Martin Anda

Waste generated from the construction and demolition sector continues to increase over time, and this negligence poses a severe threat to the environment. Reusing and recycling construction and demolition waste-derived materials must be the priority for resource sustainability and achieving a Circular Economy (CE). Many studies demonstrate that recycled concrete aggregates from demolished buildings can be used in various engineering applications. Still, there is little research to assess the environmental impact and sustainability of the product using Life Cycle Assessment (LCA) techniques. Current specifications in Western Australia require a majority (80%-90%) of the recycled base in road construction to be concrete. LCA techniques are essential to evaluate the environmental performance and sustainability of producing recycled materials in the construction and demolition industry.

The study compared the environmental impacts of the processes involved in producing Recycled Concrete Aggregate (RCA) from demolition waste and Business as Usual (BAU) cases for road construction using LCA techniques for case-specific and primarily sourced data. The results indicate that with 100% RCA used in road bases, a significant carbon emission reduction of almost 95% was observed. While only a 55% reduction was achieved when replacing the BAU scenario with 70% RCA and 30 %NA. However, if the RCA processing involves significant transportation distances and more electricity consumption, then a reduction in environmental impacts from the project is unlikely.

The findings prove that data collection, location, in-situ utilization of the recycled materials, and backhaul plans are the ideal components for CE in the recycling industry. Further investigation on a similar topic is needed to understand recycled products’ environmental impacts and sustainability so policymakers can be informed when legislating the necessary regulations and guidelines.

The return of investment of a microgrid (MG) project can be accelerated by minimizing the cost of energy production. Implementing demand response (DR) is one of the inexpensive solutions to accelerate this investment return rate. Under a DR program, MG loads can be re-scheduled from peak to off-peak periods, or shaved and shed during peak periods, depending on the loads' flexibility. However, additional costs are needed to provide the enabling technologies. On the other hand, DR execution may reduce customers' comfort; thus, the MG operator should provide some incentives to the participants for compensation. The given incentives should be effective and feasible for both DR participants and the MG operator. This study aims to determine the DR incentives derived from the differences of MG profit before and after implementing this program. The given incentive varies based on the discomfort level, felt by the participants, and the load's economic value. A Genetic Algorithm tool is used as the optimization method in this study.

A desktop study examined water meter readings of secondary schools in the Perth metropolitan area of Western Australia. From this, a suitable metric for measuring water use in secondary schools was determined. Water use quartiles on a per person basis were also calculated based on 70 secondary schools and benchmarks were established. In addition, a water audit of 9 high water using secondary schools (>20,000 kL/a) was performed to identify key areas where water is used and where water savings can be made. Total water use of these schools decreased by 13% in the 12 months following the completion of the water audits. Having determined water use averages, benchmarks and key areas for water savings, the education industry can make informed decisions about their water use and how to increase efficiency at the schools.

Water availability is an important aspect for sustainable regional development. Yogyakarta has problems in water availability. The demand for water in Yogyakarta Province is gradually increasing with higher consumption for human consumption, industry, and agriculture and livestock production. Also, more inhabitants and farmers are utilizing groundwater for domestic purpose and irrigation due to long drought, respectively. This problem will be increasing as higher population leads to higher water consumption and food production. Therefore, this study aim to understand the current situation and long-term projections of water sources, and demands in 2017-2030 by using water balance concept. After that, the assessment of alternative scenarios to overcome water availability problem was performed using managed aquifer recharge concept and efficient irrigation. The result shows that within the period 2017-2030, water storage is negative in 3 (three) regencies. This means that water deficit had occurred in these regencies where water demand rate is higher than recharge rate of groundwater. Also, it might shows that most of storm water goes to surface runoff and/or most of groundwater abstraction for water demand becomes waste water production. According to the Scenario-1, recharging the aquifer with storm water, converting 45% of surface runoff to groundwater can reduce water deficit in only 2 regencies. Scenario-2 shows that converting 65%, can overcome all 3 regencies from water deficit. Combining aquifer recharge by storm water and effective irrigation can solve water deficit problem in all regencies by only converting 40% of surface runoff to groundwater. The study shows that both approaches of managed aquifer recharge and effective irrigation are applicable in Yogyakarta. In small scale, these applications can be low cost, but at larger scale, can require higher investment cost. Therefore a site-specific knowledge on the project field is very important. Large scale application will need more stakeholders and regulators involvement, and also social awareness and acceptance.

The main energy challenge in the smart cities development is the optimization of the energy system to reduce energy cost and greenhouse gas (GHG) emissions. The low feed-in tariff offered by the electricity retailer is another incentive to trade the energy within the project boundaries or neighbouring precincts using the Blockchain peer to peer energy trading. This study develops an energy system model for the RENeW Nexus project as part of smart city development at stage one in the City of Fremantle for a small community (Lot 1819) comprising 36 townhouses and 50 apartments. The system was developed to simulate the optimal Power to Gas (P2G) system for excess renewable energy storage in combination with shared strata battery towards an energy self-sufficiency system. The rooftop area of the townhouses in the developed precinct has been used to generate excess renewable energy from solar photovoltaic (PV) to compensate for less area available on the rooftops of the multi-story apartment's buildings in the presence of a large-scale centralised strata battery. The peer to peer energy trading takes place using Blockchain technology to achieve the energy self-sufficiency goal. The study also identifies the techno-economic viability of P2G system over the large-scale energy storage systems. The model simulation demonstrated that the initial cost of the P2G system is comparably less than the current conventional battery systems.

This paper focuses on the selection of an appropriate standalone electricity supply system for a small island of Western Australia, Australia. To reduce the cost of electricity generation and to determine the most economically feasible solution for this island, several configurations are considered. The considered systems vary from a fully diesel generator-based option towards a hybrid system composed of diesel generators, wind turbines, solar farm and battery energy storage. Each system is analyzed by HOMER software and using the real demand data of the island, as well as the prices of different electrical components in the Australian market. The system which yields the minimum lev-elized cost of energy over the project's lifespan and the minimum net present cost is identified and suggested as the most economic option.

This paper presents a feasibility analysis for running a water treatment system by renewable energies in a regional town of Western Australia. The main motivation is the inadequate capacity in the electricity feeder supplying the town especially in summer. Instead of augmenting the feeder to the town to supply the electricity demand of the water treatment system, locally installed renewable energies seem to be sustainable, cost effective and attractive for the local electricity utility. This paper finds an economically attractive and technically feasible solution in the form of integrating a distributed system of rooftop solar photovoltaic systems with wind energy and existing grid to supply the energy demand of the town, as well as the new water treatment system. The proposed hybrid energy system provides electricity at a lower cost than the current energy solution, while improving the penetration of renewable energies in the region.

The essential connection between energy and water, also defined as the energy-water nexus, has been recognized by scientists and policy makers worldwide. Integrated solutions and policies that consider both energy and water aspects into future planning have been developing at a fast pace. In this paper, we review the state of the art of the energy-water nexus, with particular focus on the integration between renewable energy and desalination technologies. We also model the integration of reverse osmosis (RO) desalination and solar photovoltaics in an edge-of-grid coastal town in Western Australia. The current literature agrees on the sustainable use of renewable energy sources to improve the water-energy nexus in the context of water desalination. Although the integration of solar and wind energy with desalination technologies is a mature and well-proven solution at both small and large scales, the intermittency and fluctuating nature of wind and solar power still constitute the main technical challenge that has limited the diffusion of renewable energy powered desalination on a large scale. Several successful applications of renewable energy powered desalination in remote, off the grid, locations have tackled the issue of power intermittency by the use of batteries and diesel generators. Such systems often couple reverse osmosis desalination with solar photovoltaic energy. Large desalination plants have been successfully connected to wind farms and grid electricity to secure uninterrupted plant operations, thus meeting water targets in large-scale systems. Our review identifies a knowledge gap in the integration of decentralized energy systems, e.g. rooftop solar photovoltaic, with small scale RO desalination. Such configuration would benefit those regional towns that have historically suffered from weak and unreliable connections to the electricity grid, thus helping them secure both their energy and water requirements. The modelling exercise on a renewable energy powered RO plant in an edge-of-grid town in Western Australia has identified an operating strategy that maximizes the renewable energy fraction and secures the annual supply of water. The system involves operating the RO unit for six months of the year at a daily variable load and integrating solar energy with grid electricity. Careful evaluation of the RO performance under such operating conditions is necessary to ensure a safe and reliable water treatment process. A niche in the literature of the energy-water nexus has been identified in the integration of rooftop solar photovoltaic, grid electricity and desalination technologies applied in a regional context. A future study will consider the rollout of rooftop solar photovoltaic installations across the whole town, thus enabling the active engagement of the community by integrating the households’ energy demand response patterns to the operations of both rooftop photovoltaics and the desalination unit.

Top-down sanitation programs that promote a specific sanitation technology based on the presumptions of 'outside experts' have been criticised for endorsing unsustainable, expensive and inappropriate technologies. In response to these failings, a new era of demand-led sanitation programs (including community-led total sanitation and sanitation marketing) encourage greater participation of users to create appropriate sanitation technologies. This paper examines the use of participatory design sessions with local builders and householders in three rural districts in Malawi. The paper provides an account of the participatory design methodology and critically reflects on the processes and challenges in relation to power, creativity and ownership. The designs created during the sessions are presented with recommendations for further testing and structural refinement.

This paper reports on the development and experimental evaluation of a bubble column – passive condenser system as a method for small-scale brackish water or seawater desalination. Particular focus is on the novel condenser prototype. A long narrow condenser of 10cm width and 150cm length demonstrates the best results. In the winter season under favourable ambient conditions, distillate recovery rates of 73% are commonly achieved. Sodium chloride salt removal is found to be highly effective with distillate salt concentrations between 69μS and 101μS. The condenser prototype presented here provides a building block towards the development of a novel bubble column – greenhouse desalination system.