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Electricity and CO₂

What does a website cost in electricity, per year?

A WordPress site has a server standing ready day and night, even when nobody is looking. A site at Spaicely is a folder of files that only costs something when someone opens it. We worked out how big that difference is, from public figures and with every assumption shown.

Work it out yourself How we calculated

One business site, for a year

Electricity for the hosting at 3,000 visits a month

WordPress

9.1 kWh

A share of a shared server that is always on, plus sending the pages.

Spaicely

0.15 kWh

The files in storage, plus sending exactly the same pages.

Two meters, one year

000000000000

Move across to go through the year

Left: WordPress on a shared serverRight: the same site on SpaicelyThe mark on the disc A year in forty seconds. The two meters are identical: one turn of the disc is the same amount of electricity on both. After a year the left one reads 9.1 kWh and the right one 0.15 kWh, so the left disc turns 63 times as fast. The register counts hundredths of a kWh; the last two digits are after the decimal point.

What runs

A WordPress site is software that is always on.

For one WordPress site a web server and a database run day and night, and PHP stands ready to build a page at any moment. At 3,000 visits a month, 99% of the electricity for the hosting goes into that standing ready. For a site at Spaicely nothing runs: only the files are waiting.

Why Spaicely hosts only static sites, with measurements

PHP
Every visit that does not come from a cache has PHP build the page: load WordPress, the theme and every plugin, and put it all together. Whether PHP keeps running between two visits differs per host; that is explained below.
Database
Next to PHP runs MySQL or MariaDB, with part of the memory as a buffer. For one page WordPress asks that database dozens of questions: the page, the menu, the settings, the widgets.

No PHP.No database.No server waiting for your site.

A site at Spaicely is already built the moment you publish it. Nothing has to stand ready to make it, so nothing runs.

Both sites draw their power from the same grid, fed by wind turbines and by power stations with chimneys alike. That is why this page uses the same CO₂e per kWh for both, without green certificates.

Standing ready, up close

Three in the morning. Nobody is visiting your site.

Layer by layer: what is switched on for a WordPress site, and what there is for a site at Spaicely.

Server

WordPress running

A server that is always on

Processor, memory, disks, fans and a web server (Apache, nginx or LiteSpeed) are on, because your site has to be able to answer at any moment. With no work a server still draws about a fifth of its maximum: 70 W against 373 W at full load, in the SPECpower measurements.

Spaicely shared

Our servers

These are on too, but they deliver the files of thousands of sites at once. We count their power per gigabyte sent, and exactly the same for WordPress.

PHP

WordPress standing ready

PHP, ready to build

Whether PHP processes keep running between two visits depends on how the host has set PHP up. More on that below.

Spaicely none

No PHP

When someone comes, nothing gets built. The page is already finished.

Database

WordPress running

MySQL or MariaDB

MySQL or MariaDB always runs, even when no site on the server has a visitor. It keeps the tables of all sites in memory as far as it can, so a visit does not have to wait for the disk.

Spaicely none

No database

Menu, texts and settings are already in the files. There is nothing to ask questions of.

Your site

WordPress running

WordPress, theme and plugins

Hundreds of PHP files that put a page together from the database again on every visit.

Spaicely stored

Your pages, already built

HTML, CSS and images in 3 copies on SSD storage. An SSD that reads nothing draws almost no power; we count 1.2 W per TB.

Does PHP keep running? That depends on the host.

A host can run PHP in three ways. They differ in what is on between two visits and in what one visit costs.

Always on

Web serveralready runningstays on
PHPwaiting, with WordPress in memorystays on
Databasealready running, for every sitestays on

On demand

Web serveralready runningstays on
PHPstarts if it is off, and loads WordPressstops after a quiet spell
Databasealready running, for every sitestays on

Per visit (CGI)

Web serveralready runningstays on
PHPa new process reads and compiles every filestops at once
Databasealready running, for every sitestays on

Spaicely

Web serverclose to the visitor; sends the file as it isshared by all sites

No PHP, no database: the page is already made.

One visit, four ways. With WordPress every visit goes through the web server to PHP, which builds the page with dozens of queries to the database; only PHP differs between hosts. At Spaicely the visit ends at the first server.

PHP, three ways

Click the server for an extra visit, or the knob for the next mode.Lamp on: this is running Always on keeps five processes ready, even when nobody comes; five is the PHP-FPM default. On demand starts a process for a visit and lets it wait ten seconds afterwards, also a default. Per visit starts a new process for every visit, which stops straight away. The database runs in all three modes. The visits are an example, and each visit is slowed down so you can see it.

Each strip is a day and a night with five visits (▲). A bar means: this process is running.

  • Always on

    A fixed group of PHP processes stands ready, with WordPress already compiled in memory (OPcache). A visit is fast, but the memory stays taken day and night, even if nobody comes for a week.

    mod_php in Apache · PHP-FPM with pm = static or dynamic

  • On demand

    PHP starts on the first visit and stops after a while of quiet. This is common on shared hosting, because more sites fit on one server that way. Between visits little or nothing runs for your site.

    PHP-FPM with pm = ondemand · LiteSpeed (LSAPI)

  • Per visit (CGI)

    Every visit starts a new PHP process, which stops as soon as the page is ready. Between two visits no PHP runs at all. But every visit starts from zero: start PHP, then read and compile every file of WordPress, the theme and the plugins, because no cache survives the process. So every visit costs more processor time. You still see this with older hosting.

    CGI · suPHP

  • And the database? It is on in all three.

    MySQL or MariaDB is one process that runs day and night for all sites on the server, whatever way PHP runs. It keeps a buffer in memory with the tables needed most recently, writes changes to disk in the background and cleans up old versions of rows. For every page PHP builds, WordPress opens a connection and asks dozens of questions: the settings it always loads, the page itself, the menu, the widgets. A site at Spaicely has no database: the answers to those questions are already in the files.

    MySQL · MariaDB · innodb_buffer_pool_size

However PHP runs, the server, the web server and the database stay on. The setting shifts the use between memory that stays taken and processor time per visit. That is why we count the power of the whole server, divided by the number of sites on it. A host that sets things up frugally fits more sites on it; for that, we also count with 100 and with 800 sites per server below.

And at Spaicely? There the page is already made.

WordPress builds a page on every visit. With static hosting that work happens once: when you publish. After that it is only copying.

You or your AImakes the pages: HTML, CSS, images
Storagefiles on disk; nothing runs
Server close to the visitorkeeps the copy, for all sites at once
Visitorgets the page ready-made
This is how static hosting works. When you publish a new version, we put the new files in place and the servers throw away their old copy. Between two visits nothing runs for your site.

Pages that are already made

Click for a visit

This is how a site at Spaicely works: every page has already been made and is ready. For a visit the card of that page lifts, a copy goes to the visitor and the card drops back. Between visits nothing runs for this site, so the lamps stay off. The server that delivers the copy works for a great many sites at once.

Where the difference is

A server that waits uses electricity too

How much electricity that standing ready takes depends on how the WordPress site is hosted: with hundreds of sites on one server, or on a server of its own. Three figures.

9 kWh
is what the WordPress site uses in a year without a single visitor. At Spaicely it is 0.012 kWh: just the storage.
49 kWh
a year if the WordPress site has its own small VPS instead of a place on a shared server.
3.5 to 27
kWh a year for shared hosting, from 800 down to 100 sites on one server. Hosts quote figures across that whole range; we use 300.

Calculator

Fill in your own site

We start from an ordinary business site: 3,000 visits a month and pages of 2,150 kB, the middle of the WordPress sites we measured. At Spaicely we send the same pages, so that only the hosting differs.

63× less electricity for the hosting at Spaicely

WordPress 9.1 kWh
Spaicely 0.15 kWh

How long that electricity keeps an 8 W LED bulb lit:

WordPress 48 days

Spaicely 18 hours

Standing ready: server with PHP and database, or storage
9 kWh0.012 kWh
Sending the pages
0.13 kWh0.13 kWh
Hosting in total, electricity a year
9.1 kWh0.15 kWh
Hosting in total, CO₂e a year, hardware included
4 kg0.51 kg
CO₂e is CO₂ together with the other greenhouse gases, converted to CO₂.

Have your AI move your WordPress site

How we calculated

WordPress on shared hosting: a server drawing 200 W on average, between idle (70 W) and full load (373 W) of a recent server in the SPECpower results, times a PUE of 1.54 for cooling and power supply, divided by 300 sites. On a VPS: electricity per vCPU and per GB of memory from Cloud Carbon Footprint, at 10% load. On top of that, making the server: 590 kg CO₂e according to Dell, spread over 4 years and over the sites or the vCPUs.

Spaicely: the files of a site (0.25 GB) in 3 copies on SSD storage, with the electricity per TB from Cloud Carbon Footprint and the same PUE.

Sending costs both the same per GB. By default we use Akamai's CDN: 1.7 MWh per Gbps of capacity a year, from their sustainability report, at 25% utilisation. Calculating cautiously takes the average data centre from the Sustainable Web Design Model, 0.055 kWh per GB.

Electricity becomes CO₂e on the grid you choose: Germany, where our storage is, at 335 g per kWh in 2025 according to Electricity Maps, or the world average of 494 g. Both sides get the same grid, without green certificates: those say something about purchasing, not about what happens on the grid. Making hardware we count at the world average, as the Sustainable Web Design Model does.

Every figure in the sum
WhatValueSource
PUE: what a data centre uses on top for cooling and power supply, as a factor1.54Uptime Institute, Global Data Center Survey 2025
Average power of a shared hosting server, in W200SPECpower_ssj2008, results Q4 2025
WordPress sites on one shared server300 (100–800)cPanel community: accounts per server
vCPUs of a small VPS2Our assumption
Memory of that VPS, in GB4Our assumption
Average load of those vCPUs10%Our assumption
Electricity of a vCPU at rest, in W0.74Cloud Carbon Footprint, methodology
Electricity of a vCPU at full load, in W3.5Cloud Carbon Footprint, methodology
Electricity of memory, in W per GB0.392Cloud Carbon Footprint, methodology
Threads of a whole server, to share its hardware over vCPUs128Our assumption
Making and shipping a server, in kg CO₂e590Dell, Product Carbon Footprints (PowerEdge R660xs)
Lifetime of a server, in years4Dell, Product Carbon Footprints (PowerEdge R660xs)
Size of a site at Spaicely, in GB0.25Our assumption
Copies of those files3How we store sites
Electricity of SSD storage, in W per TB1.2Cloud Carbon Footprint, methodology
Electricity of a CDN, in MWh per Gbps of capacity a year1.7Akamai, Sustainability Report 2021
Average use of that capacity25%Our assumption
Data centre, electricity per GB, for the cautious sum, in kWh0.055Sustainable Web Design Model v4
Data centre, hardware per GB, in kWh0.012Sustainable Web Design Model v4
Grid in Germany 2025, in g CO₂e per kWh335Electricity Maps, Grid Review 2025: Germany
Grid world average, in g CO₂e per kWh494Sustainable Web Design Model v4
LED bulb to compare the electricity with, in W8Our assumption

Worked out on 7 November 2026; the calculator uses the same figures. If you know a better source, mail info@spaicely.com and we will work it out again.

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