Sci/Tech: Green construction

Friday, July 11

While new residential or industrial buildings inevitably have an energy and carbon impact, these can be minimised through planning and intelligent design.

A great deal of current policy focuses on the scope for increased energy efficiency and reduced emissions in power generation, but huge gains can be made by reducing the waste of this power once it is used, in domestic and industrial buildings. Green construction technologies, supported by clear, coordinated national and international policy, and augmented through innovative town planning, can help achieve this goal.

Building techniques

The ideal is to make buildings as 'passive' as possible, meaning they can satisfy most of their occupants' heating, cooling and lighting needs from the outside environment. On the construction front, research is needed to develop cheap glazing and insulation materials that can adapt to changes in lighting or heating loads over the course of a day or season, in areas where the climate is more extreme.

Growing public concern over spiralling fuel prices and climate change has meant that house purchasers are increasingly receptive to energy-efficient design, because of potential long-term financial benefits. However, psychological and institutional barriers prevent energy-efficient buildings being built as cheaply as their conventional counterparts:

• If engineers have to struggle with unfamiliar green-architecture techniques, they will incur a heavy 'transaction' cost through mistakes and delay.
• If renewable energy technologies are added, projects will have higher capital construction costs.
• Rental sector clients may have little interest in paying, as tenants reap rewards.

Policy and planning

These barriers can partly be overcome by mandating particular targets. Policy measures for new buildings are beginning to be implemented:

• Last year’s US Energy Independence and Security Act requires all federal buildings to meet specific goals, and introduces tougher energy targets for commercial and residential buildings.
• In Europe and elsewhere similar, or tougher, targets often are being made legally binding on many buildings.

However, the developing world is the most important focus for attention, as growing populations will necessitate significant increases in construction.

Related to policy planning is the issue of urban design, in which energy use can be made most efficient by restructuring (or designing afresh) entire conurbations.

Intelligent layout includes organising residential centres so that motorised transport is minimised, green spaces are frequent and energy from power stations is used efficiently.

Rising populations provide significant resource challenges, but also opportunities to develop new eco-cities, which potentially could be sustainable and carbon neutral.

Developing sustainable cities will be essential in coming decades.  Coordinated national and international policy is required that combines financial incentives with pressure to ensure adequate industry research and development, and encourage energy efficient construction.