# Solar photovoltaics: Correlation

Prices it moves with, and why

Source page: https://www.materialinsights.org/energy/e_pv/correlation/

Solar PV costs are set by module prices, now largely made in China, plus inverters, mounting, land and finance. Module prices follow polysilicon, silver and glass costs and swings in Chinese capacity, while Indian duties shape local prices.
 No public price Solar photovoltaics has no public monthly price series: Module prices are private quotes; no free long monthly series here.

#### What its price moves with

 Chemical [pSi Polysilicon](https://www.materialinsights.org/chemicals/polysilicon/)Main input

Wafers are cut from polysilicon, which is the largest single material cost of a crystalline module. Overbuilding in China caused polysilicon prices to crash, pulling module prices to record lows.
 No public price for polysilicon, so the link is explained in words only.

 Commodity [Ag Silver](https://www.materialinsights.org/commodities/silver/)Main input

Silver paste forms the fingers that collect current on each cell. Solar is now a major silver buyer, and high silver prices push makers to use less silver or switch to copper.
 Not enough overlapping price history to measure.

 Commodity [Al Aluminium](https://www.materialinsights.org/commodities/aluminum/)Frame and mounting

Module frames and many mounting structures are aluminium. Aluminium prices raise the cost of each panel and of the support frames in solar parks. Some makers now test steel frames to cut this cost.
 Not enough overlapping price history to measure.

 Commodity [Cu Copper](https://www.materialinsights.org/commodities/copper/)Wiring cost

Cables, inverters and grid connections in solar parks use copper. Copper prices affect the cost of the system beyond the module. Large solar parks also need long cables to connect to the grid, adding further copper.
 Not enough overlapping price history to measure.

 Commodity [Te Tellurium](https://www.materialinsights.org/commodities/tellurium/)Thin-film input

Cadmium telluride thin-film panels, the main rival to silicon, need tellurium, a by-product of copper refining. Limited tellurium supply caps how far this technology can grow. Its price can spike when demand rises.
 No public price for tellurium, so the link is explained in words only.

 Energy [Gas Natural gas](https://www.materialinsights.org/energy/natural_gas/)Rival source

Gas often sets the power price that solar replaces. Gas price spikes make solar more valuable and speed up buying, especially in Europe and parts of Asia. Cheap gas slows the switch.
 Not enough overlapping price history to measure.

How to read these numbers

**Correlation of monthly changes** (the number in the coloured pill) compares how much each price moved, month by month, since 2006 or the first month both series exist. It runs from −1 to +1: near +1 the two usually rise and fall in the same months, near 0 there is no link, and a negative number means they tend to move in opposite directions. Above 0.7 is strong, 0.4 to 0.7 moderate, 0.2 to 0.4 weak.

**12-month changes** compare year-on-year moves, which shows whether two prices share the same cycles even when the month-to-month noise differs.

**Price function** is a straight-line fit of the two prices on logarithmic scales: price ≈ k × (partner price)^β. β is how much this price moves, in per cent, for a 1% move in the partner over the whole period, and R² is the share of the variation the fit explains. Two prices that both drift up with inflation can fit well without any real link, so read it together with the monthly correlation.

**Lead or lag** checks whether the monthly correlation is clearly higher when one price is shifted by 1 to 6 months.

Correlation is not cause. The reasons on each card explain the economic link; the numbers show how strongly it has shown up in prices. Proxy series are US producer price indexes or related prices and can blur the real link.

Data: World Bank Commodity Price Data (Pink Sheet), October 2026; US Bureau of Labor Statistics producer price indexes, IMF primary commodity prices and US EIA prices via FRED, Federal Reserve Bank of St. Louis, retrieved November 2026. Calculations by this site.

## Other sections

- [Summary](https://www.materialinsights.org/energy/e_pv/index.md)
- [Overview](https://www.materialinsights.org/energy/e_pv/overview/index.md)
- [Efficiency](https://www.materialinsights.org/energy/e_pv/efficiency/index.md)
- [Techniques](https://www.materialinsights.org/energy/e_pv/techniques/index.md)
- [Resources and labour](https://www.materialinsights.org/energy/e_pv/resources/index.md)
- [Impact on the biosphere](https://www.materialinsights.org/energy/e_pv/biosphere/index.md)
- [Relationships](https://www.materialinsights.org/energy/e_pv/links/index.md)