Iberdrola said on Friday it would buy 88% of ENWL for 2.5 billion euros under the agreement.
The deal is in line with the Spanish company's strategic shift towards upgrading and expanding power grids like those controlled by ENWL, attracted by the stable and predictable returns on offer at a time when the renewable energy sector is under pressure from high interest rates and debt costs.
It also fits with its growing focus on the United States and Britain, which according to Executive Chair Ignacio Galan, offer some of the best returns for network businesses.
Galan had recently said the company was interested in ENWL, confirming earlier Reuters reports.
With deep pockets after selling some assets in Mexico and scrapping the planned purchase of U.S. energy firm PNM Resources, Iberdrola sealed a deal that helps connect areas it already serves through its Scottish Power business.
The acquisition makes Iberdrola the second-largest electricity network operator in Britain, with around 12 million customers, a network of more than 170,000 km (105,633 miles) and more than 8,500 employees, it said.
"The agreement is also consistent with our strategy to invest in countries that have ambitious investment plans and stable and predictable regulations," Galan said in a statement.
"As a result of this acquisition, our regulated networks asset base in the UK is now valued at 14 billion euros. When combined with the Unites States, these two markets now represent two-thirds of our total global regulated asset base."
The remaining 12% stake in ENWL will be controlled by a consortium of Japanese investors led by Kansai, Iberdrola said, adding that a shareholders' agreement will guarantee long-term collaboration.
BNP Paribas was the lead advisor to Iberdrola on the deal and Barclays also advised the group, sources said. Both banks declined to comment.
