Let’s talk embodied energy

We were lucky enough to stumble across a timber clearing auction recently and managed to snag a truck load of reclaimed Oregon (or Douglas Fir) beams for very little outlay. Oregon is a wonderful timber for construction. It’s light, easy to work with and has a high bending load capacity. The drawback is that it is very hard to get in long lengths and if you can find it, it’s also very expensive. The folks at Recycled Timber Discounters in Woodend were having a clear out of old stock – lucky for us! They are really nice people too.

So how come we need construction materials when we already have a shed? We built our first shed on a relatively small footprint for a number of reasons. Cost and space were contributing reasons. Every dollar we put into shedding was a dollar we didn’t have to put into the rest of the farm and similarly ever square metre we used up was area that couldn’t be used for production. So we built the smallest shed we could reasonably get away with.

However, there is a broader and more compelling reason – embodied energy.

It’s estimated that up to 8% of global carbon output is attributable to concrete and steel production up to 7%. But! When you need a farm shed to be erected quickly and be highly resistant to fire and weather impacts then a steel shed on concrete slab is the only affordable solution.  However, the emissions required to produce and construct that shed, even at a modest 50 square metres, were substantial and we are going to have to work very hard over the next couple of years to claw that back.

Literally everything we do has an environmental impact, even dying! That’s OK though! Dying is not OK of course, but accepting we cannot have zero impact on the environment is – because when you accept that, you can work to minimise or offset that impact. In later posts we’ll talk about closing the loop, that is, essentially putting back what you take out from natural systems and how we can minimise our impact on those systems.  However, there are some impacts that are difficult to offset quickly and embodied energy is one of those. Everything we make has a carbon cost in its sourcing and/or manufacture and often it’s not obvious. This article around the carbon footprint (paw print?) of your dog makes interesting reading for example.

There’s a lots of ways to address this issue, we’ll cover a couple now.

The parable of the cheapest shoes being the most expensive – given the modern disconnect in footwear and clothing between quality and cost this doesn’t really hold true anymore but hey it’s just a parable to illustrate a point – it goes like this; two people buy shoes, one person is of modest means and can only afford 20 dollar shoes, the other is comparatively wealthy and can easily afford  200 dollar shoes. The dearer shoes are exquisitely made and are intended to last a life time. The 20 dollar shoes however, are of dubious quality and last only 6 months of use. After 10 years the wealthy person has bought only one pair of shoes, the original 200 dollar pair, the other person has now had to purchase 20 pairs of the 20 dollar shoes. In total requiring twice the outlay the wealthy person made a decade before on their one pair of shoes.

There’s a whole thread around economic injustice woven into, what is on the surface is a facile little fable that applies to people and to nations, but that one is for discussion on another time. What is relevant to embodied energy that can be drawn from this fable is that if you cannot avoid a carbon cost or an environmental impact then make it only once and make sure it is defrayed over a very long time frame. Check out these vertical windmills in Iran that have been in continuous use  for over a thousand years! Now that’s an investment!

Not suggesting you should aim for a thousand year life span, but you should avoid anything that requires substantial carbon input in its manufacture or transportation and also outputs carbon on an ongoing basis or requires further carbon emitting inputs. Solar panels are a great example. Although they are warrantied for 20 years, for tier 1 panels at least (we’ll cover those in the next off grid post) their life expectancy is much, much longer albeit with some drop in efficiency. Check out this 60 year old solar cell.

After 2 or 3 decades solar panels have paid off many multiples of the carbon embodied in the manufacture against the emissions saved. They are very much the 200 dollar shoe. There are nickel iron batteries still fully functional after a century and strawbale houses well into their second century. There are nearly always solutions to avoid the 20 dollar shoe and the good news is many of them aren’t costly! They might require changes in lifestyle or circumstance to accommodate them, but such tradeoffs are not necessarily expensive. Trading floor space for energy efficiency is an obvious one. Building a smaller house that requires little or no energy input rather than a larger house that requires constant carbon hungry inputs. We shudder in horror driving through the developing suburbs of outer Melbourne when we see huge houses that are designed and constructed in a way that will require mechanical cooling and heating for the life of the building.

The other way to attend to embodied energy is to use material that is derived from atmospheric carbon wherever possible. But I hear you say “if there was only a machine that took atmospheric carbon and turned it into building materials!”. Luckily there is – they’re called trees – you might have seen them ;-). Which is why we are building our house from timber. We are quite literally sequestering carbon from plantation pine. In earlier posts we explained in part, the practical considerations behind our choice of building and this now is the ethical consideration. Although a timber house may not enjoy the longevity of a brick house for example, its contribution to atmospheric carbon pollution is a fraction of the latter.

There’s a whole heap of other carbon sequestering materials we will be using we’ll take you through as we build too! A really interesting method for house construction coming through is Hempcrete. Not only is it quite low carbon in its manufacture it actually absorbs more carbon from the air as it ages! A lot of carbon in fact, much more than was used to produce it. A pretty cool high performance building material, but still quite new and out of our budget unfortunately. On the subject of locking up carbon and some really innovating down cycling have a look the ByFusion’s waste plastic building system.

So this a long way of explaining why, for our various production activities, we didn’t just build one huge shed. We will build what we need close to the site of where we are growing that particular produce. And what’s more, we’ll build it from beautiful, century old timber that was economical and has no further carbon impact apart from sequestering it’s own carbon in our drying house, propagation spaces and the many other areas we’ll need.

Check you next time – stay well!