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The New Zealand's Greenshell™ mussel (Perna canaliculus) aquaculture industry is being affected by summer mortality events associated with increasing seawater temperatures and pathogens. In this study, challenge experiments were conducted to investigate, for the first time, the effects of pathogen coinfection on the survivability and haemolymph immune responses of juvenile and adult mussels. Animals were injected with marine broth (control), Vibrio mediterranei, Photobacterium swingsii, or a mixture of V. mediterranei and P. swingsii. Then, mussel survival was monitored for 72 h, and haemolymph was sampled for bacterial quantification and metabolomics analyses at 24‐ and 48‐h post challenge. Coinfected adults and juveniles showed 100% mortality. Bacterial colony counts in haemolymph decreased as infection time continued, especially in juveniles. The haemolymph metabolome of mussels exposed to single bacterial species and coinfection showed response changes largely within energy metabolism. Mussels infected with V. mediterranei exhibited increased metabolites linked to the glutathione pathway, branched‐chain amino acids, and others over time, supporting structural functions. Conversely, mussels infected with P. swingsii showed no metabolic differences over time. The coinfection group exhibited large decreases in important metabolites, such as fatty acids as an alternative energy source and amino acids to support immune functions and protein synthesis. [ABSTRACT FROM AUTHOR]

This work discusses the perspectives of New Zealand to progress toward net zero, within a scenario of stable total energy supply. The renewable energy contribution is expected to dramatically grow from 35% in 2021, by increasing the non-dispatchable power generation by solar photovoltaic and wind. Phased with this growth of non-dispatchable power generation, energy storage primarily by hydrogen must also increase, to make dispatchable part of this non-dispatchable supply from wind and solar, and to produce green hydrogen to cover the non-electric component of the total energy supply. This is partially acknowledged by the local intelligentsia, which assumes the total energy supply may reduce in time, thanks to the electrification of almost every component of the total primary energy and living-with-less, and transformation to pumped hydro of the Lake Onslow hydroelectric plant could suffice to accommodate an acceptable growth of wind energy. Opposite, we believe a much larger growth will be necessary for both wind and solar, and the larger will be the share of wind and solar contribution to the total energy supply, the larger will have to be the share of hydrogen, with living-with-less arguments difficult to couple to a growing country in a growing world. [ABSTRACT FROM AUTHOR]

Renewable energy sources have been utilized by countries worldwide, but offshore energy exploitation projects remain highly promising for both the world and New Zealand specifically. The selection of equipment installation locations can be challenging and requires significant investment, prompting the need for optimization in offshore energy exploitation. Wind and wave location (WWL) integrated sites offer a highly potential solution for reducing installation costs and enhancing efficiency in renewable energy exploitation. However, the decision‐making process for selecting equipment locations is crucial and directly affects the outcome. This study aims to evaluate and consider sustainable and effective equipment installation sites based on both quantitative indicators and behavioral psychology of decision making. To achieve this goal, the study utilizes the prospect theory Data Envelopment Analysis (PT‐DEA) model, which builds on PT to analyze and evaluate the effectiveness of offshore installation site selection with consideration for human psychology. By combining the results of quantitative indicators and decision‐making behavior, the study identifies sustainable and effective offshore installation sites, recommending appropriate equipment installation locations WWL. The study is also compared and referenced with relevant plans, projects, and development policies in New Zealand for confirmation. [ABSTRACT FROM AUTHOR]

The restructuring of the energy industry is imperative, as New Zealand strives to reduce greenhouse gas emissions. New Zealand has abundant renewable energy resources, and about 85% of current electricity generation is from renewable energy sources. However, in recent years, it appears that a considerable fraction of wind energy has been underutilized. This article reviews the history, current status, and future trends of wind energy development in New Zealand. The main challenges to the current development of wind energy are summarized compared to other countries. The main challenges come from the bi-cultural influence, environmental influence, and economic and social influence due to the variable nature of wind power, it is critical to store and operate power safely and reliably during peak power generation periods. This article compares seven mainstream wind energy storage technologies and analyzes the best solution for wind energy storage in New Zealand. This article analyzes the feasibility of using small-scale household (standard power rating range from 0.004 to 16 kW) wind turbines in New Zealand cities regarding their construction and operation process. The life cycle and the maximum capacity coefficient of such small-scale wind turbines are overviewed via three case studies and later compared with large commercial wind turbines (standard power rating ranges from 1 to 3 MW) in power generation capacity. It has been found that small-scale household wind turbines have notable power generation potential and economic benefits in the long term. [ABSTRACT FROM AUTHOR]

The use of renewable energy as a fuel source and expansion of forest areas are the best ways for reducing CO2 emissions. This study aims to examine the effects of forest plantation area, renewable energies, real gross domestic product (GDP), and technological innovation on CO2 emissions in 9 regions of New Zealand between 2006 and 2019. For this purpose, it employs a pooled mean group methodology. Investigating the regional impacts of various variables, especially the forest area, on CO2 emissions is the main contribution of this study. The results suggest that planted forest areas can reduce CO2 emissions in the long run, but its impact in the short run is not significant. Non-renewable energy consumption is the major contributor to CO2 emissions in both the short and long run. While technological innovation and renewable energy consumption appear effective in reducing carbon emissions in the short term, they still contribute to increased CO2 emissions in the long term. At the regional level, we found that the forest plantation areas in Manawatu-Whanganui and Gisborne are important regions for reducing CO2 emissions. By taking account of these results, New Zealand should take swift action to properly manage and increase the current level of forest areas and if applicable expand them. It also needs to improve the current level of use of renewable energy to achieve its abatement goals. [ABSTRACT FROM AUTHOR]

In this new era of energy transition, access to reliable and correctly functioning electricity markets is a huge concern for all economies. The restructuring path taken by most electricity markets involves the movement towards green generation structures and the increasing integration of wind and solar photovoltaic energy sources. Furthermore, it involves the electrification of energy systems, which implies a substantial increase in electricity demand levels. It is also important to add that electricity use has been pivotal in achieving efficient productivity levels in many sectors and is thus crucial to boosting economic activity. Nevertheless, this shift in generation structures has raised several challenges in electricity markets, mainly because the electricity produced from wind and solar photovoltaics is intermittent. In turn, adopting green power sources has been claimed to increase electricity price volatility and thus increase pricing risks. Therefore, to ensure that the right market signals are being sent to investors, the behaviour of electricity prices should be carefully assessed. There are three main types of pricing mechanisms commonly used in electricity markets: zonal, uniform and nodal. This study provides a short literature survey on these three pricing mechanisms. Our analysis has revealed that the assessment of the behaviour of nodal electricity price volatility is rarely studied in the literature. This fact has motivated the exploration of this topic and the consideration of the New Zealand electricity market case. The New Zealand electricity market is an energy-only system with no interconnections with other electricity markets. Furthermore, it has plenty of electricity produced from hydropower, which has a high potential to reduce price volatility through its backup role. The nodal pricing mechanism is complex, and data on it are hard to process. This paper elucidates the main challenges in processing electricity big data. Three different procedures to make this data more useable are described in detail. The main conclusions of this paper highlight the need to access easy-to-manage data and identify certain variables that significantly affect nodal prices for data which are unavailable. [ABSTRACT FROM AUTHOR]

This paper aims to design an integrated offshore structure capable of supporting a hybrid assembly of one wind plus two tidal turbines. The monopile has been found to be a suitable foundation type as the most inexpensive solution in water depths of less than 30 m. The Cook Strait in New Zealand is an ideal location for wind and tidal renewable energy sources due to its strong winds and tidal currents. Finite element analysis was performed to determine the displacement of the structure for different types of soils using OPTUM G3. After that, a macro-element model for soil was represented, considering the monopile as a Euler–Bernoulli beam model. The results enable the finding of optimum dimensions of monopiles with allowable tilt and deflection. Based on this, the diameter, thickness, and length of the monopile can be 6, 0.083, and 60 m, respectively. The maximum load occurs in extreme wind load scenarios when wind and waves move in same direction. [ABSTRACT FROM AUTHOR]

The ongoing integration of artificial intelligence (AI) into the fundamental fabric of society constitutes a transformative process, with the potential to exert profound influence on various facets of human existence including environmental quality. Our research investigates the interaction of AI and renewable energy production in 22 leading robotics and innovative countries, providing crucial insights into a previously underexplored domain. The study's novelty and originality are in demonstrating the precise impact of AI in enhancing and revolutionizing renewable energy production, consequently addressing, and filling a critical study gap. Our analysis comprises both asymmetric and symmetric assumptions to cover the positive and negative shocks of artificial intelligence on renewable energy from 1991 to 2020. The findings from the panel NARDL analysis provide substantial support for the profound impact of changes in artificial intelligence (AI) on the substantial stimulation of renewable energy in the long-run. Furthermore, AI plays a substantial role in enhancing long-term renewable energy production in the panel symmetric ARDL. In the country-specific investigation, it is found that Austria, Germany, and New Zealand are the nations where both affirmative and adverse changes in AI improve clean energy structure significantly in the short run. Natural resources, information communication technology (ICT), and economic growth also enhance renewable energy production. Finally, policies are directed to increase renewable energy production. [ABSTRACT FROM AUTHOR]

Municipal solid remains an issue that needs to be addressed globally towards a more circular economy and lower environmental impacts. In Colombia, over 96% of municipal solid wastes are landfilled, with little recycling or revalorisation of wastes and several environmental implications. With the technological development of different waste-to-energy routes, the energy revalorisation of solid wastes is increasingly becoming an attractive business opportunity. The waste-to-energy potential of the Atlantic Department (Colombia) was estimated based on the characteristics and daily availability of municipal solid wastes for different technologic routes. The implementation of the technological routes discussed could replace from 1 to 49 % of the demand for energy carriers like natural gas, electricity, or gasoline. This energy potential could replace from 2 to 106% of the energy demanded by the power generation, transport, residential, industrial, and commercial sectors. Furthermore, these technology routes could reduce greenhouse gas emissions by 46 to 92% of the greenhouse gas emissions resulting from landfilling. These results stress the need to upgrade energy policies in the country and to introduce new incentives to overcome economic and other barriers precluding the widespread use of waste-to-energy technologies. Abbreviations: Tuning in to Kids (TIK); Parental Reflective Functioning (PRF) Australian New Zealand Clinical Trials Registry (ANZCTR) number: ACTRN12618000310268 [ABSTRACT FROM AUTHOR]

This paper proposes and evaluates an optimized system of tidal turbines as a renewable energy generating unit in New Zealand. A comprehensive simulation model has been set up, using several available commercial software packages to test the performance, capacity and efficiency of the proposed system. Available tidal records have been used to find four regions that are suitable for tidal energy generation and conduct simulation model runs at one of them, Foveaux, to provide the electricity for the isolated area of Stewart Island. Generation of electricity with tidal turbines depends on the water currents and cut-in speed of the tidal turbines. In other words, to reach maximum efficiency from tidal power, the first step is to analyse the water currents of the site where turbine will be located and then estimate the generated power from that turbine. To do it, it is necessary to find the range of water currents and the tidal directions with demonstrating tidal rose and also find how to get maximum power by choosing a proper tidal turbine. Based on tidal flows of the Foveaux straight, two tidal turbines (Schottel 54 kW and 70 kW) with different cut-in speeds are selected. The results indicate that choosing Schottel 54 kW with 0.2 m/s less cut-in speed in comparison to Schottel 70 kW can generate 4.7 times more power. [ABSTRACT FROM AUTHOR]

Geothermal systems are an important resource in the global effort to reduce fossil fuel use. They are formed by convection of water heated at depth, but without external controls convection is unstable and upflows move or dissipate. In the central Taupo Volcanic Zone in New Zealand, the geothermal systems have been in the same locations for more than 50 kyr. We created heat and fluid flow models with uniform geology and basal heat which showed that the known topography localizes convective upflows. Fourteen out of 19 known geothermal systems in the model area were correctly located beneath topographic lows. Even at 3 km depth, inclusion of topography in our models improved agreement between the locations of upflows and low‐resistivity zones derived from 3‐D inversion of magnetotelluric data. Therefore, while topography is not the only factor that influences geothermal convection, its contribution is on a larger scale than is generally assumed. Plain Language Summary: Geothermal systems are a clean, renewable energy source. They are created by water that is heated at several kilometers depth and rises to the surface in distinct "plumes." We don't know why the plumes rise where they do or why they seem to stay in the same place for hundreds of thousands of years. We used specialized computer code to look at whether topography can keep these plumes in place. With uniform geology and heat flow at depth, our simplified models show that high topography can drive water downwards even at 3 km depth. The geothermal systems form between these highs, in valleys and topographical lows. Faults and localized heat sources will also be playing a part, but topography is known accurately and can explain the locations of 14 of the 19 geothermal systems in the Taupo Volcanic Zone, New Zealand. Before, it was thought that topography mainly affected nearby shallow fluid flow. Future geothermal exploration and modeling of warm water extraction should take these results into account. Key Points: Geothermal systems in the Taupo Volcanic Zone are long‐lived and stable, which requires non‐uniformityTopography can provide this non‐uniformity and explain the locations of 14 of 19 geothermal systems in our fluid and heat flow model areaTopographically driven convection can extend to several kilometers depth, even with moderate surface relief [ABSTRACT FROM AUTHOR]

The utilization of geothermal reservoirs as alternative energy source is becoming increasingly important worldwide. Through close-range aerial photogrammetry realized by unmanned aircraft systems (UAS), this study investigates the surface expression of a leaking warm water reservoir in Waiwera, New Zealand, that has been known for many centuries but remained little explored. Due to overproduction during the 1960s and 1970s the reservoir has suffered significant pressure reduction, which resulted in the loss of artesian conditions and led to the desiccation of the hot springs in close succession. However, shortly after the recent shutdown of the primary user (Waiwera Thermal Resort & Spa) renewed artesian activity was reported by locals but no hot spring activity has been observed so far. Therefore, this study was carried out in October 2019 to assess the actual conditions of thermal activity in the area of the former hot springs. UAS with coupled thermal infrared cameras were used for thermal mapping and the obtained data show renewed activity of the hot springs on the beachfront of Waiwera. Faults and fractures were identified as important fluid pathways, as well as individual fluid conducting lithologies. [ABSTRACT FROM AUTHOR]

Purpose: In recent years, the building sector has highlighted the importance of operational energy and efficient resource management in order to reduce the environmental impacts of buildings. However, differences in building-specific properties (building location, size, construction material, etc.) pose a major challenge in development of generic policy on buildings. The aim of this study was to investigate the relationship between energy and resource management policies, and building-specific characteristics on environmental impacts of refurbished office buildings in New Zealand. Methods: Life Cycle Assessment (LCA) was performed for 17 office buildings operating under seven representative climatic conditions found in New Zealand. Each building was assessed under four policy scenarios: (i) business-as-usual, (ii) use of on-site photovoltaic (PV) panels, (iii) electricity supply from a renewable energy grid, and (iv) best practice construction activities adopted at site. The influence of 15 building-specific characteristics in combination with each scenario was evaluated. The study adopted regression analysis, more specifically Kruskal-Wallis and General Additive Modeling (GAM), to support interpretation of the LCA results. Results and discussion: All the chosen policies can significantly contribute to climate change mitigation as compared to business-as-usual. However, the Kruskal-Wallis results highlight policies on increasing renewable energy sources supplying national grid electricity can substantially reduce the impacts across most environmental impact categories. Better construction practices should be prioritized over PV installation as use of on-site PV significantly increases the environmental impacts related to use of resources. The GAM results show on-site PV could be installed in low-rise buildings in regions with long sunshine hours. The results also show the strong influence of façade elements and technical equipment in determining the environmental performance of small and large buildings, respectively. In large multi-storied buildings, efficient HVAC and smaller window area are beneficial features, while in small buildings the choice of façade materials with low embodied impacts should be prioritized. Conclusions: In general, the study highlighted the importance of policies on increasing renewable energy supply from national grid electricity to substantially reduce most of the impacts related to buildings. In addition, the study also highlighted the importance of better construction practices and building-specific characteristics to reduce the impacts related to resource use. These findings can support policy makers to prioritize strategies to improve the environmental performance of existing buildings in New Zealand and in regions with similar building construction and climate. [ABSTRACT FROM AUTHOR]

• A novel holistic method for off-grid microgrid planning optimisation is introduced. • The potential of state-of-the-art metaheuristics in better nearing global optimality is shown. • A high penetration of EVs are integrated using specific demand response strategies. • The importance of energy resilience in isolated microgrid sizing is highlighted. • The potentially significant impact of characterising uncertainties in optimal microgrid planning is substantiated. The resilient microgrid (MG) capacity planning and optimisation problem is widely recognised as a non-deterministic polynomial time-hard (NP-hard) problem. Accordingly, metaheuristics – top-level algorithms inspired by various natural and physical processes – can be utilised to determine the near optimality in designing MGs. However, a comprehensive review of the mainstream literature has shown that the performance of several metaheuristics has not yet been evaluated. In response, this paper first systematically benchmarks the efficiencies of previously unexplored metaheuristics in MG sizing applications against the well-established metaheuristic in the literature, namely the particle swarm optimisation (PSO) algorithm. To this end, the metaheuristics are separately integrated into a novel MG sizing method, which is aware of the optimal demand response capacity procured from electric vehicle (EV)-charging loads. Two grid-independent, 100%-renewable MGs are modelled, which enable the reliable and robust supply of electrical loads in areas far removed from the grid. Furthermore, an advanced EV-charging demand response program is integrated into the overall method, whilst quantifying various sources of time-series data uncertainty and considering specific resilience constraints. The simulation results yielded from three real-world isolated community case studies in Aotearoa-New Zealand confirm the effectiveness of the proposed stochastic, resilience-oriented, EV-charging demand response-addressable MG sizing method. Importantly, the comprehensive statistics-based performance evaluations indicate that new metaheuristics have the potential to outperform the PSO by up to ∼6% in MG sizing applications. This indicates the potentially significant implications of using advanced metaheuristics for improving the economics – and, therefore, rolling out – capital-intensive grid-isolated 100%-renewable MGs. [ABSTRACT FROM AUTHOR]

Future climate change is expected to have wide ranging impacts on the hydrology of mountain rivers because of changes in the magnitudes and timing of rain and snow, as well as the significant spatial variability of topography and other catchment characteristics. In New Zealand, hydropower generation in mountain basins is the primary source of electricity and renewable energy resource in the country. The goal of this study was to simulate and evaluate the potential effects of climate change on hydropower operations in three mountain headwater lakes (lakes Pukaki, Tekapo, and Ohau) in the Upper Waitaki Basin of the central South Island. The TopNet hydrological model was used to estimate catchment runoff and lake inflows based on the 1990s (baseline), 2040s, and 2090s periods. Average temperature and precipitation results from an ensemble of 12 Global Circulation Models based on the IPCC 4th Assessment Report A1B emissions scenario were used as input to TopNet. Linked hydropower lake water balance models were developed and used to simulate hydropower operations including discharge, hydroelectric power generation, and spill based on TopNet future inflow predictions, projected electricity demand, and lake storage and outflow characteristics. Our results indicate that annual lake inflows increase under future climate scenarios, but that there are seasonal effects with increasing flows in winter and early spring, and summer flows decreasing somewhat as a result of increasing temperatures and greater winter rain with less snow. Although overall hydropower generation can increase with the increasing flows and projected electricity demand, the seasonal changes result in demand being met in winter and spring with potential shortfalls in summer and autumn. Maximum annual generation can be achieved for some generating stations, but generation will decrease at other stations and more spill will likely be required through the 2090s because of the seasonal changes. Therefore flood and drought risk could also increase for downstream areas. Results also indicate that by the 2090s electricity demand could exceed generation capacity for these headwater lakes. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Reduction of the energy use and emissions associated with the provision of transport services is one of the most challenging areas of energy policy. This arises both from the pervasive nature of transport use in modern society and its dependence on the most limited of fossil fuels. Advances in renewable energy utilization offer an avenue by which this may be addressed, including the possibility of achieving fully sustainable transport energy supply. The article considers what potential exists for sustainable road transport energy in New Zealand. That country already has high renewable energy utilization, but also a high per-capita transport demand and limited domestic hydrocarbon resources. Three main routes for renewable fuel supplies are examined, with the conclusion that two (the production of biofuels from forest products, and the amplification of electricity supply from renewable energy sources for use in electric vehicles) offer technically feasible pathways toward a fully sustainable transport energy system. Cost and confidence in investment remain the principal barriers to this development. [ABSTRACT FROM AUTHOR]

New Zealand has a long history in producing a major part of its electricity from low-carbon resources. A major transition from a state owned and operated electricity sector to an open electricity market model and the policies adopted during this period have shaped the generation mix of New Zealand to its current form. Currently, domestic fossil fuel resources offer opportunity for economic growth, while renewable energy resources are significant and present opportunities for green growth in both domestic and global markets. What is particular about the New Zealand case is the "middle out" approach of the national renewable energy strategy, rather than the common top-down approach of many other countries. Consenting is done on a case by case basis at regional level, allowing for wide community and stakeholder participation. This paper describes the transitions in the electricity sector and renewable energy policy of New Zealand, and presents an assessment using sustainability indicators to study the impact of this transition on the level of sustainability of the country's electricity supply system. Although the electricity mix has seen a transition from hydropower towards gas, geothermal, and wind energy, there has been no significant change in the overall sustainability index of the New Zealand electricity supply. This is because the system remains based on renewable sources and gas, which scores relatively high in the model we have applied. Using the country-specific values for the indicators would give a more reliable model to assess the sustainability of the electricity system in detail from its economic, social, and environmental aspects. [ABSTRACT FROM AUTHOR]

Understanding the impact of climate change on renewable energy resources is increasingly vital as our energy systems transition towards higher levels of renewable generation. This paper explores power system transition under climate change impacts on hydro resources, as well as the impact of climate change on the cost of decarbonisation. An integrated energy systems assessment tool is used to investigate the impact of altered seasonal availability factors on the optimal energy investment pathways. The cost of decarbonisation is assessed under climate change impact on the hydro resources, as well as the impact of discount rate assumptions on the total cost of decarbonisation. Results show that in the case of New Zealand, more hydro will be available in winter due to climate change, but less in summer, which is compensated for with increased solar capacity. Decarbonisation in New Zealand sees a major transformation in the transport sector, supported by a relatively moderate increase in overall demand in the electricity sector. While climate change impact on the hydro resource may reduce the total cost of decarbonisation in New Zealand, this cannot be generalised, as these impacts vary across countries and regions. • Climate change amplifies seasonal availability of hydro in New Zealand. • Climate change has indirect effects on optimal long-term energy system investments. • Cost of decarbonisation decreases slightly due to climate change in New Zealand. • Trade-off between solar and wind to support hydro under climate change. [ABSTRACT FROM AUTHOR]

This paper examines the dynamic causal relationship between renewable energy prices and economic growth in the cases of Norway, New Zealand, and two Canadian provinces. A Markov-switching vector autoregression (MS-VAR) model is used with model parameters being governed by a hidden Markov chain, allowing the causal relationship to vary amongst different states of the economy. A unidirectional causal link, running from economic growth to renewable energy is found in the case of New Zealand, Alberta, and Ontario. The causality emerges in the cases of New Zealand and Ontario, during periods of high economic growth, whilst it materializes in the cases of Alberta during periods of low economic growth. Our empirical results document the existence of a time-dependent causal relationship between renewable-energy prices and economic growth. • Causality link between renewable-energy (RE) prices & economic growth (EG) is probed. • The cases of Norway, New Zealand (NZ) and two Canadian provinces are presented. • Oil prices & interest rate are control variates in a Markov-switching VAR model. • There is a unidirectional causality (EG to RE) at high EG period for NZ & Ontario. • A unidirectional causality is found from EG to RE at low EG period for Alberta. [ABSTRACT FROM AUTHOR]

Carbon Emissions Pinch Analysis (CEPA) and Energy Return on Energy Investment (EROI) analysis are combined to investigate the feasibility of New Zealand reaching and maintaining a renewables electricity target above 90% through to 2050, while also increasing electricity generation at an annual rate of 1.5% while allowing for a 50% switch to plug in electric vehicle transportation for personal use vehicles. Under this scenario NZ’s electricity demand is anticipated to reach a maximum of between 70 and 75 TW h by 2050. If NZ is carbon emissions constrained to 1990 levels, to minimise energy expended, electricity growth will predominantly come from wind (18 TW h) and geothermal (13 TW h), and hydro (5.6 TW h) to a lesser extent. Renewables resources will produce nearly 95% of electricity generation. The analysis demonstrates that NZ is in a very good position to sustainably meet their future electricity needs while maintaining very low carbon emissions levels and economically desirable EROI levels. [ABSTRACT FROM AUTHOR]

To maximize uptake of micro renewable-energy generation, specifically small wind-turbines, it is crucial to permit for tower heights which allow maximum utilization of the available wind resource. Within New Zealand, municipal governments have authority to place limitations on the height of built structures in rural areas, including wind turbines. Numerical simulations using Computational Fluid Dynamics (CFD) are used to examine the effects of simple house shapes and heights on the characteristics of the air flow reaching wind turbines. Within New Zealand, municipal governments have authority to place limitations on the height of built structures in rural areas, including wind turbines. However at present they have insufficient information to understand which height limitations may decrease wind-resource utilisation by small wind-turbines installed in these areas. This research finds that current permitted structure heights are not sufficiently high, necessitating either lengthy planning consent processes or acceptance of sub-optimal turbine output. Municipal councils in New Zealand could reduce barriers to small wind-turbine installations by considering taller towers, in the 15-20m range, acceptable. This 15-20m range is transferrable to all rural areas, in other developed or developing countries, where a lone small turbine or small number of small wind-turbines are being considered for installation near dwellings. [ABSTRACT FROM AUTHOR]

Reanalysis data are widely used for simulating renewable energy and in particular wind power generation. While MERRA-2 has been a de-facto standard in many studies for a long time, the newer ERA5-reanalysis recently gained importance. Here, both datasets were used to simulate wind power generation and evaluate their quality in terms of correlations and error measures compared to historical data of wind power generation. Due to their coarse resolution, reanalyses are known to fail to represent local climatic conditions adequately. Hence, mean bias correction was applied with two versions of the Global Wind Atlas (GWA) to the reanalysis data and the quality of the resulting simulations was assessed. Potential users of these datasets can also benefit from our analysis of the impact of spatial and temporal aggregation on indicators of simulation quality. We also assessed regions which differ significantly in terms of the prevailing climate, some of which are underrepresented in similar studies: the US, Brazil, South-Africa, and New Zealand. Our principal findings are threefold. (i) ERA5 outperforms MERRA-2 in terms of the assessed error measures. (ii) Bias-correction with GWA2 does not improve simulation quality substantially, while bias-correction with GWA3 is detrimental. (iii) Temporal aggregation increases correlations and reduces errors, while spatial aggregation does so consistently only when comparing very fine and very coarse granularities. • ERA5 outperforms MERRA-2 for wind power simulation. • GWA bias correction does not consistently reduce the error. • GWA2 can be used for bias correction, while GWA3 is not recommended. • Bias between observed and simulated wind power varies strongly depending on location. • Temporal aggregation increases simulation quality, spatial aggregation does not. [ABSTRACT FROM AUTHOR]

The article discusses seven assumptions to public opposition to renewable energy projects in New Zealand. Topics covered include the negative impact of these assumptions on the relationship between the public, government and the energy sector, the problem concerning the transfer of knowledge from the academic sphere to the real world and the importance of a deeper understanding of these assumptions.

This paper describes ocean testing of the half-scale Wave Energy Technology-New Zealand (WET-NZ) prototype wave energy converter (WEC) using the Ocean Sentinel instrumentation buoy during a 6-week deployment period in August-October 2012. These tests were conducted by the Northwest National Marine Renewable Energy Center (NNMREC) at its Pacific Ocean test site off the coast of Newport, Oregon. The WET-NZ is the product of a research consortium between Callaghan Innovation, a New Zealand Crown Entity, and Power Projects Limited (PPL), a Wellington, New Zealand private company. The Oregon deployment was project managed by Northwest Energy Innovations (NWEI), a Portland, OR firm. NNMREC is a Department of Energy sponsored partnership between Oregon State University (OSU), the University of Washington (UW), and the National Renewable Energy Laboratory (NREL). The Ocean Sentinel instrumentation buoy is a 6-m surface buoy, developed in 2012, that provides a stand-alone electrical load, WEC generator control, and data collection for WECs being tested. The Ocean Sentinel was deployed and operated for the first time during the 2012 WET-NZ tests. During these tests, the operation of the WET-NZ was demonstrated and its performance was characterized, while also proving successful deployment and operation of the Ocean Sentinel. [ABSTRACT FROM AUTHOR]

The establishment of the concept of sustainable, decentralised, multi-carrier energy systems, together with the declining costs of renewable energy technologies, has proposed changes in off-grid electrification interventions towards the development of integrated energy systems. Notwithstanding the potential benefits, the optimal capacity planning of such systems with multiple energy carriers—electricity, heating, cooling, hydrogen, biogas—is exceedingly complex due to the concurrent goals and interrelated constraints that must be relaxed. To this end, this paper puts forward an innovative new optimal capacity planning method for a first-of-its-kind stand-alone multiple energy carrier microgrid (MECM) serving the electricity, hot water, and transportation fuel demands of remote communities. The proposed off-grid MECM system is equipped with solar photovoltaic panels, wind turbines, a hydrogen-based energy storage system—including an electrolyser, a hydrogen reservoir, and a fuel cell—a hybrid super-capacitor/battery energy storage system, a hot water storage tank, a heat exchanger, an inline electric heater, a hydrogen refuelling station, and some power converters. The main objective of calculating the optimal size of the conceptualised isolated MECM's components through minimising the associated lifetime costs is fulfilled by a specifically developed meta-heuristic-based solution algorithm subject to a set of operational and planning constraints. To evaluate the utility and effectiveness of the proposed method, as well as the technical feasibility and economic viability of the suggested grid-independent MECM layout, a numerical case study was carried out for Rakiura–Stewart Island, Aotearoa–New Zealand. Notably, the numeric simulation results highlight that the optimal solution presents a low-risk, high-yield investment opportunity, which is able to save the diesel-dependent community a significant 54% in electricity costs (including electrified space heating)—if financed as a community renewable energy project—apart from providing a cost-effective and resilient platform to serve the hot water and transportation fuel needs. [ABSTRACT FROM AUTHOR]

Geothermal, as a source of renewable energy (power and heating), has the potential to meet 3-5% of global demand by 2050. For some high-temperature reservoirs, a technical challenge that may constrain deployment is ground subsidence caused by reservoir pressure decline. At the Wairakei-Tauhara geothermal system in New Zealand, an integrated geotechnical-geoscientific investigation of the causes of local subsidence anomalies (up to 15 m, accumulated over 50 years) has successfully identified and modelled the factors, mechanisms and processes involved. Zones of hydrothermally altered porous sediments and clays, at up to 400 m depth, display inelastic deformation behaviour, yielding to a highly compressible state once subjected to a fluid pressure decline. Monitoring shows that pressure dissipates slowly through these low-permeability capping formations. Adaptive management involves continued monitoring of subsidence rates, and sampling, analysis and predictive modelling where necessary. Simulation modelling indicates that long-term mitigation can be achieved by sustaining pressures through targeted shallow injection. [ABSTRACT FROM AUTHOR]

Abstract: World over, sustainability and carbon emissions are two major growing concerns. Energy efficiency and larger proportion of renewable energy integration are treated as two of the solutions for electricity sector by governments, utilities as well as large end users. Many different small-scale renewable generation technologies are being developed and tested for grid performance motivated by reducing transmission and distribution loss, reducing peak demand, maintaining security of supply, and a possible reduction in electricity charges [1]. It is foreseen that once small scale renewable generation cells become economically competitive, the growth of them in existing electricity networks could be dramatic. Many of the existing small scale renewable generation technologies rely on electronic inverter switching [2–4] at the integration point. Currently, due to the switching characteristics of inverters power quality could become a problem for end users and also impact on regulatory limits for distribution line utilities. The existing inverter technology application of micro wind turbine and solar photovoltaic cells is being currently deployed and assessed several distribution network utilities like Vector in New Zealand. In this paper the outcome of these trials are analysed in addition to proposing the modelling framework to quantify the power quality effect of small scale renewable generation cells. A practical and comprehensive way to assess the power quality impacts due to large scale integration of these new renewable generation devices is also presented. Software such as ATP-EMTP and DIgSILENT PowerFactory is used in this work to provide the platforms for assessment of an individual device and overall network effect, respectively. [Copyright &y& Elsevier]