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Wind Turbine Lubrication
Published in Leslie R. Rudnick, Synthetics, Mineral Oils, and Bio-Based Lubricants, 2020
There are some key barriers to wind energy development. Wind turbines only generate electricity when the wind is blowing. Customers who need uninterrupted electricity supplies need a backup of more reliable electricity sources, such as natural gas- or coal-burning plants, nuclear power plants, or hydropower plants. This contributes to serious grid curtailment problems for wind energy development [9]. Curtailment occurs when there is wind energy available, yet grid operators do not allow the wind farm to send power to the grid. In 2016, China’s national average curtailment rate was at 17%, and for some areas as high as 43%. Wind energy storage is not cost effective [10]. With the recent development of cryptocurrency, where large amounts of electricity are needed to “mine” cryptocurrency [11], the curtailed wind energy may find an outlet.
Electric Utility Integration of Renewable Energy Systems
Published in Radian Belu, Energy Storage, Grid Integration, Energy Economics, and the Environment, 2019
Power system operation practice requires that no power unbalances occur, in order to maintain perfect operation and the standard power quality levels. In the events when the power systems tend to be unbalanced, for example driven by an increased renewable energy generation, the power unbalances must be mitigated. In order to do that, individual or combined solutions to mitigate the power unbalance issues, such as curtailment of renewable energy generation, interconnections with other power systems or the use and addition of energy storage. The renewable energy generation curtailment consists in the event of power unbalance to cut-off partially or totally the RES and DG generation. RES curtailment implies a waste of the energy resources, and an increase into the fossil fuels consumptions, being recommended to be considered only in the extreme contingency cases. Strong power systems interconnections are an important advantage in terms of energy management and local power unbalances. Larger RES and DG integration into today grids is one of the drivers to reinforce the grid interconnection capacities in order to create a diversified mix and to extend the RES grid integration. However, there are some constrains in its application, such as the potential of the simultaneous power unbalances in the interconnected power systems. Energy storage offers an important benefit in the utility settings, decoupling the demand from the supply, thereby mitigating the power unbalances, allowing increased asset utilization, facilitating the RES and DG penetration, while improving electrical grid flexibility, reliability and efficiency. The energy storage option requires large investments, but can avoid the renewable energy curtailment disadvantage and/or the power exchange through grid interconnections constraints.
Introduction
Published in Sharlissa Moore, Sustainable Energy Transformations, Power, and Politics, 2018
Because electricity supply and demand are balanced within a system, the market for electricity differs from markets for commodities such as crude oil or oranges. The discourse on supply and demand is limiting, but is also crucial to understanding electricity systems. Özden-Schilling (2015) observes that the process of maintaining supply and demand in electrical power systems is so unique that what is typically a discourse used by economists has been reified as a priority for a variety of actors in the power system. In the early 1900s, system builders treated baseload power plants as “load-seeking turbines,” constantly creating new demands for electricity in order to utilize surplus supply, rather than designing storage technologies or more flexible power plants (Nye, 1990; Rose, 1995). Unlike coal and nuclear, renewable energy sources are intermittent because the sun obviously does not always shine, nor does the wind always blow; renewable resources vary by season as well. “Curtailment” of renewable electricity occurs when renewable facilities are shut down because baseload power plants cannot easily be ramped down to prioritize supply from green electrons. Thus, issues of timing relate not only to how fast an energy transformation could occur, but also to how temporality is managed within the electrical power system, as more asynchronous renewable energy, subject to the natural temporal cycles of wind, sun, and seasons, is added to the electricity system. Useful here is the concept of “timescapes” developed by Adam (1998) to stress “rhythmicities, timings and tempos, changes and contingencies” (p. 10). The timescape of the grid relates to the temporalities of how people consume electricity, and how new technologies, such as distributed and renewable supply or electric vehicle charging, are changing the temporal management of the power system.
Identifying Research Priorities for the further development and deployment of Solar Photovoltaics
Published in International Journal of Sustainable Energy, 2019
Serafeim Michas, Vassilis Stavrakas, Niki-Artemis Spyridaki, Alexandros Flamos
Curtailment is a proven method that helps maintain the safety limits of the electricity network and avoid costly network upgrades which would be mandatory if excess RES generation was injected, however, should be the last option when network balancing is needed because it also incurs financial burdens for PV generators. As such, there is a need to explore policy schemes capable of balancing the socio-economic effects of curtailment with the network expansion costs burdening the grid operator. Such policy schemes should be considering curtailment in combination with flexibility options (storage, demand side management, flywheels etc.), for better network optimisation, with minimum curtailment need and a parallel RES integration capacity increase. On a national level, curtailment-related studies should consider the national cost–benefit ratios, the boundary conditions and the prosumer compensation rules, aiming to reduce network upgrade costs. The examples of other countries on the compensation levels and schemes could be a useful source of input for policymakers. Finally, RES curtailment on distribution level is still missing. In a distributed generation regime curtailment studies on distribution level should be promoted with parallel technological R&D investments in novel network components (i.e. inverters with integrated communication capabilities).
An overview on the status quo of onshore and offshore wind power development and wind power enterprise localization in China
Published in International Journal of Green Energy, 2019
Ruixiaoxiao Zhang, Geoffrey Q.P. Shen, Meng Ni, Johnny K.W. Wong
Figures 10 and 11 illustrate the abandoned wind power and wind curtailment rate in specific regions from 2013 to 2018. A common reason for wind curtailment could be attributed to local network transmission congestion due to overcapacity and grid planning mismatching between grid companies and wind power developers (Gu and Xie 2014; Z.-Y. Zhao, Chang, and Chen 2016). In the year 2013, about 16,300 GWh of wind energy was curtailed over China, or about 8.4% of total wind power production, following 20,820 GWh in 2012 (Bai 2014). Although about 7.3% of wind generation was curtailed in 2014, the wind curtailment problem was even worse in the year 2015 and 2016, with 18% and 21% of wind generation being abandoned, respectively. The wind curtailment rates are extremely severe in Hebei, Inner Mongolia, Gansu, Xinjiang, Liaoning, Jilin, and Heilongjiang. Most of them are the leading regions in terms of installed capacity and are also areas with abundant wind resource. Therefore, the wind power curtailment is highly related to the wind turbine installed capacity and mainly occurs in North China grid, Northeast China grid and Northwest China grid where most of the wind farms are located, whereas the power demand is relatively low, and the transmission capacity to higher power demand regions is rather insufficient. Due to an urgent need to solve this problem, in 2015 and 2016, the National Energy Bureau (NEB) has consecutively issued the two Notices on Wind Power Grid Connection and Consumption, which stipulates those areas to privilege the use of wind power and cut down the wind curtailment rate. As a result, the wind power curtailment rate in 2017 and 2018 decreases heavily, which is 13.2% in 2017 and 7% in 2018.
Impact of electric vehicles on smart grid and future predictions: a survey
Published in International Journal of Modelling and Simulation, 2022
Ali A. Ismail, Nsilulu T. Mbungu, A. Elnady, Ramesh C. Bansal, Abdul-Kadir Hamid, Mohammad AlShabi
Direct integration of renewable energy into the power grid can harm the electrical network when it is not well coordinated. The curtailment of variable renewable energy is a challenge that decreases the economic benefits of the system. The bootable behavior, elastic, intelligent and predictable energy storage device power consumption effectively solve this problem [90]. The battery charging of EVs with its bidirectional power flow solves power quality problems when their integration is optimally coordinated and synchronized with the power grid.