Embodied Energy Building Regulations: Yes or No?

We read this great report from the College of Architecture, Texas A&M University that reviews whether there is a need to put in place regulations to enforce measuring embodied energy in our buildings.
At eTool we think a ‘whole of house’ approach is extremely important to give you the bigger picture when measuring your environmental impact and thought you would enjoy reading this too!

Here is the abstract summary:

Buildings consume a vast amount of energy during the life cycle stages of construction, use and demolition. Total life cycle energy use in a building consists of two components: embodied and operational energy. Embodied energy is expended in the processes of building material production, on-site delivery, construction, maintenance, renovation and final demolition. Operational energy is consumed in operating the buildings. Studies have revealed the growing signicance of embodied energy inherent in buildings and have demonstrated its relationship to carbon emissions.

Current interpretations of embodied energy are quite unclear and vary greatly, and embodied energy databases suffer from the problems of variation and incomparability. Parameters differ and cause significant variation in reported embodied energy figures. Studies either followed the international Life CycleAssessment (LCA) standards or did not mention compliance with any standard. Literature states that the current LCA standards fail to provide complete guidance and do not address some important issues. It also recommends developing a set of standards to streamline the embodied energy calculation process.

This paper discusses parameters causing problems in embodied energy data and identifies unresolved issues in current LCA standards. We also recommend an approach to derive guidelines that could be developed into a globally accepted protocol.

Click here to read the full report.

Australian Energy Use Explained

This is a really interesting topic. It turns out that Australia is extremely rich in energy sources.  I love the below diagram from the Publication “Energy in Australia 2010” by the Australian Bureau of Agriculture and Resource Economics and Sciences. Two things become very evident. The first is easy to see, we are exporting an ENORMOUS amount of energy. In fact, we export 10 times the amount import, and use only 25% of the energy we produce.  The other point of interest nearly needs a magnifying glass. There’s a tiny line at the bottom of the diagram signifying the flow of renewable energy production. It’s nearly insignificant next to the non-renewable energy production.  Although approximately a third of the non renewable energy we export is uranium (there is a difference between low carbon and renewable), it still highlights how dependent Australia is on fossil fuels.


Before going on, I’ll attempt to quantify the figures in the above diagram. What is a petajoule (PJ).  Well, one petajoule of electricity would power a standard 200W lightbulb for over 150 Million years.  Or in other words, would power 150,000,000 light bulbs burning non stop for one year. Of course you’d power a hell of lot more energy efficient compact flouros but let’s not go there. It’s A LOT of power. Where does it go? Well about 75% is exported and the rest of consumed internally.

Looking at the internal Australian demand for energy the figures get a little mixed up and hard to follow in the flow diagram. I’ll do my best to explain. We lose a lot of energy in the production of electricity (represented largely by the circle in the middle of the diagram). This is because your average coal or gas fired power station in Australia has a thermal efficiency of around 30%. So 70% of the energy created (heat) from burning the fossil fuels escapes directly into the atmosphere as waste heat. We also loose energy in tranportation (gas, oil, coal etc), transmission and distribution (electricity).

The remaining energy then finally makes it to the consumers in the form of electricity, distributed gas, LPG, diesel, petrol or other fuel. How we use this energy is listed on the right hand side of the diagram. The two that seem to get all the attention are “Residential” and “Transport”. The others actually account for more energy consumption (commerce and services, agriculture and mining, manufacturing). So we can very nearly breath a big sigh of relief in the knowledge that most of our energy consumption is related to industry and business – not our problem, right?  Wrong.

As consumers, we are the ones that demand that energy production. Sure, some of these goods and services are exported, however we also import (usually more) goods and services that in turn demand somebody else’s energy consumption.  So our personal energy use in Australia, when you average it per person is equivalent to leaving forty old energy guzzling light bulbs on all day all year.

So is 60% or more of our environmental damage caused by our consumption of goods and services? I ran a personal energy audit a few years ago to try to verify this. Quantifying the energy demand associated with residential electricity and gas was a piece of cake. As was the energy content of the fuels used in my vehicle.  Reliable coefficients for air travel were also easy to come by. Where it got tricky was trying to quantify the primary energy content of my groceries. Energy content of groceries? Yes, how much of the “Agriculture and Mining” energy use in the ABARE figures above were required to fill my fridge and pantry?

I found the data in a great report co-authored by CSIRO and The University of Sydney.  “Balancing Act, Triple Bottom Line Reporting of the Australian Economy” is a four volume, 400+ page treasure chest of economic and environmental information. It splits our economy into 135 sectors and includes figures for energy us and carbon emissions per dollar spent in each sector.  So by reading through this report, I not only understood how much primary energy my food was responsible for, but also realised that all my expenditure (from clothing, to healthcare, to recreation, to dining out) all had an associated energy requirement.

To complete my energy audit, I categorised all my expenditure from bank statements into the most appropriate economic sector, did some simple maths and had an energy consumption estimate relating to my goods and services. To my horror, it turned out that consumption accounted for over 60% of my energy demand (whilst transport AND residential made up only 30%). Consumption = energy. If we want to do the right thing by the environment, switching off the lights might not be where we should be looking. We should in fact be feeling about 10,000 times more proud of the refurbished 2nd hand couch (avoided consumption) than cleaning our teeth in the dark to avoid turning the light on.

So why is this information so important?
Read my next post “What’s Carbon Got to Do With Me” and I’ll attempt to explain this too.

Check out the sources of this article here:



This article was written by Rich

Comparing Solar PV Systems

There seems to be a lot of confusion over solar PV; do they ever pay for themselves, is getting more kWs better and are they the best way to offset? Our clients regularly ask us these questions, so we came up with a simple way to help you find the answers.

We’ve put together a short LCA comparing an average Australian 3X2 house (benchmark), one with a 1.5kW solar PV system and one with a 5kW solar PV systems to show you how they perform on cost, embodied and operational carbon and design life.

There will be quite a few numbers coming up on your screen, but don’t worry we’ll be summarising them afterwards…

So what did you think, still confused?

As you can see from the video choosing the right solar PV system for your home has the potential to save you money and carbon both in the long and short term. In this LCA we haven’t included any government rebates at all and have worked with an average of ‘one for one’ unit of grid electricity. This gives you an average indication of savings across the design life of your house, whether it’s 15, 35 or 40+ years.

Here are some of the final figures…


Total design life cost over 15 years Total design life cost over 35 years
Benchmark Home – $168,393* Benchmark Home – $208,144*
Home with 1.5kW – $167,982* Home with 1.5kW – $197,285*
Home with 5kW     – $167,023* Home with 5kW     – $171, 948*



Embodied and operational carbon used over 15 years Embodied and operational carbon used over 40 years**
Benchmark Home – 193,795 t Benchmark Home – 414,123 t
Home with 1.5kW – 160,922 t Home with 1.5kW – 321,386 t
Home with 5kW     – 80,107 Home with 5kW    – 104,474 t


As you can see, both 1.5kW and 5kW solar PV systems are paid back within 15 years. Further into the design life of your house, they will start to save or earn you money depending on how much electricity you are using, generating and exporting.

Eventhough 5kW looks like the best solution, the initial cost outlay is considerable and there are other factors to consider. If you are looking to build a carbon neutral house, (in terms of embodied energy) using a smaller 1.5kW system and changing elements of the construction method can help you acheive this.

Have a look at some of our case studies to see what size systems other people have used.

* These costs are approximate and based on the costings in the LCA at the time of assessment.

**This takes into account the replacement of the solar systems every 20-25 years.


Written by Siobhán McGurrin.