Traditional electric power systems are designed in large part to utilize large baseload power plants, with limited ability to rapidly ramp output or reduce output below a certain level. The increase in demand variability created by intermittent sources such as photovoltaic (PV) presents new challenges to increase system flexibility. This paper aims to investigate and emphasize the importance of the grid-connected PV system regarding the intermittent nature of renewable generation, and the characterization of PV generation with regard to grid code compliance. The investigation was conducted to critically review the literature on expected potential problems associated with high penetration levels and islanding prevention methods of grid tied PV. According to the survey, PV grid connection inverters have fairly good performance. They have high conversion efficiency and power factor exceeding 90% for wide operating range, while maintaining current harmonics THD less than 5%. Numerous large-scale projects are currently being commissioned, with more planned for the near future. Prices of both PV and balance of system components (BOS) are decreasing which will lead to further increase in use. The technical requirements from the utility power system side need to be satisfied to ensure the safety of the PV installer and the reliability of the utility grid. Identifying the technical requirements for grid interconnection and solving the interconnect problems such as islanding detection, harmonic distortion requirements and electromagnetic interference are therefore very important issues for widespread application of PV systems. The control circuit also provides sufficient control and protection functions like maximum power tracking, inverter current control and power factor control. Reliability, life span and maintenance needs should be certified through the long-term operation of PV system. Further reduction of cost, size and weight is required for more utilization of PV systems. Using PV inverters with a variable power factor at high penetration levels may increase the number of balanced conditions and subsequently increase the probability of islanding. It is strongly recommended that PV inverters should be operated at unity power factor.

Grid-connected photovoltaic power systems: Technical and potential problems—A review

The non-combustion based renewable electricity generation technologies were assessed against a range of sustainability indicators and using data obtained from the literature. The indicators used to assess each technology were price of generated electricity, greenhouse gas emissions during full life cycle of the technology, availability of renewable sources, efficiency of energy conversion, land requirements, water consumption and social impacts. The cost of electricity, greenhouse gas emissions and the efficiency of electricity generation were found to have a very wide range for each technology, mainly due to variations in technological options as well as geographical dependence of each renewable energy source. The social impacts were assessed qualitatively based on the major individual impacts discussed in literature. Renewable energy technologies were then ranked against each indicator assuming that indicators have equal importance for sustainable development. It was found that wind power is the most sustainable, followed by hydropower, photovoltaic and then geothermal. Wind power was identified with the lowest relative greenhouse gas emissions, the least water consumption demands and with the most favourable social impacts comparing to other technologies, but requires larger land and has high relative capital costs.

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Assessment of sustainability indicators for renewable energy technologies

Inspired by the energy democracy movement, this conceptual review critically explores relationships between concentrated or distributed renewable energy and political power. Advocates assert that because the renewable energy transition is fundamentally a political struggle, efforts to shift from fossil fuels and decarbonize societies will not prove effective without confronting and destabilizing dominant systems of energy power. The objectives of this paper include: 1) theorizing and exploring the relationships between renewable energy and political power, 2) critically assessing tensions associated with an energy democracy agenda, and 3) drawing out the implications for democratizing renewable energy development in practice. Distributed energy-politics posits that distributed energy sources and technologies enable and organize distributed political power and vice versa. Efforts are underway to find ways to re-organize distributed energy flows into aggregated and concentrated stocks of energy and other forms of political power. More democratic renewable energy futures may benefit from strengthening democratic practices and outcomes, extending democratization of energy systems across all components, stages and end uses, and sharpening positions relative to dominant pressures of capitalism and market ideology, the ideology of unlimited growth, and the modernist/industrialist agenda. Renewable energy systems offer a possibility but not a certainty for more democratic energy futures.

Political power and renewable energy futures: A critical review

Multi-objective optimization minimizing cost and life cycle emissions of stand-alone PV–wind–diesel systems with batteries storage

Challenges and solution technologies for the integration of variable renewable energy sources—a review

The potential impacts of grid-connected distributed generation and how to address them: A review of technical and non-technical factors

This paper addresses the air emissions of grid supply versus grid-connected and off-grid photovoltaic power generation, using the framework of life-cycle assessment, in the context of rural household energy supply in Australia. Emissions of carbon dioxide, sulphur dioxide and nitrous oxides are calculated for the three life-cycle stages of manufacture, use and disposal. Sensitivities to materials and data inputs, as well as to component efficiencies, lifetimes and sizing are discussed.

For each supply option, demand management options, including insulation and appliance choice, and the substitution of solar heating or bottled gas for electricity, are considered.

The best option in all cases, in terms of life-cycle air emissions, is a grid-connected photovoltaic system used to supply an energy-efficient household with a mix of solar, gas and electric appliances. However, in financial terms, with current Australian energy prices, this option represents a high capital and life-cycle cost. Additionally, for the grid options, electricity costs do not significantly disadvantage the high demand scenarios. Both results provide a clear illustration of current Australian energy-pricing policies being in conflict with long-term environmental sustainability. © 1998 John Wiley & Sons, Ltd.

Life‐cycle air emissions from PV power systems

When a Renewable Energy (RE) power system is owned, operated or maintained by a community organisation, some of the problems associated with other rural electrification implementation models e.g. private or utility, can potentially be solved; including: lack of utility investment, barriers relating to social integration of RE technologies, lack of local maintenance capabilities, and end-user education. However, a range of challenges for community-based energy initiatives in developing countries are identified in the literature, often compromising the long-term operation of RE technologies and the sustainability of the project as a whole. Hence, questions arise around the set of community capabilities required, appropriate project design, and enabling external environment for sustainable Community RE (CRE) projects. Relatively longstanding CRE rural electrification experiences in Central America can offer useful insights on the challenges, capability requirements, and future perspectives for further deployment and governance of CRE initiatives in the developing world. In this study, a comparative analysis from case studies across Panama, Nicaragua and Costa Rica was undertaken after field investigation conducted over eight months. A cross-disciplinary method combining qualitative social research and techno-economic analysis of RE power systems was then used for data integration and sustainability assessment of selected case studies.

The future of Community Renewable Energy for electricity access in rural Central America

Peak load characteristics of Sydney office buildings and policy recommendations for peak load reduction

This paper presents an analysis of the potential impact of integrating photovoltaics (PV) into the Western Australian electricity networks. It uses real-time load and Australian Bureau of Meteorology climate data to assess PV’s ability to reduce peak generation requirements, defer network augmentation, reduce line losses and reduce the cost of conventional supply in the Western Australian electricity networks and regional grids. It then identifies existing market opportunities for PV in Western Australia (WA), examines whether these capture the identified benefits and discusses strategies for capturing the system benefits provided by PV. Copyright # 2009 John Wiley & Sons, Ltd.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/pip.889

Muriel Watt

Papers

The potential impacts of grid-connected distributed generation and how to address them: A review of technical and non-technical factors

Life‐cycle air emissions from PV power systems

The future of Community Renewable Energy for electricity access in rural Central America

Peak load characteristics of Sydney office buildings and policy recommendations for peak load reduction

Study of grid‐connect photovoltaic systems: benefits, opportunities and strategies