حاسبة تصميم وتسعير النظام الشمسي

P50, P75 and P90 are exceedance-probability energy estimates accounting for interannual weather variability. P50 is the median year (50% chance of exceeding), P90 is exceeded in 90% of years and is the conservative 'bankable' value lenders require. With a typical interannual CV of 4-6%, P90 is roughly 7-10% below P50. The calculator reports all three plus LCOE.

LCOE divides lifetime discounted costs (capex, O&M, WACC financing, inverter replacement, module degradation) by lifetime discounted energy. The calculator uses a full-cost model: 25-year life, 0.5%/yr module degradation, WACC around 6-8%, and O&M about 1-1.5% of capex yearly. A 200 kW C&I system in a 4.5 sun-hour site typically lands near $0.04-0.06/kWh.

For a fixed-tilt array, annual yield is near-optimal when tilt equals the site latitude, typically latitude minus 5-15 degrees in low latitudes to favour summer load, or latitude plus 10-15 degrees for winter-heavy or off-grid loads. At 30 deg latitude the optimum is roughly 25-35 degrees. The calculator's yield model accounts for tilt, azimuth and local irradiation.

Annual energy is roughly system kW x peak-sun-hours x performance ratio. A 100 kW array in a 4.5 sun-hour region with a PR of 0.78-0.82 yields about 100 x 4.5 x 365 x 0.80 = 131,000 kWh/yr. In sunnier regions (5.5-6 sun-hours) the same plant reaches 160,000-175,000 kWh/yr. The calculator computes P50/P75/P90 from these inputs.

Battery capacity = daily night-time load kWh divided by depth of discharge, times autonomy days. For a 40 kWh nightly load with lithium at 80% DoD and one-day autonomy you need about 50 kWh. Add 15-20% for round-trip losses (AC-coupled ~85-90% efficiency). The configurator sizes the bank, matching PCS and cell chemistry automatically.

Grid-tie is 30-50% cheaper because it omits batteries and the backup inverter. A 10 kW grid-tie system runs roughly $8,000-12,000 FOB, while an equivalent off-grid system with 20-30 kWh storage and a hybrid inverter costs $18,000-28,000. Off-grid makes sense only where grid connection is absent or very expensive; the calculator prices both scenarios.