{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"solar-panel-output"},"result":{"entity_type":"calculator","id":"solar-panel-output","calculator_id":"solar-panel-output","canonical_url":"https://tttkmbb.com/engineering/solar-panel-output","name":"Solar Panel Output Calculator","title":"Solar Panel Output Calculator – Daily, Monthly and Yearly kWh from Panel Watts, Peak Sun Hours and Performance Ratio","category":"engineering","category_name":"Engineering & Automotive","tool_name":"estimate_solar_panel_output","featured_mcp_tool":false,"description":"Estimates the energy produced by a photovoltaic array from the panel rating, number of panels, average peak sun hours per day and a performance ratio (default 0.75 for system losses), and optionally the electricity cost saved.","use_when":"You want a first-order estimate of how many kWh a solar array will generate per day, month or year, or its yearly savings at a known tariff.","do_not_use_when":"You need month-by-month production for a specific location, tilt and shading (use NREL PVWatts or a site survey), or battery sizing (use battery-runtime).","inputs":[{"name":"panel_watts","label":"Panel rated power","type":"number","unit":"W","required":true,"max":5000,"exclusive_min":0,"description":"Nameplate STC power of one panel in watts (typical residential panels 350–450 W).","example":400},{"name":"panel_count","label":"Number of panels","type":"integer","required":false,"default":1,"min":1,"max":100000,"description":"Panels in the array.","example":10},{"name":"peak_sun_hours_per_day","label":"Peak sun hours per day","type":"number","unit":"h/day","required":true,"max":12,"exclusive_min":0,"description":"Daily solar irradiation in kWh/m² on the array plane, i.e. equivalent hours of 1000 W/m² sun. Typical annual averages: 3–4 northern Europe/Canada, 4–5 most of the USA, 5–6.5 desert southwest, Australia and southern Spain.","example":4.5},{"name":"performance_ratio","label":"Performance ratio","type":"number","required":false,"default":0.75,"min":0.4,"max":1,"description":"Fraction of nameplate output actually delivered after inverter, wiring, soiling, temperature and mismatch losses; 0.75–0.80 is typical for grid-tied systems.","example":0.75},{"name":"price_per_kwh","label":"Electricity price","type":"number","unit":"per kWh","required":false,"min":0,"description":"Optional tariff in your currency per kWh; enables the savings outputs.","example":0.15}],"outputs":[{"name":"system_size_kw","label":"System size","type":"number","unit":"kWp","decimals":3,"description":"panel_watts × panel_count / 1000."},{"name":"daily_kwh","label":"Daily energy","type":"number","unit":"kWh/day","decimals":2,"description":"system_size_kw × peak_sun_hours_per_day × performance_ratio."},{"name":"monthly_kwh","label":"Monthly energy","type":"number","unit":"kWh/month","decimals":1,"description":"yearly_kwh / 12."},{"name":"yearly_kwh","label":"Yearly energy","type":"number","unit":"kWh/year","decimals":0,"description":"daily_kwh × 365."},{"name":"specific_yield_kwh_per_kwp","label":"Specific yield","type":"number","unit":"kWh/kWp/year","decimals":0,"description":"yearly_kwh / system_size_kw, a location-dependent figure of merit (≈ 800–1,800)."},{"name":"daily_savings","label":"Daily savings","type":"number","decimals":2,"description":"daily_kwh × price_per_kwh (only when price_per_kwh is given)."},{"name":"monthly_savings","label":"Monthly savings","type":"number","decimals":2,"description":"monthly_kwh × price_per_kwh (only when price_per_kwh is given)."},{"name":"yearly_savings","label":"Yearly savings","type":"number","decimals":2,"description":"yearly_kwh × price_per_kwh (only when price_per_kwh is given)."}],"input_schema":{"type":"object","properties":{"panel_watts":{"description":"Nameplate STC power of one panel in watts (typical residential panels 350–450 W). Unit: W.","type":"number","maximum":5000,"exclusiveMinimum":0,"examples":[400],"x-unit":"W"},"panel_count":{"description":"Panels in the array.","type":"integer","minimum":1,"maximum":100000,"default":1,"examples":[10]},"peak_sun_hours_per_day":{"description":"Daily solar irradiation in kWh/m² on the array plane, i.e. equivalent hours of 1000 W/m² sun. Typical annual averages: 3–4 northern Europe/Canada, 4–5 most of the USA, 5–6.5 desert southwest, Australia and southern Spain. Unit: h/day.","type":"number","maximum":12,"exclusiveMinimum":0,"examples":[4.5],"x-unit":"h/day"},"performance_ratio":{"description":"Fraction of nameplate output actually delivered after inverter, wiring, soiling, temperature and mismatch losses; 0.75–0.80 is typical for grid-tied systems.","type":"number","minimum":0.4,"maximum":1,"default":0.75,"examples":[0.75]},"price_per_kwh":{"description":"Optional tariff in your currency per kWh; enables the savings outputs. Unit: per kWh.","type":"number","minimum":0,"examples":[0.15],"x-unit":"per kWh"}},"additionalProperties":false,"required":["panel_watts","peak_sun_hours_per_day"]},"output_schema":{"type":"object","properties":{"system_size_kw":{"description":"panel_watts × panel_count / 1000. Unit: kWp.","type":"number","x-unit":"kWp"},"daily_kwh":{"description":"system_size_kw × peak_sun_hours_per_day × performance_ratio. Unit: kWh/day.","type":"number","x-unit":"kWh/day"},"monthly_kwh":{"description":"yearly_kwh / 12. Unit: kWh/month.","type":"number","x-unit":"kWh/month"},"yearly_kwh":{"description":"daily_kwh × 365. Unit: kWh/year.","type":"number","x-unit":"kWh/year"},"specific_yield_kwh_per_kwp":{"description":"yearly_kwh / system_size_kw, a location-dependent figure of merit (≈ 800–1,800). Unit: kWh/kWp/year.","type":"number","x-unit":"kWh/kWp/year"},"daily_savings":{"description":"daily_kwh × price_per_kwh (only when price_per_kwh is given).","type":"number"},"monthly_savings":{"description":"monthly_kwh × price_per_kwh (only when price_per_kwh is given).","type":"number"},"yearly_savings":{"description":"yearly_kwh × price_per_kwh (only when price_per_kwh is given).","type":"number"}}},"formula":"daily_kwh = panel_watts × panel_count / 1000 × peak_sun_hours_per_day × performance_ratio; yearly_kwh = daily_kwh × 365; monthly_kwh = yearly_kwh / 12; savings = kWh × price_per_kwh","method":"Peak-sun-hour method. The performance ratio bundles all losses; NREL PVWatts defaults to 14 % system losses plus 96 % inverter efficiency and temperature derating, giving about 0.75–0.80 overall. Savings assume all energy offsets consumption at the given tariff (no export rate).","sources":[{"name":"NREL – PVWatts Calculator documentation (system losses, performance)","url":"https://pvwatts.nrel.gov/pvwatts.php","type":"government","retrieved_at":"2026-09-24"},{"name":"U.S. EIA – Solar explained","url":"https://www.eia.gov/energyexplained/solar/","type":"government","retrieved_at":"2026-09-24"},{"name":"Wikipedia – Photovoltaic system – performance","url":"https://en.wikipedia.org/wiki/Photovoltaic_system#Performance","type":"reference","retrieved_at":"2026-09-24"}],"freshness":{"type":"static","max_age_seconds":null,"note":"Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output."},"examples":[{"name":"10 × 400 W, 4.5 sun hours, PR 0.75, 0.15/kWh","inputs":{"panel_watts":400,"panel_count":10,"peak_sun_hours_per_day":4.5,"performance_ratio":0.75,"price_per_kwh":0.15},"expected":{"system_size_kw":4,"daily_kwh":13.5,"monthly_kwh":410.6,"yearly_kwh":4928,"specific_yield_kwh_per_kwp":1232,"daily_savings":2.03,"monthly_savings":61.59,"yearly_savings":739.13},"url":"https://tttkmbb.com/api/v1/calculate/solar-panel-output?panel_watts=400&panel_count=10&peak_sun_hours_per_day=4.5&performance_ratio=0.75&price_per_kwh=0.15"},{"name":"One 300 W panel, 5 sun hours, PR 0.8","inputs":{"panel_watts":300,"peak_sun_hours_per_day":5,"performance_ratio":0.8},"expected":{"system_size_kw":0.3,"daily_kwh":1.2,"yearly_kwh":438},"url":"https://tttkmbb.com/api/v1/calculate/solar-panel-output?panel_watts=300&peak_sun_hours_per_day=5&performance_ratio=0.8"}],"faq":[{"q":"What are peak sun hours?","a":"The daily irradiation in kWh/m² expressed as hours of full 1 kW/m² sun. A site with 5 kWh/m²/day has 5 peak sun hours even though the sun shines for 12; use annual-average values from NREL or PVGIS maps."},{"q":"Why not use the nameplate wattage directly?","a":"Panels rarely operate at the 25 °C, 1000 W/m² test conditions. Heat, dirt, wiring, inverter conversion and mismatch typically cut output by 20–25 %, which the performance ratio accounts for."}],"tags":["solar panel output","solar kwh calculator","peak sun hours","pv system production","solar savings"],"related":[{"calculator_id":"electricity-cost","reason":"Compare the array's output with your appliance consumption."},{"calculator_id":"battery-runtime","reason":"How long a battery bank charged by the array lasts."},{"calculator_id":"battery-charge-time","reason":"Charging time of a battery from the daily solar energy."}],"links":{"html":"https://tttkmbb.com/engineering/solar-panel-output","markdown":"https://tttkmbb.com/engineering/solar-panel-output.md","json":"https://tttkmbb.com/engineering/solar-panel-output.json","api":"https://tttkmbb.com/api/v1/calculate/solar-panel-output","schema":"https://tttkmbb.com/api/v1/calculators/solar-panel-output","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T01:57:59Z"}