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Solar electricity that is produced from photovoltaic solar systems has the potential to deliver clean sustainable energy. Positive steps are being undertaken to minimise greenhouse gas emissions in Australia and photovoltaic solar systems are contributing towards sustainability. The current amount of installed photovoltaic solar systems cannot address the global warming issues in whole, however renewable energy production is contributing towards minimising carbon emissions. One of the main concerns for the residential householders is the economic issue on the use of photovoltaic solar systems. This paper examines life cycle cost effectiveness in using photovoltaic solar systems with capacities ranging from 1.5 kW to 5 kW in relation to the number of occupants and consumption for residential dwellings over a 25-year period. Eight major cities in Australia, including Sydney, Canberra, Melbourne, Brisbane, Hobart, Adelaide, Darwin and Perth, are investigated. Life cycle cost comparisons among different types of electricity grid connected systems, including a gross-feed-in-tariff (GFIT) scheme, a net-feed-in-tariff (NFIT) scheme and a buy-back scheme, are also explored. It is found that all major cities can receive life cycle cost saving in installing photovoltaic solar systems in their residential dwellings. The life cycle cost saving is between $273 and $53,021 and the percentage of cost saving is between 0.35% and 123.83% in a 15-year period. It appears that the GFIT and NFIT schemes offer better benefits than the buy-back scheme in installing photovoltaic solar systems. It is also found that the higher the capacity of the photovoltaic solar systems, the higher the life cycle cost saving can be received. This paper contributes to prove the cost effectiveness of using photovoltaic solar systems with the example from Australian residential dwellings. [ABSTRACT FROM AUTHOR]

Cement is one of the widely used materials in construction. Due to the adverse impacts towards the environment from cement manufacturing, green building rating tools always give a significant consideration towards concrete usage in green buildings. Irrespective of its significance in green buildings, there is a clear lack of research on life-cycle cost (LCC) impact of using supplementary cementitious materials (SCMs) in cement as required by green building rating tools. Therefore, this research analyses the life cycle costs of concrete using SCMs in obtaining concrete credits according to Green Star rating system in Australia. This research used fly ash, slag and silica fume as SCM for concrete. The SCM replacement percentage in concrete ranges from 10% to 60% as higher than 60% substitution is impractical. This research calculated LCC for each replacement percentage and specific building elements in different strength categories. LCC of concrete decreases with higher SCM replacement percentages. Further, there are only slight differences in LCC when comparing the three SCMs. In LCC, the contribution from the initial material cost is approximately 85%–87%, and in an exceptional situation such as in columns, this lowers to 66%. In larger columns, the cost of demolition is greater than that of the initial cost whereas it contributed to 61%–68% of the LCC. [ABSTRACT FROM AUTHOR]