650
Y. Mizuno et al.
43.4 Methodology of Feasibility Study
In the feasibility study of the proposed PtoG concept, the size and number of fuel
cells, electrolyzers, and hydrogen tanks, are determined through yearly electricity
and material input and output simulation. Assumed the cost of facilities, renewable
electricity, and water and based on them, levelized unit cost of hydrogen are calculated. The economic and environmental value of hydrogen is compared with that of
equivalent combination of grid electricity and heat from conventional facilities.
Specific process of the study is as follows:
1. Making the consumers’ yearly electricity and heat demand pattern.
2. Selecting fuel cells to install into the consumers and setting yearly operation
pattern of them based on the electricity and heat demand pattern.
3. Based on the weather data and capacity of renewable energy facilities, assuming
the power generation pattern.
4. Determining the hydrogen production pattern, by assuming the capacity of the
electrolyzer and the electricity intake rules.
5. Assuming the capacity of hydrogen storage facility by hydrogen demand and
supply pattern.
6. Calculating unit cost of hydrogen from the number and capacity of facilities and
assumed electricity and water cost.
7. Evaluating the economic feasibility by comparing hydrogen cost with equivalent
cost combination of grid electricity and heat from fossil fuel.
8. Evaluating CO 2 reduction from deduced grid electricity and fossil fuel consumption.
43.4.1 Step 1. Electricity and Heat Demand
The consumers of hydrogen in Rokkasho Village includes seven public facilities, 200
detached houses, and housing complex for 1,496 families. Public facilities include
one city hall, one community center, two schools, one hospital, one heated pool
facility, and one centralized kitchen for schools.
A year is represented by five seasonal patterns. Each pattern has hourly value of
electricity and heat demand. Winter, Autumn and Spring, and Summer patterns are
originated from the literatures (The Society of Heating 2015; Engineering Promotion
Association, Underground Development Research Center 2017; Hashigaki 2010;
Agency for Natural Resources and Energy 2011; Kiyota et al. 2002; Watanabe et al.
2010; Takashima et al. 2010) and corrected to the Rokkasho Village’s pattern with
climate data, facilities’ floor space data, and electricity and fuel bills. The sums of
electricity and heat demand of the months are equal to the values in electricity and
fuel bill. The transitional seasons’ patterns between Winter, Autumn & Spring, and
Summer are mean values of two patterns.
Y. Mizuno et al.
43.4 Methodology of Feasibility Study
In the feasibility study of the proposed PtoG concept, the size and number of fuel
cells, electrolyzers, and hydrogen tanks, are determined through yearly electricity
and material input and output simulation. Assumed the cost of facilities, renewable
electricity, and water and based on them, levelized unit cost of hydrogen are calculated. The economic and environmental value of hydrogen is compared with that of
equivalent combination of grid electricity and heat from conventional facilities.
Specific process of the study is as follows:
1. Making the consumers’ yearly electricity and heat demand pattern.
2. Selecting fuel cells to install into the consumers and setting yearly operation
pattern of them based on the electricity and heat demand pattern.
3. Based on the weather data and capacity of renewable energy facilities, assuming
the power generation pattern.
4. Determining the hydrogen production pattern, by assuming the capacity of the
electrolyzer and the electricity intake rules.
5. Assuming the capacity of hydrogen storage facility by hydrogen demand and
supply pattern.
6. Calculating unit cost of hydrogen from the number and capacity of facilities and
assumed electricity and water cost.
7. Evaluating the economic feasibility by comparing hydrogen cost with equivalent
cost combination of grid electricity and heat from fossil fuel.
8. Evaluating CO 2 reduction from deduced grid electricity and fossil fuel consumption.
43.4.1 Step 1. Electricity and Heat Demand
The consumers of hydrogen in Rokkasho Village includes seven public facilities, 200
detached houses, and housing complex for 1,496 families. Public facilities include
one city hall, one community center, two schools, one hospital, one heated pool
facility, and one centralized kitchen for schools.
A year is represented by five seasonal patterns. Each pattern has hourly value of
electricity and heat demand. Winter, Autumn and Spring, and Summer patterns are
originated from the literatures (The Society of Heating 2015; Engineering Promotion
Association, Underground Development Research Center 2017; Hashigaki 2010;
Agency for Natural Resources and Energy 2011; Kiyota et al. 2002; Watanabe et al.
2010; Takashima et al. 2010) and corrected to the Rokkasho Village’s pattern with
climate data, facilities’ floor space data, and electricity and fuel bills. The sums of
electricity and heat demand of the months are equal to the values in electricity and
fuel bill. The transitional seasons’ patterns between Winter, Autumn & Spring, and
Summer are mean values of two patterns.