Land-Use Planning for Zero-Energy-Buildings: Comparison of Four High-Density Cities

Abstract

A net approach to Zero-Energy-Building (Net ZEB) requires all energy demand to be met by on-site generation of renewable energy. An off-site ZEB with compensating measure (off-site ZEB_CM) allows off-site land to be used if the energy demand cannot be met due to the urban arrangement of buildings. A method is developed for evaluating the potential and risk of Net ZEB and off-site ZEB_CM in densified urban situations by examining their land-use requirement on-or off-site. Four cities with different climates are modelled: Singapore, Cairo, Beijing and Hamburg. The preliminary results indicate that (1) the rate of change in CM per unit of area of use is not a constant number and varies with numbers of storeys, urban density and climate zone; (2) to save land for the compensating measure, a small number of storeys should be used; (3) to save land in general, high plot ratio should be used. Within a high-density situation, a small number of storeys should be used. This research contributes to the discussion about urban sprawl and compact city by investigating the relationship between urban fabric and energy harvesting. It may encourage the land-use policy makers to include land-use requirement of renewable energy harvesting. Keywords: zero energy building, compensating areas, urban density, energy demand, land-use planning, low-carbon society INTRODUCTIONThe main interest of this paper is to examine the relationship between urban fabric and landuse requirements for achieving enough renewable energy to cover urban energy demand. Even though it is known that there is the discrepancy between demand and supply by the renewables, this problem is often overlooked. The importance of this problem has been further emphasized by recent studies reporting that energy sprawl, which is defined by the development of new land area required for energy production, is now one of the largest driver of land use change for the foreseeable future with increasing proportion of renewable energy harvesting. For example, Trainor et al. [1], quantify projected energy sprawl in the United States through 2040. Their results show that when land-use requirements of compensating measures (CM) are included, more than 800,000 km2 of the additional land area will be affected by energy development. Not only is this number higher than projections for future land use change from residential development or agriculture, but also that the pace of development is more than double the historic rate of urban and residential development. "The possibility of widespread energy sprawl further increases the need for energy conservation, appropriate siting, sustainable production practices, and compensatory mitigation offsets" [2]. The need for reducing energy sprawl, therefore, further enhances the importance of research that investigate the density, the geometrical and morphological characteristics of buildings that minimize the energy consumption.In order to bring primary energy consumption and CO2 emission to zero, one significant contribution is the optim...

Towards carbon free cities: interplay between urban density and energy demand

“…Therefore, finding an optimal urban density, which is defined as floor area ratio (FAR) or plot ratio, and land-use planning that could balance different development targets is a crucial step in the development a carbon free city. However, to date, most papers deal with only one specific aspect of carbon free city and there have not been many studies that include both the considerations of human scale and the land-use requirement of Zero Energy Building (Chen & Dietrich [5,6]). This paper aims to answer the following question in order to contribute to the discussion by considering multiple aspects of urban planning in the process of developing a carbon free city.…”