PUE and Data Center Value: What a 0.2 Gap Costs

Series "The data center through an investor's eyes" · Stranded asset · Article 9 · PUE and value · Retrofit

PUE is often presented as an engineer's metric. For an investor, it is a margin, capacity and value metric. A gap that looks small, 1.4 against 1.2, becomes significant when applied to several megawatts over fifteen years. Here is how to translate it into money.

PUE IN TWO LINES

PUE (Power Usage Effectiveness) divides the site's total energy by the energy used by IT equipment. A PUE of 1.0 would be perfect: all electricity would go to servers. A PUE of 1.5 means that for 1 kWh used by servers, 0.5 kWh goes to cooling, electrical losses and building services.

FIRST EFFECT: THE ENERGY BILL

Take a site with 10 MW of IT load at full load, all year.

Moving from 1.4 to 1.2 saves 2 MW continuously, or about 17.5 GWh a year. With all-in electricity between €70 and €120/MWh, that is €1.2m to €2.1m a year. Over fifteen years at the middle of that range (€100/MWh), about €26m cumulative, or about €15m in present value at 8%. At 70% average load the absolute gap is smaller, but PUE usually worsens at partial load, so a well-designed site keeps its edge.

Who captures the saving depends on the contract. In colocation, energy is often passed through to the tenant, sometimes with a contractual PUE. If actual PUE beats the billed PUE, the operator earns margin. If energy is passed through at cost, the tenant pays the gap and the site becomes less competitive against a more efficient rival.

SECOND EFFECT, OFTEN MISSED: SELLABLE CAPACITY

In France, connected power is a data center's scarcest resource, counted in years of waiting. PUE decides how much of that power can be sold to tenants.

On the same connection, a PUE of 1.2 gives 25% more sellable capacity. For an asset valued on its revenue, this is often the biggest effect, ahead of the energy saving.

THIRD EFFECT: REGULATION AND RATING

Germany already sets PUE thresholds. On 21 September 2026 the European Commission proposed a rating scheme for data centers above 500 kW, with first labels in 2027, and is consulting on minimum performance standards (see the A–G rating). A high PUE is likely to mean a poor rating, more reluctant tenants and harder refinancing. In France, the reduced electricity excise rate for data centers is also subject to environmental conditions.

DUE DILIGENCE PITFALLS

PUE does not tell everything. It measures neither water (WUE), nor reused heat (ERF), nor the carbon content of power. A site can lower its PUE by evaporating more water. That is why an investor should read it alongside other indicators, as covered in Data centers and Article 9. For existing sites, see data center retrofit.

Sources: Arcep annual survey on sustainable digital (2026, 2024 data); Uptime Institute Global Data Center Survey 2025; German EnEfG; European Commission, 21 September 2026. GridReadiness calculations: all-in electricity price assumptions of €70 to €120/MWh, to be adjusted to each contract.

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