Backend studies of the VQG optimization

Backends

Use classical and quantum backends via the cloud

Quantum-powered

Solve on quantum computers

Quantum-inspired algorithms

Implementation of multiple quantum-inspired algorithms

Why should we optimize with Quantum?

A potential use case for Quantum Computers

The Optimization of feed-in prices for the Vehicle-To-Grid approach is difficult. It presents a challenge to common classical solver and could be a use case for Quantum Computers.

A Difficult Problem

Run times of the OSQP optimizer for varying scenario sizes (hours). Instabilities in the optimization lead to outliers.

CMA versus OSQP versus Quantum-Inspired

OSQP Algorithm

In some cases the classical OSQP (Operator-Splitting Quadratic Program) solver can fail, e.g. when the problem turns out to be non-convex.

QIO Algorithms

Quantum-inspired optimization (e.g. population annealing) gives a result, where OSQP fails. The calculated profit gain through feed-in is 28 million euro for one day.

CMA-ES Algorithm

CMA-ES (Covariance Matrix Adaptation Evolution Strategy) optimization algorithm is a specific solver for non-convex problems. The result differs only slightly from the QIO result, for similar run-times. The profit gain amounts to 30 million euro.

Run-time: OSQP vs. CMA

As a solver for more general (non-convex) optimization problems, CMA-ES has a significantly larger run-time than OSQP (seconds vs. micro-seconds).

Performance of different QIO solvers

Profit gain of different solvers for varying timeouts compared to the OSQP classical solver.

Solving the Optimization with Photonic Quantum Computing (Xanadu)

Mapping QUBO to graphs

With a clever encoding, one can map the V2G QUBO problem to a densest subgraph problem.

Solution of the densest Subgraph Problem

By using Gaussian Boson Sampling, the densest subgraph problem can be solved on a photonic quantum computer and mapped back to the V2G Problem.

Solving the Optimization with Neutral Atom Quantum Computers (QuERA)

Mapping QUBO to UDG MWIS

The V2G QUBO problem can be mapped to a Maximum Weighted Independent Set (MWIS) problem on a Unit Disk Graph (UDG). These problems can be naturally encoded and solved on neutral atom quantum computers. (Image taken from Fig. 1 in 2209.03965)

MWIS Graph of the Problem

A 6-bit QUBO problem mapped to a 128-node UDG MWIS problem.

Solution with Neutral Atom QC

The transformed Problem can be solved with a quantum computer (e.g. QuEra's Bloqade simulator) and mapped back to a solution of the V2G problem.