Direct Coupling Feasibility Evaluation

Direct Coupling Feasibility Evaluation: Predicting the Price of Hydrogen Produced by Solar Energy

Schoehuijs, Tom (TU Delft Electrical Engineering, Mathematics and Computer Science)

Geerlings, J.J.C. (mentor)
Higler, Arnoud (mentor)
Isabella, O. (graduation committee)
Mulder, F.M. (graduation committee)

Delft University of Technology

Electrical Engineering | Sustainable Energy Technology

2018-07-20

This report aims to evaluate the feasibility of a small pilot plant placed near Broome, Australia to produce 3 tons of hydrogen per day using photovoltaic (PV) energy. Using PVsyst, a PV modelling software, the maximum power operating points were determined for a test layout. This was then transformed to other layouts which allowed the optimum layout to be found for a system connected to electrolyzers using maximum power point tracking technology. A second scenario using a battery was also modelled and optimized. Finally, the third scenario used direct coupling, meaning that the PV panels were not operated at their maximum power point but rather at where the electrolyzer and PV current and voltage lines crossed. This resulted in a lower power yield but also lower costs. To find the current and voltage curve for the PV field, the data from PVsyst analyzed to find the short circuit current and the open circuit voltage. This allowed the full current and voltage curve to be determined, which allowed the intersection point with the (experimental) electrolyzer current and voltage curve to be determined.

In all simulations piping storage was used to remove the intermittency of the hydrogen production by having a capacity of 3 tons of gaseous H2. This ensures a constant stream of hydrogen to the liquefaction system.

Using preliminary results an electrolyzer degradation simulation was carried out, to find how the electrolyzer would behave after 20 years of use. Although the influence of intermittency could not be found in literature, it was shown that the electrolyzer produces, on average during its 20 year lifetime, approximately 5.7% less hydrogen than it would without any degradation. This has been included in all financial analyses carried out in this report, along with a 7% weighted average cost of capital.

The financial framework has been based off of a number of different sources and forecasts. Due to the limitations of publicly available data some forecasts were replaced with constant prices which do not evolve throughout the years.

Using the hydrogen production models and financial frameworks it is possible to compare the different scenarios. From this a price of 4.16$/kg was found for a MPP coupled system, 4.39$/kg for a MPP coupled system including a battery, and 4.02$/kg for a direct coupled system. The third scenario was furthermore looked at in terms of physical layout; it was found that the decentralized layout consisting of smaller subplots was slightly more expensive than the standard centralized layout (4.09$/kg). For this pilot plant it is advised to use a decentralized topology, combined with a decentralized layout consisting of multiple smaller plots. Although the centralized layout is slightly cheaper, it contains more system critical components which could cause a large portion of the system to be inactive if they are broken.

hydrogen
Broome
solar
PV
direct coupling
electrolyzer
alkaline electrolyzer

http://resolver.tudelft.nl/uuid:cb721f6f-236b-4039-93cd-a6762d8e146b

2020-07-20

Student theses

master thesis

© 2018 Tom Schoehuijs