Abstract: Rice straw pellets are a promising fuel as a renewable
energy source. Financial analysis is needed to make a utilization
system using rise straw pellets financially feasible, considering all
regional conditions including stakeholders related to the collection and
storage, production, transportation and heat utilization. We conducted
the financial analysis of feasibility for a heat utilization system using
rice straw pellets which has been developed for the first time in
Nanporo, Hokkaido, Japan. Especially, we attempted to clarify the
effect of factors required for the system to be financial feasibility, such
as the heating energy demand and collection and storage method of
rice straw. The financial feasibility was found to improve when
increasing the heating energy demand and collecting wheat straw in
August separately from collection of rice straw in November because
the costs of storing rice straw and producing pellets were reduced.
However, the system remained financially unfeasible. This study
proposed a contractor program funded by a subsidy from Nanporo
local government where a contracted company, instead of farmers,
collects and transports rice straw in order to ensure the financial
feasibility of the system, contributing to job creation in the region.
Abstract: Certifications such as the Passive House Standard aim to reduce the final space heating energy demand of residential buildings. Space conditioning, notably heating, is responsible for nearly 70% of final residential energy consumption in Europe. There is therefore significant scope for the reduction of energy consumption through improvements to the energy efficiency of residential buildings. However, these certifications totally overlook the energy embodied in the building materials used to achieve this greater operational energy efficiency. The large amount of insulation and the triple-glazed high efficiency windows require a significant amount of energy to manufacture. While some previous studies have assessed the life cycle energy demand of passive houses, including their embodied energy, these rely on incomplete assessment techniques which greatly underestimate embodied energy and can lead to misleading conclusions. This paper analyses the embodied and operational energy demands of a case study passive house using a comprehensive hybrid analysis technique to quantify embodied energy. Results show that the embodied energy is much more significant than previously thought. Also, compared to a standard house with the same geometry, structure, finishes and number of people, a passive house can use more energy over 80 years, mainly due to the additional materials required. Current building energy efficiency certifications should widen their system boundaries to include embodied energy in order to reduce the life cycle energy demand of residential buildings.