Standard fixture performance, fed from a pressurised supply. The fixture itself is just plumbing, it draws no power. The pressure it depends on is produced upstream, either by a mains connection, where the utility supplies it and the shower keeps working through a power cut, or by a pump, where the shower inherits that pump's power dependency and fails with it. Both feeds must be potable-quality: non-potable water is not permitted for bathing. A gravity-fed shower is the passive alternative, at lower flow.
Note: Cost, carbon and footprint are rated against the other options for this same need, not in absolute terms.
No sizing or quantities: how much a technique yields, and how much a household needs, both depend on the build and the people, so the catalogue compares options rather than dimensioning them. It carries no bill of materials and no build sequence, and it is written for an oceanic, clay-soil climate (Normandy, France). Regulatory notes are indicative and need confirming locally.