European energy companies have started to disclose the timing of maintenance on oil installations - an unexpected consequence of new EU rules to improve disclosure on energy even though the regulation is not seen as covering oil.

The new rules took effect around the turn of the year and are aimed at extending the prohibitions against insider trading and market manipulation to physical commodities markets, according to international law firm, Cleary Gottlieb.

An increase in the disclosure of potentially market-sensitive outages in the opaque physical oil market could affect prices and help level the field for traders and other players.

Lawyers and EU officials have said that while natural gas and electricity are covered by the new law, oil is excluded, because it is regarded as more international than Europe's wholesale power and gas markets.

But BP Plc on Wednesday listed online an incident at the Hound Point oil terminal. A spokesman said BP was publishing more information following the new EU rules, which are called the Regulation on Energy Market Integrity and Transparency, or REMIT.

We have put in place some measures to ensure we comply with the new legislation, including publishing information on the Forties Pipeline System website on maintenance, company spokesman Matt Taylor said.

BP said on the website the Hound Point terminal, where Forties crude is loaded, would be unable to handle Very Large Crude Carriers (VLCCs) between February 1-17 due to repairs.

Oil traders said the unplanned restriction on loading 2 million barrel vessels, which sometimes head outside North West Europe, was part of the reason for a drop in the value of Forties, which hit a 15-month low on Tuesday.

In the past, BP rarely commented on incidents such as North Sea field and pipeline shutdowns.

Most of Britain's major power and gas producers have started publishing commercially sensitive outage schedules on dedicated websites or using social media such as Twitter.

Gas producers such as Shell, BP, Centrica and ConocoPhillips show details of planned spring and summer maintenance outages.

Britain's 'Big Six' utilities have also started making data available on planned power station maintenance and unplanned outages in order to increase information transparency in the market.