Break-even

Long-term ROI vs the no-solar scenario.

Payback progress

18.4%Recovered

Time elapsed

2.8 Years

Status

On Track

Initial CAPEX

$60050.60

3 entries in the system-costs ledger

Yield to Date

$11027.77

Through Jun 19, 2026 · realized $11072.68 + banked $-44.91

+$66.23 est. since Jun 20 (7d in progress) · 0 kWh in NEM bank @ $0.13/kWh

Outstanding

$49022.83

81.6% remaining until ROI realized

Maturity Date

SEP 2038

Approx. 12.3 years remaining at current burn rate

Cumulative savings projection

Compounds today's $334/mo burn at 3.0%/yr Duke escalation and −0.50%/yr panel degradation. Break-even point marked.

Net profit (15Y)

$22807.49

Avg. annual yield

8.0%

Utility offset (life-to-date)

96%

Environmental impact

Derived from 72,200 kWh of solar production over the solar era. EPA equivalency factors.

845

Trees planted equivalent

51.2 t

CO₂ emissions averted

29.5 t

Coal burned avoided

217k

Clean EV miles powered

Cost breakdown by category

install$49550.60 · 82.5%

powerwall$10500.00 · 17.5%

Methodology & caveats

Total invested sums every row in the system-costs ledger
Yield to date sums per-month value, decomposed into realized (est_without_solar − bill_amount) and banked ((nem_end − nem_start) × rate). Sunny months with surplus production show high banked value; inverter-outage months show negative banked value as the stack drew down. The two sum to total per-month savings. Through Jun 19, 2026 only — a month becomes part of this total when Duke's PDF is parsed and nem_end is on file.
In-progress estimate (the “+$X est.” line under Yield to Date) fills the gap between the last parsed bill and today by valuing daily Powerwall data at the latest known rate: (home − import) × rate for realized, export × rate for banked. Customer charge is not prorated. Reconciles to the real number when the next bill lands; off by ±5% if the next bill's rate has drifted.
Maturity date linearly extrapolates outstanding debt at the current $334/mo burn rate. This is optimistic in the early years (production accelerates as seasonal coverage matures) and pessimistic in the late years (no Duke-rate-growth tailwind modeled).
Cumulative-savings projection compounds today's $334/mo burn rate by (1 + 3.0%)(1 − 0.50%) per year — Duke retail-rate escalation tailwind minus panel-output degradation. Doesn't account for the federal tax credit already taken or year-end NEM true-up payments. Bumping rate growth higher (Duke is currently asking for >5% in their pending rate case) accelerates break-even by ~1.5 years; stiffer degradation pushes it out by similar.
Default Duke rate when nothing better is available: $0.13/kWh, with a $15.73/month minimum bill floor.

Methodology & caveats

Total invested sums every row in the system-costs ledger

Yield to date sums per-month value, decomposed into realized (est_without_solar − bill_amount) and banked ((nem_end − nem_start) × rate). Sunny months with surplus production show high banked value; inverter-outage months show negative banked value as the stack drew down. The two sum to total per-month savings. Through Jun 19, 2026 only — a month becomes part of this total when Duke's PDF is parsed and nem_end is on file.

In-progress estimate (the “+$X est.” line under Yield to Date) fills the gap between the last parsed bill and today by valuing daily Powerwall data at the latest known rate: (home − import) × rate for realized, export × rate for banked. Customer charge is not prorated. Reconciles to the real number when the next bill lands; off by ±5% if the next bill's rate has drifted.

Maturity date linearly extrapolates outstanding debt at the current $334/mo burn rate. This is optimistic in the early years (production accelerates as seasonal coverage matures) and pessimistic in the late years (no Duke-rate-growth tailwind modeled).

Cumulative-savings projection compounds today's $334/mo burn rate by (1 + 3.0%)(1 − 0.50%) per year — Duke retail-rate escalation tailwind minus panel-output degradation. Doesn't account for the federal tax credit already taken or year-end NEM true-up payments. Bumping rate growth higher (Duke is currently asking for >5% in their pending rate case) accelerates break-even by ~1.5 years; stiffer degradation pushes it out by similar.

Default Duke rate when nothing better is available: $0.13/kWh, with a $15.73/month minimum bill floor.