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[en] In order to increase energy security, production of renewable energies has been highly promoted by governments around the world in recent years. The typical base of various policy instruments used for this purpose is gross energy output of renewable energy. However, we show that basing policy instruments on gross energy output will result in problems associated with energy waste, economic inefficiency, and negative environmental effects. We recommend using net energy output as the base to apply price or quantity measures because it is net energy output, not gross energy output, which contributes to energy security. The promotion of gross energy output does not guarantee a positive amount of net energy output. By basing policy instruments on net energy output, energy security can be enhanced and the above mentioned problems can be avoided.
[en] Aim: Policy-makers typically track the rapidly evolving U.S. residential photovoltaic (PV) market by relying on price data reported by PV installers/integrators to incentive programs. Recent years have witnessed a shift toward third-party-owned (TPO) business models, in which the absence of a cash purchase price obscures data interpretation. Appraisals—often based on estimates of the average fair market value across a diverse fleet of systems—are one way TPO prices are reported. Scope: This study investigates residential PV system price drivers to improve the accuracy, consistency, and relevance of PV price-tracking efforts. Our econometric approach evaluates system price drivers using California Solar Initiative data, controlling for system, installer, and geographic variables. Conclusions: We find that reported prices for confirmed appraised systems are $1.13/W higher than non-appraised systems and do not respond to hypothesized price drivers. For non-appraised systems, we find preliminary evidence of market distortions based on the impact of the incentive level, module cost and household income on reported price. Further, unspecified installer heterogeneity—possibly due to differences in products, cost structure or reporting practices—is a substantial price driver. Using estimates, we develop a price model to approximate non-appraised system prices. -- Highlights: •This analysis evaluates residential PV price drivers using an econometric model. •Reported prices for appraised systems are $1.13/W higher than non-appraised. •Reported prices for appraised systems do not respond to expected price drivers. •We find some evidence of market distortions in non-appraised systems. •Installer heterogeneity is a substantial price driver for all systems
[en] Wind and solar energy will play an important role in the decarbonization of the European electricity generation. However, high shares of these variable renewable energies (VREs) challenge the power system considerably due to their temporal fluctuations and geographical dispersion. In this paper, we systematically analyze transmission grid extensions as an integration measure for VREs in Europe. We show the effects of grid extensions for fundamental properties of the power system as a function of the penetration and mix of wind and solar energy. Backup capacity requirements and overproduction are reduced with a powerful overlay transmission grid. We determine the costs of the grid extensions in dependence of the VRE penetration and mix and find that the grid integration costs remain below 25% of the VRE investment costs for all conceivable VRE configurations. Furthermore, robust design features of future power systems in terms of grid geometry and flexibility requirements for backup technologies are identified. We apply a spatially and temporally highly resolved techno-economic model of the European power system for our analysis. - Highlights: ► Quantification of the advantages and costs of a European overlay transmission grid. ► Grid integration costs for VREs in Europe remain below 6€/MWh. ► Application of a detailed power system model to a wide parameter space.
[en] The potential and limits of solar thermal power systems depend primarily on their capacity to meet electricity demand in mid-winter, and the associated cost, storage and other implications. Evidence on output and costs is analysed. Most attention is given to central receivers. Problems of low radiation levels, embodied energy costs, variability and storage are discussed and are found to set significant difficulties for large scale solar thermal supply in less than ideal latitudes and seasons. It is concluded that for solar thermal systems to meet a large fraction of anticipated global electricity demand in winter would involve prohibitive capital costs. - Highlights: • Output and capital cost data for various solar thermal technologies is examined. • Special attention is given to performance in winter. • Attention is also given to the effect of solar intermittency. • Implications for storage are considered. • It is concluded that there are significant limits to solar thermal power
[en] Hourly DNI data from the Australian Bureau of Meteorology over 8 years have enabled analysis of implications for solar thermal power generation systems. Six sites were selected, mostly in central Australia and the occurrence and duration of gaps in the availability of energy inputs to solar thermal generation were tallied. In a three month period late in 2010 12 periods of three or more days with an overall average DNI of 2.3 kWh/m2/day occurred. The relationship between DNI and solar thermal generation efficiency was examined and this indicated that on many more days power output would have been very low or zero. The relation between daily total DNI and hourly average DNI was also found to be important, as a high total might be made up of many hours in which DNI was too low for significant generation. These two factors show that there is a significant problem of intermittency for solar thermal systems. Although the annual output of each plant may be commercially viable a solar thermal system might not be capable of meeting demand reliably. - Highlights: • Australian Bureau of Meteorology data were examined regarding DNI patterns. • Gaps in availability of solar energy were identified. • The occurrence of low hourly DNI was examined. • Implications for the reliability of solar energy were drawn
[en] The adoption of an innovation is partly dependent on the consumers' perception of the product attributes, starting with the 'relative advantage' a product may have over another existing product, and also include issues of compatibility, complexity, observability and trialability. Using diffusion of innovations theory as a conceptual framework, this paper describes a case study that investigated the innovation adoption process that a group of identified potential adopters of domestic solar thermal systems stated they would follow. Data was generated from the results of a postal survey to a group of 43 defined innovators and a group of 350 assumed 'early majority', pragmatic consumers. The survey results showed that while the pragmatic customers did follow the process as theorised in diffusion theory, the innovators disregarded the observability attributes of the innovation and went ahead with implementation without having seen the products beforehand. The group of innovators was also split in their opinion that 'complexity' may be a limiting factor. There were differences in the pragmatic group between certain demographic sub groups. Conclusions are drawn on how the findings may impact marketing activities
[en] In planning, designing and evaluating a geothermal energy project, a number of technical, economic, social and environmental parameters should be considered. The use of computational methods provides a rigorous analysis improving the decision-making process. This article demonstrates the application of decision-making methods developed in operational research for the optimum exploitation of geothermal resources. Two characteristic problems are considered: (1) the economic evaluation of a geothermal energy project under uncertain conditions using a stochastic analysis approach and (2) the evaluation of alternative exploitation schemes for optimum development of a low enthalpy geothermal field using a multicriteria decision-making procedure. (Author)
[en] Solar resource estimation risk is one of the main solar PV project risks that influences lender’s decision in providing financing and in determining the cost of capital. More recently, a number of measures have emerged to mitigate this risk. The study focuses on solar industry’s best practice energy resource estimation and assesses its financing implications to the 27 MWp solar PV project study in Brunei Darussalam. The best practice in resource estimation uses multiple data sources through the measure-correlate-predict (MCP) technique as compared with the standard practice that rely solely on modelled data source. The best practice case generates resource data with lower uncertainty and yields superior high-confidence energy production estimate than the standard practice case. Using project financial parameters in Brunei Darussalam for project financing and adopting the international debt-service coverage ratio (DSCR) benchmark rates, the best practice case yields DSCRs that surpass the target rates while those of standard practice case stay below the reference rates. The best practice case could also accommodate higher debt share and have lower levelized cost of electricity (LCOE) while the standard practice case would require a lower debt share but having a higher LCOE. - Highlights: •Best practice solar energy resource estimation uses multiple datasets. •Multiple datasets are combined through measure-correlate-predict technique. •Correlated data have lower uncertainty and yields superior high-confidence energy production. •Best practice case yields debt-service coverage ratios (DSCRs) that surpass the benchmark rates. •Best practice case accommodates high debt share and have low levelized cost of electricity.
[en] This paper discusses some energy scenarios for photovoltaic applications in Brazil engendered by using SWERA database in order to demonstrate its potential for feasibility analysis and application in the energy planning for electricity generation. It discusses two major different markets: hybrid PV-Diesel installations in mini-grids of the off-grid Brazilian electricity system in the Amazon region, and grid-connected PV in urban areas of the interconnected Brazilian electricity system. The potential for using PV is huge, and can be estimated in tens to hundreds of MWp in the Amazon region alone, even if only a fraction of the existing Diesel-fired plants with a total installed capacity of over 620 MVA would fit to run in an optimum Diesel/PV mix. Most of the major cities in Brazil present greater electricity demand in summertime with the demand peak happening in the daytime period. This energy profile match the actual solar resource assessment provided by SWERA Data Archive, enabling grid-connected PV systems to provide an important contribution to the utility's capacity
[en] An ever-increasing body of research explores the effectiveness of Home Energy Management Systems (HEMS) in achieving energy savings in households. To date, however, the overall life cycle impact of the HEMS itself has not been taken into account. Thus, no assessment has been made whether the amount of energy saved (esaved) outweighs the energy needed for production, use and disposal (einvested). Therefore, an eco-cost and a Cumulative Energy Demand (CED) method were used to analyze three distinct types of HEMS. Based on the literature, six scenarios were developed in order to find the break-even point, where einvested=esaved. The results show that the overall impact is dependent on the type of HEMS, and that if the duration of use is short and the achieved savings are small, the benefits do not always outweigh the environmental costs. Care should be taken not to develop HEMS with unnecessarily elaborate parts or functionalities and that their own electricity consumption is minimized. The paper concludes by discussing the implication for polices concerning the implementation of smart meters and HEMS and their design. - Highlights: • We conducted a lifecycle assessment of three Home Energy Management Systems (HEMS). • We developed six scenarios to find the breakeven point where einvested=esaved. • All three HEMS can achieve net energy savings over the course of five years. • Within the scenarios, it can take up to two years to achieve net energy savings. • No HEMS achieve a positive return on investment within five years in all scenarios