the utilisation of free and available energy from our solar panels and minimise our energy expense. To date, every time that this has happened has been on a Saturday.

This is massively lucky. Saturday is my one real day off. I’ve been planning my menu ahead but it is frustrating when you look ahead and all your available cooking days have cloudy or rainy weather. On this occasion, we had a disappointing forecast of rain for the whole week, but it somehow managed to reverse, giving an impromptu day of sunshine.

Basically what this means is that I batch all my cooking into one sunny day, and simply have some form of energy consuming appliance running from morning until sundown. I bag leftovers from meals and freeze them for microwaving later, for use during cloudy periods where there’s not much free energy going.

I did the sums and realised that this process would save me between $500-$600 per annum, removing from the grid a drain of around 2200 kWh of power annually. That’s about a whole month of winter power.

It also has the effect of improving the return on investment of my 1.5 kW solar power system, without the need for battery storage. I’ve been fairly disappointed with the actual performance of my panels, which have once all the real world adjustments have been made, resulted in an annual ROI of between 4 and 5% (not amazing on a system that gradually degrades over time and may only have a 30 year lifespan). This change of use has the effect of pushing ROI up as high as 15%. Now all of a sudden solar panels can be worthwhile.

Not to mention the effect of retail energy price inflation. My sums have this at 3.11% annually, but during periods of peak inflation such as currently, it could be much higher.

The carbon emissions saving is much of a muchness, but given our reported current reliance on coal burning, it could be considerable.

Basically just really excited at my little innovation and wanted to share my nerd little achievement with the world.

I’ve recently been thinking about solar panels in a different way. Instead of dealing with capital cost and return on investment, which has chiefly been the focus of many of the other blog articles that I have written on this site, I’ve been instead thinking about managing solar panels from the standpoint of considering the diurnalilty of the sun and how we can tailor our food production approach to what’s abundant and currently available. This has led my thinking down a number of different roads, such as a general revised approach to seasonal cooking with regards to solar panels, and even looking at weather forecast applications to tailor my cooking regime and menu to the available daylight hours that can be found on a coming day.

Any New Zealand solar panel user has dealt with the frustration of seeing even small 1.5 kW solar panel systems such as ours massively overproduce in summer and massively underproduce in winter, relative to the household’s requirements. That’s the reality of living at a far point in the southern hemisphere. And many in the same position will have asked the same question – now that I’ve got them, how do I get the most out of them?

An example – the winter soup

Soups are most often associated with winter – nothing seems as warming as the thought of a freshly made winter soup in a warm oven during the colder months. Yet from an electricity consumption standpoint, if your oven is powered by electricity, then it is most likely that cooking things low and slow at a high heat intensity will result in your household overdrawing from the grid, resulting in higher winter costs and carbon emissions from dirty imported coal.

Far, far easier is it to have the soups pre-made, and simply resting in your freezer, to be reheated in the microwave when needed and in so doing to minimize the impact on your household when your solar panels are least able to support your consumption. From experience I can tell you that the flavour, if not the feel, of a reheated soup is no worse than when freshly prepared.

Solar panels are about facilities management. And there’s perhaps no greater conceptual leap in the facilities management of solar power than factoring in the integration of weather forecasts into home cooking plans. Each week I sit down at the local café and write my menu for the week. The step I have failed to consider, and which would be easy to implement, is to also look at the weather forecast for the next 7 days.

Anybody with a smartphone device is able to get relatively accurate weather forecasts through Google. At a glimpse, even in winter, one can see the relative levels of sunlight availability across each of the seven days to come (and even click into that day if you want more granular information).

By far, the least energy intensive process for heating food is microwave cooking for two or three minutes on a pre-made meal. Therefore, it stands to reason that on overcast or rainy days, we should rely on the microwave more heavily.

The most intensive is the stovetop and the electric oven. Therefore, it makes sense to have the oven running when the sun (and hence solar power generation capacity) is at its peak.

This leads on to other questions, such as:

–          How can space in the oven be maximized so as to produce multiple meals at once?

–          How can we manage the maximum storage life of freezers so as to ensure efficient recycling and minimum wastage of resources?

–          What do we have to mindful of in this process that may result in health risks?

The simple overall goal of this exercise is to minimize the kWh consumed on a basic task such as food preparation, ideally so that it can fit within the band of solar overproduction during peak periods. But I can see how following this process may lead to considerable time savings as well.

What this approach may point to is a more total shift in the thinking of how we move energy consumption from one time period (or even one season) to another. What do we need that produces energy? Then – how can we time our usage of energy to give us what we need in a way that’s least expensive and produces the least environmental impact?

In the spirit of sharing useful Excel spreadsheets, I’ve adapted Green Eatz’s table of the amount of carbon emissions from the type of food consumed into what I hope is a useful calculator.

The calculator shows you the same table, but applies it to your household. All you have to do is enter the “Amount my household consumes” column and the calculator will tell you the total amount of CO2 emissions that result from your eating choices.

That gives you a sense of the relative weighting of each food type. For me, it has been really helpful in helping me visualise the amount of emissions that result from each type of food.

For instance, even though my household consumes only a few kilograms of lamb per year, those few kilograms amount to almost ten percent of total carbon emissions from food consumption attributable to the household.

From that data it’s pretty easy to see what can be improved upon – but the improvements you make are entirely up to you. I’ve just done this based on a bit of curiosity about what switching to an EAT Lancet or vegan diet might mean for my household’s overall carbon emissions.