Effectively integrating design, technology and tools that reduce energy use and carbon emissions in our homes and businesses, and doing so whilst creating and using clean energy, is the way of the future.
Over the past few years, we have seen an increase in the uptake of renewable technology, a change in attitude and a desire for more choice. We have also collected a huge amount of data that is helping us to better plan architectural design, energy use, behaviour and technology application. But there is still a way to go before we achieve zero carbon buildings across the board.
Recently the Australian Built Environment Council (ASBEC) called for a national framework for residential ratings to be urgently established to ensure a sustainability rating is provided for residential homes, while setting firm national standards. This is a positive step forward, as a rating tool accepted by all will help people make informed decisions when buying or building a new home whilst ensuring buildings are constructed to a sustainable standard. Research shows that people desire information and value sustainability, so this tool is a must if we are to move forward cohesively.
Designing buildings that maximise their surrounding climate and environment to control indoor comfort is a first step. This ‘passive design’ is nothing new, but it cannot always be 100 per cent effective on its own. The concept was particularly popular in the 1970s, mainly in Northern Europe, with Australia slower to take up. During this evolution, there was a focus on insulation and keeping buildings airtight to keep heat and cool in, which was a game changer for design as having properly insulated and sealed building is proven to reduce energy use. Hence it is part of the building code.
Research into home energy and thermal performance continues today with projects such as CSR House in Western Sydney identifying issues specific to high performance housing that will allow further performance improvement. Another research project, the Lochiel Park Green Village in South Australia has proven that low energy housing is currently achievable through modern design concepts and building practices.
Of all the emerging technologies, rooftop photovoltaic (PV) solar is making the most impact, with a huge uptake in residential buildings. Five years ago, Australia’s solar capacity was almost non-existent but now we have five gigawatts of rooftop solar produced daily from approximately 1.4 million homes across the country. This amounts to approximately five per cent of Australia’s energy use.
A key reason for this increase in solar use is a decrease in cost. Technology is cheaper thanks to more prolific production of panels supported by government subsidies to installers. Now that costs have come down, the subsidies will probably no longer be necessary, as integrating solar in the design of new properties and adaption of older ones, is set to become the norm.
Recent developments in solar battery storage, which are being demonstrated at Josh’s House and at a precinct level at Perth’s White Gum Valley, will contribute to further uptake of solar as dependence on the grid is reduced. As Australia is sun-prolific, solar is of particular influence and you can see how energy is being supplied to the main electricity grids across Australia at any time during the day using this useful tool.
Overall, solar use is dominated by residential property, mainly because large businesses that use a lot of energy get significant discounts on their bills. However, for the small and medium sized businesses it is something to consider, particularly as businesses predominantly operate at daytime when the sun is shining.
The University of New South Wales’ (UNSW) Tyree building is a good example of how solar technology is being used to power a business premises. UNSW associate professor Alistair Sproul, who leads PV research and works in the building, explained that this highly energy-intensive-use building is producing 150 kilowatts of solar on its roof a day, which provides about 10 per cent of building energy load.
“The building has been designed to not only provide solar power for use but also for research, so it’s killing two birds with one stone. Since it was constructed it has provided us with a wealth of information,” he explained.
“Having rooftop solar on buildings is an efficient way to provide clean energy for a building and although we have been burning fuels for millennia to heat our homes and to cook, electricity is a relatively new technology. We are just getting smarter at creating and using it. Ultimately, everything we do will go to electricity and burning fuels for energy – particularly fossil fuels – will not be necessary.”
Tri-generation technology is another option for energy efficiency – but only for larger commercial buildings where it is exclusively used. Here, a gas powered generator is used to produce electricity whilst cooling and heating a building and its water. As it uses gas, this is probably not the ideal technology for the long term, however in the mid-term it offers some energy savings.
For older houses that need to be adapted, hybrid technologies help hybrid design. For example, you can install a highly efficient reverse cycle air conditioning pump that can run off your photovoltaic system. These pumps can draw as little as 400 watts, where an electric radiator might draw 2,400, so energy use is drastically reduced. This works best if the house is renovated to be properly insulated, sealed and shaded for the summer as it would be a waste of time putting in such a system if the house ‘leaked.’
There are also solar and wind farms, but they deliver power differently through transportation from source to resident, and they have to compete with wholesale price electricity, although progress is being made. Wind is on its way to being on par with fossil fuel prices, with solar a little way behind. However, a recent Bloomberg report says solar farm power is getting there, reporting that the average cost of land generated wind technology around the world dropped to $83 per megawatt hour in 2015 with solar falling to $122 per megawatt. A price on emissions and change in policy around the world will ultimately bring the price down further. It is important to note that rooftop solar is also competitive with energy markets. In many parts of Australia, it can deliver energy cheaper than fossil fuel derived electricity from the grid.
On the horizon there is also Photovoltaic Thermal (PVT) technology, which is still in its research phase. This is where heat created by solar technology is used in a similar way to tri-generation technology, except instead of gas being the energy source, solar will be used to heat air and drive a thermal cycle cooling and heat system. Colleagues at the CRC for Low Carbon Living are working on new designs for solar thermal suitable to go on roof tops, but this is still a while away.
All in all, the future is bright for integrating renewable technologies physically into our own homes and businesses or as a power source that is delivered. Mixed with passive design, ventilation and good materials to ensure a well-sealed building, residents and workplaces of the future will be built to a specification that ticks all the boxes and keeps energy use low and production high.
I predict that within the next couple of decades, many of us will be living and working in carbon neutral or positive buildings that tick all the boxes for a sustainable future.