The increasing penetration of renewable energy resources and the decreasing cost of battery energy storage in recent years has led to a growing interest in using batteries to provide grid services like frequency regul...
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ISBN:
(数字)9781665451963
ISBN:
(纸本)9781665451963
The increasing penetration of renewable energy resources and the decreasing cost of battery energy storage in recent years has led to a growing interest in using batteries to provide grid services like frequency regulation. In this paper, we discuss the advantages and disadvantages of different battery degradation models and the impacts that model choice can have on the assumed cost of energy capacity loss due to operation. We also explore the effects of modeling degradation as an uncertain process by extending a two-stage, multi-period optimization problem for scheduling the operation of a battery providing multiple services with risk aversion. We use stochastic dual dynamic programming to derive a policy for the problem. Case study results show that using a stochastic degradation model with risk aversion produces a policy for more conservative battery use and longer lifespan in comparison to that obtained with a deterministic degradation model.
We consider discrete time optimal control problems with finite horizon involving continuous states and possibly both continuous and discrete controls, subject to non-stationary linear dynamics and convex costs. In thi...
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ISBN:
(纸本)9781728113982
We consider discrete time optimal control problems with finite horizon involving continuous states and possibly both continuous and discrete controls, subject to non-stationary linear dynamics and convex costs. In this general framework, we present a stochastic algorithm which generates monotone approximations of the value functions as a pointwise supremum or infimum of basic functions (for example affine or quadratic) which are randomly selected. We give sufficient conditions on the way basic functions are selected in order to ensure almost sure convergence of the approximations to the value function on a set of interest. Then we study a linear-quadratic optimal control problem with one control constraint. On this toy example we show how to use our algorithm in order to build lower approximations, like the SDDP algorithm, as supremum of affine cuts and upper approximations, by min-plus techniques, as infimum of quadratic fonctions.
The recent integration of renewable resources in electricity markets has increased the need for producers to correct their trading position close to real time in order to avoid volatile real-time prices. The last mark...
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ISBN:
(纸本)9781665435970
The recent integration of renewable resources in electricity markets has increased the need for producers to correct their trading position close to real time in order to avoid volatile real-time prices. The last market to close before delivery is the Continuous Intraday Market. Therefore, this market is an interesting outlet for renewable units that aim at covering their forecast errors. As a starting point for tackling this problem, we characterize an optimal policy for trading a fixed quantity in a simplified market model. We use this analytical solution as a basis for developing an Approximate dynamicprogramming algorithm and an alternative stochastic dual dynamic programming that can trade under a more realistic set of assumptions.
This paper presents two algorithms for solving a medium-term hydro optimization. Considered are risk-averse operation, provision of spinning reserves as well as short-term production flexibility. Proposed is a variant...
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ISBN:
(纸本)9781479935611
This paper presents two algorithms for solving a medium-term hydro optimization. Considered are risk-averse operation, provision of spinning reserves as well as short-term production flexibility. Proposed is a variant of stochastic dual dynamic programming (SDDP) and stochasticdynamicprogramming as a benchmark. A risk measure is introduced in both methods. To deal with short-term production flexibility a decomposition of the problem into inter-and intrastage subproblems is performed. The provision of spinning reserves leads to non-convex value functions. To deal with it in SDDP a method based on Lagrangian relaxation was used which was further enhanced by locally valid cuts in order to find realistic water values.
Even with recent enhancements, computation times for large-scale multistage problems with risk-averse objective functions can be very long. Therefore, preprocessing via scenario reduction could be considered as a way ...
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Even with recent enhancements, computation times for large-scale multistage problems with risk-averse objective functions can be very long. Therefore, preprocessing via scenario reduction could be considered as a way to significantly improve the overall performance. Stage-wise backward reduction of single scenarios applied to a fixed branching structure of the tree is a promising tool for efficient algorithms like stochastic dual dynamic programming. We provide computational results which show an acceptable precision of the results for the reduced problem and a substantial decrease of the total computation time.
This dissertation comprises four different topics related to multistage stochasticprogramming (MSP) algorithms, modeling, and applications. First, we extend the adaptive partition-based approach for solving two-stage...
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This dissertation comprises four different topics related to multistage stochasticprogramming (MSP) algorithms, modeling, and applications. First, we extend the adaptive partition-based approach for solving two-stage stochastic programs with a fixed recourse matrix and a fixed cost vector to the MSP setting, where the stochastic process is assumed to be stage-wise independent. The proposed algorithms integrate the adaptive partition-based strategy with a popular approach for solving multistage stochastic programs, the stochastic dual dynamic programming (SDDP) algorithm, according to two main strategies. These two strategies are distinct from each other in the manner by which they refine the partitions during the solution process. In particular, we propose a refinement outside SDDP strategy whereby we iteratively solve a coarse scenario tree induced by the partitions and refine the partitions in a separate step outside of SDDP, only when necessary. We also propose a refinement within SDDP strategy where the partitions are refined in conjunction with the machinery of the SDDP algorithm. We then use, within the two different refinement schemes, different tree-traversal strategies, which allow us to have some control over the size of the partitions. Our numerical experiments on a hydro-thermal power generation planning problem show the effectiveness of the proposed algorithms in comparison to the standard SDDP algorithm. Moreover, the results show that the algorithms with the refinement outside SDDP strategy outperform the ones with the refinement within SDDP strategy. Second, we study an important question related to solving MSP problems with a large number of stages. A common approach to tackle MSP problems with a large number of stages is a rolling-horizon (RH) procedure, where one solves a sequence of MSP problems with a smaller number of stages. This leads to a delicate issue of how many stages to include in the smaller problems used in the RH procedure. We study
In this paper, a novel modeling framework is proposed, the multi-horizon modeling approach. This approach allows a very detailed and transparent modeling of many problems in hydro power planning by simultaneously bein...
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In this paper, a novel modeling framework is proposed, the multi-horizon modeling approach. This approach allows a very detailed and transparent modeling of many problems in hydro power planning by simultaneously being computationally very efficient. The model is applied to a complex pumped storage hydro power plant in a liberalized market environment in order to give decision support for the self-scheduling of it. The modeling framework is compared to three alternative state-of-the-art modeling approaches. The results suggest that multi-horizon models are especially valuable for the modeling of hydro power plants with different types of reservoirs. (C) 2016 The Authors. Published by Elsevier Ltd.
In liberalised power markets the inability of consumers to adapt their demand in accordance to wholesale prices is increasingly challenged. Nowadays technical progress within the smart grid industry constitutes promis...
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In liberalised power markets the inability of consumers to adapt their demand in accordance to wholesale prices is increasingly challenged. Nowadays technical progress within the smart grid industry constitutes promising changes for the integration of end-users into the power system, but the deployment of Demand Response (DR) still faces the challenge of its economic viability. This thesis aims to assess the economic value of DR. We rely on an energy-only market model under uncertainty in order to quantify the revenues of DR aggregators, classified by category of consumers and end-uses of electricity. The model is formulated as a multi-stage stochastic linear problem and solved by stochastic dual dynamic programming. It appears that in France, industrial load-shedding and load-shifting of cement, paper, and pulp are profitable. For residential and tertiary consumers, load-shifting of electric heating is not profitable. We also show that the capacity value of DR is crucial. Overall, results show that DR is beginning to become economically attractive, but that fixed costs of smart grid technologies still need to come down further to fully develop its potential.
Oppgaven utforsker vannkraftproduksjonsplanlegging i Bergsdalen vassdraget, styrt av BKK, ved hjelp av Stokastisk dual Dynamisk Programmering. Systemet er under et sett med miljørestriksjoner, innført av NVE...
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Oppgaven utforsker vannkraftproduksjonsplanlegging i Bergsdalen vassdraget, styrt av BKK, ved hjelp av Stokastisk dual Dynamisk Programmering. Systemet er under et sett med miljørestriksjoner, innført av NVE, som utfordrer løsningsmetoden. Approksimasjoner a miljørestriksjonene er presentert og diskutert, siden løsningsmetoden er prioritert.
Multi-Stage stochasticprogramming with CVaR: Modeling, Algorithms and Robustness RNDr. Václav Kozmík Abstract: We formulate a multi-stage stochastic linear program with three different risk measures based o...
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Multi-Stage stochasticprogramming with CVaR: Modeling, Algorithms and Robustness RNDr. Václav Kozmík Abstract: We formulate a multi-stage stochastic linear program with three different risk measures based on CVaR and discuss their properties, such as time consistency. The stochastic dual dynamic programming algorithm is described and its draw- backs in the risk-averse setting are demonstrated. We present a new approach to evaluating policies in multi-stage risk-averse programs, which aims to elimi- nate the biggest drawback - lack of a reasonable upper bound estimator. Our approach is based on an importance sampling scheme, which is thoroughly ana- lyzed. A general variance reduction scheme for mean-risk sampling with CVaR is provided. In order to evaluate robustness of the presented models we extend con- tamination technique to the case of large-scale programs, where a precise solution cannot be obtained. Our computational results are based on a simple multi-stage asset allocation model and confirm usefulness of the presented procedures, as well as give additional insights into the behavior of more complex models. Keywords: Multi-stage stochasticprogramming, stochastic dual dynamic programming, im- portance sampling, contamination, CVaR
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