Grid Parity Calculator Formula

Understand the math behind the grid parity calculator. Each variable explained with a worked example.

Formulas Used

Savings per kWh

savings_per_kwh = grid_price - renewable_lcoe

Annual Savings

annual_savings = (grid_price - renewable_lcoe) * annual_usage_kwh

Parity Ratio (Grid / LCOE)

parity_ratio = grid_price / renewable_lcoe

Variables

VariableDescriptionDefault
renewable_lcoeRenewable LCOE(USD/kWh)0.1
grid_priceGrid Electricity Price(USD/kWh)0.15
annual_usage_kwhAnnual Electricity Usage(kWh)10000

How It Works

What Is Grid Parity?

Grid parity occurs when the cost of renewable energy equals or falls below the retail price of grid electricity. Beyond grid parity, renewables save money compared to buying from the utility.

Formula

Savings per kWh = Grid Price - Renewable LCOE

Annual Savings = Savings per kWh x Annual Usage

If the savings per kWh is positive, the renewable source has achieved grid parity. The parity ratio shows how much cheaper (or more expensive) the renewable source is relative to grid power.

Worked Example

Solar LCOE of $0.10/kWh vs grid price of $0.15/kWh for a home using 10,000 kWh/year.

renewable_lcoe = 0.1grid_price = 0.15annual_usage_kwh = 10000
  1. 01Savings per kWh = $0.15 - $0.10 = $0.05
  2. 02Annual savings = $0.05 x 10,000 = $500/year
  3. 03Parity ratio = 0.15 / 0.10 = 1.50 (grid is 50% more expensive)

Ready to run the numbers?

Open Grid Parity Calculator