What is the best tilt for a solar panel at my home?

AA SLAI SLAA HLAI HL Solid Also in: Calculus, Geometry & Voronoi

Research question

How does the annual energy from a solar panel at my location depend on its tilt angle, and how much extra energy would adjusting the tilt each season provide?

Adapt it: change the place, the data or the comparison until the question is yours.

Why it makes a good exploration

The common rule “tilt equals latitude” is only approximate. Modelling output against tilt, and checking with PVWatts, gives an answer for your own roof.

The mathematics you'll need

Trigonometric model of sunlight on a tilted surface
Summing or integrating over the year
Maximising a function of tilt
Comparing with simulated output data

Course labels show where a technique sits; using maths from outside your course is fine if you explain it clearly and say it is new to you.

Where the data comes from

Run PVWatts for your location at a range of tilts; use sun-elevation data for your own model.

PVWatts Calculator — Estimated monthly solar-panel output for any location, tilt and orientation.
timeanddate.com sun calculator — Sunrise, sunset and day length for any city and date.

Cite every source in a footnote where you use it and in your bibliography. Check the licence of any dataset you download.

A possible outline

Explain why tilt matters.
Build a simple model from sun elevation.
Find the optimal fixed tilt.
Compare with PVWatts results.
Model seasonal adjustment and reflect on clouds and diffuse light.

Pitfalls that cost marks

Ignoring diffuse light and weather.
Mixing degrees and radians.
Treating PVWatts output as measured data.

Showing personal engagement

Use your own home's location and roof angle.
Estimate the money saved.
Compare with a friend in another country.

See Criterion C: personal engagement for what examiners look for.

Taking it further

Compare the optimum for maximising annual output with the optimum for maximising winter output.

Turn this idea into your IA

Plan this IAOpens the planner with this question, the maths and data sources filled in. Desmos workspacePlot your data, fit models and keep your graphs with your plan. AI feedback on a draftCriterion-by-criterion feedback with evidence from your own text. Coaching, not rewriting. Examiner reviewPete, a practising IA examiner, reads your draft and talks it through with you (€100).