"""

Robust optimization of a power-to-power system 
==============================================

The robust design optimization of the Levelized Cost Of Electricity for a
hydrogen-based power-to-power system for a dwelling in Belgium.

"""

# %%
# In this first example, a robust design optimization is performed on a 
# grid-connected household in Brussels, supported by a photovoltaic-hydrogen system.
# To optimize the system, 4 design variables are considered: the photovoltaic array capacity, 
# electrolyzer stack capacity, fuel cell stack capacity and
# hydrogen tank capacity. 
# The mean and standard deviation of the Levelized Cost Of Electricity (LCOE) are selected as objectives.
# The CAPEX, OPEX, replacement cost and lifetime of the components are 
# considered uncertain, as well as the wholesale electricity price, electricity demand,
# interest rate and inflation rate. A detailed illustration of the energy system model and the stochastic space is provided in :ref:`lab:pvh2model`. 

# %%
# After 150 generations, a trade-off exists between minimizing the LCOE mean and LCOE standard deviation:

import rheia.POST_PROCESS.post_process as rheia_pp
import matplotlib.pyplot as plt

case = 'H2_POWER'

eval_type = 'ROB'

my_opt_plot = rheia_pp.PostProcessOpt(case, eval_type)

result_dir = 'run_tutorial'

y, x = my_opt_plot.get_fitness_population(result_dir)

plt.plot(y[0], y[1], '-o')
plt.xlabel('LCOE mean [euro/MWh]')
plt.ylabel('LCOE standard deviation [euro/MWh]')
plt.xticks([y[0][0], y[0][-1]])
plt.yticks([y[1][0], y[1][-1]])
plt.show()

# %%
# The Pareto front illustrates a trade-off between minimizing the LCOE mean and LCOE standard deviation. 
# This means that no single design exists that simulateounsly achieves the minimum LCOE mean and minimum LCOE standard deviation.
# The optimized LCOE mean design achieves an LCOE mean of 247 euro/MWh and a LCOE standard deviation of 46 euro/MWh.
# Instead, the robust design (i.e. the design with the lowest standard deviation) achieves an
# LCOE mean of 302 euro/MWh and a LCOE standard deviation of 38 euro/MWh.
# The designs that correspond to this Pareto front have the following PV array capacity:

plt.plot(y[0],x[0],'-o')
plt.xlabel('LCOE mean [euro/MWh]')
plt.ylabel('system capacity [kWp]')
plt.legend(['PV array'])
plt.show()

# %%
# Electrolyzer array and fuel cell array capacity:

for x_in in x[1:3]:
    plt.plot(y[0],x_in,'-o')

plt.xlabel('LCOE mean [euro/MWh]')
plt.ylabel('system capacity [kW]')
plt.legend(['electrolyzer array, fuel cell array'])
plt.show()

# %%
# Hydrogen storage tank capacity:
    
plt.plot(y[0],x[3],'-o')
plt.xlabel('LCOE mean [euro/MWh]')
plt.ylabel('system capacity [kWh]')
plt.legend(['storage tank'])
plt.show()

# %%
# These results indicate that the optimized LCOE mean is achieved by a PV array.
# In order to improve the robustness of the LCOE, the optimizer gradually increases
# the electrolyzer, fuel cell and storage tank capacity.