The oil-rich UAE began construction on Tuesday of a second nuclear power plant, one of four reactors aimed at cutting carbon dioxide emissions by some 12 million tonnes a year in 2020.

Emirates Nuclear Energy Corp (ENEC) said it poured the first part of safety concrete for Unit 2, in a ceremony attended by visiting Korean Trade, Industry and Energy Sang-jick Yoon.

In 2009, an international consortium led by the state-run Korea Electric Power Corp won a $20.4 billion (15.8 billion euro) deal to build four nuclear power plants in Baraka, west of Abu Dhabi.

Under the biggest single contract Seoul has ever won abroad, South Korean firms including Samsung, Hyundai and Doosan Heavy Industries will build the four 1,400-megawatt reactors.

Work began last year on the first plant, which is expected to enter service in 2017 after further regulatory approvals.

Unit 2 is to begin commercial operations in 2018.

In addition to diversifying the UAE's energy supply once operational, the four plants should cut 12 million tonnes of CO2 emissions annually by 2020, ENEC said.

ENEC said it had applied in March to the Federal Authority for Nuclear Regulation for construction licences for Units 3 and 4, but did not indicate when work would begin.

The UAE sits on a large wealth of oil and gas, and pumps 2.8 million barrels per day of crude oil.

In March, Abu Dhabi opened the world's largest operating plant of concentrated solar power, which has the capacity to provide electricity to 20,000 homes.