Solar City Research Articles

Toward a solar city: Trade-offs between on-site solar energy potential and vehicle energy consumption in San Francisco, California

ABSTRACTThis study demonstrates the trade-offs between vehicle energy consumption and on-site solar energy potential in a city landscape. While higher urban density may curb many of the problems associated with sprawl mainly by reducing vehicle travels and associated energy use, it can also limit on-site rooftop solar energy utilization due to more shade on rooftops in dense urban settings and less available rooftop area per person. Using travel survey, Geographic Information System (GIS) and Light Detection and Ranging (LiDAR) data, we estimated vehicle energy use and rooftop solar potential in the City of San Francisco as a case study and calculated possible offsetting effects between vehicle energy consumption and rooftop solar potential. Given the prevalence of gasoline-based vehicles and today's solar photovoltaic (PV) panel efficiency, vehicle energy use per capita appears to exceed energy generated by rooftop solar PVs per capita across all density ranges, especially in lower density environments. At the point when electric cars and advanced, highly efficient solar PV panels penetrate the market, the results change based on the combination of different technological options. A significant reduction of energy consumption can be achieved through the immediate and rapid spread of energy efficient technologies in vehicles and solar PVs along with the long-term effect from gradual urban densification.

Why a clearer ‘green industrial policy’ matters for India: Reconciling growth, climate change and inequality

To ensure a healthy growth of the economy particularly in the manufacturing sector, the Indian Government is more than ever focussed on promoting the use of sustainable and affordable energy resources. Recent initiatives such as the Solar Cities Development Programme are a good example. However, in order for these initiatives to gain legitimacy as part of a new ‘green industrial policy’, the Indian Government needs to do more, especially by bringing on board strategies for combating poverty within the gamut of this emerging ‘green industrial policy’ as well as to re-think India’s position on global conventions on climate change.

Potential of distributed photovoltaics in urban Chile

In this article, we present an updated potential of distributed photovoltaics in cities in Chile, which is one of the most promising regions for solar energy utilization because of high insolation, high energy costs and rapid urbanization. The study is based on detailed analysis of the spatio-temporal solar potential including load matching in a southern Chilean city, which is then extrapolated to all cities with more than 15,000 inhabitants. In addition, we estimate the cost-effectiveness of such solar city schemes. Our results show that in the city of Concepción PV could cover up to 90% of the annual electricity demand. On national scale, cities could on average produce 83% of their annual electricity demand, but in the northern part this could exceed even 100%. If scaling the PV yield from distributed PV in cities to whole Chile that would correspond to 22% of country’s electricity demand. The cost (LCOE) of PV in cities seems to be cost-effective against grid electricity, i.e. in the Chilean context PV has already reached grid-parity in cities.

Optimal Operation of Distributed Energy Storage Systems to Improve Distribution Network Load and Generation Hosting Capability

This paper proposes a strategy for optimal integration of battery energy storage systems (BESSs) to improve the load and distributed generation (DG) hosting ability of the utility grid. An effective tool that determines the optimal capacity and day-ahead operation strategy for deployment of distribution network operator (DNO)-controlled BESSs is presented. It is a cost-based multiobjective optimization strategy that considers two primary factors: 1)distribution system cost; and 2)battery cycling cost. Quantitative analyses on the benefits and tradeoffs of BESS installations are carried out considering different service options. BESS is investigated for three main service options: 1)voltage regulation; 2)loss reduction; and 3)peak reduction. The performance and benefits of the optimized BESS to control one service option exclusively or multiple services simultaneously is compared. The analysis is further extended to study the effect of installation site on the size, management strategy, and the service option. Results show that optimal integration of BESSs can realize maximum operational and cost benefits while effectively elevating the load and DG hosting capability of the network. The approach is developed using MATLAB interior-point algorithm. Simulations are conducted for the medium voltage (MV) IEEE 33 bus system and a low voltage (LV) distribution network in Western Australia studied during the Perth Solar City Trial.

A solar city strategy applied to six municipalities: integrating market, finance, and policy factors for infrastructure‐scale photovoltaic development in Amsterdam, London, Munich, New York, Seoul, and Tokyo

Policy support platforms like the Feed‐in Tariff and the Renewable Portfolio Standard have been very successful in accelerating renewable energy development around the world. Nonetheless, the sustained and consistent transition to a renewable energy future required, e.g., to avoid further climate change, continues to elude societies. To achieve substantial energy transformation, reconsideration of the finance–policy–market interaction is required and is contemplated here by positioning the build‐out of a particular renewable energy technology, photovoltaic (PV) energy, as a commitment to infrastructure‐scale development. A so‐called ‘solar city’ strategy is analyzed in which large‐scale deployment of PV throughout the urban fabric essentially constructs an urban renewable energy power plant by utilizing the vast rooftop real estate available in all cities. The article explores a capital market strategy for practical implementation of urban PV in six case study cities—Amsterdam, London, Munich, New York City, Seoul, and Tokyo. This study demonstrates the substantial potential of the solar city concept in each location and outlines a financing strategy to realize the potential. WIREs Energy Environ 2016, 5:68–88. doi: 10.1002/wene.182This article is categorized under: Photovoltaics > Economics and Policy Solar Heating and Cooling > Systems and Infrastructure Energy and Development > Economics and Policy

High resolution measured domestic hot water consumption of Canadian homes

The modeling and simulation of domestic hot water systems, including solar thermal and co-generation technologies, relies on accurate, high time-step resolution water consumption profiles. Due to the expensive nature of field studies, previous profiles have been limited in number of participants, or have been generated synthetically using probabilistic modelling techniques. The Solar City program in Halifax has measured hot water flow rate and temperature data in 119 homes at a time-step of 1min; and includes a survey of occupancy rates and other relevant meta-data. In this paper, we discuss the data acquisition and processing (with a focus on flow rate data), and conduct analysis to reveal consumption trends and produce a new set of time-step profiles for modeling and simulation. Average hot water consumption per household is 172L/day with a strong dependency on number of occupants. The hourly profile peaks twice daily, and shifts by several hours on Sunday. The average draw temperature was found to be 51.8°C, which is lower than the default value of 55°C applied by many building modeling/simulation packages. The average cold water supply temperature was found to be roughly sinusoidal about 12.4°C with approximately one-month lag compared to ambient air temperature.

Power to change: Analysis of household participation in a renewable energy and energy efficiency programme in Central Australia

The Australian government funded a national Solar City program (2008–2013) to support communities to increase adoption of energy efficiency measures and renewable energy technology. One community was Alice Springs, a town with about 9000 households in the geographic centre of Australia. The programme offered a package of support: free energy audits, discounts for the purchase of renewable energy technology and energy efficiency measures, and ongoing information. Households that adopted solar hot water and photovoltaic systems reduced their electricity usage immediately after adoption by 10% and 34% respectively, and this was maintained in the long term. A small rebound effect of 15% was observed in the photovoltaic adopters. It was observed that, on average, households that adopted only energy efficiency measures did not have a significant reduction in their electricity usage over the long term. However, consistent with expectations, this study did show that there was a significant correlation between the number of energy efficiency measures adopted and the greatest household reduction in electricity usage. These contrary results indicate that there are additional factors involved. The connection between the effective use of measures, coincident behavioural change or increased energy awareness and greater energy reduction is discussed.

The Emergence and Spread of Ecourban Neighbourhoods around the World

In modern times, efforts to construct sustainable alternative neighbourhood scale developments date to isolated voluntary initiatives in 1970s Europe and the United States. Since about 2006, they have increased rapidly in popularity. They now go by many names: ecodistricts, écoquartiers, eco-cities, zero/low-carbon/carbon-positive cities, ecopolises, ecobarrios, One Planet Communities, and solar cities. They have become frames—sometimes the dominant frame—used to orient the construction of new pieces of a city in a growing number of countries. Despite numerous standardization efforts, the field of ecourban neighbourhood planning and practice lacks a consistent cross-cultural understanding of what constitutes meaningful ecourbanism in specific economic, political, ecological, social, and design-based terms. Ecourban neighbourhood projects also respond to strictly local challenges and opportunities and express themselves in fragmented ways in different contexts. This article presents an original typology of ecourbanism as the integration of seven extreme type principles. We developed this typology through an abductive approach, or the back and forth testing of observed practices with arguments advanced in theories of sustainable development, planning and urban studies. While ecourban neighbourhood developments by definition express integrative goals, this typology permits assessment of the extent to which outcomes are being achieved in terms of each specific principle. We define and present a limiting case for each of these extreme type principles. Rather than attempting to render different standards equivalent across national contexts, this typology-based approach to understand the outcomes of ecourban neighbourhood developments promises a means to facilitate orienting these developments toward higher levels of integration within a common set of principled boundaries, as they are developed around the world.

Comprehensive optimal photovoltaic inverter control strategy in unbalanced three‐phase four‐wire low voltage distribution networks

The continuous expansion of consumer-driven installations of residential rooftop photovoltaic (PV) systems causes serious power quality, notable voltage variations and unbalance, which limit the number and capacity of the further connections. The latent reactive power capability of PV inverters can increase the network PV hosting capability. This study proposes both reactive power control and real power curtailment as a comprehensive inverter control strategy to improve the operating performance of unbalanced three-phase four-wire low voltage distribution networks with high penetrations of residential PV systems. A multi-objective optimal power flow (OPF) problem that can simultaneously improve voltage magnitude and balance profiles while minimising network loss and generation costs is defined. The solution is found using the global solver based on Sequential Quadratic Programming algorithm with multiple starting points in Matlab. Detailed simulations are performed and analysed for typical operating scenarios over 24-h period on a real three-phase four-wire unbalanced distribution network in Perth Solar City trial, Australia. Smart meter readings are used to justify the accuracy and validation of the network model and the proposed multi-objective OPF model.

Optimal PV Inverter Reactive Power Control and Real Power Curtailment to Improve Performance of Unbalanced Four-Wire LV Distribution Networks

The rapid uptake of residential photovoltaic (PV) systems is causing serious power quality issues such as significant voltage fluctuation and unbalance that are restricting the ability of networks to accommodate further connections. Based on the latent reactive power capability and real power curtailment of single-phase inverters, this paper proposes a new comprehensive PV operational optimization strategy to improve the performance of significantly unbalanced three-phase four-wire low voltage (LV) distribution networks with high residential PV penetrations. A multiobjective optimal power flow (OPF) problem that can simultaneously improve voltage magnitude and balance profiles, while minimizing network losses and generation costs, is defined and then converted into an aggregated single-objective OPF problem using the weighted-sum method, which can be effectively solved by the global Sequential Quadratic Programming (SQP) approach with multiple starting points in MATLAB. Detailed simulations are performed and analyzed for various operating scenarios over 24 h on a real unbalanced four-wire LV distribution network in Perth Solar City trial, Australia. Finally, smart meter readings are used to justify the validity and accuracy of the proposed optimization model and considerations on the application of the proposed PV control strategy are also presented.

Open Source Architecture for "Nuovo CEP"

The Open Source Architecture (OSArc) is a new collaborative way to design common and shared areas at an architectural level, but also at an urban and technological level, etc.. It allows you to participate in the design phase both practically, with your technical contributions, and actively, with constructive criticism and intelligent and innovative suggestions. We thought of using this new design paradigm to make the Nuovo CEP project feasible and economically sustainable through the cooperation of both professionals and non-professionals (i.e. inhabitants, students, etc.). Nuovo CEP is a project, which aims to redevelop a suburban neighbourhood and transform it into a mini smart solar city. The OSArc for Nuovo CEP is realized by means of a wiki website where all interested users can register and insert their contributions together with others members of the community. In this paper, we are going to explain the Nuovo CEP project and its objectives, which will be a guideline and an inspiring source for users contributions. Then we will explain the wiki website structure used to implement the platform for the OSArc.

Impacts of the Alice Solar City Program on the Local Tourism Industry

Impacts of the Alice Solar City Program on the Local Tourism Industry The Alice Solar City (ASC) project was one of seven under the Australian Government’s Solar Cities Program. This paper investigates the actual and potential multi-dimensional impacts of the Alice Solar City project on the local tourism industry in Alice Springs. The results suggest that the ASC project was not a tourist attraction. There was a positive contribution from the ASC to the image of the town as well as significant impacts, both economic and non-economic, on the local community. The Solar City project made a positive contribution to the environmental sustainability of the whole tourism industry in the region. Nevertheless, the project had a minimal impact on attracting tourists or persuading them to extend their stay in the town. The indirect and/or non-economic impacts of the ASC possibly could have been turned into a positive contribution to the increase in tourist numbers and tourist nights, but this required a basic re-ordering of the town’s tourism “brand”.

Solar city, bike city, growth city: governance and energy in Davis, California

Solutions to the climate and energy crises will likely involve large scale renewable energy technology deployment and of renewable energy technologies in building energy systems and transportation systems. But they will also require changes in lifestyle, behavior, and social organization. Solar heating and bicycle use are well-developed technologies that exemplify social-technological hybrids. Davis, California, has established a national reputation as a bike-friendly city and has been an international leader in supporting energy efficient housing developments. Support, however, has waxed and waned over the years. Davis provides an ideal case study to explore the conditions necessary to develop a sustained community commitment to passive solar design and human powered transport at a scale large enough to make a difference. This analysis points to the importance of local politics, municipal identity tied to an energy or environmental vision, and the organization of social capital to influence broad-based technological choice.Key words: solar heating, bicycle lanes, social capital, behavior, environmental politics.

A Hybrid Model for Residential Loads in a Distribution System With High PV Penetration

This paper presents a hybrid model for residential electricity demand. Consumer load is modeled in two parts. A low frequency model uses a compact Fourier series to represent slowly changing diurnal loads. Cluster analysis is applied to identify particular load classes and a load classifier based upon quadratic discriminant functions is developed. Once the low frequency load components are removed a high frequency residual load remains. This component is modeled using a power spectrum representation. The load modeling approach was used to model consumption on high demand days for households within the Perth Solar City high photovoltaic penetration feeder trials. The load models were successfully validated against physical data sets with respect to load aggregation behaviors and load cumulative probability functions.

Solar City Indicator: A methodology to predict city level PV installed capacity by combining physical capacity and socio-economic factors

Shifting to renewable sources of electricity is imperative in achieving global reductions in carbon emissions and ensuring future energy security. One technology, solar photovoltaics (PV), has begun to generate a noticeable contribution to the electricity mix in numerous countries. However, the upper limits of this contribution have not been explored in a way that combines both building-by-building solar resource appraisals with the city-scale socio-economic contexts that dictate PV uptake. This paper presents such a method, whereby a ‘Solar City Indicator’ is calculated and used to rank cities by their capacity to generate electricity from roof-mounted PV. Seven major UK cities were chosen for analysis based on available data; Dundee, Derby, Edinburgh, Glasgow, Leicester, Nottingham and Sheffield. The physical capacity of each city was established using a GIS-based methodology, exploiting digital surface models and LiDAR data, with distinct methodologies for large and small properties. Socio-economic factors (income, education, environmental consciousness, building stock and ownership) were chosen based on existing literature and correlation with current levels of PV installations. These factors were enumerated using data that was readily available across each city. Results show that Derby has the greatest potential of all the cities analysed, as it offers both good physical and socio-economic potential. In terms of physical capacity it was seen that over a 15year payback period there are two plateaus, showing a marked difference in viability between small and large PV arrays. It was found that both the physical and socio-economic potential of a city are strongly influenced by the nature of the local building stock. This study also identifies areas where policy needs to be focused in order to encourage uptake and highlights factors limiting maximum PV uptake. While this methodology has been demonstrated using UK cities, it is equally applicable to any country where city data is available.

Solar City in China

This article introduces examples of solar cities, such as the Sutton Beddington Community in United Kingdom and the Abu Dhabi City in United Arab Emirates. Meanwhile, the spate of solar city is described in detail. The most important, we point out the confusion of China's solar cities development.

From Glass City to Solar City: Toledo Ohio reinvents itself

From Glass City to Solar City: Toledo Ohio reinvents itself

Transnational Municipal Networks in Climate Politics: From Global Governance to Global Politics

In a multilevel and multicentric governance arena, pathways and mechanisms of influence are several and non-state capacities for technical leadership and norm entrepreneurship prove more significant than is the case within a strictly multilateral framework. Among actors with such capacities are municipalities, which multiply their influence through horizontal and vertical relationships. Transnational municipal networks present opportunities for both intermunicipal dialogue and the pooling of global influence, highlighting the presence and influence of the city in the world. This paper examines the collective response of some cities to climate change, exploring the place of cities in global environmental politics through analysis of two transnational municipal networks: the International Council of Local Environmental Initiatives' Cities for Climate Protection and the International Solar Cities Initiative. The article addresses the following questions: How might municipal efforts toward a climate-stable future be significant to the larger issue of ecological justice in global environmental politics? Might cities be able to redefine the rules of the game and take a stand on ‘inefficient’ norms? After briefly accounting for the relationship between cities and the world, the article characterizes technical leadership as a legitimizing force of and in global environmental governance and norm entrepreneurship as a potential source of contestation and subversion in global environmental politics. The paper describes what cities are globalizing, in terms of pollution, environmental degradation, and risk, and in terms of management and politics. Finally, the article explores the possibility that emerging horizontal and vertical relationships, intermunicipal relationships, and relationships between cities or networks of cities and other scales of governance potentiate legitimizing roles for cities in climate governance and subversive roles in climate politics. A Chinese version of this article's abstract is available online at: www.informaworld.com/rglo

An integrated assessment of options for rural wastewater management in Austria

This paper reports a recently finished, interdisciplinary project on rural wastewater management in Austria. The objective of the project was to study alternative wastewater management options based on separation of the wastewater into its constituent parts, and to compare them with conventional ones. Thereby, a feasibility study of both conventional and alternative options for wastewater management in six model regions was carried out. Life cycle costs and social acceptance were analysed by using a case study-based assessment approach. However, hygienic and environmental risks were evaluated on a more general level. In order to complement the findings, a survey on urine separation system users in the Solar City of Linz was conducted. Based on these assessments and empirical findings, the paper concludes that options using a full separation of all wastewater fractions should be considered with care. Options based on a separation of only grey water and black water or in the liquid/solid phase can offer ecological and financial advantages over conventional options. Further, options combining wastewater management and regional biogas plants were identified as an interesting solution. However, legal constraints restrict this option currently.

Beyond Peak Oil: Will Our Cities Collapse?

Global oil seems to be at or close to its full capacity, meaning that oil production is at its peak and soon will begin to decline. This paper discusses what this decline in oil production and availability will mean for the future of cities. Four possible scenarios are suggested: collapse, the ruralization of cities; divided cities in which those with the most means will move to city centers while the dispersed suburbs become the home of the poor; and the resilient, sustainable, solar city. To move toward this last scenario, it is important to take the threat seriously and create peak-oil strategies. Cities should be planned and built with reduced car dependence and peri-urban agricultures should be rebuilt. It is also important to facilitate localism, regulate for the post-oil transition and prepare risk management scenarios for the future.