Drivers of photovoltaics cost evolution

Thesis: Ph. D. in Engineering Systems, Massachusetts Institute of Technology, School of Engineering, Institute for Data, Systems, and Society, 2018.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 99-109).Photovoltaics (PV) have experienced notable development over the last forty years. PV module costs have declined 20% on average with every doubling of cumulative capacity, while global PV installations have increased at an average rate of 30% per year. However, costs must fall even further if PV is to achieve cost-competitiveness at high penetration levels and in a wide range of locations. Understanding the mechanisms that underlie the past cost evolution of PV can help sustain its pace of improvement in the future. This thesis explores the drivers of and constraints to cost reduction and large-scale deployment of PV. By developing novel conceptual and mathematical models, we address the following questions: (1) What caused PV's cost to fall with time? (2) How may materials constraints influence PV cost and deployment? These questions are addressed in the analyses presented in Chapters 2-4. Chapter 2 assesses the causes of cost reduction observed in PV modules since 1980. We develop a new model that identifies the causes of improvement at the engineering level and links these to higher-level mechanisms such as economies of scale. The methodology advanced can be used to evaluate the causes of improvements in any technology. By developing a model of PV modules, we find that in the early stages of the technology (1980-2001), improvements in the material usage and module conversion efficiency played an important role in reducing module cost. These improvements were mainly driven by research and development (R&D) efforts. As the PV technology matured (2001-2012), economies of scale from larger manufacturing plants resulted in significant gains. Both market-expansion policies and public R&D stimulated cost reduction, with the former contributing the majority of the cost decline from 1980 to 2012. Chapter 3 turns to assessing the materials constraints to PV cost reduction. We ask how fast metals production should be scaled up to match the increasing demand by the PV sector, if installations grow to meet a significant portion of energy demand. Unlike previous studies, which primarily used inherently uncertain factors such as reserves to estimate limits to technology scalability, we use past growth rates of a large set of metals as a benchmark for future growth rates. This analysis shows that thin-film PV technologies such as CIGS and CdTe that employ rare metals would require unprecedented growth rates in metals production even for the most conservative PV growth scenarios. On the other hand, crystalline silicon PV can provide 100% of global electricity without silicon exceeding the historical growth rates observed by all metals in the periodic table. Chapter 4 assesses the risks that material inputs bring to technologies today. This study develops cost-riskiness metrics based on the price behavior of metals along two dimensions: average price and price volatility. We first compare a large set of metals using these cost-riskiness metrics. We observe that metals obtained as byproducts have higher risk than major metals. We then apply these metrics to different PV technologies by treating them as a portfolio of metals. We find that designs such as CIGS and CdTe, which use byproduct metals with high average prices and price volatilities, show signals of cost-riskiness. The approach advanced here can serve as an assessment of the cost-riskiness of technologies introduced by their materials inputs.by Goksin Kavlak.Ph. D. in Engineering System

Metals Production Requirements for Rapid Photovoltaics Deployment

If global photovoltaics (PV) deployment grows rapidly, the required input materials need to be supplied at an increasing rate. In this paper, we quantify the effect of PV deployment levels on the scale of metals production. For example, we find that if cadmium telluride {copper indium gallium diselenide} PV accounts for more than 3% {10%} of electricity generation by 2030, the required growth rates for the production of indium and tellurium would exceed historically-observed production growth rates for a large set of metals. In contrast, even if crystalline silicon PV supplies all electricity in 2030, the required silicon production growth rate would fall within the historical range. More generally, this paper highlights possible constraints to the rate of scaling up metals production for some PV technologies, and outlines an approach to assessing projected metals growth requirements against an ensemble of past growth rates from across the metals production sector. The framework developed in this paper may be useful for evaluating the scalability of a wide range of materials and devices, to inform technology development in the laboratory, as well as public and private research investment

Growth in metals production for rapid photovoltaics deployment

If global photovoltaics (PV) deployment grows rapidly, the required input materials need to be supplied at an increasing rate. We quantify the effect of PV deployment levels on the scale of annual metals production. If a thin-film PV technology accounts for 25% of electricity generation in 2030, the annual production of thin-film PV metals would need to grow at rates of 15-30% per year. These rates exceed those observed historically for a wide range of metals. In contrast, for the same level of crystalline silicon PV deployment, the required silicon production growth rate falls within the historical range.United States. Dept. of Energy (Grant DE-EE0006131

Environmental Implications of Jatropha Biofuel from a Silvi-Pastoral Production System in Central-West Brazil

We present a life cycle assessment of synthetic paraffinic kerosene produced from Jatropha curcas. The feedstock is grown in an intercropping arrangement with pasture grasses so that Jatropha is coproduced with cattle. Additional innovations are introduced including hybrid seeds, detoxification of jatropha seedcake, and cogeneration. Two fuel pathways are examined including a newly developed catalytic decarboxylation process. Sensitivities are examined including higher planting density at the expense of cattle production as well as 50% lower yields. Intercropping with pasture and detoxifying seedcake yield coproducts that are expected to relieve pressure on Brazil’s forests and indirectly reduce environmental impacts of biofuel production. Other innovations also reduce impacts. Results of the baseline assessment indicate that innovations would reduce impacts relative to the fossil fuel reference scenario in most categories including 62–75% reduction in greenhouse gas emissions, 64–82% reduction in release of ozone depleting chemicals, 33–52% reduction in smog-forming pollutants, 6–25% reduction in acidification, and 60–72% reduction in use of nonrenewable energy. System expansion, which explicitly accounts for avoided deforestation, results in larger improvements. Results are robust across allocation methodologies, improve with higher planting density, and persist if yield is reduced by half

Evaluating the causes of cost reduction in photovoltaic modules

Photovoltaic (PV) module costs have declined rapidly over forty years but the reasons remain elusive. Here we advance a conceptual framework and quantitative method for quantifying the causes of cost changes in a technology, and apply it to PV modules. Our method begins with a cost model that breaks down cost into variables that changed over time. Cost change equations are then derived to quantify each variable's contribution. We distinguish between changes observed in variables of the cost model – which we term low-level mechanisms of cost reduction – and research and development, learning-by-doing, and scale economies, which we refer to as high-level mechanisms. We find that increased module efficiency was the leading low-level cause of cost reduction in 1980–2012, contributing almost 25% of the decline. Government-funded and private R&D was the most important high-level mechanism over this period. After 2001, however, scale economies became a more significant cause of cost reduction, approaching R&D in importance. Policies that stimulate market growth have played a key role in enabling PV's cost reduction, through privately-funded R&D and scale economies, and to a lesser extent learning-by-doing. The method presented here can be adapted to retrospectively or prospectively study many technologies, and performance metrics besides cost. Keyword: Photovoltaics (PV); Solar energy; PV modules; Cost model; Technological chang

Life cycle carbon benefits of aerospace alloy recycling

The goal of this project is to determine the reductions in greenhouse gas (GHG) emissions associated with the recycling of aerospace alloys. This study is based on an aerospace recycler that sells much of its high-performance alloy scrap directly to remelters that produce these alloys for aircraft engine component manufacturers, with significant potential environmental benefits arising from the substitution of recycled materials for virgin materials. The project team explored existing sources of environmental data for all of the metals that make up aerospace alloys, and ten common alloys were chosen as case studies. Certain metal elements, including niobium, rhenium, tungsten, and zirconium, did not have any robust environmental impact information, and for these GHG emissions factors from primary production were modeled using a variety of statistical and industrial data sources. The project team then investigated the forms of metal inputs into alloying operations to ensure that the model reflects actual industrial practices and that the alloy scrap substitutes for virgin materials. GHG emissions are also incurred through alloy scrap collection and processing, and so a carbon footprint was performed for alloy recycling operations in order to determine these burdens. Overall, the recycling of aerospace alloys for reuse in the aerospace industry represents significant reductions in GHG emissions for each of the ten alloys considered, while emissions associated with collection and processing are <5% in comparison. Certain elements occur in small quantities in aerospace alloys, such as rhenium (Re) and tantalum (Ta), but due to their high carbon intensity they significantly influence the final results. \ua9 2014 Elsevier Ltd. All rights reserved

Sources of Cost Overrun in Nuclear Power Plant Construction Call for a New Approach to Engineering Design

© 2020 Elsevier Inc. Nuclear plant costs in the US have repeatedly exceeded projections. Here, we use data covering 5 decades and bottom-up cost modeling to identify the mechanisms behind this divergence. We observe that nth-of-a-kind plants have been more, not less, expensive than first-of-a-kind plants. “Soft” factors external to standardized reactor hardware, such as labor supervision, contributed over half of the cost rise from 1976 to 1987. Relatedly, containment building costs more than doubled from 1976 to 2017, due only in part to safety regulations. Labor productivity in recent plants is up to 13 times lower than industry expectations. Our results point to a gap between expected and realized costs stemming from low resilience to time- and site-dependent construction conditions. Prospective models suggest reducing commodity usage and automating construction to increase resilience. More generally, rethinking engineering design to relate design variables to cost change mechanisms could help deliver real-world cost reductions for technologies with demanding construction requirements. Nuclear power plants provide roughly half of the low-carbon electricity in the US. However, projections of nuclear plant costs have repeatedly failed to predict the cost overruns observed since the 1960s. We study the mechanisms that have contributed to the rise in nuclear construction costs over the past 5 decades to understand the divergence between expected and realized costs. We find that nth-of-a-kind plants in the US have been more expensive than first-of-a-kind plants, with “soft” factors external to reactor hardware contributing over half of the cost increase between 1976 and 1987. Costs of the reactor containment building more than doubled, primarily due to declining on-site labor productivity. Productivity in recent US plants is up to 13 times lower than industry expectations. A prospective analysis of the containment building suggests that improved materials and automation could increase the resilience of nuclear construction costs to variable conditions. We study nuclear plant costs in the US over the past 5 decades to understand the mechanisms that contributed to cost escalation and the repeated underestimation of construction cost. We show that declining labor productivity and “soft” costs were leading contributors. Counter to expectation, nth-of-a-kind plants have been more expensive than first-of-a-kind plants. Our prospective analysis of the containment building suggests that the cost resilience of nuclear construction could be increased through improved materials and automation

Technology Improvement and Emissions Reductions as Mutually Reinforcing Efforts: Observations from the Global Development of Solar and Wind Energy

Mitigating climate change is unavoidably linked to developing affordable low-carbon energy technologies that can be adopted around the world. In this report, we describe the evolution of solar and wind energy in recent decades, and the potential for future expansion under nations’ voluntary commitments in advance of the 2015 Paris climate negotiations. Solar and wind energy costs have dropped rapidly over the past few decades, and commitments made in international climate negotiations offer an opportunity to support the technological innovation needed to achieve a self-sustaining, virtuous cycle of emissions reductions and low-carbon technology development by 2030. If countries emphasize renewables expansion, solar and wind capacity could grow by factors of 4.9 and 2.7 respectively between the present day and 2030. Based on future technology development scenarios, past trends, and technology cost floors, we estimate these commitments for renewables expansion could achieve a cost reduction of up to 50% for solar (PV) and up to 25% for wind. Forecasts are inherently uncertain, but even under the more modest cost reduction scenarios, the costs of these technologies decrease over time.MIT International Policy La

Criticality of the Geological Copper Family

Because modern technology depends on reliable supplies of a wide variety of materials, and because of increasing concern about those supplies, a comprehensive methodology has been created to quantify the degree of criticality of the metals of the periodic table. In this paper, we apply this methodology to the elements of the geological copper family: Cu, As, Se, Ag, Te, and Au. These elements are technologically important, but show a substantial variation in different factors relating to their supply risk, vulnerability to supply restriction, and environmental implications. Assessments are made on corporate, national, and global levels for year 2008. Evaluations of each of the multiple indicators are presented and the results plotted in “criticality space”, together with Monte Carlo simulation-derived “uncertainty cloud” estimates for each of the aggregated evaluations. For supply risk over both the medium term and long term, As is the highest risk of the six metals, with Se and Ag nearly as high. Gold has the most severe environmental implications ranking. Vulnerability to supply restriction (VSR) at the corporate level for an invented solar cell manufacturing firm shows Se, Te, and Cu as approximately equal, Cu has the highest VSR at the national level, and Cu and Au have the highest VSRs at the global level. Criticality vector magnitudes are greatest at the global level for As (and then Au and Ag) and at the national level for As and Au; at the corporate level, Se is highest with Te and Cu lower. An extension of this work, now in progress, will provide criticality estimates for several different development scenarios for the period 2010–2050