The carbon footprint of data storage, explained

Data does not sit still: it consumes energy

It is tempting to think of stored data as inert: written once, then quietly waiting until someone needs it. Physically, that is not what happens. A file at rest still lives on powered hardware inside a datacenter, and that hardware draws electricity every second of every day. The data storage carbon footprint is the sum of all that continuous, background energy use, and it is far larger than most organizations realize.

The energy behind a stored gigabyte comes from several layers, all running at once:

• Power to the media. Disks spin and solid-state arrays stay energized so data can be read on demand. Even "cold" storage must be kept online and periodically checked.
• Cooling. Every watt a server draws becomes heat that has to be removed. Cooling can rival the compute and storage hardware itself for energy consumption.
• Replication. For durability, cloud and enterprise storage keep multiple copies of your data, often across separate sites. One logical gigabyte can be three or more physical gigabytes, each independently powered and cooled.
• Backups. On top of live replicas, snapshot and backup regimes create yet more copies that also consume energy and, in turn, their own cooling.

So a single file you never open again is not one idle gigabyte. It is several powered copies, plus the cooling around them, running indefinitely.

The numbers behind datacenter emissions

Zoom out from a single file to the global picture and the scale becomes clear. Datacenters are estimated to account for roughly 2.5% of global emissions (Nature Climate), putting the digital storage and compute industry in the same broad conversation as sectors we already treat as major emitters.

On the electricity side, the International Energy Agency reports that global datacenter electricity use runs at approximately 205 TWh per year (IEA, Electricity 2024). That is a national-grid-scale amount of power devoted to keeping the world's data available, and demand is trending upward, not down, as data volumes grow.

The uncomfortable implication is that the emissions attached to storage are not a rounding error. They are a real, measurable share of the global total, and every organization that stores data owns a slice of it.

Dark data is wasted emissions

Here is where it stops being an abstract industry statistic and becomes a problem you can act on. Not all stored data earns its energy. The Veritas Databerg report found that around 52% of enterprise data is "dark": retained but never used, of unknown or no value.

Combine that with everything above and the conclusion is stark: if roughly half of stored data is dark, then a large share of storage's power draw, cooling, replication and backup energy (and therefore its carbon) is being spent on data that delivers nothing. This is wasted emissions in the most literal sense. You are heating a datacenter to preserve duplicates, obsolete project files, and content from systems that were decommissioned years ago.

Unlike many sustainability challenges, this one has no downside to fixing. Reducing dark data does not cost you a capability or a service level. It removes a liability that was quietly costing you both money and carbon.

Why "just add renewables" is not the whole answer

Powering datacenters with clean energy matters, but it does not make wasted storage acceptable. Renewable capacity is finite and in demand across the whole economy; every megawatt-hour spent keeping useless data alive is one not available to decarbonize something essential. The most sustainable gigabyte is the one you never had to power in the first place. Deletion is the efficiency measure that comes before, and complements, cleaner energy.

Deleting ROT cuts both cost and CO₂

The practical lever is removing ROT data: redundant, obsolete and trivial files. Because storage cost and storage carbon share the same root cause (powered bytes), cutting ROT reduces both at the same time. Delete a terabyte of duplicates and you stop paying for it and stop emitting for it, along with all the replicas, backups and cooling it dragged along.

That shared root cause is why the smartest way to measure a cleanup is in two units at once: euros and CO2. A euro figure gets the project funded; a carbon figure lets it count toward sustainability and reporting goals such as the CSRD. The same action satisfies finance and ESG, which is rare and worth designing for.

The hard part, again, is finding the ROT across a real, multi-platform estate, and doing it safely, without deleting something that turns out to matter. That is the specific problem TerraBytes exists to solve.

How TerraBytes measures and reduces data carbon

TerraBytes is a storage cleaner and optimizer designed around this cost-and-carbon reality. It is serverless and private by design: your data never leaves your environment, and everything is encrypted. One scan spans SharePoint, OneDrive, NetApp, NAS and local drives, flagging duplicate, outdated, oversized and risky files, and it shows the impact of each in both euros and CO2, so the biggest emissions savings are also the biggest budget savings.

Nothing is deleted automatically. TerraBytes flags and recommends; you decide what to keep, archive or remove. The result is a documented, defensible reduction in stored data that you can report to both finance and sustainability teams.

If carbon accountability is driving this, start with the regulatory angle in CSRD and data carbon, then see the measured numbers in the TerraBytes impact report.