Friday, July 17, 2015

el nino

The bureau of meteorology says that we are in an el nino. This would explain the dry winter we are having so far.

As I said in planning for water scarcity, Winter is the time to prepare for summer*. Our rainwater tanks are now completely full. That is 37000 litres of water we have stored, and it is comforting to reflect on that as we head into a summer that may well involve water rationing (Adelaide's reservoirs are at 50% capacity).

Kitchen waste water

Last Summer we bucketed out kitchen water onto the garden, using it to water trees. I feel that this is not sustainable -- the bucket is heavy and awkward, and the risk of indoor spillage is worth considering. We visited some near by friends recently, Ash and Annie, who have set up a worm farm outside their kitchen window, into which their kitchen waste water drains. From the worm farm, the water drains to an underground sump from which a small solar powered pump drives the water around their garden.

It's a great setup and inspired us to do something similar, but we wanted to try something a bit simpler (whether ours works long-term without blocking remains to be seen). My parents were able to get me a 200 L plastic barrel. I turned it on its side, and cut a square lid. We put some broken concrete in the bottom, covered it with geo-textile and covered the textile with compost and food scraps, before introducing the worms. I then cut a hole in the bottom and installed a hose plug, to which I've connected a hose that drains to citrus trees in the front garden. I expect that this hose will block up, and will need to be periodically "blasted through" with high pressure water.

Here is a diagram of the setup
Diagram of barrel. The barrel is on an angle (that was just the easiest way to get it to the optimum height), masonry inside it, geo-textile [soil barrier] on top of the masonry, worm bedding on top. The 50mm PVC pipe is shown, with small holes in the bottom to distribute the water inside the barrel. I added the tap at the front so that we can use worm tea when we want (worm tea on tap! ;-)

This has been running for about 3 - 4 weeks now -- the worms are not yet established, but it seems to be working so far. I think it has about 20 L per day going through it. The water that comes out is quite rich, and I'm hopeful it will make for some very happy trees!

Getting the PVC pipe from the sink to the barrel was very straight-forward. We have an S-trap under the sink. It has a rubber seal on the back, and the pipe that came out of that went through our outside wall, 90-degree bend and straight into the sewer. I cut that pipe near the ground, and was able to twist the whole thing sideways to point towards the barrel (the pipe swiveled within the rubber seal). Then I used some plumbers' glue to extend the pipe, and put another 90-degree bend in it directing it into the barrel.
The waste-water worm farm. The pipe is visible exiting from the kitchen on the right. Below that, the waste to the sewer is visible (blue arrow) where I cut it off and bent it around (the original path of the waste pipe is shown by the red line). Also visible is the (grey) join that I used to extend it (red arrow)


I managed to get the biggest free load of mulch ever. It was about 10 cubic meters, and I've been steadily moving it onto the front garden and the path. I now have lots of mulch in the front garden -- more than 40 cm deep in places. Need to be a bit careful here, as it takes quite a bit of rain to penetrate the mulch and get to the soil where the roots can access it. Also, mulch can deplete the soil of nitrogen as it decomposes. Immediately around all the trees, there is also lots of compost, which will hopefully provide sufficient nitrogen. Also, when I water the trees in summer, I usually give them at least 10L each so that will soak down into the soil. Such think mulch will help keep the roots cool and moist in summer.


Along with the washing machine and kitchen sink, the toilet uses a lot of water. I've been experimenting with a bucket composting loo that I empty into a wheely bin in the backyard. This saves water and retains the nutrients for the garden. I'm the only person in our house currently using this, but if we all exclusively used it it would save about 30 - 50 L freshwater per day. My plan is to build a bucket composting toilet from plywood.
(By the way, I mix carbon-rich things in to the bucket such as cardboard and mulch. It doesn't smell at all)

Wood heater

We've had quite a bit of cold weather recently -- I finally replaced the glass in our combustion heater (it was missing when we moved into the house two years ago) and it has been fantastic. We don't need to burn a lot of wood with it, but it makes a big difference! I think it's original to the house (about 60 years old) -- it's really in very good condition.


I'm not really sure how to conclude this, since it's a work in progress. I've recently started another job, so am busier and fewer projects are happening, but I hope to keep turning things over. I've ordered a heap of acrylic sheeting to add secondary glazing to most of our windows -- I will blog about this as I do it.

* This is a general truth I believe. For most natural resources (energy included) there are times of abundance, and times of scarcity. Use the times of abundance to prepare for the times of scarcity.

Thursday, July 2, 2015

Peak oil, debunked

For years, I've been trying to find a sensible debunking of peak oil. Clearly, the reality that oil production will, at some stage, peak is incontrovertible. The debunking I was seeking concerned the nature of EROEI and renewables, and whether it would be possible to successfully transition from a fossil-fuel society to a renewable society in the sort of time frames that remain to us.

There are many peak-oil writers who contend that this is not possible and that because of this, industrial society will disappear over the next few centuries. I wanted to find an opinion that countered this (I like to read all sides of a debate).

Finally, I've found one: Bountiful Energy

This is a sensible, well-written blog that attempts to systematically dismantle the idea that industrial civilisation is failing because of peak oil. But, is it right?
(I encourage you to read it yourself, but here are some of my thoughts)

The good

The blog makes some new observations that I'd not previously seen in the peak oil debate:
  1. EROEI for oil in transport is a lot lower than reported because of the poor efficiency of the internal combustion engine. The author estimates EROEI of about 4 for fossil-fueled transport. This is a pretty low bar for renewables to clear!
  2. The author also develops the idea of cost of net energy, which is the cost of the energy gain from a process. He contends this to be more useful a metric than EROEI. I'm inclined to agree.
  3. The author observes that a lot of the embodied energy we see can be recycled. For example, a lot of the embodied energy in solar PV installations is used to manufacture the aluminium racking. This is almost completely recoverable at the end of life, and so that should be considered when assessing the EROEI for solar PV. This will make the EROEI of PV better.

The bad

The biggest problem I have with the blog, is that he appears to believe (I am discussing this with him) that pollution and environmental catastrophes will not affect industrial civilisation. My feeling is that it is impossible to separate peak oil from the effects of pollution since the extraction of more marginal fossil fuels (one can't call tar sands "oil" in any meaningful sense) is inherently more polluting (per unit of net energy) than conventional oil plays. In other words, the negative effects of peak oil could manifest as environmental degradation rather than high/low prices, etc. (quoted from a comment I left on his blog, to which he has not yet responded).


I will keep reading and thinking about his blog. My feeling for now is that it helps clarify for me the way industrial society is likely to follow the trajectory of limits to growth. For example, taking his blog at face-value, I could see industrial civilisation making a significant transition to renewables this century, but still failing to contain pollution which will drive down quality of life. This could also be seen to tie in with David Holmgren's brown tech scenario.

In a nutshell, the author of Bountiful Energy is bringing interesting new arguments and insights, but I am not yet convinced that the future will be business-as-usual.
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