This one-page report contains my computation of our our total (direct + indirect) household carbon footprint for 2022.
We needed to buy about 4.5 tonnes of CO2 to achieve net zero emissions for the year. This amount was somewhat larger than last year primarily due to reduced solar PV exports resulting from lower solar production under the prevailing La Nina weather conditions.
Toward the end of last year, we reached 10 years in our house. In effect our energy transition has been underway for a decade. We made great progress in the first few years of the project but inevitably our action has slowed in recent years as we have neared our ‘fossil fuel free family’ target. So I have now decided to no longer produce ‘Annual Reports’.
From now on I will simply produce annual energy updates – these will simply show our aggregated energy use (+some carbon footprint data) for each year.
As far as I’m concerned there is one big transition step outstanding – the replacement of our aging Hyundai i30 with an EV. I’ve been really heartened by the surge in EV uptake in Australia in recent years, and can now see that it won’t be long before we have two EVs in the family.
Looking further out, I’m keen to get involved in V2G so that our house and EV more or less merge into one single (carbon-free) energy centre. Maybe we then get hooked up to a community battery? The energy evolution still has a long way to run!
This is our Annual Report for 2021. This is in the same format as the previous Annual Reports I have posted. Given the relatively mature state of our energy transition I intend to post much simpler and more succinct annual reports in future. I imagine that they will be in the form of an ‘Annual Update’ highlighting any key events and presenting energy/carbon footprint trends in tables and graphs with minimal discussion.
In summary 2021 was similar to 2020. I think for the first time in many years we didn’t make any major additions or changes to our house energy systems. The big win was in us getting a Tesla Model 3. It is absolutely wonderful! At last we now have an EV which is a total ICE replacement. This means that we can now go on extended road trips without having to resort to buying petrol.
COP 26 is now over. Ignoring all the hype, it looks like we are still on a trajectory of going to about 2 degrees of global warming. As far as I can ascertain this means that we are heading to around 600 ppm of CO2 in the atmosphere in the next 50 years or so.
Putting aside the predictions of catastrophic climate change at 600 ppm, those of you who are familiar with indoor air quality studies will recognize that 600 ppm is the level at which CO2 begins to effect human cognitive performance (scores in cognitive tests have been found to degrade once the CO2 in a room reaches a level of 600 ppm). Similar work shows that humans begin to get drowsy once CO2 levels in a room reach 1000 ppm.
If we do reach a CO2 global atmospheric background level of 600 ppm, ambient CO2 levels in urban areas are likely to be around 650 ppm. Prolonged exposure to levels of over 1000 ppm may well be commonplace. We will no longer be able to just ‘pop outside to get some fresh air’.
In my children’s lifetime I imagine that humans will be facing some real challenges, but with reduced cognitive function and a dulled sense of alertness. We are poisoning both the planet and ourselves.
In late 2016 I bought a CO2 monitor to check the air quality inside our house. On the basis of this monitoring, which revealed poor ventilation, we decided not to seal up our house in order to save energy. We chose rather to live in a fresh-air house keeping our windows open throughout the year. We coupled this with keeping warm by heating ourselves, not the air in our house. Very comfortable; very energy efficient. At that time I produced a Microsoft Sway which described my monitoring and decision making process.
Since that time I’ve heard little mention of indoor CO2 monitoring in the mainstream media but in recent weeks it has suddenly become a topic of great interest. Indoor air quality experts are now talking seriously about using indoor CO2 levels as an indicator for the likelihood of Covid 19 spread. High levels of indoor CO2 = low rates of fresh air exchange in a room = potential high viral load in the air people are breathing.
The moral of the story appears to be simple: monitor the CO2 in your living areas and ventilate well. In my view breathing good air, and minimising the spread of Covid, is more important than saving energy [though I believe in our house we have managed to both improve our air quality and lower our energy use].
For a whole range of reasons, not least my growing frustration with the lack of Government action on climate change, I’ve decided that I need to take more immediate action to progress our energy transition.
Without getting bogged down in details, I recently came to the conclusion that the best way to move quickly toward zero petrol use in our household was to replace our wonderful (not very old) Gen 2 Nissan Leaf with a Tesla Model 3. It appeared to me that I will only get full family support for being a petrol free household if we have an all‑purpose EV: an EV that will be a total ICE replacement car. I was very sad to let go of the Leaf but I’m sure it will find a good home – I believe adding one more great second‑hand EV to the car fleet in Australia can only be a good thing.
We just love the Model 3! It has met, indeed exceeded, my expectations.
In a similar ‘letting go of the past’ vein, I decided now was also the time to retire my much loved ‘home grown’ direct EV solar charging set‑up (I’ve written about this at length in my Annual Reports) and replace it with a ‘proper’ system: the Zappi. This works wonderfully well!
The photo below shows our Model 3 being charged by our Zappi in our garage at home.
I think we’re now much better placed to become a ‘two EV family’. Watch this space.
This short report contains my computation of our our total (direct + indirect) household carbon footprint for 2020.
The size of our total carbon footprint for 2020 was similar to the previous year but its composition was different. Our direct carbon footprint (petrol + grid electricity) was smaller but our indirect footprint was greater. The increase in our indirect carbon footprint was mainly due to us having a holiday in Singapore in 2020 as opposed to only flying to NZ in 2019.
We added a 6kW solar PV system to our house in April 2020 and this enabled us to increase our export of carbon free electricity over the year. Accordingly, we needed to buy a substantially reduced amount of carbon offsets compared to the previous year in order to achieve ‘net zero emissions’ status for 2020.
This is my fifth Annual report. Despite all the external struggles of 2020 we seem to have come through pretty much unscathed. The major event of the year was us maxing out the solar PV on our roof – we added a new 6kW system. The new system is export limited in order to constrain our total output to 15kW. Petrol remains by far the biggest fossil based contributor to our household direct carbon footprint.
We did a fair bit of work this year on ideas for reducing our indirect carbon footprint.
For some years now, I’ve wanted to try out a mobile FIR heater.
You’ll have gathered from my many comments on domestic heating on this site that I am a great fan of FIR heating. However, conventional FIR heaters are generally fixed panels and this can often mean that the beautiful low intensity radiant heat is not delivered in the optimum way to a receiver sitting in a chair. For example, there may be no room on a wall or the ceiling to fix the FIR panel close to the receiver; or maybe furniture gets in the way and blocks some of the radiant heat.
On the other hand a mobile FIR heater ideally allows a user to position the heater in a place which optimises the radiant heating experience.
After several years of trying in vain to buy a mobile FIR heater I finally decided to make one! I bought a conventional FIR panel (with the lowest power rating I could find – 400W) and instead of fixing it on a wall I attached it to a mobile structure which I have constructed. This can be seen in the two photos. [In designing and building this I was very conscious of the need for it to be safe – in particular I wanted it to be very stable and also to be able to be easily moved without a person’s body coming into contact with the hot surface.]
It is early days, and we have missed winter, but my wife seems to really like it. She has happily been using it on most evenings as we make our way through an unusually cool Canberra spring.