Compressed-air and CO2 storage: Correlation
Prices it moves with, and why
Compressed-air storage pumps air into salt caverns or tanks using spare power and releases it through turbines. Costs are mostly compressors, expanders, caverns and heat stores, and earnings depend on power price spreads.
Proxy US PPI: air and gas compressors index · monthly, Jan 2006 to Sep 2026There is no free public price for Compressed-air and CO2 storage itself, so this tab uses the closest public series as a stand-in. Read the numbers as an indication, not as the price of this exact item.
What its price moves with
Selected linkCompressed-air and CO2 storage and Mechanical power transmission
Monthly changes 0.41 moderate correlation 12-month changes 0.91 strong correlation Last 5 years 0.29 monthly changes Lead or lag none No clear lead or lag Price function, Jan 2006 to Sep 2026 Compressed-air and CO2 storage ≈ 0.164 × (Mechanical power transmission)1.30 R² 0.99 On this fit, a 10% higher mechanical power transmission price goes with a 13.2% higher Compressed-air and CO2 storage price over the long run. Units: index and index.Chart: Compressed-air and CO2 storage and Mechanical power transmission prices rebased to 100 at Jan 2006, log scale
Both prices rebased to 100 at Jan 2006, on a log scale so equal percentage moves look the same size.Chart: Compressed-air and CO2 storage price against Mechanical power transmission price, monthly, log scales, with fitted line
Each dot is one month; paler dots are older (2006), darker dots recent (2026); the ringed dot is the latest month. The dashed line is the fitted price function. Both axes are logarithmic.Compressors and gearboxes are made by similar machinery firms and follow the same industrial cycle. The two indices correlate at 0.41 for monthly moves and 0.91 for yearly moves, a common driver rather than a direct input.
moderate co-movement month to month · 249 months Show chartsLarge electric motors drive the compressors. The motors index correlates with the compressor proxy at 0.38 for monthly moves and 0.89 for yearly moves, as both reflect metal and machinery costs.
weak co-movement month to month · 249 months Show chartsOlder plants burn gas in a turbine to expand the stored air, and newer designs use dedicated expanders. The turbine index shows little link to the compressor proxy, with monthly moves at 0.12 and yearly moves at 0.18.
little or none co-movement month to month · 234 months Show chartsConventional compressed-air plants burn natural gas when generating, so higher gas prices raise running costs. The European gas price is unrelated to the compressor proxy, with monthly moves at 0.06, since the proxy measures equipment.
little or none co-movement month to month · 249 months Show chartsThe cheapest storage uses caverns dissolved out of underground salt layers by solution mining, which also produces brine. The salt index shows little relation to the compressor proxy, with monthly moves at 0.07.
little or none co-movement month to month · 162 months Show chartsSome newer designs store carbon dioxide as a liquid in tanks instead of air in caverns, so they can be built almost anywhere. The carbon dioxide index correlates at 0.35 for yearly moves with the compressor proxy.
little or none co-movement month to month · 248 months Show chartsHow 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.