High Penetration Of Variable Generation Research Articles

Wind power deviation charge reduction using long short term memory network

High penetration of variable generation like wind in modern power systems results in frequent load-generation imbalances. Additional spinning reserves and balancing services are deployed to reduce or avoid such imbalances. However, these additional balancing services result in increased total operation costs and it is generally shifted to Wind Power Generation Companies (WPGC) as Deviation Charges (DCs). The high DCs diminish the profitability of WPGCs. DCs are directly proportional to forecasting errors and can be reduced by enhancing forecasting accuracy. This paper proposes a Long Short-Term Memory (LSTM) network to reduce DCs. LSTM is a special kind of recurrent neural network and it is capable of learning long-term and short-term dependencies effectively. Therefore, the LSTM network can produce minimal error wind power forecasts and this helps to reduce DCs. The performance of the proposed LSTM network is realized using the real system data. Results obtained from the proposed LSTM model are compared with various forecasting models like ARIMA, ANN, and SVR. The comparison shows that the proposed LSTM model shows the least total DCs on most of the days followed by ANN, SVR, and ARIMA. The proposed LSTM, ANN, SVR, and ARIMA models show an average total DC of 6194.25$, 8459.32$, 15822.22$, and 38269.89$ respectively. Thus, the proposed LSTM model is capable of reducing 517.82%, 155.43%, and 36.56% DCs from ARIMA, SVR, and ANN models respectively, and helps the WPGCs to enhance their profitability.

Design of a Self-Supporting Liner for the Renovation of a Headrace Tunnel at Chivor Hydropower Project

Ensuring access to affordable, reliable, sustainable, and modern energy, as declared in the United Nations’ Agenda 2030, requires both the inclusion of new renewable energy sources, and the renovation of existing hydropower infrastructure, since this resource is considered a key strategy to support flexibility in electric grids with high penetrations of variable generation. This paper addresses the design of a self-supporting lining for the renovation of a headrace tunnel, that has been affected by a buckling event, in order to extend the operating life of the Chivor Hydropower Project, located in Colombia. Studies performed by AES Corporation about the buckling events that affected the headrace tunnel and the condition assessment are first described. Then, the design alternatives to renovate this important part of the hydropower plant’s infrastructure are presented in a general way. The detailed design and construction planning for the selected alternative are then illustrated by showing some calculations used in hydropower design. Such a renovation project is one of the first of its class in Colombia and goes from studies of the buckling events to the design of a modern lining that will be constructed while keeping the 1000-MW (6% of Colombia’s demand) hydropower plant in operation conditions, in order to extend its life for 50 more years, which represents an example for managers and practitioners of large-scale hydraulic engineering projects.

An insurance mechanism for electricity reliability differentiation under deep decarbonization

Securing an adequate supply of dispatchable resources is critical for keeping a power system reliable under high penetrations of variable generation. Strategic reserves have been used by a range of jurisdictions to procure investment in additional generation reserves given the missing money problem in energy only market designs. Given the growing flexibility and heterogeneity of load enabled by advancements in distributed resource and control technology, strategic reserve procurement needs to be able to reflect the different preferences of energy consumers. To address this challenge this paper develops an insurance risk mechanism for the procurement of strategic reserves that is adapted to a future with variable generation and flexible demand. The proposed design introduces a central insurance scheme with prudential requirements that align diverse consumer reliability preferences with the financial objectives of an insurer-of-last-resort. We illustrate the benefits of the scheme in (i) differentiating load by usage to enable better management of the system during times of extreme scarcity, (ii) incentivizing incremental investment in generation infrastructure that is aligned with consumer reliability preferences and (iii) improving overall reliability outcomes for consumers.

Electricity market games: How agent-based modeling can help under high penetrations of variable generation

Integrating increasingly high levels of variable generation in U.S. electricity markets requires addressing not only power system and grid modeling challenges but also an understanding of how market participants react and adapt to them. Key elements of current and future wholesale power markets can be modeled using an agent-based approach, which may prove to be a useful paradigm for researchers studying and planning for power systems of the future.

Transmission, Variable Generation, and Power System Flexibility

Long-term transmission and generation planning face numerous challenges to accommodate the integration of a high penetration of variable generation (VG). System flexibility, or the ability of a system to meet changes in demand and VG production, is one such issue receiving much attention. This paper presents a methodology to assess the flexibility of a power system while explicitly considering the limitations of the transmission network. By determining only the flexibility available from resources which could be realized in real-time operation due to transmission constraints, a more realistic assessment of a system's flexibility can be made. The flexibility of the IEEE Reliability Test System is assessed using two metrics. Transmission is shown to have a significant effect on the availability of flexibility and the risk posed to the system by net load ramps. The impact is seen to be strongly dependent on the variability of the net load and on the distribution of online resources. A nonlinear relationship between the installed VG and system flexibility is found, with regions of significant inflexibility occurring at certain VG penetrations.

Is Deferrable Demand an Effective Alternative to Upgrading Transmission Capacity?

AbstractWith high penetrations of variable generation from wind turbines in remote locations, transmission capacity may be inadequate to transfer this relatively inexpensive source of generation to demand centers. The major reason is that transmission corridors into load centers are often congested when the system load is high, and additional wind generation is effectively shut out. In contrast, when the system load is low and the wind is blowing, wind generation may be able to meet most of the load throughout the network subject to the specific limitations of the network’s topology. This paper compares the system costs of two very different ways of reducing congestion on the network to increase the annual amount of potential wind capacity dispatched. The first way uses the standard supply side solution of upgrading transmission capacity on the network. The second way uses a demand-side approach in which deferrable demand shifts the system load from on-peak periods to off-peak periods. In addition, the de...

Studying the Variability and Uncertainty Impacts of Variable Generation at Multiple Timescales

With increasing levels of variable renewable energy, there is a growing need to study its impacts on power system operation. Variable generation (VG) is variable and uncertain at multiple timescales, and it is important that system operators understand how each of these characteristics impact their systems since each may have different mitigation strategies. To date, many of the studies of VG integration are limited to studying at one time resolution and therefore cannot analyze the variability and uncertainty impacts across multiple timescales. Here we study the variability and uncertainty impacts across multiple operational timescales. A model is used which integrates multiple scheduling sub-models with different update frequencies, time resolutions, and decision horizons. Using metrics that describe reliability and costs with a methodology that describes the sensitivities and tradeoffs of variability and uncertainty impacts separately with respect to the conditions that cause those impacts, case studies are performed which display greater information on expectations of these impacts on future systems with high penetrations of VG.