Assessing the potential of hydrogen energy storage in a stand-alone electricity grid : applying mathematical programming to balance electricity production and consumption : a case study on the Faroe Islands

2020

The increasing adaption of renewable energy sources (RES), with intermittent and nondispatchable

production output, requires an increased effort to continuously balance supply

to meet demand in electricity grids. Failing to establish this balance can lead to blackouts.

Energy storage technologies can be applied to increase the utilization of RES and maintain

a balanced grid. This is especially relevant for stand-alone systems that are unable to

import or export electricity. A technology showing great potential in resolving this issue

is the production and storage of hydrogen gas (Power-to-Hydrogen, PtH2) utilizing excess

electricity.

This thesis seeks to answer what combinations of production and storage technologies in

a stand-alone, multi-energy system (MES), make PtH2 a cost-effective option to balance

production and demand. To do this, a mixed integer linear programming model (MILP)

is developed and applied to a case study on the Faroe Islands.

The model objective is defined to minimize lifetime costs of acquiring, installing and

operating the system components while continuously satisfying demand. The model

optimizes the system based on one year of input data with hourly resolution. Through

six distinct scenarios, each containing different combinations of technologies, we create

hypothetical environments with unique characteristics to uncover when PtH2 is a costeffective

method of balancing a stand-alone grid. Three sensitivity analyses are conducted

to asses how the cost-effectiveness of PtH2 is affected by shifting production towards RES.

The results show that PtH2 can be a cost-effective technology, significantly contributing

to reduced lifetime costs of a stand-alone energy system. However, some prerequisites

are needed for this to be the case. Specifically, PtH2 is cost-effective when large hydro

power capacities are unavailable and there is a focus on shifting production from diesel

generators towards renewable production. In cases where large capacities in hydro power

or diesel generation is available, PtH2 does not prove to reduce total costs of the system.

Keywords – Power-to-Hydrogen, Multi-Energy System, Grid-Balancing, Renewable

Energy Sources, Energy Storage, Optimization, Mathematical Programming, MILP