Contrary to the pursued drastic decrease in greenhouse gas emissions towards 2050, in
Belgium, various sectors are still dominated by fossil fuels such as transport and industry,
that need alternatives provided by upcoming technologies. As such, The Belgian industry
has a large use of fossil-based hydrogen (’grey hydrogen’). Most progress has been made in
the electricity sector with increasing amounts of renewable energy sources (RES). However,
the intermittent character of solar and wind power and the specific location (cf. offshore
wind) entails challenges as well: grid imbalances due to periods of extremely low or high
RES generation, and grid connection issues.

With the aim to find a solution to these issues, the future role of green hydrogen in the
Belgian energy system is the subject of this research. Electricity from renewables can be
converted into hydrogen through electrolysis resulting in a green and valuable gas.
First, the green hydrogen demand in 2050 is forecasted in different sectors (industry,
transport and heating). The total demand is estimated 55 TWh or 1660 kton of hydrogen.
The largest demand is found in the transport sector, followed by industry.

This demand is the starting point of the design of a hydrogen production system. The
system is connected to an offshore wind farm and two scenarios are compared that differ
in the way of bringing offshore wind energy ashore: (1) an electric grid with onshore
electrolysis and (2) offshore electrolysis where hydrogen is transported ashore via existing
gas pipelines. A 22 GW electrolyser and a 24.5 GW wind farm are the cost-optimal
dimensions that meet the hydrogen demand. The electrolyser uses its entire capacity for
43% of the time as it is dependent on intermittent offshore wind power.

A socio-economic analysis shows that onshore electrolysis has a lower levelised cost of
hydrogen (LCOH) than offshore electrolysis, mainly because of the high additional costs for
operating offshore. The LCOH of the onshore scenarios is estimated 4.5 €/kg, compared
to the offshore LCOH of 5.2 €/kg. However, in neither scenario, the green hydrogen
produced will be competitive with grey hydrogen (2.88 €/kg). The electricity cost is
clearly the dominating element in the LCOH.

The third part focuses on the role of green hydrogen in grid-balancing, in a 2050 RES
electricity scenario for Belgium. Large excesses and deficits, often lasting for longer periods,
are observed that can be dealt with by hydrogen long-term storage. Opportunities arise
since excesses often coincide with low or negative prices, and residual load with high prices.
Hydrogen storage is expected to be economically feasible since hydrogen production at
negative prices drives down the cost. However, electricity prices contain much uncertainty
and in general, it is concluded that a large spread between the electricity prices when
consuming and reinjecting is required.

Finally, the energy systems for demand and storage purposes are coupled by using the
electrolyser in the onshore scenario for grid-balancing purposes as well. The integrated
system has a lower system cost, even though the difference is rather small.