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a b s t r a c tEnergy and water infrastructure in Abu Dhabi provides a strong example of the interconnection between energy and water, where the majority of its electricity and water demand is jointly produced from cogeneration plants. The total cost of fuel used for cogeneration plants are heavily depending on the efficiency level of end-use energy and water consumption. Buildings are the major electricity and water consumers with 84.6% and 92.2% respectively from the entire demand. The aim of this study is to analyze the energy and water consumption reduction by implementing Estidama pearl regulations and compare it with Business as Usual -the normal execution of things as they always do-for three sample buildings (villa, multistory residential and office building). For energy assessment, eQUEST software was used to examine the energy performance of the chosen buildings and to evaluate the energy saving potential after applying Estidama requirements. While for water assessment; Estidama and LEED calculation tools were used to do the same. The results of energy simulation and water analysis of the chosen buildings showed a potential of electricity reduction between 31% and 38% and a potential of water reduction between 22% and 36% depending on building type and other parameters. Also, a total monetary savings of 19 Billion AED can be achieved cumulatively over ten years period (2011e2020) after Estidama regulations have been applied. In addition, a reduction of 31.4 Million ton of CO 2 eq cumulatively can be achieved.

Summary Microalgal biodiesel has emerged as a promising fuel source, but has still not been adopted commercially. One of the several inherent challenges is its high production cost, which mandates the need to develop an integrated process to produce other valuable coproducts economically. This article combines life cycle assessment and preliminary life cycle cost assessment of a proposed biorefinery, in which a high value product, β‐carotene, is coproduced from microalgae with biodiesel. The GaBi 6 environmental management software was employed to investigate the environmental impact associated with the production life cycle. The mass flow rates and the energy consumed in all stages of biodiesel and β‐carotene coproduction for the functional unit of 1 kg of biodiesel were assessed. When the coproduction of β‐carotene was not taken into consideration, the total energy input for a functional unit of 1.0 kg biodiesel/m2/y and the net energy ratio, that is, energy returned on energy invested were estimated to be 128.1 GWh/y and 0.27, respectively. The life cycle cost analysis showed that although the total production cost associated with coproduction of β‐carotene from Dunaliella salina was higher than that of the sole production of biodiesel, it generates a hiked revenue of up to $37 million/y. Over the system lifetime of 10 years, the sole production of biodiesel showed a loss of US$345 million per functional unit, whereas the coproduction of β‐carotene achieved a net profit of US$120.7 million per functional unit. This work clearly showed that the coproduction of β‐carotene with biodiesel from D. salina overcomes the cost‐ineffectiveness resulting from the production of biodiesel alone.