Solar vs Grid Electricity Cost — 2026 Comparison

There is no single “solar versus grid” number. Three calculations answer different questions: simple lifetime cost per kWh, discounted levelized cost of energy (LCOE), and household bill savings. A valid comparison states which one is being used and does not compare an undiscounted solar cost with an escalated grid price as if both were measured on the same basis.

1. Simple lifetime cost per kWh

The simplest planning calculation is:

simple_solar_cost_per_kWh =
  undiscounted_lifetime_solar_costs / undiscounted_lifetime_solar_generation

Include the cash-equivalent installed cost after only verified incentives, plus assumed operating, maintenance and replacement costs. Estimate annual generation, degradation and system life explicitly. This ratio is easy to audit, but it ignores the timing of costs and generation. It should be called simple lifetime cost per kWh, not discounted LCOE.

Loan payments can be totaled for a cash-flow comparison, but financing and system price should remain visible as separate inputs. Otherwise a high dealer fee or long loan term can be hidden inside one per-kWh result.

2. Discounted LCOE

DOE defines LCOE as the present value of lifetime costs divided by the present value of lifetime energy production. A residential solar form of the DOE LCOE formula is:

discounted_LCOE =
  [I0 + Σ(t=1..n) ((It + Mt + Ft) / (1 + r)^t)]
  -------------------------------------------------
          [Σ(t=1..n) (Et / (1 + r)^t)]

Where:

• I0 is the net initial investment at time zero.
• It is any later investment or replacement expenditure in year t.
• Mt is operation and maintenance cost in year t.
• Ft is fuel cost in year t, normally zero for rooftop PV.
• Et is electricity generated in year t after degradation and losses.
• r is the discount rate and n is the analysis life.

Use consistent real or nominal assumptions. If costs include inflation, use a nominal discount rate; if costs are in constant dollars, use a real rate. Discount energy in the denominator as the DOE formulation does. Changing the discount rate can materially change LCOE even when physical production is unchanged.

LCOE measures the cost of generation. It does not tell you what each solar kWh is worth on a household bill.

3. Bill savings and cash benefit

The exact bill calculation is:

bill_savings_t = bill_without_solar_t - bill_with_solar_t

For a simple tariff, an approximate expanded form is:

gross_bill_savings_t =
  (self_consumed_kWh_t × avoided_import_rate_t)
  + (exported_kWh_t × export_credit_t)
  - new_solar_customer_charges_t

net_cash_benefit_t =
  gross_bill_savings_t - solar_O&M_t - financing_payments_t

The avoided import rate is the marginal volumetric charge actually reduced by self-consumption, not necessarily total bill divided by kWh. Exported generation must use the applicable export credit, which may be lower than the import rate and may vary by hour or season. Demand charges, minimum bills, non-bypassable charges and credit-expiry rules require the actual tariff rather than this shortcut.

Fixed charges usually remain

A monthly customer charge that applies before and after solar is not avoided by producing more kWh. It cancels out in bill_without_solar - bill_with_solar, but it still appears on the post-solar bill. Minimum bills and non-bypassable charges can also limit savings. Any new solar-specific fee should be subtracted explicitly.

This is why comparing solar LCOE directly with “my bill divided by usage” can overstate savings. The average bill rate blends fixed and volumetric components, while solar usually offsets only particular volumetric charges and earns a separate export value.

What the national grid average does and does not show

The EIA Electric Power Monthly Table ES1.A reported a preliminary U.S. residential average price of 18.44 cents/kWh for May 2026. EIA calculates the statistic from residential revenue and sales across the country.

That national average is useful context, not a tariff for a particular home. It combines many states, utilities, rate classes and billing structures. It also cannot tell you the marginal import rate, export credit, fixed charge or time-of-use period that controls household solar savings. Use the current utility tariff and a recent bill for the project calculation.

Keep the comparison internally consistent

Question	Solar input	Grid input	Appropriate output
What does generation cost without time value?	Undiscounted lifetime costs and kWh	Comparable undiscounted cost stream if used	Simple cost per kWh
What does generation cost in present-value terms?	Discounted costs and generation	Discounted alternative cost or value	Discounted LCOE
How much can the household save?	Hourly or billing-period production and costs	Actual import, export and fixed-charge tariff	Bill savings and net cash benefit

Do not apply escalation only to grid prices while leaving future solar costs and the discount rate unexplained. Test a zero-escalation case and additional scenarios rather than presenting one forecast as certain. Also keep backup-power value separate: a battery may provide resilience, but that value is not automatically a utility-bill saving.

Apply it to a real proposal

Use the Cost of Solar Panels Calculator to establish the cash-equivalent installed cost, then replace the planning input with a current quote. Use the Solar Panel Output Calculator to estimate generation and degradation scenarios. Finally, apply the serving utility’s import rates, export credits, fixed charges and billing rules.

The short answer is: solar can have a lower cost per generated kWh than the national grid average and still produce weak bill savings for a particular home. Conversely, a project with a higher LCOE may be valuable where self-consumption avoids expensive marginal imports. Cost, value and cash flow are separate calculations.

Sources and methodology

• U.S. Department of Energy levelized cost of energy methodology — present-value cost and generation framework
• EIA Electric Power Monthly Table ES1.A — source and period for the national residential electricity-price context