As Keith Bailey (letter, 11 August) correctly notes, many of the loads in modern buildings require low-voltage DC - all electronics, computers and data-processing equipment, for example - and others can operate equally well on DC as on alternating current (AC). Within a single building, the distances involved are not so great as to require cables "of enormous size". A single AC-to-DC converter between the mains and the building could supply the DC wiring. DC losses may be compensated by the savings achieved by eliminating the AC-to-DC "power pack" in every piece of consumer electronics. Using DC directly also avoids the problem of AC disturbances or "spikes" that can fry every chip in a database.
Moreover, many of the most promising new generating technologies, including fuel cells and photovoltaics, deliver DC directly. A building wired for DC can use this supply on the premises.
Senior Research Fellow, Energy and Environmental Programme
Royal Institute of International Affairs
London SW1Reuse content