The road map to quick wins
What should be the first priorities in achieving buildings that are more sustainable and use less energy? Mike Malina of Energy Solutions Associates shares his experiences.
I’m often asked what is the easiest or quickest way to take action and make progress when trying to achieve a more sustainable and less wasteful building design or operation.
My answer is always to refer them to the energy hierarchy (Fig. 1). This assessment should be the basis for all processes and projects, and it is absolutely key to successful low-carbon building-services-engineering specification.
The most important step towards energy efficiency in building services is to make the energy hierarchy the underpinning strategy behind every design, installation and operation for the future. It is a simple but extremely effective strategy. It is also important to remember that achieving a good plan based on this hierarchy will also improve the cost-benefit analysis on projects. Too often, people think that ‘green’ building is expensive, but energy efficiency and cost savings are actually coterminous. It is all about the long term. Short termism is the enemy of sustainability, along with a host of other things in modern society.
The energy hierarchy shows us that it is important to reduce the need for energy and water use in the building’s design in the first place. This means considering various factors, like making sure that the building’s lifecycle is taken into account.
It is important to examine the energy flow in the entire lifecycle of all materials that go into the building, minimising resource use and any waste.
First there is a need look at the external envelope of the building. It is important to conserve the energy, so why design something that will be naturally wasteful? Having studied the building envelope first, the designer and engineer then need to ensure that all the systems are integrated so that they naturally use the least energy possible. At the same time, it is important to look at the carbon impact and usage of the materials involved.
In the first stage of the design process, therefore, the designer has to look at the embodied energy, which refers to the amount of carbon used to manufacture and transport the materials and the energy input within the process. This should be the first priority in any building design.
Fig. 1: Cost-effective use of resources — using less energy more efficiently offers greater environmental and financial benefits than investing in low-carbon and renewable energy sources.
Secondly, it is important to use energy more efficiently in the building once it is being operated. This can be significantly affected by the early design process. The key point in this second part of the process is the issue of systems integration and controls. This involves utilising building technology and controls to monitor and operate the building services, and to make sure that all the building services performing different tasks are integrated, not competing against one another. It means working for the benefit of the operation of the systems themselves.
This hierarchy means that steps one and two can be taken into account from the start of the design process. Only then do we need to consider the third element of the energy hierarchy, and to start looking at the supply of energy from renewable and low-carbon technologies, because this can only sensibly be done once steps one and two have been undertaken.
In recent times, however, there is an increasing trend by society, building end users and designer for people to want to start the process with step number three. This is because there is a growing awareness of the need to utilise energy from renewable sources, and people want to help this process along. People want to be ‘green’. Therefore, many are going out and spending large capital sums on renewable and low-carbon technologies as they think it will help mitigate climate change.
Unfortunately, this trend can actually be detrimental to carbon consumption if it means that this aspect is focused on to the exclusion of working on steps one and two of the energy hierarchy (Fig. 1). The reduction in embodied energy from alternative technologies can be really insignificant in comparison to the savings that would be achieved by getting steps one and two correct. There would be a much better return on investment, in terms of both carbon reduction and financial savings, if these steps were taken to reduce the need for the energy in the first place.
When nuclear power first came along, the catchphrase was that it would be able to provide limitless energy that became ‘too cheap to meter’. We now know this was totally wrong. Nuclear is about the most expensive form of energy going, factoring in the issue of nuclear waste that always seems to be ignored in these equations
Despite this experience, similar expectations are forming around renewable energy sources. Once again, as a society, we expect it to produce limitless cheap energy. Sadly, it is not that simple. The technologies involved are very expensive, but will reduce in price as they become more established.
|Fig. 2: If a building leaks energy, those leaks should be put right rather than just continuing to meet the excessive energy requirement.|
I believe that there are far better things to do to save energy. By following steps one and two of the energy hierarchy first, we can reduce our overall need for energy and increase our control over its use.
People may feel good about installing a solar photovoltaic panel, but it takes more than 10 years to pay back.
If, by contrast, we reduce energy need, by for example, installing more insulation, developing more effective building-management systems and control strategies and implementing methods of energy reduction, the payback is comparatively very quick indeed. We need to think of the existing situation like a giant leaky bucket (Fig. 2). Plug the holes rather than pouring yet more resources, energy and water into it.
The combination of effective resource management in the design and whole-life building operation and the future for sustainable buildings will involve the use of the building information modelling (BIM) process that makes co-operative working in the construction team more realistic.
We will also need to see a much closer consideration of the building's life cycle, including its energy and water use over the long term and its actual performance compared to the design. At the same time continuous commissioning and maintenance should be a much higher priority for the future.
These principles will be the bedrock of a holistic approach that offers the best possibility of achieving low carbon and sustainable buildings.
Mike Malina is director of Energy Solutions Associates and author of ‘Delivering a sustainable built environment’, to be published by Wiley-Blackwell in January 2013