Scottish Power: Divisions and subsidiaries
Scottish Power was the larger of the two Scottish energy companies and benefited from being both a generator and supplier of power. In 1995 it acquired the English Regional Electricity Company, Manweb which supplied Merseyside and North Wales. In 1996 the company diversified into the water supply business with the purchase of Southern Water (which was sold again in 2002). When the supply of energy into British homes was opened up to competition, ScottishPower entered this market, stealing share from the previous gas supply monopoly British Gas and also building new market share in England and Wales.
Scottish Power established the telecommunications company, Thus (originally known as ScottishTelecom). This was floated on the London Stock Exchange with ScottishPower retaining a 20% stake, until 2002 when it sold its interest.
In 2000, Scottish Power completed the acquisition of Pacificorp which supplies electricity in the western United States, which operates as Pacific Power (in the regulated energy industries of the states of Oregon, Wyoming, Washington, and California), and as Utah Power (in the regulated energy industries of the states of Idaho and Utah). In May 2005 ScottishPower announced that it had agreed to sell Pacificorp to MidAmerican Energy Holdings Company, a company controlled by Warren Buffet's company Berkshire Hathaway, for US$5.1 billion in cash and US$4.3 billion in debt and preferred stock. The successful completion of the deal was announced on 21 March 2006, after securing regulatory approvals. The deal did not include PPM Energy (which as Pacificorp Power Marketing was formerly the non-regulated subsidiary of Pacificorp). Scottish Power intends to return a large proportion of the proceeds to its shareholders.
Rejected takeover bid from E.ON
Following the announcement, the group's share price rose, but were now widely seen as vulnerable to a takeover. It was soon revealed that German energy group E.ON, who also own Powergen, were interested in a takeover. On November 22 2005 the board rejected an offer from E.ON of 570 pence a share, which would have valued the group at £10.7 billion. 
Takeover bid from Iberdrola
On November 28 2006, the board of directors of ScottishPower agreed to a £11.6 billion takeover bid by the Spanish energy firm Iberdrola. If approved by shareholders next year, the deal could create Europe's third largest utility company.
The Energy Retail division contains Scottish Power Energy Retail Ltd which holds the gas and electricity supply licenses and has over 5.2 million customers in the UK. Also included in this division is SP Dataserve Ltd which is responsible for the metering and data management work and is the first ever meter reading company to allow customers to text in their meter readings.
The Energy Networks business contains three asset owning companies SP Transmission Ltd - holds the transmission license for central and southern Scotland and owns the part of the Moyle Interconnector with Northern Ireland Electricity, SP Distribution Ltd - holds the distribution licence for central and southern Scotland and SP Manweb Plc - holds the distribution licence for North Wales, Merseyside and Cheshire. A fourth asset management business SP Power Systems Ltd maintains and repairs the distribution networks on behalf of the owners and acts as the Distribution Network Operator. The work on the transmission grid is carried out by National Grid plc.
Energy Wholesale contains two companies ScottishPower Generation Ltd which generates 6,200MW of electricity power in the United Kingdom using coal fired thermal power stations, combined cycle power stations, hydro-electric schemes, pumped storage generation and substantial wind farms.On 2006-04-27 Scottishpower were granted permission to build Europe's largest on-shore windfarm. The 322 MW / 140 turbine site will cost an estimated £300m and cover an area of approximately 55 km² of moorland south of Glasgow. Also within this division is ScottishPower Energy Management Ltd which is responsible for buying and selling wholesale energy.