Lessons in sustainability with off-grid guru Michael Mobbs

Michael Mobbs lives off grid in the heart of Sydney – yes that city of 5 million. I share what I learned at a recent workshop. 


While most of us spend at least few hundred dollars each quarter on household utilities, Michael and his family of four has spent less than $300 a year in energy and water bills for the last 20 years. His property has also captured and processed 2 million litres of sewer water on site.

This has been achieved through a combination of smart system redesign, energy efficient appliances and choice of materials, rather than intense personal sacrifice. To see where he lives, you can visit the Powerhouse Museum’s Ecologic exhibit, which features a replica of his terrace home, or take a house tour when offered. The kitchen (heart of any home I want to live in or visit) is bright, large and dispels any idea that living sustainably means a trade off between function and aesthetics.

I jumped at the opportunity to attend a workshop he was giving at the Barrett Sustainability House in Randwick, hosted by Rhubarb Food Coop. A group of us gathered – some renters, some owners, some renovators – to learn from one of the best. And learn we did. I could’ve listened and asked questions for much longer, and I thoroughly enjoyed the company of all the others present. For me, taking this workshop was less about bills today and more about up-skilling for the future, wherever I might be living. Rates are rising – here is some background. The best thing we can do is require less energy.

We can’t all immediately go off-grid, but there are plenty of low tech, common sense ways to help our homes use less energy and water. Michael covered a number of them (LED lighting, smart pantry layout, magnetic strip cheats’ double glazing’, making electric water heaters more efficient, etc.), but I wanted to share some of the big picture ideas, as he calls them. Here are some of the highlights of my morning with this local legend.

1. Saving water saves greenhouse gases too

When a household is charged for water, we are paying the base rate, i.e. the privilege of being connected, plus a variable rate based on how many litres we pipe in for taking showers, flushing toilets, washing dishes, cooking and so on. But that’s not the whole story. Water also has an energy footprint that is connected to volume.

Although pipes are a more efficient way to get water around town, rather than say bottling water in plastic and trucking it, it still takes a lot of energy to pump water to and from our homes. Potable water comes in, sewer water leaves, and rather unfortunately gets discharged into Sydney Harbour. It follows that Sydney Water is a major user of GHGs. The energy impact doesn’t stop there. In the shower or while washing the dishes, the water is usually 50-70% heated. The more we use, the more energy we use. Luckily there is a less masochistic way to address this than taking cold showers. Retrofit the shower head to use much less water. Aim for a flow rate of 7.5L per minute and you could achieve financial pay back in a matter of months. Not to mention, you’ll be mitigating the amount of sewage flushing into the ocean, and coal being burned on you behalf. Renters can take faucets with them when they leave. If you want a so-easy-why-didn’t-I-think-of-that way to test the flow rate, set a bucket under the tap, capture all of the water that comes out for 10 seconds. Measure how many litres come out, then multiply by 6 and that’s your L/min.

Anyone looking to go further in the water saving realm could either look to Michael’s layered multi-tank water capture and recycling system or communist Hungary (a fellow workshop attendee shared this story of his visit to relatives in Hungary and the rather resourceful way they made every drop count). Both are examples of where water is/was intentionally slowed and recycled as it travels through the home landscape. The latter by using plugs to capture anything obtained from the tap so that if could be manually trafficked to laundry, toilet flushing, etc. In both systems, the sequence of use matches the priority for potable water. Shower and cooking water is reused for clothes washing and toilet flushing. The output from that feeds the garden. Oh and the water comes from the sky, for free. Low tech stuff. I do my own version of this, especially during the summer.

2. Solar: buy the performance, not the hardware

Solar energy is undergoing a boom. Prices are down, installation is up. With that comes the challenge of understanding whether your solar installer is well-qualified. The best will take their cues from permaculture (observe for over shadowing and so on), the middling may simple design an inefficient system where batteries wear our prematurely, and the worst (including some of the largest and longest in the business) might not even manage to connect your panels to the house at all.

Resist the urge to focus on the hardware, says Michael. It doesn’t matter if you invest in the best solar panels in the world if they aren’t compatible with your inverter or commonly these days, your battery. Instead, focus on making sure the system is operating as proposed. Ask for a chart of the projected annual energy production and hold your installer to it. Specifically, negotiate up front to that 10% of the fee will be withheld until several weeks of successful system output. That timeframe should reveal any major issues that can be rectified without hassles like contract disputes and lawsuits.

3. Change is happening very quickly

LED lightbulbs are vastly outperforming CFLs. Try replacing these next time a bulb burns out. Sydney Opera House is doing this and will transition from a 3 month to a 13 year replacement rate!

The cost of solar panels is plummeting too, while output is rapidly improving.

Michael encouraged anyone renovating to future proof their homes by installing additional pipes to facilitate sequenced greywater use, using curved not right angled joints, and generally avoiding ‘baking in’ systematic inefficiencies. Future inhabitants will be able to tap into the design already there without re-renovating and creating tonnes of additional landfill waste.

4. Eat local 

The conversation veered towards food and specifically Michael’s aha moment. He described the moment he realized his home was sustainable, but he wasn’t, after meeting a chef at Google who was passionate about local food. What he learned was that while the average Sydneysider uses 260L of water a day in the home, an average meal consumes 1000L. And most of us eat three times a day and waste significant amounts. Consuming locally grown food not only connects us with the natural limits of our own land, it can save considerable resources.

How can we recognize local food? Short of growing it, the best way is to step outside the supermarket. Consider that labels and packaging may be thought of a way to broker trust between unrelated parties trading through long supply chains. Perhaps that’s one reason it’s hard to shop without packaging in the supermarket –  most of what’s on offer is not in season, and comes from far away. Farmers markets and food co-ops are incredible resources and we will lose them if we don’t use and value them.

5. Saving resources is not always about personal sacrifice

I half expected the workshop to be filled with the kind of lectures my Dad would give us: ‘put on a sweater!’ ‘ where are your slippers?’ ‘close the blinds!’ and so on (side note: Thanks Dad! You prepared me very well for Australian non-insulated homes.) The workshop was not focused on changing personal behaviours, but instead on smart system design, which is basically biomimicry, or in fact permaculture. Taking a shorter shower will have even more impact if you have a shower head that doesn’t waste water in the first place. Fans of Paul Hawken will recognize similar concepts from his book The Ecology of Commerce. He calls it radical resource efficiency. It’s not just about cycling resources for reuse, but reducing the need for those resources, while accomplishing the same or better results. Michael Mobbs’ sustainable home makes radical use of resources to slash his energy and water footprint, and yet he lives in abundance.

6. While we’re still on the grid, there are better energy suppliers

We had a group discussion about energy providers. On moving to Sydney, I chose to go with Powershop based on this Australian focused Greenpeace electricity guide. I can contribute a bit more and fund green and community energy projects, or just pay the regular rates and know that I’m supporting a better company. They also provide a tracking app and benchmarks to let you know whether you’re doing better of worse than the average for a similar sized household. If you’re in NSW and want to switch to Powershop, use this link to get $75 credit on your first bill (I’ll get a credit too).

Low bills and life skills

When we think of saving, there are grim cultural connotations of pain and sacrifice. And yet when we save money on energy, we have the capacity to invest in other areas of our lives. We can eat well, save for the future, take a job for the right reasons not for the money and spend more time with loved ones. None of us benefit from spending too much on inputs that flow rapidly in and then out of our homes as a result of endemic poor design. While some of us will be able to afford the high cost of energy as rates rise, pensioners, students and others on fixed or low incomes will feel the pinch rather strongly. I want low bills for me, and for everyone else too. For more inspiration, please check out Michael’s blog. If you have the chance to meet him or tour his home, consider it an excellent investment in the future.

3 thoughts on “Lessons in sustainability with off-grid guru Michael Mobbs

  1. As i used to live in the same suburb as Michael! I’m so sad that his many compost bins on the verges around the suburb were unable to keep functioning – it was such a great resource for an apartment dweller to dispose of green/food waste.

  2. I don’t think it was council. I guess they become hard to manage – using the compost but dealing with passerby putting plastic bags or nappies in?!

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