Saving the environment

Our new off-grid solar goes in

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One of the things we liked about our farm when we bought it was that it was truly off-grid. That means managing our own power, water and sewage. Truly living the eco dream!

What we weren’t so excited about was the terrible state of the solar generation system. It hadn’t been serviced in the last decade, meaning the lead-acid batteries had been allowed to go dry, the generator was failing, and the lights dimmed every time the water pump when on.

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The old batteries, hugely heavy (50kg+), which had been allowed to go dry

So a brand new PV system was required. Our immediate challenge was finding someone who could sell and install a solar solution.

Our farm is located in a rural setting surrounded by rainforest and fields. But it’s also just 10 minutes away from the nearest town, making it semi-urban.

The net effect is that very few of the local PV systems are off-grid, and few of the local installers had experience with off-grid setups. We wanted someone nearby to do the work, so we could get good post-installation support.

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Installing the new panels on the roof

It’s worth  highlighting at this point that there are power lines that run across a corner of our property. Connecting to the grid, however, would cost $20-30k, and then we’d have to pay electricity bills.

We ended up getting one good quote for a new system, for a total cost of $30k. So the same up-front cost, but with a lifetime of free power. That was an easy decision.

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The heart of the new system, a Sunny Island controller, and a Sunny Boy inverter

The key components of the system are as follows:

  • SMA 6Kw Sunny Island, which is a beautiful bit of kit that charges the battery and manages the local grid
  • 5Kw of solar panels, on the north-facing roof of the house
  • Sunny Boy inverter for the panels
  • 17Kwh of battery storage, utilising lead-carbon gel batteries
  • 7Kw Honda petrol generator, with auto-start
  • web-based interface for monitoring the system

It took the team three days to strip out the old system and to install the new one. Right from the beginning it’s been working well, and getting enough sun even in mid-winter (where the sun hits the panels at 11am, until 3pm when the sun dips behind the mountain).

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The new lead-carbon batteries, quite a difference from the old monster batteries!

A few notes:

  • The general rule of thumb for off-grid is to have 3 days of usage in the batteries, to cover off the occasional rainy week.
  • The generator has been configured to kick in if the batteries reach 30% of capacity, and to then take them back up to 70%.
  • We didn’t use lithium-ion batteries (like the Tesla Powerwall) because they’re not yet designed for off-grid, and the price is still too high.
  • The system operates as a “local grid”, allowing me to re-install the old PV panels on the new shed, connect them to a small inverter, and then just to wire that into the grid. T’he Sunny Island then manages the load across the system as a whole, which is a very elegant solution.

It’s early days for our solar setup, and we’ll report back as the months unfold.

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The new panels in place, three rows for a total of 5Kw

 

 

Railway passage garden going strong

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My guerrilla gardening alongside the railway passage
My guerrilla gardening alongside the railway passage

Back in 2014, I started planting alongside the pedestrian pathway that runs from Lewisham Station through to West St. There have been ups and downs, but I’m now up to 30 metres of garden, with a mix of small trees, bushes and ground covers (all natives).

And then I paused, as I’d been reported to the council for planting trees (shock horror!).

I ended up having a visit from the tree officer at Inner West Council, who turned out to be delightful. Not only did he approve of the work (his first question was: “are you going to do the rest?”), but he offered some free trees.

Council-planted native trees alongside the railway passage
Council-planted native trees alongside the railway passage

A month or so later, the council planted eight Lilly Pillies, plus a variety of other trees. This has doubled the length of the garden, to approximately 60 metres. Which is about half of the entire length of the passageway. Now we’re getting there!

I offered to mulch under the council trees, so I collected free cardboard boxes from the recycling bins at Pig and Pastry, plus free mulch from the Council. Two full ute loads of mulch later, I’m only half way. Phew! Still it’s good exercise, and there’s a palpable sense of progress now.

I’ll be at this for a few years yet, so say hi if you see me working away. And any volunteer help would be gratefully received!

Reworking our Aerobins

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One of our two Aerobins, alongside our worm farm
One of our two Aerobins, alongside our worm farm

At present, we have three Aerobins and one worm farm. The thing that makes the Aerobins special is the  patented lung ® or aeration core inside. This is a series of connected pieces that provides greater levels of circulation, and therefore faster decomposition.

The pieces of the Aerobin "lung", mangled through use.
The pieces of the Aerobin “lung”, mangled through use.

 

At least, that’s the theory. In practice, the pieces often get mangled when turning over the contents of the Aerobin, and several of my hat-like structures have been damaged beyond use. I know I’m not the only one to experience this.

A replacement aeration method, made of out 90mm pipe
A replacement aeration method, made of out 90mm pipe

Taking a suggestion from my dad, I emptied out each of the Aerobins, and removed the aeration core pieces. To replace this, I drilled holes in a length of 90mm polypipe, adding a cap on the end. (These are standard plumbing items that can be obtained from the nearest hardware or plumbing store.)

The result is a more robust source of air circulation, that should be resilient against day-to-day use. Touch wood, it should still give me the faster aerobic breakdown of compost.

The Aerobin refilled, with its new home-made air spike
The Aerobin refilled, with its new home-made air spike

Starting a new strip of guerrilla gardening alongside the railway line

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Bare earth and hardscrabble weeds, begging for transformation.
Bare earth and hardscrabble weeds, begging for transformation.

About six months ago I started planting natives beside Lewisham train station, taking the initiative where the council and railways hadn’t. That patch is growing well, although it’s constantly under threat from work vehicles which tend to drive down the pedestrian path.

So to diversify my risks, I’ve started guerrilla gardening the other end of the pedestrian way, where it meets West St. As can be seen from the photo above, it was hardly a delight for those walking by.

Having removed the grass and weeds, the soil is dug over and boosted with compost.
Having removed the grass and weeds, the soil is dug over and boosted with compost.

The starting point was to mattock over all the ground, breaking it up, and pulling out the grass and weeds. A full barrow-load of my best compost then went it to add some life back into the soil, along with a few handfuls of native-friendly fertiliser.

It's handy having a ute when it comes to collecting mulch!
It’s handy having a ute when it comes to collecting mulch!

Marrickville Council nursery kindly maintains a pile of mulch, for free use by locals. Now that I have a ute, I took full advantage 🙂 What wasn’t used on the new strip went to supplement the existing plantings.

A well-prepared strip of garden, ready for planting.
A well-prepared strip of garden, ready for planting.

The result is a new strip of guerrilla gardening ready to be planted. It’s also a great way to get some exercise, as it took a fair portion of a day to get everything done.

The start of a brand new native garden, for the enjoyment of all.
The start of a brand new native garden, for the enjoyment of all.

With a week of grey rainy days ahead (in contrast to the recent heat and humidity!), I got the first plants into the ground. Most of these were cuttings from my previous plantings, but I also added a few new things that I picked up at the council nursery. This included Indigofera Australis (native indigo) and Pomaderris Intermedia, both of which should grow into attractive mid-sized bushes.

Our mini green roof is getting greener

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Our mini green roof is finally, well, green.
Our mini green roof is finally, well, green.

Eighteen months ago we created a mini green roof over the far end of the chicken run. The main goal was to learn more about the practicalities of building a green roof, as adding a bit more visual interest to that corner of the garden.

It hasn’t been the easiest of journeys. Within a fortnight, the local possum ate our green roof down to the ground. The Australian weather was also punishing, even in this relatively shaded and protected spot.

The turning point was switching our planting strategy, narrowing down to two incredibly hardy plans: dianella and bracken fern. Both were transplanted from other areas of the garden, and they settled in quickly.

While it’s still got a little way to go, the photo above shows that the green roof is finally … green. Phew.

 

Completing the set: we now have solar hot water

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A shiny new set of 30 evacuated tubes on the roof
A shiny new set of 30 evacuated tubes on the roof

When the feed in tariff for solar electricity was put in place, we were one of the early movers, installing a 1.6kw solar PV system on our roof. With the limited space on our roof, we had to pick between solar electricity and solar hot water, and we chose the former.

Once we finished our renovation, however, we had 99m2 extra of flat roof to play with.

Nonetheless, we’d already purchased a super-efficient instantaneous gas system to replace our 1988-era electric hot water tank. We’d hardly be saving the environment if we threw that away, so solar hot water remained on the long-term to-do list.

With the likelihood of rising gas prices over the next few years, I recently looked back into solar hot water options.

What I discovered is that it was possible to reuse our instantaneous gas system as part of a solar hot water installation.

It’s simple really: the evacuated tubes on the roof heat up the water in a storage tank (shown below). The output of the tank goes through the instantaneous gas system. If the water is already hot, the gas system does nothing. If it’s only warm, it boosts it as required.

So no manual boosting or fiddling around, with a 100% guarantee of hot water.

We ended up purchasing a system with 30 evacuated tubes, plus a 300L storage tank. This is far in excess of what we need for two people, but with the roof partially shaded in winter, the extra tubes were chosen to ensure we take maximum advantage of the morning sun.

We’ll be getting back $1300 from the government for the STCs (solar credits).

On current gas prices, the payback period is 8-10 years, which isn’t great. But I’m expecting the gas prices to rise, which should seriously shorten the payback period.

Anyway, it’s good to complete the set of environment-saving technologies 🙂

PS. after 3+ months of no rain, we had 2 solid weeks of rain immediately after putting in the solar hot water. Not great for our solar generation, but good for the garden I guess 😉

The 300L tank gets squeezed into the side passage of the house.
The 300L tank gets squeezed into the side passage of the house, alongside the instantaneous gas system.

We’re opening our house for Sustainable House Day 2014

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One of the best things about our eco efforts is the way it helps us connect with locals from across Lewisham, Leichhardt and beyond. We’ve had many conversations across the front fence, about our vege patch, the solar panels, bees and more.

This year, we’re opening the house for even more conversations, as part of Sustainable House Day 2014.

On Sunday September 14th, 10am – 4pm, you’re most welcome to drop in for a house tour, and an opportunity to connect up with other folks interested in urban sustainability. (Note: we’re only opening on the 14th, and we won’t be opening on the 7th.)

Our house will be up on the SHD website shortly, which will give you the address a few days before we open the house. In the meantime, add the 14th into your diary.

See you soon!