Building Experience: Energy Efficient Buildings
Issue: The development of large commercial, governmental and even residential buildings which take advantage of energy efficient design and incorporate on-site renewable energy sources could have a major impact on achieving and maintaining Kyoto targets on reducing carbon dioxide (CO2) emissions in the future. Although demonstration sites across Europe have been built, the lessons learnt in their development and subsequent performance have not penetrated the wider marketplace.
Relevance: Since the 1997 Kyoto agreement renewed attention has been paid to carbon dioxide emissions. Heavy industry and transport usually bear the brunt of controls, while buildings, covering all sectors including non-industrial, are neglected. With many major construction activities planned years in advance it is important to ensure that energy efficiency considerations are a high priority.
For a number of years questions of energy efficiency, energy security and protection of the environment have been the top of the developed world’s political and economic agenda. Much has been made of the effects of industrial activity and transport in these areas. After the Kyoto round of discussions on global climate change there is even greater pressure on developed countries to renew efforts to minimize emissions and improve energy efficiency throughout industry. The concentration on transport, and heavy industry has already started to bear fruit, and not only environmentally. US President, Bill Clinton recently stated that, 'Every action the US has taken since 1970 to clean up the environment has led to more jobs and a diversifying economy', emphasizing the opportunities that can arise from environmentally sound practices and innovation.
Until recently, however, the impact of one of the major net contributors to CO2 emissions -buildings- has been virtually ignored. It is now widely recognized that buildings contribute almost 50% of all CO2 emissions. Yet, despite this alarming estimate there has been little evidence of widespread uptake of energy efficient technologies and designs, although they have been known about for decades. One of the main deterrents is cost; it is the common perception that implementing new concepts requires large investments. The lack of forward-looking companies, together with capital market imperfections, means that the long term financial benefits of reduced energy consumption tend not to be fully grasped. Moreover, the benefits to the workforce from improving working conditions and reducing possible effects from so-called 'sick-building syndrome' induced by artificial air-conditioning systems and poor material use, are hard to quantify.
Buildings are by their nature intended to be long lasting, so relying solely on new building projects cannot be the only solution. It is also necessary to address the important issue of retrofitting old buildings. This would not necessarily involve a complete overhaul of existing sites, nor would this be practical, but some retrofitting could be accomplished stepwise. However, to assess which option - retrofitting or new building - is most beneficial 'whole-life costs' must be taken into account.
Energy efficiency trends for a number of years have focused on electronic equipment such as low energy lighting and office equipment. There has been less emphasis on the building envelope. In particular this refers to:
general physical attributes - roof, walls, foundation, insulation, seals, doors
fenestration (design and placement of windows)
movements of air in and out of the building (infiltration, exfiltration)
heat loss and gain through windows, ceilings floors and walls, and
internal heat transfer mechanisms.
Some of these aspects are described in Table 1. Approaches to energy efficiency must adapt these factors to suit the climate in which the building project is situated.
Another factor currently being considered, although we will not look at it here, is studying the energy efficiency of supplying the raw materials by a complete examination of their life-cycle.
In the US efforts are concentrating on considering the 'whole building'. From an engineering perspective this means that the building should be viewed as an integrated systems design rather than a number of individual components. It is easier for designs of this type to incorporate new technologies and take advantage of solar and other renewable energy sources. The US Department of Energy has developed a modelling tool which can evaluate the energy performance of small commercial building designs. It hopes that by doing this, the service will promote the dissemination of experience, and help companies to understand the potential benefits of utilizing designs of this type.
Experience with New and Older Buildings
There are examples of where energy efficient programmes have been able to use energy efficiency technologies, as seen in Table 2, all of which have been supported by the THERMIE Programme.
This demonstration part of the JOULE-THERMIE programme has supported, and continues to part-fund, projects which clearly show the benefits of new energy efficient technologies and designs. However, the question arises as to why the dissemination of these practices is so limited, despite the European Commission’s efforts. At the recent Expo98 in Lisbon, emphasis was placed on the use of existing, but little used, technologies in the building of the exhibition. What was also stressed was that no extra cost was involved. As regards housing, some French architects have claimed that designing in energy saving features would add only 1% to their fees, but would reduce energy consumption by up to 30%.
In the UK, the Building Research Establishment set up an Environmental Assessment Method (BREEAM) eight years ago, which aimed to get the message over to developers and to gauge results. In the financial year to April 1997, the estimated energy savings/benefits of their programme totalled ECU615m, equivalent to an emission reduction of 1.4 million tonnes of carbon. They themselves have recently moved into new offices which make use of many of the practices they promote and believe the result is 30% more energy efficient than standard designs.
Many opportunities to innovate in the construction sector are left to new developments. More often than not the tailored solution to a problem is not immediately transferable to a second project, although there is a basis for some sort of standardization. Energy labelling offers a way of giving information about the energy-related properties of materials. The use of U-values - a measure of insulating ability (low U-values means better insulating capacity) is an example of this, but so far users are not particularly familiar with it.
There are considerable opportunities for improving energy efficiency and reducing subsequent emissions to be obtained by refitting existing buildings. Stepwise approaches rather than complete overhaul (1) could catalyse the market for better and more energy efficient components. Increased demand could lead to reduced cost and so encourage greater uptake.
Location, location, location
In many cases it is not a simple matter of examining the application of materials and structural design of the building itself. As we shall describe, it is also necessary to assess the location and situation of the construction site itself. These environmental factors should not concentrate only on climate considerations - i.e. cool northern Europe and warmer southern Europe, but also on the scope of the local landscape to contribute to the energy needs of the site. There may be opportunities to take advantage of renewable energy sources -wind and tidal power as well as solar. In many cases this can contribute to national resources as well as meeting the building’s energy needs.
Two recent designs in the UK, a Sainsbury’s supermarket at the Millennium Village in Greenwich, London and Hyndburn Council offices in Lancaster, demonstrate this - both are currently under construction and both involve the regeneration of a brown-field site.
At the London site, Sainsbury’s opted for
natural-ventilation and lighting
underfloor heating using waste heat from refrigerators
thick concrete walls and floors to a store heat energy during the day and release it at night
earth mounded sides to reduce heat loss in winter and heat gain in summer. This will also enable them to absorb noise from delivery lorries
renewable energy sources - wind turbines and solar cells
The Lancaster council project, which is part-funded by Thermie and touted to be the UK’s first zero-energy public building, will use,
south facing orientation to make best use of sunlight
renewable energy sources
wind - a single turbine
solar cells - roof mounted and providing 35MWh a year (20% of the site’s annual requirement)
water - a water-to-water heat pump
thick walls to reduce heat loss
lighting control systems to maximise daylight use
The site is an excellent example of how the natural environment can be exploited without negative impacts, and in fact, the building’s lower energy requirements mean that the site is a net contributor to the national grid.
The question of cost will always be paramount in the minds of companies planning major, or even minor, building developments. There is no shortage of design know-how, technologies or overall experience, but as is often the case for the acceptance and application of new and innovative technologies, cost is very much the limiting factor.
However, as an opportunity to meet new environmental controls and standards, energy efficient construction stands out as a possible solution to the growing concerns over CO2 emissions. The combination of energy efficient buildings with measures affecting electrical appliances could have a major impact and is an area which, if targeted, could have short and long term benefits for all concerned.
At a recent conference held by the European Commission in Lisbon there again was a call for support for research and demonstration projects. Funding of ECU300m was proposed. However, at the same conference, the reasoning behind this funding was questioned because few 'ordinary people' benefited from the results. With the Fifth Framework Programme also dedicating part of its work to the 'city of tomorrow' and 'energy efficiency for a competitive Europe', and again looking for demonstration projects, it is important to promote innovative approaches which are able to benefit Europe’s citizens directly.
The underlying problem is that whereas the financial means exist for the development exploitation of these projects in demonstration projects, there is little effective dissemination of the lessons learned to the wider-market place. And it is here where a much larger impact could be envisaged environmentally, economically and socially. Inertia on the part of industry could be addressed through tax incentives for the application of the technologies, or tighter regulation at the planning stage. A fuller understanding of the cost/benefit of using these alternatives could also play a role, as could identifying more closely at which stakeholders in the decision making process to target the relevant information.
A combination of these efforts could have a significant impact across a broad range of industries. Apart from creating new employment opportunities they would support the creation of sustainable cities rather than providing just a small number of sustainable buildings.