4.1 The Link Between Renewable Energy and Hydrogen
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The “renewable power-following” is done at a constant fixed percentage. The
curtailment can finally be “load-following” where the curtailment rate is defined
at a fixed level of the electrical load (Arabzadeh, Pilpola, and Lund 2019).
A global review of the wind and solar energy curtailment showed the growing share of wind and solar energy generation is responsible for the increasing
levels of curtailment. In 2013, China had 77.16 gigawatts of wind power capacity producing 142 terawatt-hours of energy for which 16.23 terawatt-hours was
curtailed (Bird et al. 2016). The highest levels of curtailment were observed in
the north-eastern regions of China. In these regions, there is a high concentration
of wind generation capacity associated with a low energy demand and an insufficient transmission capacity. Moreover, the lack of flexible peak power generation
capacity and the absence of demand-site management hinder the integration of
additional intermittent renewable power generation in the electricity mix.
In 2012, Japanese utilities still held their rights to curtail wind and solar
energy up to thirty days per year (8% annual) before implementing curtailment of
other power producers and suppliers (i.e. combustion and baseload power plants)
(Bird et al. 2016).
Where the grid operations are managed based electricity market signals,
automated methods for enabling curtailment are more efficient than manual curtailment processes. They can reduce the overall curtailment levels. It also allows
solar and wind power producers to choose not to generate if prices are negative
(Bird et al. 2016).
An alternative or complementary strategy to the curtailment consists on storing
the electricity when it is not needed and have it available when the demand increases or when the grid frequency needs to be stabilized. The energy storage provides
additional flexibility to the electricity system and contribute to mitigate curtailment. It is a complex process and different storage technologies are available with
very distinctive characteristics (Luo et al. 2015). Depending on the location, the
performance and the costs, some storage technologies will be better suited than
others (Lewandowska-Bernat and Desideri 2017).
Renewable energy under the form of electricity can be converted to chemical
energy in the form of hydrogen through the water electrolysis process (Carmo and
Stolten 2018). Hydrogen can be stored in large quantity. The storage duration can
range from hours to months. Fuel cells can then discharge energy into the grid at
power rating within a range of seconds to hours.
The process of converting renewable electricity to hydrogen through the water
electrolysis process finds other applications than the storage of energy. Called
power-to-gas, this technology finds several applications that can be considered
for a deep decarbonisation of industry sectors using fossil fuel-based hydrogen as
feedstock.
31
The “renewable power-following” is done at a constant fixed percentage. The
curtailment can finally be “load-following” where the curtailment rate is defined
at a fixed level of the electrical load (Arabzadeh, Pilpola, and Lund 2019).
A global review of the wind and solar energy curtailment showed the growing share of wind and solar energy generation is responsible for the increasing
levels of curtailment. In 2013, China had 77.16 gigawatts of wind power capacity producing 142 terawatt-hours of energy for which 16.23 terawatt-hours was
curtailed (Bird et al. 2016). The highest levels of curtailment were observed in
the north-eastern regions of China. In these regions, there is a high concentration
of wind generation capacity associated with a low energy demand and an insufficient transmission capacity. Moreover, the lack of flexible peak power generation
capacity and the absence of demand-site management hinder the integration of
additional intermittent renewable power generation in the electricity mix.
In 2012, Japanese utilities still held their rights to curtail wind and solar
energy up to thirty days per year (8% annual) before implementing curtailment of
other power producers and suppliers (i.e. combustion and baseload power plants)
(Bird et al. 2016).
Where the grid operations are managed based electricity market signals,
automated methods for enabling curtailment are more efficient than manual curtailment processes. They can reduce the overall curtailment levels. It also allows
solar and wind power producers to choose not to generate if prices are negative
(Bird et al. 2016).
An alternative or complementary strategy to the curtailment consists on storing
the electricity when it is not needed and have it available when the demand increases or when the grid frequency needs to be stabilized. The energy storage provides
additional flexibility to the electricity system and contribute to mitigate curtailment. It is a complex process and different storage technologies are available with
very distinctive characteristics (Luo et al. 2015). Depending on the location, the
performance and the costs, some storage technologies will be better suited than
others (Lewandowska-Bernat and Desideri 2017).
Renewable energy under the form of electricity can be converted to chemical
energy in the form of hydrogen through the water electrolysis process (Carmo and
Stolten 2018). Hydrogen can be stored in large quantity. The storage duration can
range from hours to months. Fuel cells can then discharge energy into the grid at
power rating within a range of seconds to hours.
The process of converting renewable electricity to hydrogen through the water
electrolysis process finds other applications than the storage of energy. Called
power-to-gas, this technology finds several applications that can be considered
for a deep decarbonisation of industry sectors using fossil fuel-based hydrogen as
feedstock.