5 research outputs found
A Consensus-ADMM Approach for Strategic Generation Investment in Electricity Markets
This paper addresses a multi-stage generation investment problem for a
strategic (price-maker) power producer in electricity markets. This problem is
exposed to different sources of uncertainty, including short-term operational
(e.g., rivals' offering strategies) and long-term macro (e.g., demand growth)
uncertainties. This problem is formulated as a stochastic bilevel optimization
problem, which eventually recasts as a large-scale stochastic mixed-integer
linear programming (MILP) problem with limited computational tractability. To
cope with computational issues, we propose a consensus version of alternating
direction method of multipliers (ADMM), which decomposes the original problem
by both short- and long-term scenarios. Although the convergence of ADMM to the
global solution cannot be generally guaranteed for MILP problems, we introduce
two bounds on the optimal solution, allowing for the evaluation of the solution
quality over iterations. Our numerical findings show that there is a trade-off
between computational time and solution quality
Centralised and Distributed Optimization for Aggregated Flexibility Services Provision
The recent deployment of distributed battery units in prosumer premises offer
new opportunities for providing aggregated flexibility services to both
distribution system operators and balance responsible parties. The optimization
problem presented in this paper is formulated with an objective of cost
minimization which includes energy and battery degradation cost to provide
flexibility services. A decomposed solution approach with the alternating
direction method of multipliers (ADMM) is used instead of commonly adopted
centralised optimization to reduce the computational burden and time, and then
reduce scalability limitations. In this work we apply a modified version of
ADMM that includes two new features with respect to the original algorithm:
first, the primal variables are updated concurrently, which reduces
significantly the computational cost when we have a large number of involved
prosumers; second, it includes a regularization term named Proximal Jacobian
(PJ) that ensures the stability of the solution. A case study is presented for
optimal battery operation of 100 prosumer sites with real-life data. The
proposed method finds a solution which is equivalent to the centralised
optimization problem and is computed between 5 and 12 times faster. Thus,
aggregators or large-scale energy communities can use this scalable algorithm
to provide flexibility services.Comment: 10 pages, 7 figure
Scheduling of Resources in Renewable Energy Communities
This work presents a detailed study of the scheduling of power and energy resources in renewable energy communities (RECs). The study has been developed starting from the analysis of a single basic unit of the community, i.e., the prosumer and its microgrid, to the scheduling and expansion of the energy community concept with several prosumers through several scenarios.
The individual scheduling problem of the prosumer has been studied as a day-ahead deterministic problem and as a multistage stochastic problem to consider uncertainties associated with energy generation and energy consumption. Furthermore, an approach has been formulated to consider the integration of bidirectional charging services of electrical vehicles within a local energy system with the presence of renewable generation.
Moreover, this thesis focuses on the scenario in which direct energy transactions between prosumers located within a REC are allowed in addition to the energy transactions with the external energy provider. The day-ahead scheduling problem has been addressed by a centralized approach and by a distributed approach based on the alternating direction method of multipliers (ADMM). The developed approaches provide the scheduling of the available energy resources to limit the balancing action of the external grid and allocate the internal network losses to the corresponding energy transactions.
Finally, the thesis presents a coordinated day-ahead and intra-day approach to provide the optimal scheduling of the resources in a REC. In this case, the ADMM-based procedure, which is aimed at minimizing the total energy procurement costs, is adapted to cope with the impact of the fluctuation of both the local energy generation and demand during the day. To achieve this, a day-ahead multistage stochastic optimization approach is combined with an intra-day decision-making procedure, able to adjust the scheduling of the energy resources according to the current operational conditions