Benchmarking Philosophy

eTool recently changed from offering numerous fairly localised benchmark options to a single international average benchmark for each building type.  The decision making process was interesting so I thought I’d quickly document it.

The purpose of the eToolLCD benchmark is:

  • To establish a common measuring stick against which all projects are assessed so that any project can be comparable to another (for the same building type);
  • To create a starting point, or “average, business as usual case” from which to measure improvements.

From the outset we’ve always understood that a benchmark needs to be function specific.  That is, there needs to be a residential benchmark for measuring residential buildings against etc.  The first point essentially addresses this.

The second point introduces some complexity.  What is, or should be, “average, business as usual”?  More specifically, are people interested in understanding how their building performs when compared compared locally, regionally, nationally, or internationally?

When we started trying to answer this question, some scenarios were very helpful.  If a designer wants to compare locally, the benchmark needs to reflect the things that are most important to the overall LCA results.  The two most critical things are probably electricity grid and climate zone.  Localising just these two inputs gets pretty tricky and the number of possible benchmark permutations starts to add up pretty quickly.  In Australia there are four main independent electricity grids (NEM, SWIS, NWIS and Darwin).  In the Building Code of Australia there’s 10 climate zones.  Accounting for which climate zones occur within each grid, there’s about 20 different benchmarks required.  To add to the complexity though, the NEM is split into different states (New South Wales, Victoria, Australian Capital Territory, Queensland, Tasmania and South Australia).  Generally, because the National Greenhouse and Energy Reporting guidance splits the NEM into different states, the NEM is usually considered as six different grids. So there’s upwards of 50 different benchmarks we’d need to create and maintain for Australia alone just to localise electricity grids and climate zone.

One disadvantage of this method is it’s still not all-accommodating.  It doesn’t account for remote grids of which there are many in Australia.  An example is Kunnanurra which is 100% hydro power.  So even in this scenario where we had 50 or so benchmarks for Australia, there’s still big potential for a designer patting themselves on the back for a great comparison to the benchmark when really it’s just a local condition, and vice versa.  The same can be said about an off grid scenario (effectively just a micro grid of it’s own).

The other disadvantage is maintenance of all these benchmarks.  Expanding the above scenario internationally there could easily be 1000’s of possible benchmarks.  There’s so many that it would be hard for eTool to initially create them, and even harder to subsequently maintain them.  Clearly the localised benchmark option had some big challenges.

At the other end of the benchmarking philosophy we considered just having generic benchmarks, or even one global benchmark.  This is perhaps a more user-centric, or building occupant sensitive system.  That is, the building occupants are probably more interested in this measure as it’s more about how they live compared to the global community.  So a building may be “average” compared to the local context, but actually be very low impact compared to the broader average (due to favourable local conditions).  Conceivably, the local conditions contributing to the ease with which a building can perform may be part of people’s motivation for living in a particular area.

The disadvantage of the generic benchmarking approach is that it isn’t as useful for a designer to compare their building’s performance against this as the local conditions (which may create a significant advantage of disadvantage) aren’t considered.  This was a big consideration for us, eToolLCD is a design tool, it has to be relevant to designers.  Interestingly though, the way eToolLCD is generally used is the base design is modelled, and then improvements are identified against this base design.  The benchmark is usually only used towards the end of the process as a communication and marketing tool.

Also, there’s no reason why the designer can’t model their own local benchmark, for example, a code compliant version of their own design.

This topic spurred some serious debate at eTool.  In the end, the deciding factors were:

  • A local approach couldn’t really be adopted without localising at least the grid and climate zone for each benchmark option.  That is, it would have been too difficult to go half way with localisation (for example, only localising climate zone and not grid), as this really just revoked the whole advantage of localising the benchmarks.
  • Taking the very localised approach was going to put a huge benchmark creation and maintenance burden on eTool which wasn’t necessarily productive
  • The choice of a generic benchmark didn’t detract from the function of eToolLCD as a design tool.
  • Greenhouse Gas pollution is a global problem not a local problem, we feel people probably need to measure and improve their performance against a global benchmark rather than a local one.

So the single global benchmark was the direction we choose.  Once this decision was made, we needed to determine how to statistically represent global averages.  We decided to choose an aspirational mix of countries to make up the global benchmark, that is, select the standard of living that we felt most people in the world aspire to and determine the average environmental impacts of buildings in these demographic locations.   This does mean the global benchmarks are generally higher than the actual global average building stock for a given function.  That doesn’t stop us from estimating what the sustainable level of GHG savings is against this aspirational benchmark (90%+).  It also enables us to strive for this level of savings without adversely effecting our standard of living aspirations (globally).  The global benchmark created using this approach is the residential benchmark.  More information about how this was conducted can be found here.

For those people or organisations that would like a customised benchmark, eTool can provide this service.  Please get in touch.

A Rough Carbon Budget For Buildings

Why A Carbon Budget?

As we learn more about greenhouse (GHG) pollution and global warming we’re getting better at understanding cause and effect. There’s lots of complexity, obviously. However, the variables are slowly being identified, tested, and fed back into the models. Last year the media latched onto a story that global warming had ceased. I wish the stories indeed did debunk climate theory. Unfortunately not. We’re just in a period of warmer oceans and cooler atmosphere. Will Steffen explained this in a very objective manner when questioned in the Senate Committee on Extreme Weather Events (see page 12 of this transcript). Anyway, all the scientific research into climate change now enables us to make predictions of warming based on the volume of GHG we release into the atmosphere. And we’re even able to make predictions about what effects this may have. The below infographic is an incredibly good summary of these predictions, and the background data is rock solid if you’re interesting in looking into this further.

KIB_Gigatons_CO2_Apr14_A4

 

It’s pretty clear we need to try to limit warming to two degrees. The big reason for this is that there are tipping points for our climate, which trigger events that force more warming. Some examples include melting of arctic tundra and stored methane, release of methane from sea bed methane clathrates or the collapse of the amazon due to drought and fire. We don’t actually know at what point these events will happen and they may even happen before we get to two degrees warming. What we do know, is that it’s highly likely they will happen if we keep warming the planet. Even without these events occurring, we’re on track for four degrees of warming by the end of the century. Four degrees will probably put so much pressure on food resources there’ll be major global conflict. Not over land, or oil, but over food. It could get very messy.

A Per Capita Carbon Budget

So, we need to work out how much more carbon we can release to avoid these events, we need to set a budget. There is actually a level of GHG pollution that the planet can happily cope with naturally through chemical and biological sequestration. It’s a rubbery number, but sits at about 2.0 tCO2e per person. In 2050, accounting for population growth, we really need to be aiming for approximately 1.0 t CO2e per person per year which would actually enable us to reduce the GHG in the atmosphere. This, then, is our sustainable level of GHG emissions on a per capita basis. Some calculations on this here and here (with slightly different results).

Apportioning to Economic Sectors

Relating this to buildings is a little difficult because we don’t really know how the economy is going to decarbonise. There might be breakthroughs in certain sectors that enable it to effectively zero its GHG emissions, whilst others may find it very hard to shake the existing thirst for fossil fuels (or land use change). If however, we assume that all major sectors of the economy decarbonize together, then we can essentially take each sector’s current percentage of GHG emissions and multiply it by 1.0 t CO2e to yield the per capita budget for each sector. This is one of the best diagrams I have come across to explain GHG flows through the economy. It’s taken from a great publication called Navigating the Numbers.

GHG Flows

GHG Flows

In the diagram, the column “end use activity” is what we need to focus on to determine how current GHGs are apportioned across our economy. Directly, buildings are responsible for 15.3% of GHGs. However, there are a lot of indirect emissions that relate to buildings if you take a life cycle approach to measuring an impact of a building. These include transportation of materials to the site, transportation of equipment and labour, construction energy, emissions relating to materials production, further transport, and equipment use to maintain the building. Then deconstruction, demolition and landfill emissions. There may also be land use change emissions associated with some building products, or urbanisation as well. If we make the below assumptions regarding the allocation of these indirect emissions to buildings (which are not based on research, but I believe are reasonable), we land at a number of 26% of total GHG emissions relating to buildings.

  • 60% of building energy use relates to electricity to determine distribution and transmission losses
  • 70% of coal is used for electricity or downstream processes attributed to buildings
  • 30% of oil and gas gets used for electricity or downstream processes that can be attributed to buildings
  • Unallocated fuel combustion is proportionally attributed to all end uses
  • 1% of air transport and 10% of all other transport relates to building construction, maintenance, design or management.
  • 50% of iron, steel and cement is used in building construction or maintenance
  • 10% of chemicals are used in building construction or maintenance
  • 25% of aluminium and non ferrous metals are used in building construction or maintenance
  • 10% of other industries are providing materials or services to building construction or maintenance
  • 25% of land use change emissions due to harvest and management of forests relate to construction and maintenance of buildings
  • 15% of all landfill gas emissions relate to disposal of construction waste
  • 75% of waste water treatment emissions relate to building waste water

Building Related Emissions

These assumptions and calculations at this point are moving pretty quickly towards “back of the envelope”. The only way I can really justify this is that there are no numbers out there telling us what is a sustainable level of GHG emissions for buildings. So don’t hang your hat on these numbers, however, in lieu of more robust calculations, here’s a starting point.

A Carbon Budget For Buildings

We can now set a rough carbon footprint for environmentally sustainable buildings at 260kgCO2e per year per capita. This will be split between residential dwellings and other buildings. If we assume the split is the same as the direct GHG split in the “Navigating the Numbers” flow chart, that gives us a budget of 168kgCO2e per year per capita for residences, with the remainder of building related GHG distributed to workplaces, hospitals, civic buildings etc. We haven’t done any work on how to distribute the remainder amongst these other buildings as it gets pretty complex but watch this space. For residential buildings in Australia, we have a lot of work to do to achieve this budget. See the below chart for a visual on that.

Australian Residential Buildings

Close

Although these numbers require more work to confirm, they provide some guidance in lieu of other sources. They display the extent of the challenge. In particular, note in the last chart that the target is many times less than even the embodied GHG of current “average” buildings in Australia. I extend on this topic in this post, exploring some lateral thinking to solving the challenge of hitting our carbon budget for buildings. Note, this is an update on the video attached to the next post so you may spot a difference in the figures.

 

 

Vote for eTool in GE’s Ecomagination Challenge

GE’s Ecomagination are looking for breakthrough ideas, technologies and innovations to help lower ANZ’s carbon footprint. They launched a competition back in August to search for the brightest ideas and there are only a few days left with the deadline closing in fast this Friday.

We’ve added our LCA software into the mix and would love your support!

All you have to do it head over the website here, log in via Facebook, Twitter or LinkedIn (only takes a second) and then hit the ‘I support this idea’ button. If you’re feeling inspired, leave a comment about our LCA and how you think it can help lower ANZ’s carbon impact!

Energy efficient fridges – a waste of money or saving the planet?

Although energy efficiency appliances have improved dramatically over the past decade, we’re always a little cautious about recommending highly rated energy efficient fridges to our clients, as the main focus is on temperature performance to keep food fresh for longer periods, which can become problematic when looked at a little more closely.

Let’s explain what we mean exactly…some fridges save on energy by having longer “compressor-off cycles”, which causes the temperature inside to fluctuate. Ice-cream is a good indicator of temperature fluctuation, as it can partially melt during the off cycle and then form gritty crystals when it refreezes – we’ve all been there! Poor uniformity may mean that there is a 3°C average in the fresh food compartment, but more than 5°C in other parts, such as the door shelf. This can result in milk going off much faster than you would expect or are happy about.

In terms of environmental impact, the embodied energy of the food is likely to be at least 10 times more than the energy consumed by the fridge, so sometimes a fridge which is actually less efficient and uses a bit more power can extend the life of food quite considerably, making it the more sustainable option! So what can you do to make a lower rated fridge even more sustainable?

Well, properly ventilated fridges can represent large savings in energy efficient houses and when considered as part of the kitchen design, it’s very simple to achieve. Clever options include sealing the fridge into the cabinets and making use of the cool air and exhaust ducting; the closed space keeps cold air inside and around the fridge, away from the kitchen. The air that becomes hot as it passes through the refrigeration mechanism is drawn either up to the ceiling and exhausted outside the house or over the top of the refrigerator and can be ventilated into an upstairs room such as bathroom or laundry to dry the towels.
The ability to increase the efficiency of a fridge with well designed cabinetry and ventilation is not related to the fridge specification, however, so is something we can comfortably model in our LCAs.

In addition to being wary of the energy rating and trying to implement the refrigeration air flow in your home,  we would always suggest buying the right sized appliance to suit your needs. A large model with the same star rating as a smaller model uses more energy and generates more Greenhouse Gas, and if you think about it, do you really need a gigantic fridge?
A cool cupboard will keep most of your fruits and vegetables in good nick in most climates, allowing you to choose a smaller fridge. Cool cupboards should be located in the coolest part of the house (usually your kitchen or pantry) and have good airflow in at floor level and out through the ceiling.

We know it’s become a bit of a habit in Australia, but try and think of a way to do without a second fridge to save on both the cost of buying and running it and the environmental impact of its use, manufacture and disposal.

Ongoing running costs can easily exceed the original purchase price of an appliance, so always add the purchase cost and the lifetime running cost together to get a more accurate picture of the total cost of an appliance. For example, a fridge that consumes 1kWh extra per day represents over $800 extra operating costs in a decade, without even considering potential energy price increases.

One last tip – especially if you have kids at home – hang a sign on the fridge door that says ‘Only open when necessary!’ Opening fridge doors only when you need to get something out or put something back in, as opposed to leaving it open whilst your make a sandwich, will save between 5-10% in running costs.

References:

http://sustainablehouse.com.au/ Michael Mobbs’ Book

http://www.choice.com.au/reviews-and-tests/household/kitchen/fridges-and-freezers/fridges-review-and-compare.aspx

http://www.yourhome.gov.au/technical/fs64.html