Methodology

The conservative posture

Every assumption on this site skews toward under-stating the benefit of plug-in solar. The vertical panel angle, the self-consumption rate, the shading derate, the product prices we cite — each is chosen so a Canadian who actually installs a system should see better results than our numbers claim.

This is deliberate. A campaign that over-promises and under-delivers hands opponents a permanent talking point. A campaign that under-promises and over-delivers wins trust. We publish the floor, not the ceiling.

Solar production

Monthly kWh output is computed using NREL PVWatts v8 with the National Solar Radiation Database (NSRDB) satellite dataset. NSRDB coverage is comprehensive across Canada to about 60°N, usable and modeled to ~70°N (Yellowknife, Iqaluit, Whitehorse all fall in this zone), and sparser beyond (we do not make community-specific claims above 70°N).

Balcony-specific tuning

Why vertical panels outperform roofs in Canadian winter

In Alberta and the Prairie provinces, 90° vertical south-facing panels produce more in winter than summer because the sun is lower — Calgary 1200W panels generate ~448 kWh December through March vs ~360 kWh May through August. This is the opposite of roof-mounted systems. It is a genuine and unusual outcome of vertical mounting at high latitude, and it makes balcony solar particularly well-suited to Canadian winter reliability.

Reference systems

Rather than run PVWatts per individual product, we compute production for five reference configurations and link each product listing to its closest match. This keeps the math tractable, cached, and comparable across listings.

Electricity rates

Canadian residential electricity bills have multiple components. The variable portions — energy charge, variable transmission & distribution, variable riders like carbon levy — scale with usage, so solar offsets them fully. The fixed portions (monthly connection fees, admin charges) stay the same regardless of consumption and are not displaced.

We use the full variable displaced rate (energy + T&D + variable riders) for payback math, not just the energy line. In Alberta the energy line is typically less than half the bill; using energy alone would understate savings by ~50%.

Product prices

Product listings are sourced from EU manufacturer and retailer pages (Amazon PA-API and Shopify public endpoints will expand this pool shortly). Each listing is a real product with a cited URL.

VAT and FX methodology

German retail prices include 19% VAT. Canadian residential electricity bills show pre-tax variable charges (GST is added on top). For an apples-to-apples comparison:

1. We strip 19% VAT from each German listing to get the pre-VAT wholesale equivalent.
2. We convert using the Bank of Canada EUR/CAD spot rate (currently ~1.62).
3. The resulting CAD pre-tax figure is directly comparable to Canadian electricity rates.

Every CAD-equivalent figure on this site — on the prohibition exhibit, in each province’s payback block, in aggregates — uses this same pre-GST methodology. The figure answers the question “what would this kit cost in Canadian dollars if sold in Canada before sales tax?” and is comparable to Canadian retail pre-tax pricing. The inc-VAT source price (what German consumers actually pay today) is shown alongside on every card for transparency.

Wrinkle, because the topic is messy: a Canadian who imports one of these kits today typically pays the German VAT anyway (the retailer collects it at the checkout regardless of the buyer’s country), plus Canadian import GST on arrival. The pre-GST CAD number we display is the hypothetical Canadian-market price — what a Canadian retailer would charge if the EU supply chain’s scale economics reached a legalized Canadian market. That is the price Canadians could pay if plug-in solar were legal here; the current grey-imports-plus-duties figure is always higher.

Current listings

53 listings shown (verified). 65 additional listings ingested from Shopify feeds are held in a review queue until a human confirms category, wattage, and price. Only verified listings back the aggregates above.

Payback math

Simple payback only. No NPV, no IRR, no time-value-of-money. Adding those invites method arguments; simple payback is unimpeachable.

Math: monthly_savings = production_kWh × (1 − shading_derate) × self_consumption_rate × variable_displaced_¢_per_kWh. Cumulative savings per month with annual degradation applied. Payback month is the first month cumulative savings meet or exceed the product cost in CAD.

Data freshness

• Solar production (PVWatts): cached per region × reference system × orientation. Re-run on NSRDB version change (annual) or methodology change. Current dataset: NSRDB (as of 2026-04-16).
• Electricity rates: append-only records with effective_from / effective_to. New rate orders create new records; old records preserved for audit. Target refresh: quarterly audit + on notification of utility rate changes.
• Product prices: Currently manual — first 6 listings researched 2026-04-16. Planned automated refresh via Amazon PA-API and Shopify ingesters.
• FX rates: Approximate spot rate (€/CAD = 1.62) for MVP. Planned: Bank of Canada monthly average pulled per calendar month, versioned.

External sources cited

• NREL PVWatts v8 API documentation
• National Solar Radiation Database (NSRDB)
• Bank of Canada exchange rates
• Utilities Consumer Advocate — Alberta default rates
• EPCOR Edmonton Rate of Last Resort
• ENMAX Calgary Rate of Last Resort
• Rocky Mountain Solar — Alberta rate analysis
• Alberta Utilities Commission
• ENMAX distribution tariff schedules