Cost optimization of green hydrogen production at Pikerfoss RoR hydropower plant

Abstract

More sustainable energy solutions are of high interest as the global energy demand continues to grow. Hydropower is a well-developed renewable energy technology that has great potential for integrating power-to-gas technology. P2G is an innovative solution for long-term energy storage and transporting energy. It is particularly optimal for run-of-river hydropower plants that lack storage for excess energy. Given the increasing hydrogen demand in the industrial sector, P2G technology implementation in renewable energy systems can offer a sustainable method to produce green hydrogen. A common challenge in integrating hydrogen infrastructure is the production cost.

This thesis analyzed different cost optimizations for green hydrogen production from PEM electrolysis. Å Energi is planning on constructing a hydrogen plant at Pikerfoss RoR hydropower plant. Å Energi provided historical data on the electricity production at Pikerfoss RoR hydropower plans and the electricity prices in the NO1 area of Norway. Spring and Summer of 2018, 2020, and 2022 were analyzed in this study.

Optimization 1 was based on having a constant hydrogen production rate. This resulted in the highest average unit production prices but provided high stability and predictability in production planning. This optimization was especially vulnerable to increases in electricity prices, which led to higher production costs.

Optimization 2 was based on a fixed schedule for maximized production at nighttime between 01:00 and 03:00. This approach provided stability and predictability in the production planning. However, the optimization was vulnerable to electricity price spikes during typical off-peak hours at night.

Optimization 3 was based on using uses day-ahead electricity prices to maximize hydrogen production at a fixed number of hours each day. This optimization showed the ability to adapt to electricity price fluctuations while providing predictability in production planning.

Optimization 4 used a threshold price calculated from a threshold percentile for each pickup interval. The hydrogen production was at maximum capacity when the electricity prices did not exceed the threshold price. This approach resulted in the lowest average hydrogen production unit prices. With high fluctuation in electricity prices, some unpredictability in the production planning must be considered in this optimization.

In all seasons analyzed an increase in the average unit price for hydrogen production was observed moving from Optimization 1 to Optimization 4. Stable electricity prices resulted in similar unit prices for all optimizations. However, varying electricity prices showed the ineffectiveness of Optimization 1 and 2. The analysis of the average unit production prices for all seasons resulted in Optimization 4 being the optimal approach.\\