18 September 2012

Sergio Sanz: low energy buildings, albeit at a reduced cost

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How to limit the costs of energy buildings? Before technologies allowing energy consumption reduction are accepted by the market, their cost has to decrease

Sergio Sanz, depty manager of the Energy Division of CARTIF and co-ordinator of the EU funded DIRECTION project talks about the possibility of limiting the costs of very low energy buildings.

40% of our energy consumed in buildings. Now, the EU has introduced a new legislation called the Energy Performance of Buildings Directive (EPBD) to ensure that buildings consume less energy.  Before technologies allowing energy consumption reduction are accepted by the market, the price of the low energy buildings has to come down below the 10% increase estimated by the European Commission.

How much additional cost is associated with low energy buildings?
This has yet to be determined. In our economic feasibility study we will do a building model solely based on minimum national requirements. We will therefore be able to determine the exact additional cost at the scale of each energy reducing measure implemented in each building showcase. To give an idea of the scale, for the CARTIF show case, which covers four thousand square meters, additional cost corresponds to about €200,000. This is less than the 10% plus estimated by the Commission to ensure that these buildings are very efficient. Besides, it is also worth replacing the cost issue into its wider, long term context. To achieve our target of 60 kWh/m2/yr, a higher initial investment is required. But operating costs will be reduced significantly in the long term.

How can downstream operating energy savings be factured in?
The problem is that energy ratings are given prior to construction. If there was a procedure to qualify buildings after they have started being operational, the rating would reflect the costs of operation. As a result, it would clearly differentiate the buildings one from another, making the most efficient the most attractive. Thus, to improve the energy efficiency of any building would become a requirement to keep the market value against that of the more efficient buildings.

Is there a viable strategy to lower additional cost?
It would require lowering technology costs. For example, by using cheaper materials or by improving their production processes. This can only be achieved through R&D specific to each technology. On the other hand, there is a need to improve the construction processes because there are additional costs incurred by constructing with non-standard technologies.  Other sources of additional costs include equipment to generate, distribute and use the energy (such as boilers etc.) and architectural solutions, such as insulation, glazing and control systems.

What is the role of the new energy efficiency directive?
The EPBD has set the basis for the reduction of buildings’ energy impact through, for example, a standardised calculation of energy efficiency and the development of a procedure for systems’ inspection. However, the concept of a "low energy building" goes beyond the minimum requirements dictated by regulations.
The intention is for low energy buildings to have very little total consumption and maximum efficiency in their energy processes. This can be achieved through technological innovation in architectural design so to reduce energy demand, through the selection of very efficient equipment and through an effective building energy management system. A fourth fundamental factor is the holistic approach toward the building, since the right mix of available technologies can give better results than the ones achieved with each one separately. Moreover, if we add to the concept of "low energy building" systems that produce energy from renewable resources, we could also aim at "zero emissions” buildings
 

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