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Modern wind turbines already represent a tightly optimized confluence of materials science and aerodynamic engineering. Veers et al. review the challenges and opportunities for further expanding this technology, with an emphasis on the need for interdisciplinary collaboration. They highlight the need to better understand atmospheric physics in the regions where taller turbines will operate as well as the materials constraints associated with the scale-up. The mutual interaction of turbine sites with one another and with the evolving features of the overall electricity grid will furthermore necessitate a systems approach to future development. Science , this issue p. eaau2027 Harvested by advanced technical systems honed over decades of research and development, wind energy has become a mainstream energy resource. However, continued innovation is needed to realize the potential of wind to serve the global demand for clean energy. Here, we outline three interdependent, cross-disciplinary grand challenges underpinning this research endeavor. The first is the need for a deeper understanding of the physics of atmospheric flow in the critical zone of plant operation. The second involves science and engineering of the largest dynamic, rotating machines in the world. The third encompasses optimization and control of fleets of wind plants working synergistically within the electricity grid. Addressing these challenges could enable wind power to provide as much as half of our global electricity needs and perhaps beyond.

India has led the developing world in addressing rural energy problems. By late 2012, the national electricity grid had reached 92 percent of India s rural villages, about 880 million people. In more remote areas and those with geographically difficult terrain, where grid extension is not economically viable, off-grid solutions using renewable-energy sources for electricity generation and distribution have been promoted. The positive results of the country s rural energy policies and institutions have contributed greatly to reducing the number of people globally who remain without electricity access. Yet, owing mainly to its large population, India has by far the world s largest number of households without electricity. More than one-quarter of its population or about 311 million people, the vast majority of whom live in poorer rural areas, still lack an electricity connection; less than half of all households in the poorest income group have electricity. Among households with electricity service, hundreds of millions lack reliable power supply.

Bangladesh is one of the world's poorest countries. Nearly 80 percent of the nation's 140 million people reside in rural areas; of these, 20 percent live in extreme poverty. Geographically, many low-lying areas are vulnerable to severe flooding, while other regions are prone to drought, erosion, and soil salinity. Such an unfavorable agricultural landscape, combined with mismanagement of natural resources and increasing population pressure, is pushing many of the rural poor to the brink. Because Bangladesh is such a poor country, it also is one of the world's lowest energy producers. Total annual energy supply is only about 150 liters of oil equivalent per capita (International Energy Agency, or IEA 2003); in rural areas, conditions are even worse. Compared to other developing countries, Bangladesh uses little modern energy. Despite its successful rural electrification program, close to two-thirds of households remain without electricity and, with the exception of kerosene, commercial fuels are beyond reach for many. Moreover, biomass fuels are becoming increasingly scarce. Collected mainly from the local environment as recently as two decades ago, bio-fuels are fast becoming a marketed commodity as access to local biomass continues to shrink. This study, the first to concentrate on Bangladesh's energy systems and their effects on the lives of rural people, drew on these background studies, as well as other World Bank-financed research on indoor air pollution (IAP) and rural infrastructure, to present a rural energy strategy for the country. Much of this study's analytical underpinning was based on several background studies. This study also reanalyzed data from earlier research to better understand the benefits of modern energy use for rural households, farm activities, and small businesses.

The reliability of the electricity supply is important since any interruption to the supply has direct and indirect consequences for its users. A reliable electricity supply requires a reliable electrical grid system to transmit and distribute the power from the generating plants to the consumers. This study reviewed the literature to find out how the reliability concept has been understood with a special focus on grid electricity reliability, what factors influence grid electricity reliability, what measures have been used to measure grid electricity reliability, which theories and methodologies have been applied to study grid electricity reliability and what are the likely research gaps that require future address. This review found that the literature documents four categories of factors that influence grid electricity reliability, and these are environmental, security, organizational and technical. The biggest influencers of grid electricity reliability were the technical-related factors followed by the environmental-related factors. In addition, we found that sixty studies focused on one subsystem, eleven on two subsystems while seven studies considered three subsystems. Most studies were found to address the distribution of subsystem reliability. As per the methodology adopted, this review found that eleven studies used a qualitative approach, forty-five studies used a quantitative approach, while eleven studies used a case study approach to study the concept of grid electricity reliability. In addition, we found that thirty-seven studies used the duration and frequency of power outages to measure grid electricity reliability.

Encouraged by the declining cost of grid-scale renewables, recent analyses conclude that the United States could reach net zero carbon dioxide emissions by 2050 at relatively low cost using currently available technologies. While the cost of renewable generation has declined dramatically, integrating these renewables would require a large expansion in transmission to deliver that power. Already there is growing evidence that the United States has insufficient transmission capacity, and current levels of annual investment are well below what would be required for a renewables-dominated system. We describe a variety of challenges that make it difficult to build new transmission and potential policy responses to mitigate them, as well as possible substitutes for some new transmission capacity.

For the past 40 years, the dominant ‘policy’ on cooking energy in the Global South has been to improve the combustion efficiency of biomass fuels. This was said to alleviate the burdens of biomass cooking for three billion people by mitigating emissions, reducing deforestation, alleviating expenditure and collection times on fuels and increasing health outcomes. By 2015, international agencies were openly saying it was a failing policy. The dispersal of improved cookstoves was not keeping up with population growth, increasing urbanisation was leading to denser emissions and evidence suggested health effects of improved stoves were not as expected. A call was made for a new strategy, something other than ‘business as usual’. Conventional wisdom suggests that access to electricity is poor in Sub-Saharan Africa (SSA), that it is too expensive and that weak grids prevent even connected households from cooking. Could a new strategy be built around access to electricity (and gas)? Could bringing modern energy for cooking to the forefront kill two birds with one stone? In 2019, UK Aid announced a multi-million-pound programme on ‘Modern Energy Cooking Services’ (MECS), specifically designed to explore alternative approaches to address cooking energy concerns in the Global South. This paper outlines the rationale behind such a move, and how it will work with existing economies and policies to catalyse a global transition.

The physics of an electrical grid requires that the supply injected into the grid is always in balance with the quantity consumed. If that balance is not maintained, cascading outages are likely to disrupt supply to all consumers on the grid. In the past, vertically integrated monopoly utilities have ensured that supply is adequate to meet demand and maintain grid stability, but with deregulation of generation, assuring adequate supply has become much more complex. The unique characteristics of electricity distribution means that there are immense potential externalities among market participants from supply shortfalls. In this paper, we discuss the institutions that US electricity markets have developed to avoid such destabilizing supply shortfalls when there are multiple generators and retailers in the market. Though many of the markets rely on standardized requirements for supplier reserves, we conclude that recent technological progress may steer future evolution towards a system that relies to a greater extent on economic incentives.

The technology focus in the automotive sector has moved toward battery electric vehicles (BEVs) over the last few years. This shift has been ascribed to the importance of reducing greenhouse gas (GHG) emissions from transportation to mitigate the effects of climate change. In Europe, countries are proposing future bans on vehicles with internal combustion engines (ICEs), and individual United States (U.S.) states have followed suit. An important component of these complex decisions is the electricity generation GHG emission rates both for current electric grids and future electric grids. In this work we use 2019 U.S. electricity grid data to calculate the geographically and temporally resolved marginal emission rates that capture the real-world carbon emissions associated with present-day utilization of the U.S. grid for electric vehicle (EV) charging or any other electricity need. These rates are shown to be relatively independent of marginal demand at the highest marginal demand levels, indicating that they will be relatively insensitive to the addition of renewable electricity generation capacity up to the point at which curtailment occurs regularly unless the most carbon-intensive electricity sources are preferentially deactivated. We propose a simplified methodology for comparing emissions from BEVs and hybrid electric vehicles (HEVs) based on the marginal emission rates and other publicly available data and apply it to comparative case studies of BEVs and HEVs. We find that currently there is no evidence to support the idea that BEVs lead to a uniform reduction in vehicle emission rates in comparison to HEVs and in many scenarios have higher GHG emissions. This suggests that a mix of powertrain technologies is the best path toward reducing transportation sector emissions until the U.S. grid can provide electricity for the all-electric fleet infrastructure and vehicle operations with a carbon intensity that produces a net environmental benefit.

Despite the East Asia and Pacific (EAP) region's impressive economic growth, over 1 billion of its people still lack access to electricity and modern cooking solutions. To achieve universal access to modern energy by 2030, this book exhorts EAP countries to advance simultaneously on two paths: (1) accelerate programs for grid and off-grid electricity through appropriate policies and innovative technologies; and (2) scale up access to clean cooking fuels and efficient cooking stoves, particularly for biomass in poor rural areas.