Quantifying the impact of performance improvements and cost reductions from 20 years of light-emitting diode manufacturing

With the aim of identifying and quantifying the principal sources of performance improvements and cost reductions in white light emitting diode manufacturing, we collect historical data on device cost and performance, technological breakthroughs and manufacturing innovation for phosphor-converted white light-emitting diodes for the past 20 years. We find that technological breakthroughs and process innovation contributed to performance improvements across the entire range of LED device sub-efficiencies, resulting in the overall increase in the lamp efficiency for the highest performing devices at a test current of 350mA from 5.8% to 38.7% between 2002 and 2020. We further develop a bottom-up manufacturing cost model with process-step resolution that captures improvements in throughput, yield and related costs of all relevant manufacturing steps, as well as economies of scale, to analyse progress in LED manufacturing cost structure between early manufacturing in 2002 and mature industry in 2020. We estimate that the cost of manufacturing low-power and mid-power light-emitting diode packages at a US location using state-of-the-art equipment has dropped from 1.11$(2020) in 2002 to 0.05$(2020) in 2020, a 95.5% decrease. We also find that the largest contribution to overall cost reduction has come from increase in wafer size, and that in 2020, LED chip packaging is the largest contributor to cost at 60%

Not in my backyard, but not far away from me: Local acceptance of wind power in China

Local acceptance of wind energy technology has become an important factor to consider when designing local and national wind energy technological innovation policies. Previous studies have investigated the factors that shape the local acceptance of wind power in high-income countries. However, to the best of our knowledge, these factors had not been investigated in China. Utilizing a survey and quantitative analysis, we have identified the factors that are correlated with local acceptance of wind power in China. We conducted our study in the city of Jiuquan, Gansu Province, which currently possesses the largest installed capacity for wind power generation in China. Two factors, namely, perceived economic benefits and perceived environmental costs, influence local acceptance of wind power in China most significantly. Local acceptance of wind power in China can be described as "not in my backyard, but not far away from me". In other words, the acceptance rate is lowest when the source of wind power is located in their village or community, highest when the project is located in their county and city and decreases for projects that are constructed further away

Towards sustainability in water-energy nexus: Ocean energy for seawater desalination

Seawater desalination is an important option for addressing the world's water supply challenges. Current desalination plants use enormous quantities of energy and cause a number of environmental issues. Renewable energy options, mostly solar and geothermal systems, have been examined in detail to supply the energy needed for water desalination. The co-location benefit of energy derived from the ocean to power seawater desalination processes is appealing. However, the promise and potential of ocean-based power generation for desalination systems has not been investigated in detail. The development of such systems has been limited due to technological and economic limitations of energy harvesting and transport as well as device maintenance under water. In this paper, we review the state of the art of ocean energy in desalination. It explores different sources of energy from the ocean that include electricity generation, as well as mechanical force and thermal energy and salinity gradients that can also be directly harnessed for powering the desalination processes. We also examine recent advances in scaling up for commercial deployment, and discuss relevant cost, environmental and social concerns. The great potential of ocean energy for seawater desalination in terms of diverse energy forms, flexible integration methods and various deployment strategies can provide important environmental, water and social benefits for seawater desalination, thus promote sustainability in water-energy nexus. The use of ocean energy in desalination applications could benefit the future development of ocean energy technology in renewable energy sector

Why is China's wind power generation not living up to its potential?

Following a decade of unprecedented investment, China now has the world's largest installed base of wind power capacity. Yet, despite siting most wind farms in the wind-rich Northern and Western provinces, electricity generation from Chinese wind farms has not reached the performance benchmarks of the United States and many other advanced economies. This has resulted in lower environmental, economic, and health benefits than anticipated. We develop a framework to explain the performance of the Chinese and US wind sectors, accounting for a comprehensive set of driving factors. We apply this framework to a novel dataset of virtually all wind farms installed in China and the United States through the end of 2013. We first estimate the wind sector's technical potential using a methodology that produces consistent estimates for both countries. We compare this potential to actual performance and find that Chinese wind farms generated electricity at 37%–45% of their annual technical potential during 2006–2013 compared to 54%–61% in the United States. Our findings underscore that the larger gap between actual performance and technical potential in China compared to the United States is significantly driven by delays in grid connection (14% of the gap) and curtailment due to constraints in grid management (10% of the gap), two challenges of China's wind power expansion covered extensively in the literature. However, our findings show that China's underperformance is also driven by suboptimal turbine model selection (31% of the gap), wind farm siting (23% of the gap), and turbine hub heights (6% of the gap)—factors that have received less attention in the literature and, crucially, are locked-in for the lifetime of wind farms. This suggests that besides addressing grid connection delays and curtailment, China will also need policy measures to address turbine siting and technology choices to achieve its national goals and increase utilization up to US levels

Co-benefits of greenhouse gas mitigation: A review and classification by type, mitigation sector, and geography

The perceived inability of climate change mitigation goals alone to mobilize sufficient climate change mitigation efforts has, among other factors, led to growing research on the co-benefits of reducing greenhouse gas (GHG) emissions. This study conducts a systematic review (SR) of the literature on the co-benefits of mitigating GHG emissions resulting in 1554 papers. We analyze these papers using bibliometric analysis, including a keyword co-occurrence analysis. We then iteratively develop and present a typology of co-benefits, mitigation sectors, geographic scope, and methods based on the manual double coding of the papers resulting from the SR. We find that the co-benefits from GHG mitigation that have received the largest attention of researchers are impacts on ecosystems, economic activity, health, air pollution, and resource efficiency. The co-benefits that have received the least attention include the impacts on conflict and disaster resilience, poverty alleviation (or exacerbation), energy security, technological spillovers and innovation, and food security. Most research has investigated co-benefits from GHG mitigation in the agriculture, forestry and other land use (AFOLU), electricity, transport, and residential sectors, with the industrial sector being the subject of significantly less research. The largest number of co-benefits publications provide analysis at a global level, with relatively few studies providing local (city) level analysis or studying co-benefits in Oceanian or African contexts. Finally, science and engineering methods, in contrast to economic or social science methods, are the methods most commonly employed in co-benefits papers. We conclude that given the potential mobilizing power of understudied co-benefits (e.g. poverty alleviation) and local impacts, the magnitude of GHG emissions from the industrial sector, and the fact that Africa and South America are likely to be severely affected by climate change, there is an opportunity for the research community to fill these gaps

Substantial emission reductions from Chinese power plants after the introduction of ultra-low emissions standards

In 2014, China introduced an ultra-low emissions (ULE) standards policy for renovating coal-fired power-generating units to limit SO2, NOx and particulate matter (PM) emissions to 35, 50 and 10 mg m−3, respectively. The ULE standard policy had ambitious levels (surpassing those of all other countries) and implementation timeline. We estimate emission reductions associated with the ULE policy by constructing a nationwide, unit-level, hourly-frequency emissions dataset using data from a continuous emissions monitoring systems network covering 96–98% of Chinese thermal power capacity during 2014–2017. We find that between 2014 and 2017 China’s annual power emissions of SO2, NOx and PM dropped by 65%, 60% and 72%, respectively. Our estimated emissions using actual monitoring data are 18–92% below other recent estimates. We detail the technologies used to meet the ULE standards and the determinants of compliance, underscoring the importance of ex post evaluation and providing insights for other countries wishing to reduce their power emissions

A collaboratively-derived science-policy research agenda

The need for policy makers to understand science and for scientists to understand policy processes is widely recognised. However, the science-policy relationship is sometimes difficult and occasionally dysfunctional; it is also increasingly visible, because it must deal with contentious issues, or itself becomes a matter of public controversy, or both. We suggest that identifying key unanswered questions on the relationship between science and policy will catalyse and focus research in this field. To identify these questions, a collaborative procedure was employed with 52 participants selected to cover a wide range of experience in both science and policy, including people from government, non-governmental organisations, academia and industry. These participants consulted with colleagues and submitted 239 questions. An initial round of voting was followed by a workshop in which 40 of the most important questions were identified by further discussion and voting. The resulting list includes questions about the effectiveness of science-based decision-making structures; the nature and legitimacy of expertise; the consequences of changes such as increasing transparency; choices among different sources of evidence; the implications of new means of characterising and representing uncertainties; and ways in which policy and political processes affect what counts as authoritative evidence. We expect this exercise to identify important theoretical questions and to help improve the mutual understanding and effectiveness of those working at the interface of science and policy

Design, construction and operation of the ProtoDUNE-SP Liquid Argon TPC

The ProtoDUNE-SP detector is a single-phase liquid argon time projection chamber (LArTPC) that was constructed and operated in the CERN North Area at the end of the H4 beamline. This detector is a prototype for the first far detector module of the Deep Underground Neutrino Experiment (DUNE), which will be constructed at the Sandford Underground Research Facility (SURF) in Lead, South Dakota, U.S.A. The ProtoDUNE-SP detector incorporates full-size components as designed for DUNE and has an active volume of 7 × 6 × 7.2 m3. The H4 beam delivers incident particles with well-measured momenta and high-purity particle identification. ProtoDUNE-SP's successful operation between 2018 and 2020 demonstrates the effectiveness of the single-phase far detector design. This paper describes the design, construction, assembly and operation of the detector components

Energy innovation funding and institutions in major economies

Accelerating energy innovation for decarbonization hinges on public investment in research, development, and demonstration (RD&D). Here we examine the evolution and variation of public energy RD&D funding and institutions and associated drivers across eight major economies, including China and India (2000-18). The share of new clean energy grew at the expense of nuclear, while the fossil fuel RD&D share remained stable. Governments created new institutions, but experimented only marginally with novel designs that bridge lab to market to accelerate commercialization. In theory, crisis, cooperation, and competition can be drivers of change. We find that cooperation in Mission Innovation is associated with punctuated change in clean energy RD&D growth, and cleantech competition with China is associated with gradual change. Stimulus spending after the financial crisis, instead, boosted fossil and nuclear only. Looking ahead, global coopetition—the interplay of RD&D cooperation and cleantech competition—offers opportunities for accelerating energy innovation to meet climate goals.We acknowledge funding from the Hellman Fellows Fund; the Institute for Advanced Sustainability Studies; the USDA National Institute of Food and Agriculture, Hatch Project Accession Number 1020688; the William & Flora Hewlett Foundation, Grant Number 2019-9339, regranted through the California-China Climate Institute; and the EU Framework Programme for Research and Innovation H2020 under Grant Agreement Number 730403 (INNOPATHS)