Solar Payback in BC
Solar payback in BC: how to calculate your real payback period
Payback isn't one number you look up, it's a short chain of multiplications, and BC's cheap hydro plus the 2026 net-metering change bends every link of it. Here's the exact formula, step by step, with honest BC numbers so you can ballpark your own.
The payback formula at a glance
- 1. Production = size (kW) × regional yield (kWh/kW/yr) × orientation derate.
- 2. Split production into self-consumed (~40% without a battery) vs exported.
- 3. Value it: self-consumed at retail (~13.1¢), exported at the new ~10¢ rate.
- 4. Net cost = installed cost − rebates.
- 5. Payback = net cost ÷ annual bill offset.
Step 1, Production: how many kWh your roof makes
Start with how much energy the array actually generates in a year:
Production = system size (kW) × regional yield (kWh per kW per year) × orientation derate.
BC yields vary by region (NRCan, south-facing at latitude tilt): the coast ~1,000 kWh/kW (Vancouver 1,007), the Southern Interior ~1,130 kWh/kW (Kelowna 1,132), and the north ~1,050 kWh/kW (Prince George 1,056). Orientation matters too, relative to a clean south-facing roof: south = 1.00, SE/SW ≈ 0.95, E/W ≈ 0.83, flat ≈ 0.90.
Example: a 6 kW system, on the coast, facing south: 6 × 1,000 × 1.00 = 6,000 kWh/yr.
Step 2, Split it: self-consumed vs exported
This is the step most online calculators skip, and it's the one that matters most in BC. Solar generates midday; most homes use power in the evening. Without a battery, only about 40% of production is typically consumed on-site, the rest is exported to the grid.
Example: of 6,000 kWh, roughly 2,400 kWh is self-consumed and 3,600 kWh is exported.
Step 3, Value each part
The two halves are worth different amounts, and that gap is the whole story:
- Self-consumed energy avoids buying power, so it's worth the full retail rate, about 13.1¢/kWh.
- Exported surplus, under the new BC Hydro RS 2289 rate (from July 1, 2026), earns only about 10¢/kWh, below retail.
Example: 2,400 × $0.131 + 3,600 × $0.10 ≈ $674/yr bill offset. Under the old 1:1 RS 1289 rate, every exported kWh was worth full retail, so the same system would have offset about $786/yr. That difference is exactly why the 2026 net-metering change lengthens payback, and why self-consumption is now the biggest lever you control.
Step 4, Net cost: installed price minus rebates
Net cost = installed cost − rebates. As a rough BC ballpark, installed solar runs about $2.50–$3.00 per watt, so a 6 kW system is roughly $15,000–$18,000. Against that, BC Hydro rebates can take a meaningful bite: up to $5,000 for solar and up to $5,000 for a battery, landing many homes around $11,000–$14,000 net. Your stack depends on eligibility; see BC solar rebates 2026 for the catches.
Step 5, Payback: net cost ÷ annual offset
Now divide:
Payback (years) = net cost ÷ annual bill offset.
Example: ~$12,000 ÷ ~$674 ≈ ~18 years (illustrative). That's the simple version, and it deliberately ignores two real effects that pull in opposite directions:
- Rate inflation, BC Hydro rates rise over time, so each offset kWh is worth more in future years. This shortens payback.
- Panel degradation, panels lose roughly 0.5%/yr of output, so production slowly drops. This lengthens payback.
For a quick ballpark these roughly offset; for a real decision you model both year by year, which is what the kit does.
The honest verdict
Because BC hydro is so cheap, payback here is often 10–15+ years, longer than the sunny-state numbers solar marketing quotes. A battery usually lengthens pure payback rather than shortening it, unless you're capturing Peak Saver value on top. And under RS 2289, self-consumption is the single biggest lever: the more of your own solar you use instead of exporting at 10¢, the faster the whole thing pays back. None of this means "don't", it means run the real numbers before you sign. Is solar worth it in BC? walks through when the answer is yes.