Flow batteries: Correlation
Prices it moves with, and why
Flow batteries store energy in liquid electrolytes held in tanks, so energy and power can be sized separately. Vanadium electrolyte is often the largest cost, while zinc-bromine, iron and organic designs aim to avoid it.
Proxy US PPI: storage batteries excl. lead-acid index · monthly, Jan 2006 to Sep 2026There is no free public price for flow batteries 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 linkFlow batteries and Sulphuric acid
Monthly changes -0.01 little or none correlation 12-month changes 0.39 weak correlation Last 5 years -0.12 monthly changes Lead or lag −1 mo Flow batteries tends to lead by 1 month (r 0.12) Price function, Jan 2006 to Sep 2026 Flow batteries ≈ 44.6 × (Sulphuric acid)0.30 R² 0.17 On this fit, a 10% higher sulphuric acid price goes with a 2.9% higher flow batteries price over the long run. Units: index and index (BLS base period). The fit is loose, so treat the function as a rough guide.Chart: Flow batteries and Sulphuric acid 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: Flow batteries price against Sulphuric acid 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.Vanadium redox batteries use vanadium dissolved in acid on both sides. Vanadium comes mostly as a by-product of steelmaking slag, so its price swings with Chinese steel output, and some suppliers lease the electrolyte to cut upfront cost.
Not enough overlapping price history to measure.Vanadium is dissolved in sulphuric acid to make the electrolyte. Acid is cheap, so it adds little cost, and the acid index shows no link to the battery proxy, with monthly moves at -0.01.
little or none co-movement month to month · 220 months Show chartsZinc-bromine and zinc-iron flow batteries plate zinc during charging. The battery proxy is a broad US index dominated by lithium products, so it shows no link to zinc, with monthly moves at -0.03.
little or none co-movement month to month · 243 months Show chartsZinc-bromine batteries use bromine compounds as the positive electrolyte. Bromine comes from brines, chiefly in Israel and Jordan, the US and China, so supply is concentrated in a few places.
Not enough overlapping price history to measure.All-iron flow batteries use cheap iron salts as the active material, aiming for very low cost per stored hour. The iron ore price shows no useful link to the battery proxy, with monthly moves at -0.16.
little or none co-movement month to month · 243 months Show chartsLFP batteries have become so cheap that they win most grid storage tenders, even for longer durations. Flow batteries must win on lifetime and safety. Both use the same battery index on the site, so no statistics are shown.
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.