• Energy Research
• 2021-2025close

This study aims to provide a detailed spatial and temporal characterization of China’s wind and solar energy resource potential. Quantifying this potential is necessary to identify pathways to achieve a deep decarbonization of its electric power system as this nation pursues carbon neutrality by 2060. This study identifies and characterizes sites suitable for onshore wind and ground-mounted solar PV deployment, quantifies their electricity generation potential, and assesses their spatial heterogeneity across the country and temporal variability throughout the seasons. Resource potential estimates are obtained by combining the latest data with high spatiotemporal resolution with a geographic information system (GIS) analysis that compiles information on wind and solar energy resources, land use, surface elevation and slope, and geomorphology. Results show that China’s vast resource potential for wind and solar is enough to provide one-and-a-half times 2050′s expected electricity demand. Results also demonstrate that China’s resource-rich areas do not correspond to demand centers, except for provinces like Shandong, Hebei, and Jiangsu, which have high electricity demand and renewable potential. The seasonal patterns show that China should develop wind and solar energy simultaneously, to exploit wind’s highest potential during winter and early spring, and solar’s higher production during late spring and summer. These findings shed light on the sites that should be prioritized for renewable development and the need to expand power transmission capacity connecting energy-rich areas with load centers, and energy storage capacity and flexible resources to balance variable renewable output with load.

The role of dispatchable resources evolves over space and over time as the power sector decarbonizes; this evolution reconfigures the spatial layout of China's power system, eventually redrawing its economic, social, and environmental maps.

Abstract This study explores the performance of the Duke Energy Carolinas/Progress (DEC/DEP) electric power system under one hundred forty-one configurations combining different capacities of utility-scale photovoltaics (PV) and battery energy storage (lithium-ion batteries or BES). The different configurations include PV installations capable of providing 5–25% of the systems energy and batteries with varying duration (energy-to-power ratio) of 2, 4, and 6 h. A production cost model comprised of a day-ahead unit commitment and a real-time economic dispatch simulates the optimal operation of all the generation resources necessary to supply hourly demand and reserve requirements during the year 2016. The model represents in detail the generation fleet of the system, including 221 nuclear, natural gas, coal and hydro power generators with a combined installed capacity of 37.8 GW. Results indicate that: 1) adding BES to a power system that includes PV further reduces carbon dioxide emissions while also lowering the cost of carbon abatement. 2) The optimal power rating of a BES system that supports PV seems to be lower than 25% of the capacity of the PV. 3) BES of short duration (2-h) are more cost-effective (i.e., result in a lower cost of abatement) when the level of PV penetration is low (lower than ~12.5%), while BES of longer duration (6-h) are more cost-effective when there are larger shares of PV. 4) The installation of optimal configurations of PV + BES to reduce carbon emissions in the DEC/DEP system by ~14–57% would increase the levelized cost of electricity (LCOE) ~8–65%. 5) If projections of declining costs for the next decade materialize, the installation of up to 15 GW of PV + 1.88 GW / 3.76 GWh of BES would reduce the LCOE while achieving up to 33% reduction in carbon emissions.

Variable renewable energy (VRE) and energy storage systems (ESS) are essential pillars of any strategy to decarbonize power systems. However, there are still questions about the effects of their interaction in systems where coal’s electricity generation share is large. Some studies have shown that in the absence of significant VRE capacity ESS can increase CO2 emissions. This paper shows that contrary to this intuition, ESS reduces operational costs and emissions even without higher penetration of VRE in power systems with large shares of coal. It also shows that when combined with VRE, ESS delivers higher benefits. These findings are based on the examination of China Southern Power Grid under seven VRE and ESS penetration scenarios. Results show that at the 2018 penetration levels, ESS alone reduced operational costs by 2.8% and CO2 emissions by 1% and that by being paired with VRE, these reductions increased to 8.1% and 6.5%, respectively. The results clarify the synergy between ESS and VRE and explain the underlying mechanism. While VRE lowers coal units’ economic efficiency and environmental performance (measured in RMB/MWh and kg CO2/MWh), ESS offsets this effect by increasing large coal units’ power generation and improving their efficiency. ESS reduces coal consumption and CO2 emissions by substituting power generation from low-efficiency coal units with electricity from high-efficiency units and allowing them to operate at levels closer to full capacity and avoid start-ups.

AbstractHigher education institutions have long played a key role in solving society's most pressing problems. However, as the scale and complexity of socio‐environmental problems has grown, there has been a renewed debate about the role that academic institutions should play in developing solutions and how institutional structures should be redesigned to encourage greater interdisciplinarity. In the following pages, we present a graduate student perspective on this debate. Specifically, we identify challenges facing interdisciplinary graduate student researchers and present a series of recommendations for how institutions can better prepare them to become the next generation of leaders in interdisciplinary, action‐oriented research focused on solving socio‐environmental problems.

Resource adequacy, or ensuring that electricity supply reliably meets demand, is more challenging for wind- and solar-based electricity systems than fossil-fuel-based ones. Here, we investigate how the number of years of past weather data used in designing least-cost systems relying on wind, solar, and energy storage affects resource adequacy. We find that nearly 40 years of weather data are required to plan highly reliable systems (e.g., zero lost load over a decade). In comparison, this same adequacy could be attained with 15 years of weather data when additionally allowing traditional dispatchable generation to supply 5 % of electricity demand. We further observe that the marginal cost of improving resource adequacy increased as more years, and thus more weather variability, were considered for planning. Our results suggest that ensuring the reliability of wind- and solar-based systems will require using considerably more weather data in system planning than is the current practice. However, when considering the potential costs associated with unmet electricity demand, fewer planning years may suffice to balance costs against operational reliability.

Abstract This perspective investigates the impacts of disparate energy disruptions during Winter Storm Uri, which in 2021 caused severe power outages across the state of Texas leading to numerous deaths and billions of dollars of damage to property and infrastructure. The paper focuses on the potential injustice along ethnic lines in the distribution of power outages across the state. By analyzing data from the hourly rate of power outages aggregated by counties in Texas we find that among rural populations, Hispanic households faced substantially higher outage rates throughout the storm compared to other racial and ethnic groups. This reveals an inequitable distribution of energy disruptions. We propose that further nuances may be uncovered if more granular data were made available, delving into intra-county disparities. Only through comprehensive examination and proactive measures can we mitigate the adverse effects of future energy disruptions and safeguard the well-being and lives of all citizens, irrespective of their race, ethnicity, or socioeconomic status.

Abstract In contrast to battery storage systems, power-to-hydrogen-to-power (P-H2-P) storage systems provide opportunities to separately optimize the costs and efficiency of the system’s charging, storage, and discharging components. The value of capital cost reduction relative to round-trip efficiency improvements of P-H2-P systems is not well understood in electricity systems with abundant curtailed power. Here, we used a macro-energy model to evaluate the sensitivity of system costs to techno-economic characteristics of P-H2-P systems in stylized wind-solar-battery electricity systems with restricted natural gas generation. Assuming current costs and current round-trip P-H2-P efficiencies, least-cost wind and solar electricity systems had large amounts of excess variable renewable generation capacity. These systems included P-H2-P in the least-cost solution, despite its low round-trip efficiency and relatively high P-H2-P power discharge costs. These electricity system costs were not highly sensitive to the efficient use of otherwise-curtailed power, but were sensitive to the capital cost of the P-H2-P power discharge component. If the capital costs of the charging and discharging components were decreased relative to generation costs, curtailment would decrease, and electricity system costs would become increasingly sensitive to improvements in the P-H2-P round-trip efficiency. These results suggest that capital cost reductions, especially in the discharge component, provide a key opportunity for innovation in P-H2-P systems for applications in electricity systems dominated by wind and solar generation. Analysis of underground salt cavern storage constraints in U.S.-based wind and solar scenarios suggests that ample hydrogen storage capacity could be obtained by repurposing the depleted natural gas reservoirs that are currently used for seasonal natural gas storage.