The move comes almost a year to the day that Woodside Petroleum's Singaporean trading unit signed a heads of agreement with Pertamina to supply about 500,000 tonnes to 1 million tonnes of LNG a year from its LNG portfolio over 20 years.
Under the new memorandum of understanding with ExxonMobil, Pertamina will buy 1MMtpa of LNG starting in 2025, by which time Indonesia wants to lift the share of natural gas in its energy mix to about 22%.
The latest deal was part of 11 agreements worth about US$10 billion signed by US and Indonesian companies on Friday as part of wider efforts between the two countries to reduce trade barriers and boost investment.
The deals were announced by visiting US Vice President Mike Pence in Jakarta on a business trip in Asia.
Energy Information Administration figures show Indonesia's energy consumption rose 43% between 2003 and 2013.
The Asian pivot by the US under the new administration puts more meat in the move flagged by US President Donald Trump but barely enacted.
Indonesia lies at the heart of the Association of South East Asian Nations, founded in 1967, which has a combined GDP of about $A3.351 billion, and includes Malaysia, the Philippines, Singapore and Thailand, and has since expanded to include Brunei, Cambodia, Laos, Myanmar and Vietnam.
The region is located at the fulcrum of the Asia Pacific and is home to the Malacca Straits, a critical global shipping route, particularly for energy resources.
The region is bound by China to the north, US power projection to its east, an emerging India to its west and US-linked Australia to its south.
Like European and Cold War power struggles in earlier periods, ASEAN is the site of contemporary geopolitical competition which USAsia Centre director Andrew Pickford says could play a bigger role, particularly as LNG comes further to the fore.
The US administration is big on exporting its LNG, while Indonesia wants all the energy it can get for its growing population.
Key driver
Western Australia-born Pickford, director of USAsia's Indo-Pacific Energy Security Program, said in a report this month on The transformation of ASEAN that the speed and extent to which Indonesia successfully implemented its ambitious 2014 National Energy Plan was perhaps the key driver of the transition occurring within ASEAN.
The plan envisages doubling the use of natural gas and tripling coal use by 2025 which, if achieved, will create a much larger energy system and alter import and export patterns.
"While liquid fuels are not an important part of the electricity sector and are mainly used in the transport sector, it is expected that Indonesia will become a net importer of oil," Pickford said.
"Indonesia's National Energy Plan focuses on re-establishing its energy independence by redirecting energy resources from export to the domestic market to rebalance the energy mix towards indigenous energy supplies.
"In practical terms, this translates into minimising oil consumption, increasing the exploitation and consumption of renewables and coal, and optimising gas production and consumption."
However, ambitious energy plans in both industrialised and developing nations nearly always face the challenge of implementation.
Indonesia President Joko Widodo's November 2015 announcement of his plan to procure 35 gigawatts of additional generation was viewed by energy and financial analysts as a tough ask.
While progress has been made, the analysts have not been far off the mark as various bottlenecks and regulatory processes have held up the deployment.
Pickford pointed out that even a lower rate of installation, adding 5GW a year - up from 2-3GW in the past - suggested some success.
"The experience of greater international investment in the sector and expansion of network and generation capacity will be important for the 2020s if electricity demand accelerates," he said.
"At a minimum, the additional capacity will reduce the likelihood of shortages, which will provide greater business confidence and encourage investment."
