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The 2020 challenge - Carbon Neutral buildings

GBCA has recently received numerous queries on the topics of 'carbon neutral' and 'zero net operating emissions'. We expect that we will continue to hear about projects wishing to pursue these goals.

The challenge has now been set for the property industry to take a closer look at how the buildings can be carbon neutral by 2020. Buildings need to have zero emissions in their construction, operation and embodied energy to be truly carbon neutral. Although it is possible to achieve zero net operational carbon emissions from buildings by 2020, truly carbon neutral buildings are a significant challenge.

How Buildings Achieve Zero Net Operating Emissions

It is possible now for buildings to achieve zero net operating emissions. There are already a number of projects worldwide that achieve this.

New and existing buildings are taking steps towards becoming carbon neutral now by including a range of initiatives and technologies:
- Passive design;
- On-site generation of energy from renewable sources;
- Efficient appliances and light fittings;
- Purchasing green power;
- Introducing alternative ways to learn; and
- Optimising, upgrading or removing HVAC systems
(Further information regarding each of these will be covered in this article)

How Buildings Can Go Carbon Neutral, Including Embodied Energy

Embodied energy is all the energy required to produce a building. This can include energy required for producing and transporting building materials, on-site processes for constructing the building, as well as demolition of the building when time comes.

There are some things that can be done now to reduce the embodied energy in buildings, such as:
- Measuring the embodied energy;
- Re-using and reducing materials;
- Re-using and refurbishing existing buildings as opposed to constructing new buildings; and
- Considering how the building material is transported.
(These will be discussed further in the rest of this article)

What About Green Star?

Green Star - Office Design v3 and Green Star - Office As Built v3 award maximum points within the Energy Calculator to projects that achieve zero net operating emissions by reduced emissions and on-site energy generation.

Currently in Green Star - Office Design v3 and Green Star - Office As Built v3 zero net operating emissions include the operation of HVAC systems, lights, hot water, lifts and other base building energy allowances.

Carbon neutral is currently not specifically rewarded in Green Star.

Moving from neutral impact to positive impacts.

Environmental impacts from energy use in buildings are important; however the environmental impacts beyond energy must be considered. Furthermore, the future goal is to go beyond negating the environmental impacts from buildings to create a built environment that is restorative to the natural environment.

Passive Design

Passive design refers to the use of simple design techniques that assist in controlling ventilation and the temperature of a building, without the use of any mechanical systems. This can be achieved through:

- Proper site orientation - ensure that the occupied areas are facing north while locating all services to the south, east, or west.
- Adequately sized, properly shaded operable windows to the north, while minimizing the glazing extent to the east and the west. Shading devices must be designed to permit solar access in winter, but ensuring that it is blocked in the summer.
- Using the right insulation for the right climatic conditions will ensure that the building's internal temperature stays at a comfortable level. Depending on your climate conditions, the amount, type, and location of insulation will change.

There are a number of techniques available that can also be used to increase thermal comfort in the winter and colder climates. The use of thermal mass in the project assists in controlling and stabilizing the temperature of a building. Materials that can assist in achieving thermal mass include concrete and rammed earth.

On-site energy generation from a renewable source

Sources of renewable energy generation are very varied in their source as well as their generation techniques. Energy sources that are acknowledged as "renewable" can vary from scheme to scheme, and provider to provider. However the overriding principle is that the fuel source is "renewable", be it the sun, the wind, the tide, the waves or even the crops that we grow.

Renewable energy generation can vary in scale from capacity equivalent to a small coal fired power station, e.g. a large scale wind farm, down to the photovoltaic cells you find on everyday calculators.

On-site renewable energy generation can take two forms: that of "building integrated" renewable energy generation, or "stand-alone" generation.

Building integrated solutions: An example
Solar hot water collectors can be mounted on the north-facing roof of a building to produce hot water to be used within the building. Photovoltaic panels can be used as cladding to a north fa├žade or even as roof tiles, generating electricity at the point of use.

Stand alone solutions: An example
Imagine an industrial site on the outskirts of the urban environment with good access to the right kind of wind. Here there is potential to build a medium scale wind turbine that feeds the buildings directly adjacent to it with electricity via its own power cable. At times of high production from the wind turbine, and low demand from the buildings on site, electricity could be exported to the Grid at times of peak demand, and at low production the building could draw on the Grid for top up electricity.

The Green Star - Office Design v1 certified project CH2 (Council House 2) in Melbourne has included on-site generation of energy from renewable sources in its design.

Efficient appliances and light fittings

Efficient light fittings in combination with intelligent control systems can significantly decrease the energy consumption associated with lighting in buildings.

The traditional light bulb can be replaced by efficient fluorescent lights, or even more efficient LED lights. These fittings produce a similar quality of light while using less energy.

An example of intelligent control systems is a motion sensor system, where the lights are automatically switched off when the space is unoccupied. Another example is individually controlled workspace lights - only the workspaces that are occupied are lit at appropriate levels.

Appliances in offices and homes are assessed under the Energy Star rating system, which is an international standard for energy efficient office equipment including computers, printers and photocopiers, as well as home electronics. More information about Energy Star can be found at www.energystar.gov.au. Specifying appliances that are labelled with Energy Star ensures that energy efficient appliances are installed.

It is important to consider the energy efficiency of all appliances and light fittings in a project, as well as to evaluate if all of them are necessary and how they can be placed in the space for best operating efficiency.

Green Power

Green power is a term typically used to describe electricity generated from renewable energy sources that is sold through the Grid by energy suppliers. This "green power" travels down the same cables as the electricity generated by coal fired power stations.

For further information see:

Alternative ways to learn, work and play
Innovative ways of living, learning and playing should be considered in the initial design phase of a project. One example of such thinking was implemented in the 5 Star Green Star - Office As Built v1 certified project, RAAF Richmond Squadron 36 and 37 Headquarters, where a hot desk system was introduced. The project team realised that all the employees will almost never be in the office at the same time, hence it was unnecessary to provide office space for all staff. This initiative reduced the size of the development, which in turn reduced energy demand, as well as the amount of materials used.

The many innovative IT-technology solutions that are available today provide opportunities for flexible workplaces. Designing workspaces and methods that encourage working from home and remote location can decrease the need for office space as well as the energy used for commuting to work. Education buildings can provide outdoor learning spaces, requiring less energy for air-conditioning and lights.

Optimise, upgrade or remove HVAC systems, cooling towers, etc.

There is potential to decrease energy consumption by optimising the operation of the existing HVAC system. This might have significant impact depending on they current state of the HVAC system. An additional benefit of this approach is that it doesn't have to require any capital investment.

The efficiency of HVAC systems has been improved significantly over recent years, with new HVAC technology that has been developed. Replacing an existing HVAC system with a newer model might be a worthwhile energy initiative, however it might be worth consider what can be done with the existing equipment in terms of tuning and installing advanced control systems. It is important to plan how the equipment that is discharged can be recycled or responsibly disposed. The existing HVAC equipment was upgraded in the Green Star - Office Design v1 certified project 500 Collins Street in Melbourne.

An energy initiative that has been implemented in the Green Star - Office Design v2 certified project Bushell's Warehouse in Sydney, was to remove the existing inefficient HVAC systems and replace them with innovative energy efficient solutions. The cooling towers in the Bushell's warehouse project will be completely removed, making room for additional roof top communal space. The colder temperature in Sydney harbour will be used for cooling the building.

Begin measuring embodied energy

Embodied energy can be used to demonstrate the environmental preference of competing products, and can provide a consumer with a powerful decision-making tool that is conscious of the need to reduce greenhouse gas emissions.

By demanding this type of information from the market, consumers can generate a market transition that would deliver positive environmental outcomes. The building and property industry has an important role to play in this market transformation since buildings include large quantities of products.

Transportation of building materials

Building products have to be transported from their point of origin to the construction site. The energy used for this activity is generally included in the embodied energy of products. This energy, while small compared to the energy used in the manufacture of the product, can be reduced by:

- Changing the mode of transportation, e.g. using train or ship freight rather than trucks;
- Using a fuel source with less environmental impact for transporting materials, e.g. hybrid vehicles or LPG;
- Smart route planning, where trips to several destinations in close proximity of each other are combined.

Additional research would be required if we are to accurately account for all transport-related embodied energy of building materials.