Europe's buildings are receiving an energy-efficiency makeover, and a host of innovative, green building technologies are the perfect tools for the job.
Europe's homes, businesses and public buildings sap up about 40% of all energy in circulation, more power than in either the industrial (32%) or transport (28%) sectors. This translates into about 20 exajoules of energy per year - the rough equivalent of 3.5 billion barrels of oil - and means our buildings are responsible for about 36% of the continent's carbon emissions.
As Europe pushes forward to shrink both its energy consumption and carbon footprint, revamping the region's buildings has been given top priority. Countless numbers of buildings are slated for renovation in the coming years, and millions more will be constructed or refurbished after tougher EU guidelines take effect in 2020 (see Outlook below).
In response, the green-building sector has taken off. The European efficiency-related construction market is expected to double to €140 billion by 2020. Meanwhile, green-construction-related patent filings have tripled in little over a decade (see infographic).
About half of a building’s total energy is devoted to heating, ventilation and air-conditioning (HVAC). So it is hardly surprising that the field has become a focal point for innovation.
One of many promising HVAC patent areas is air purification, which incorporates technologies such as ultraviolet light and photo-reactive chemicals similar to those that occur in the Earth's atmosphere. Such systems enable buildings to reuse large amounts of their internal air and help lower heating costs.
Another up-and-coming field is passive solar and radiant heating, where warm, sunlit air is diverted to heat a building or, during the summer months, used to draw in colder air for ventilation. Such passive solar designs are used in many high-efficiency buildings, including the large glass dome of the German Bundestag in Berlin and the new Raiffeisen RHW-2 building in Vienna.
Energy-efficient heating can only keep a building warm if there is sufficient thermal insulation to keep the heat inside.
Many commonly used, high-efficiency insulators were developed several decades ago and have seen gradual improvements and refinements since. These include insulating concrete forms (ICFs), the brainchild of German-Canadian engineer Werner Gregori. ICFs use interlocking polystyrene concrete forms to create a seamless wall through which air cannot penetrate.
Structural insulated panels (SIPs) are another frequently used insulation option, partly because they can be integrated into a number of materials, including particle and gypsum board, sheet metal, plastics and foams. They work by sandwiching insulation into interlocking sheets of building material to create uniform coverage.
A new type of insulation, which employs a different thermal principle, has been creating a small sensation in the field since its emergence a little more than five years ago. Unlike typical insulation that traps air in pockets, often between strands of fibrous material to resist the flow of heat, phase-change materials (PCMs) absorb or discharge heat as they change back and forth from a solid to liquid state. In a sense they "melt" and "freeze" at conditions close to room temperature and draw in or release heat in the process.
Keeping our homes and workplaces well lit eats up energy as well - somewhere between 10 and 30% of a building's total energy consumption. The number of innovations to develop more efficient lighting technologies is growing at an incredible rate.
Numerous LED (light emitting diode) and OLED (organic light emitting diode) applications promise to make a big dent in the amount of energy spent on lighting.
LEDs require about one tenth of the energy of incandescent light bulbs and roughly half of that of the compact fluorescent lights (CFLs) which are standard in Europe. They also last at least 40 times longer.
2007 EIA finalist Shuji Nakamura was part of a team of scientists that created the first LEDs to emit blue light, which paved the way for all colours, including white, to be produced. British scientists and 2006 EIA finalists Richard Friend, Jeremy Burroughes and Donal Bradley created the first OLEDs, whose slim size allows them to be incorporated into building materials such as tiles and transparent window-like materials that allow in the sun's rays during the day and illuminate at night.
The transition to true green buildings - the realm of net-zero-energy construction and beyond - will not be complete until such structures are not only extremely efficient, but also produce enough power to cover their own energy requirements and even send excess energy back into the power grid. Here, solar and wind power are promising technologies, and various innovations that help integrate these technologies into buildings.
Skyscrapers provide ideal locations for roof-mounted wind turbines. Thanks to nearly constant air currents at higher altitudes, turbines can generate a considerable portion of a building's own power requirements.
Solar power is a more widely tested method for buildings to create renewable energy. Photovoltaic cells are found not only on rooftops but also on building facades and even in transparent modules used as windows and skylights.
One of the more striking examples of the clever incorporation of solar- and wind-power technology is the refurbished CIS tower in Manchester, England. It relies on a photovoltaic skin to generate up to 180 000 kWh of electricity per year and has two dozen wind turbines that produce about one tenth of its energy requirement.
The EU's Energy Efficiency Plan 2011 (EEP) has identified the construction sector as the area where the greatest significant energy and emissions savings can be made. The plan requires 3% of all public buildings to be renovated per year until 2020. After 2020 all buildings constructed must be virtually carbon-free.
The Buildings Performance Institute Europe estimates net energy cost savings of €1.3 billion by 2050 through implementing widespread green building practices in line with the EU’s plans. The EU calculates annual financial savings of up to €1 000 per household and a reduction of 740 million tons of greenhouse gases per year from its entire Europe 2020 programme.
The initiative will also translate into increased revenues for the European construction sector, which represents about 10% of the region's GDP and is one of the largest single-sector employers. Moreover, as other countries throughout the world, in particular the US and China, also push for more energy-efficient and ecologically friendly buildings, innovations developed in Europe will pay back with dividends.