analysis
| . - 1 Comment
"How much you earn is based on the average kW your battery contributes per event. A typical home battery could contribute an average of 5 kW per event. This would earn $1,375 per year." Here is a first take analysis of what that might mean.
Are the assumptions below reasonable for how you arrived at the $1,375/yr credit amount? This analysis takes into account that, for each year, the cost to the property owner is:
$$yearlyCost = amortizedCostOfBatterySystem + electricityExported$$
```python
# KWH exported
discharge = 5 # kwh
hrs_per_event = 3
events_yr = 60
credits_kwh = 275 # $/kw
credits_yr = credits_kwh * discharge
exported_KWH_yr = discharge * hrs_per_event * events_yr # not aavailable for consumption
print(f"At a discharge of {discharge} kw, {hrs_per_event} hrs per event, {events_yr} events per year,")
print(f"exported_KWH_yr = {exported_KWH_yr} kwh")
cost_kwh = .34 # per kwh
exported_value = exported_KWH_yr * cost_kwh
print(f"exported_value = ${exported_value:,.0f}")
# Capital costs Tesla Power Wall
battery_size = 13.5 # kwh
battery_cost = 11500 # $
installation_cost = 2000 # $
useful_life = 10 # years
system_cost = battery_cost + installation_cost
tax_credit = .30
sys_cost_w_credit = system_cost * (1 - tax_credit)
print(f"A 13.5 kwh system_cost w {tax_credit:.0%} tax credit = ${sys_cost_w_credit:,.0f}")
amortized_cost_yr = sys_cost_w_credit / useful_life
print(f"amortized_cost_yr = ${amortized_cost_yr:,.0f}")
costs_yr = exported_value + amortized_cost_yr
print(f"credits_yr = ${credits_yr:,.0f}")
print(f"amortized costs + energy exported = ${costs_yr:,.0f}")
roi_yr = credits_yr - costs_yr
print(f"retun on invetment / yr = ${roi_yr:.0f}")
```
At a discharge of 5 kwh, 3 hrs per event, 60 events per year,
exported_KWH_yr = 900 kwh
exported_value = $306
A 13.5 kwh system_cost w 30% tax credit = $9,450
amortized_cost_yr = $945
credits_yr = $1,375
amortized costs + energy exported = $1,251
retun on invetment / yr = $124
