Julie Boulton (the greening of) — Issue #21

I need to answer Andy’s pressure cooking question as he is threatening to stop reading this newsletter altogether unless I provide him with some research. Actually, he doesn’t want to read this newsletter at all. He would rather I podcast my musings because reading is so yesterday, however, because he sits two desks down from me at work and is wary of receiving my wrath should he choose to unsubscribe from this newsletter, he continues to read (and supply me with almonds) so I should reciprocate by providing him with research on pressure cookers.

Andy’s specific question — whether cooking using a pressure cooker is the most energy efficient method of cooking one can do — came about over a bowl of Andy’s homemade hummus — that he made in a pressure cooker. Andy really loves pressure cookers and Andy also makes super tasty hummus. Therefore, just for Andy, I am prepared to head on down memory lane, recalling my Dad’s most excellent caramel dumplings and my Mum’s not so excellent chow mien, conjured up with packet chicken noodle soup mix and cabbage, both of which were made in a pressure cooker in the 1980’s, to consider the environmental credentials of the pressure cooker.

I have to start with the fact that, last year, Husband and I bought what I thought was an amazing stove/oven combination for our house. A six burner gas cook top with double electric oven underneath. It is a beautiful, industrial looking thing that I thought I would love forever but now I am not so sure, largely thanks to Andy and his pressure cooker.

We chose gas as we thought it was way better than electric for cooking: more efficient, (it is — this has been proven…) cheaper (maybe not the case anymore) and produces better cooking results (I stand by this for wok cooking but Andy’s hummus has me thinking). I also liked the blue flame and am particularly fond of saying “cooking with gas” when I am cooking with gas!

Like coal, natural gas is a fossil fuel, which means it is a non-renewable fuel source. Like coal, it was formed over hundreds of millions of years from organic matter, such as plankton and plants, buried by sand, sediment and rock. Officially, it’s a naturally occurring hydrocarbon, (a particle made of hydrogen and carbon atoms), but consisting mainly of methane, which, coincidentally is the same thing that cows produce (and they produce a lot of the stuff — anywhere between 100 liters to 500 litres of the gas per day). Natural gas is split into two types: conventional gas, meaning it is easily extracted; and unconventional gas, which requires more sophisticated extraction technologies, (this is where fracking comes in).

Again, like coal, Australia has huge reserves of gas both on and offshore — it is Australia’s third largest energy resource after coal and uranium. But, happily, it is a little better to use than coal. Natural gas emits around half the carbon of coal when used to generate electricity. It is also easy to store, transport and distribute. But, ultimately, gas is a non-renewable resource and our supplies, (particularly supplies that are sold in Australia), are dwindling. If we continue to rely heavily on gas as a primary source of energy then conventional gas extraction may have to be supplemented by unconventional gas. Extracting unconventional gas from the ground, via methods like fracking, is an entirely different exercise to conventional gas extraction and the environmental impacts are not pretty, (see this article for some examples of what fracking results in).

So where does that leave me and my much loved gas cooktop? While cooking with gas is more efficient than electric cooktops, I feel a little uncomfortable that I am relying on a dwindling, non-renewable resource to boil my chickpeas, which go into my “not as tasty as Andy’s but I’m trying” hummus). Would a pressure cooker increase my chances at winning the hummus off that we are planning for the next work morning tea, and also be better for the environment? Yes. Yes, it would.

Here are the wins for Andy’s pressure cooker:

  • It can be powered by renewable energy (assuming he plugs it into a green power source);
  • It is the second most energy efficient cooking appliance after microwaves; and
  • It saves about 75% electricity comparing to a slow cooker making a similar dish.

Andy did also muse about whether cooking with a pressure cooker on an induction cooktop would be the best thing you could ever do. And he is also right about that (although, apparently, you have to change your method of pressure cooking cooking a little — see below for advice). The benefits of induction cooking include:

  • Energy transfer of 90% from the induction cooktop to the pot (compared to 47% by an electric burner and 40% of gas cooktops (it is estimated that up to 60% of the cooking heat is lost to heating your stovetop);
  • 90% energy efficiency in terms of power usage, using 2.8 kW to deliver 2.52 kW (electric cooktops are 55% efficient, using 2.0 kW to deliver 1.1 kW, and gas is 50% efficient, using 3.5 kW to generate 1.75 kW.

So what to do? I still love my industrial looking gas cooktop and I am not proposing to throw it out — which would be ridiculously wasteful and so not environmentally friendly — but I am a little wary of relying on it for all recipes, particularly for things like stews and boiling chickpeas. The 1980s reliance on pressure cookers and Andy’s fervant enthusiasm for the appliance is to be commended! See below for pressure cooker buying guides if I have also convinced you to get on board the pressure cooker bandwagon.

See you next week.


Natural gas versus coal

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Natural Gas Really Is Better Than Coal Science | Smithsonian — www.smithsonianmag.com 
 If too much methane leaks during production, though, the benefits will be lost

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Natural Gas or Coal: It’s All About the Leak Rate — Cool Green Science — blog.nature.org 
 As the arguments for coal versus natural gas play out in the coming months, the choice will depend upon the leak rate for natural gas.

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Natural Gas Emissions Will Surpass Those from Coal in U.S. — Scientific American — www.scientificamerican.com 
 Carbon dioxide emissions from natural gas–fired power plants will be 10 percent greater than emissions from coal-fired plants in 2016

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Gas prices will rise and there’s not much we can do to stop it — ABC News (Australian Broadcasting Corporation) — www.abc.net.au 
 The steep rise in Australia’s gas prices became inevitable once approval was granted for 10 giant LNG plants that lock the nation in to a competitive global market, writes Michael Janda.

Pressure cooking

Learn pressure cooking

Ways to Conserve Energy: The Cooking Efficiency Challenge — www.pressurecookerdiaries.com 
 We set out to answer a simple question: What is the most energy efficient way to cook? 4 loads of the Devil’s soup later we had our answer.


7 DO’s & DON’Ts of Pressure Cooking with Induction ⋆ hip pressure cooking — www.hippressurecooking.com 
 Unlike pressure cooking on gas, or an electric coil, induction cooking turns the pressure cooker’s base into the heat source — heating only the base of the cooker to cook the food!

Induction cooktops

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Induction cooktops — now we’re cooking! — Sanctuary Magazine — www.sanctuarymagazine.org.au 
 Going off gas can make both environmental and economic sense, as the ATA’s newly released report has found. The organisation’s Sophie Liu, who has recently made her own happy induction cooktop purchase, considers what this means in the kitchen.

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Induction Cooking: Most Sustainable Option for the Kitchen? — sustainablog.org 
 Induction cooking is a promising new technology that could make food preparation much more energy-efficient (as well as time-saving).

Green your kitchen

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Cook efficiently | Green Strata — greenstrata.com.au 
 Electric cooking can also be a major contributor to evening peak electricity demand. As electricity suppliers introduce time-of-use pricing or peak demand charges, it will be important to manage cooking demand. Gas prices are also increasing.

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10 ways to make your kitchen more green : TreeHugger — www.treehugger.com 
 Learn how to prepare food in an energy-efficient manner, use equipment made from sustainable materials, and dodge toxic chemicals with our “How To” guide

Fracking (unconventional gas production)

What is fracking? › Ask an Expert (ABC Science) — www.abc.net.au 
 We hear a lot about fracking as a mining technique for extracting gas from coal seams and shale deposits. How is it done? And when is it used?

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Victoria Becomes First State To Ban Fracking — www.huffingtonpost.com.au 
 It has been called a ‘win for regional Victoria’.

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The Fracking Facts | Something about Coal Seam Gas Stinks and its not the methane! — www.frackingfacts.com.au

Coal Seam Gas Mining is controversial, it is being spruiked as a cleaner source of fuel, but there is a growing lack of trust within the community and genuine anxiety about the future…fracking has the potential to cause many more serious long term problems, with the loss of valuable water and fertile land for producing food. Continue reading →


States reject PM’s urging on gas development — www.skynews.com.au 
 The states are rejecting calls from PM Malcolm Turnbull to relax restrictions on gas development.

Pressure cooker buying guides

Snap, snap

I have posted this before but it is somewhat appropriate here!
someone decided to no longer cook electric
the super efficient microwave
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