Here's a portion of an example test case..
periods_per_year = 12
energy_production_annual = 44570000. -- kWh/kW or kWh annual energy output per rated kW
energy_output_cert_annual = 43288918. -- kWh/kW
forecast_peak_power = 2298.01 -- hours (was base_sys_perf)
annual_system_degredation = 0.005 -- percent as decimal
system_power_output_peak = 19395. -- kW
sys_output_period = 0 -- kWh
ppa_rate = .2 -- $/kWh
ppa_escalation = .025 -- percent as decimal (factor)
power_revenue_period = 0 -- $ (was direct_income)
\#
period = i + 1
periods_per_year = periods_per_year
year = int( ( ( i + periods_per_year ) / periods_per_year ) )
next_year = year.i + 1
prev_year = year.i - 1
sys_output_period = acc_fin::energy_output forecast_peak_power system_power_output_peak annual_system_degredation year.i periods_per_year ;
power_revenue_period = sys_output_period.i * ppa_rate * pow( 1 + ppa_escalation , prev_year.i )
\#
i period next_year year sys_output_period power_revenue_period
\#
sum_periods = f::sum \$i_list ;
sum_power_revenue_period = f::sum \$power_revenue_period_list ;