The LNG will come from ADNOC's Ruwais LNG project and deliveries are expected to begin in 2028, ADNOC said in a statement.
ADNOC has sharpened its focus on natural gas, seeing it as a transition fuel as the world tries to curb planet-warming emissions, and as competition for LNG has ramped up since Russia's invasion of Ukraine in February 2022.
Ruwais is expected to more than double ADNOC's LNG production to around 15 million tons per annum from 6 million tons.
The deal is the second supply agreement from Ruwais, following a similar 15-year deal signed with a Singapore-based subsidiary of China's ENN Natural Gas in December.
ADNOC's deal on Monday was also with a Singapore subsidiary, SEFE Marketing & Trading Singapore Pte.
"Gas accounts for almost a quarter of Germany's primary energy use, and we look forward to supporting its efforts to diversify its energy sources and enhance its energy security," ADNOC's Fatema Al Nuaimi, executive vice president, downstream business management, said in the statement.
Ruwais, where early civil works have already begun, is expected to receive a final investment decision this year.
Earlier this month, ADNOC issued a limited notice to proceed (LNTP) to a joint venture including Technip Energies, JGC Corporation and National Petroleum Construction Company for early engineering, procurement and construction activity.
ADNOC is not alone in its growing focus on gas, with Saudi oil giant Aramco also looking for a slice of the market, while regional gas heavyweight Qatar recently announced a further expansion of its North Field project that will cement it as one of the world's top LNG exporters.
