Pathways to commercial wind power in the US, Europe and Japan: The role of demonstration projects and field trials in the innovation process

A growing, but little understood area of Government involvement in promoting renewable energy, is the use of demonstration projects and field trials (DTs) as a policy tool. This paper explores the historical role of DTs in the commercialisation of wind turbines. We review information from government, academic and industry sources, together with the newly created Cass Wind DT database, and consider the context, objectives, participants and nature of wind DTs in the EU, US and Japan.Overall, it is difficult to identify the benefits of wind DTs for many of the key actors. Government funding of DTs does not appear to be shaped by coherent or targeted strategic objectives–indeed governments use DTs differently despite similar stated objectives. A common theme has been the involvement of many stakeholders, with local authorities, utilities and operators taking the lead rather than manufacturers. Wind DTs appear to have neither enabled participating manufacturers to become significant global suppliers–with a few exceptions driven by additional financial and legislative support from national governments-nor to have established a dominant design. The major benefit of wind DTs appears to have been ‘learning by using’ for utilities and wind farm operators, reducing operational costs.     

Substrate to substrate aluminized bonding of 10 cm round silicon substrates for application in solar photovoltaics

Large area silicon solar cells with screen printed contacts have been realized for the first time on 10 cm diameter, p-type, Cz silicon wafers which were bonded to silicon substrates by alloying of a suitably thick screen printed layer of Al on them. In cells made on 300 μm thick wafers without texturization, antireflection coating and passivation of the front surface, the values of the open-circuit voltage (V_oc), the short-circuit current density (J_sc), curve factor (CF) and the efficiency (η) were found to be in the range 572–579 mV, 16–19.2 mA cm⁻², 0.53–0.61 and 5.5–5.89%, respectively, under simulated tungsten halogen light of 100 mW cm⁻² intensity. Using thinner wafers and having optical confinement, surface passivation and effective back surface field, the cell performance would be substantially improved. In fact, an efficiency close to 18% (AM1.5) would be realizable with this approach. Another attractive feature of this approach is that a low-cost silicon substrate could be used at the bottom that would act as support for the thin top surface without disadvantage to the cell performance. In this paper only the principle has been demonstrated experimentally. Possible improvements have been shown by computer simulation.     

Perceptions of opinion leaders towards CCS demonstration projects in China

We present results of a major survey of Chinese opinion leaders conducted from March to April 2009, supported by EU–UK–China near zero emissions coal (NZEC) initiative. Respondents were drawn from 27 provinces and regions using an online survey with follow-up face-to-face interviews. A total of 131 experts and decision-makers from 68 key institutions were consulted through online survey. This survey is the first to focus on demonstration projects in particular and is the most geographically diverse. We aim to understand perceptions of applying CCS technologies in the first large-scale CCS demonstration project in China. Though enhanced oil recovery (EOR) and enhanced coal bed methane recovery (ECBM) may not be long-term solutions for CO₂ storage, they were viewed as the most attractive storage technologies for the first CCS demonstration project. With regard to CO₂ capture technology, on the whole, post-combustion (which would be most applicable to the vast majority of existing power plants which are pulverised-coal) received slightly higher support than pre-combustion. More surprising, respondents from both the power and oil industries favoured pre-combustion. There was no consensus regarding the appropriate scale for the first demonstration. A large number of respondents were concerned about the energy penalty associated with CCS and its impact on the long-term sustainability of coal supply in China, although such concerns were much reduced compared with surveys in 2006 and 2008.     

Assessment of high penetration of solar photovoltaics in Wisconsin

This paper provides an assessment of the large-scale implementation of distributed solar photovoltaics in Wisconsin with regard to its interaction with the utility grid, economics of varying levels of high penetration, and displaced emissions. These assessment factors are quantified using simulations with measured hourly solar radiation and weather data from the National Solar Radiation Database as primary inputs. Hourly utility load data for each electric utility in Wisconsin for a complete year were used in combination with the simulated PV output to quantify the impacts of high penetration of distributed PV on the aggregate Wisconsin electric utility load.     

A technological evolution from bulk crystalline age to multilayers thin film age in solar photovoltaics

Recent advances in solar cell device technologies are surveyed, and a new trend underlying is predicted by a term “technological evolution from the bulk crystalline age to the multilayered thin film age”. In the paper, firstly, recent progress of thin film fabrication technologies for active materials of photovoltaic device are reviewed, and their significancies such as wide area, low temperature growth etc., are pointed out from currently developed live technologies. Secondly, some R & D efforts to develop the next generation type solar cells utilized by full use of multi-layers thin film growth technology are introduced together with some newly developed integrated process technology for the thin film solar cells. Then, some topics in the high cost performance multi-layers thin film solar cells are also introduced. In the final part of this paper, the current state of the art in the field of thin film solar cells and their industrialization are overviewed and the market expansion toward the 21st century is forecast, and discussed.     

Land-use requirements and the per-capita solar footprint for photovoltaic generation in the United States

In this report, we estimate the state-by-state per-capita “solar electric footprint” for the United States, defined as the land area required to supply all end-use electricity from solar photovoltaics (PV). We find that the overall average solar electric footprint is about 181 m² per person in a base case scenario, with a state- and scenario-dependant range from about 50 to over 450 m² per person. Two key factors that influence the magnitude of the state-level solar electric footprint include how industrial energy is allocated (based on location of use vs. where goods are consumed) and the assumed distribution of PV configurations (flat rooftop vs. fixed tilt vs. tracking). We also compare the solar electric footprint to a number of other land uses. For example, we find that the base case solar electric footprint is equal to less than 2% of the land dedicated to cropland and grazing in the United States, and less than the current amount of land used for corn ethanol production.     

Review and analysis of demonstration projects on power-to-X pathways in the world

Transforming the energy system towards more sustainability can only be achieved through a combination of low-carbon energy, energy efficiency, and the coupling of energy sectors. In this context, the application of Power-to-Hydrogen concepts for managing demand, providing seasonal storage, and linking elements between different sectors has attracted significant interest during the last decade.Demonstration is a key first step towards large-scale market introduction. This paper presents the results of a review of 192 Power-to-X demo projects in 32 countries. Results show that the features of demonstrations have evolved significantly over the years: electrolysis capacity has increased, both for PEM and alkaline systems, and the potential for balancing and ancillary services is increasingly investigated via grid-connected demos. The scope of Hydrogen-to-X pathways has also evolved over the years, mainly to include industry applications. This work was carried out under the umbrella of Task 38 of the IEA Hydrogen Technology Collaboration Programme.     

Evaluating the limits of solar photovoltaics (PV) in traditional electric power systems

In this work, we examine some of the limits to large-scale deployment of solar photovoltaics (PV) in traditional electric power systems. Specifically, we evaluate the ability of PV to provide a large fraction (up to 50%) of a utility system's energy by comparing hourly output of a simulated large PV system to the amount of electricity actually usable. The simulations use hourly recorded solar insolation and load data for Texas in the year 2000 and consider the constraints of traditional electricity generation plants to reduce output and accommodate intermittent PV generation. We find that under high penetration levels and existing grid-operation procedures and rules, the system will have excess PV generation during certain periods of the year. Several metrics are developed to examine this excess PV generation and resulting costs as a function of PV penetration at different levels of system flexibility. The limited flexibility of base load generators produces increasingly large amounts of unusable PV generation when PV provides perhaps 10–20% of a system's energy. Measures to increase PV penetration beyond this range will be discussed and quantified in a follow-up analysis.     

Beyond technology-push and demand-pull: Lessons from California's solar policy

The scale of the technological transformation required to reduce greenhouse gas emissions to “safe” levels while minimizing economic impacts necessitates an emphasis on designing climate policy to foster, or at least not impede, environmental innovation. There is only a weak empirical base for policy-makers to stand on regarding the comparative innovation effects of various climate policy options, however. Empirical scholarship in environmental innovation is hindered by the complexity of both the innovation process and the interactions between the dual market failures of pollution and innovation that are in play, and it appears that the field would benefit from the structure provided by a common lexicon. This paper focuses on the issues related to policy categorization in this field; these issues have received little attention in the literature despite their importance to making insights gained from empirical studies generalizable. The paper reviews the origins, strengths, and weaknesses of the dominant policy typology of technology-push versus demand-pull instruments. Its primary contribution, however, is to assemble a comprehensive chronology of solar policy in California and its impacts on innovation, where known, and then use this as a basis for building a new policy categorization that takes advantage of the intuitive resonance of the dominant typology, while encompassing the broader range of policy instruments that are employed in practice in order to stimulate environmental innovation. The most noteworthy aspect of the new categorization is that it introduces a third category of environmental innovation policy instrument that focuses on improving the interface between technology suppliers and users. This reflects developments in the economics of innovation literature as well as considerable evidence in the domain of distributed solar energy technologies that opportunism by some of the actors that work at this interface can be a barrier to innovation.     

The impact of cooling on cell temperature and the practical solar concentration limits for photovoltaics

The solar concentration limit for densely packed, high‐concentrated photovoltaic (HCPV) cells was analyzed for a novel two‐phase cooling design. Eight working fluids were examined in the two‐phase cooling analysis: R134a, R11, R113, R114, R123, R141b, water, and ammonia. In addition, the study investigated the concentration limit for mass flow rates ranging from 10^?3 to 1 kg s^?1. Results from this analysis showed that the limits neared 2000 suns for the six organic fluids examined, whereas for water and ammonia, the practical concentration limit reached about 4000 and 6000 suns, respectively. It was concluded that water and ammonia exhibited greater limits of concentration because they possess greater values of sensible and latent heats compared with the organic fluids examined. The results using this two‐phase cooling design were then compared with computational and experimental reference data from other HCPV studies conducted that used cooling mechanisms, such as impinging jets, liquid immersion, and microchannel cooling. Together, the data was compiled and compared with a simplified, one‐dimensional, theoretical model using a generic, hypothetical cooling mechanism for densely packed HCPV cells. The general, practical solar concentration limit was predicted to be approximately 10 000 effective suns for a cooling device with a heat transfer coefficient on the order of 10⁶ W m^?2 K^?1. At this limit, it was determined that the cells' conductive resistance, rather than the external cooling mechanism, becomes the controlling factor for heat removal. Copyright © 2010 John Wiley & Sons, Ltd.     

Engineering,institutions, and the public interest: Evaluating product quality in the Kenyan solar photovoltaics industry

Solar sales in Kenya are among the highest per capita among developing countries. While this commercial success makes the Kenya market a global leader, product quality problems have been a persistent concern. In this paper, we report performance test results from 2004 to 2005 for five brands of amorphous silicon (a-Si) photovoltaic (PV) modules sold in the Kenya market. Three of the five brands performed well, but two performed well below their advertised levels. These results support previous work indicating that high-quality a-Si PV modules are a good economic value. The presence of the low performing brands, however, confirms a need for market institutions that ensure the quality of all products sold in the market. Prior work from 1999 indicated a similar quality pattern among brands. This confirms the persistent nature of the problem, and the need for vigilant, long-term approaches to quality assurance for solar markets in Kenya and elsewhere. Following the release of our 2004/2005 test results in Kenya, the Kenya Bureau of Standards moved to implement and enforce performance standards for both amorphous and crystalline silicon PV modules. This appears to represent a positive step towards the institutionalization of quality assurance for products in the Kenya solar market.     

Assessing the lifecycle greenhouse gas emissions from solar PV and wind energy: A critical meta-survey

This paper critically screens 153 lifecycle studies covering a broad range of wind and solar photovoltaic (PV) electricity generation technologies to identify 41 of the most relevant, recent, rigorous, original, and complete assessments so that the dynamics of their greenhouse gas (GHG) emissions profiles can be determined. When viewed in a holistic manner, including initial materials extraction, manufacturing, use and disposal/decommissioning, these 41 studies show that both wind and solar systems are directly tied to and responsible for GHG emissions. They are thus not actually emissions free technologies. Moreover, by spotlighting the lifecycle stages and physical characteristics of these technologies that are most responsible for emissions, improvements can be made to lower their carbon footprint. As such, through in-depth examination of the results of these studies and the variations therein, this article uncovers best practices in wind and solar design and deployment that can better inform climate change mitigation efforts in the electricity sector.     

Using solar energy to arrest the increasing rate of fossil-fuel consumption: The southwestern states of the USA as case studies

The paper first reviews some recently introduced ideas concerning the feasibility of realizing concentrator photovoltaic systems on a very large (state-wide) scale. In particular, energy and cost assumptions are re-discussed, the concepts of double and triple sustainability are recalled and used to perform a sensitivity study of the various assumed parameter values. The model is then applied to each of the southwestern states of the USA in order to assess the economic potential for each state to freeze its fossil fuel consumption at present levels and to provide all future electricity needs entirely from solar. It is found that the scheme is economically feasible for all of the states considered, varying in attractiveness from Utah (where low electricity tariffs are problematic), to California and Nevada, where the economics are by far the most attractive among all the states.     

Socio-geographic perception in the diffusion of innovation: Solar energy technology in Sri Lanka

Understandings of the diffusion process have tended to emphasize either the adoption perspective, which focuses on individual characteristics, or the market perspective, which focuses on institutional context. In this paper we bring these two perspectives together by recognizing that people are embedded in socio-geographic contexts that affect their perceptions of their situations, which in turn shape the innovativeness of individuals and places. Focusing on the diffusion of Solar Home Systems (SHS) in Sri Lanka, we explore the role of context at the village (by comparing adoption rates among villages) and individual (by comparing time-to-adoption among household decision makers in a case-study village) scales. At the village scale, we find that expectations of government policy based on interactions related to ethnicity and politicians’ previous power-grid connection promises are significant drivers of SHS adoption, along with perceived tolerance levels in the village for non-conformist behavior. Among household decision makers within the case-study village, we analyze relative adoption time and the duration of the innovation-decision process and find that perceiving strong village-level social control inhibits SHS adoption decision making. The results add to innovation diffusion theory and provide policy recommendations for agencies promoting solar energy in developing countries.     

Salt diffusion in a temperature field: Application to salinity profiles in solar ponds

In the present investigation, the process of diffusion of salt in a vertical column of liquid, subjected to temperature variations of the types T(x) = constant, linear ( = a + bx) and parabolic ( = a + bx - cx²); with a constant concentration difference between the top and the bottom (0 and 25 per cent, respectively) is studied. It is seen that a linear temperature gradient, T(x) = a + bx, leads to a near convex parabolic salt concentration profile with maximum deviations increasing from 13.5 per cent (at 40°C) to 14.8 per cent (at 70°C) and eventually to 15.7 per cent (at 90°C) with respect to the linear concentration value of 12.5 per cent (by weight) at the midpoint. Conversely, the parabolic temperature profile as well as the modified profile due to the Soret effect leads to near cubic salt profiles which differ only by 2–3 per cent in the upper half of the pond. However, they show a point of inflexion at larger depths near the bottom around which the convex profiles change over and become concave. Subsequently, these studies have been extended to compute the salinity profiles of thermal configurations of the operational solar pond.     

Development and performance analysis of a two‐axis solar tracker for concentrated photovoltaics

This study presents a two‐axis solar tracking system equipped with a small concentrator module for electricity generation through a multijunction solar cell. The system can accurately track the sun without the need of calibration for an extended period and operate as a stand‐alone system. High‐precision solar tracking was achieved by a combination of open‐loop and closed‐loop controls. A camera tracking sensor was introduced as a feedback device in closed‐loop control. Two different types of solar concentrator modules were designed and fabricated. Their concentration ratios were analyzed against solar tracking errors by means of ray tracing software. One is made up of a paraboloidal primary concentrator and a paraboloidal secondary reflector, whereas the other has a paraboloidal primary concentrator and a hyperboloidal secondary reflector. Both modules showed an almost identical concentration ratio of 610 provided that the solar tracker is pointing perfectly at the sun. However, their performance differs considerably when tracking error is present. The maximum power output was obtained near solar noon with multijunction cells, whose average solar conversion efficiency was 21%, much higher than that of conventional photovoltaic systems. Copyright © 2015 John Wiley & Sons, Ltd.     

Analysis of solar photovoltaic and wind power potential in Afghanistan

Afghanistan has a need for increased access to energy to enable development. In this paper we analyze the potential for large-scale grid-connected solar photovoltaic (PV) and wind power plants in two of Afghanistan's most populous provinces (Balkh and Herat) to meet a large fraction of growing electricity demand. The results presented here represent the first quantitative analysis of potential capacity factors and energy yields of power plants in the country using measured wind speed and typical solar radiation data. Variability of resources is also investigated by comparing temporal profiles with those of electricity demand, using residual load duration curves to determine penetration and curtailment levels for various demand scenarios. We show that solar PV and wind power plants in two provinces could achieve penetration levels of 65%–70% without significant curtailment, which in turn would mean less reliance on unpredictable and unstable power purchase agreements with neighboring countries, longer life of limited domestic fossil fuel resources, and lower imports of diesel fuel, thus avoiding rising costs and detrimental environmental impacts. Our results point to an alternative development pathway from that of previous recommendations for conventional thermal power plants, controversial hydroelectric projects, and a significant dependence on imported power.     

Public energy performance policy and the effect on diffusion of solar thermal systems in buildings: A Dutch experience

Energy performance policy is an important element in the European Energy Performance of Buildings Directive (Directive 2002/91/EC—in short: EPBD, published 4 January 2003), which the European Commission is now urging all European member states to introduce for the building sector by 2006. One of the expected benefits of energy performance policy is that it can help to introduce innovations such as solar thermal systems. However, few studies have analysed this so far. This paper describes the extent to which the penetration of solar thermal systems in the residential building sector is directly related to energy performance policy in the Netherlands. The concept of energy performance policy is explained and the effects of using energy performance policy for several years in the Netherlands are described, through the results of an empirical study. Statistical analysis appears to show no association between Dutch energy performance policy and the application of solar thermal systems in the domestic sector.     

Holding a candle to innovation in concentrating solar power technologies: A study drawing on patent data

Improved understanding of the innovative pathways of renewable energy technologies is vital if we are to make the transition to a low carbon economy. This study presents new evidence on innovation and industry dynamics in concentrating solar power (CSP) technologies. Though CSP is undergoing a renaissance, existing innovation studies have explored innovative activity in solar technologies in general, ignoring the major differences between solar photovoltaic and CSP technologies. This study, based on patent data, examines the level and dynamics of innovative activity in CSP between 1978 and 2004.     

Research and demonstration on hydrogen compatibility of pipelines: a review of current status and challenges

Hydrogen transportation by pipelines gradually becomes a critical engineering route in the worldwide adaptation of hydrogen as a form of clean energy. However, due to the hydrogen embrittlement effect, the compatibility of linepipe steels and associated welds with hydrogen is a major concern when designing hydrogen-carrying pipelines. When hydrogen enters the steels, their ductility, fracture resistance, and fatigue properties can be adversely altered. This paper reviews the status of several demonstration projects for natural gas-hydrogen blending and pure hydrogen transportation, the pipeline materials used and their operating parameters. This paper also compares the current standards of materials specifications for hydrogen pipeline systems from different parts of the world. The hydrogen compatibility and tolerance of varying grades of linepipe steels and the relevant testing methods for assessing the compatibility are then discussed, and the conservatism or the inadequacies of the test conditions of the current standards are pointed out for future improvement.