LONDON/DUBAI (Reuters) -Saudi Arabia and the United Arab Emirates' national oil companies plan to extract lithium from brine in their oilfields, in line with efforts to diversify their economies and profit from the shift to electric vehicles (EVs), three sources told Reuters.

Other oil companies, including Exxon Mobil and Occidental Petroleum, plan to take advantage of emerging technologies to filter lithium from brine, as the world seeks to move away from fossil fuels.

Saudi Arabia, whose economy for decades has relied on oil, has spent billions on trying to turn itself into a hub for EVs as part of Saudi Crown Prince Mohammed bin Salman's attempts to find alternative sources of wealth.

Three people familiar with the matter said Saudi Aramco and Abu Dhabi National Oil Company (ADNOC) were in the very early stages of work to extract lithium, regarded as a critical mineral by many major economies because of its use in battery manufacture.

They declined to give detail on the type of direct lithium extraction (DLE) technology that would be used.

Aramco did not respond to a request for comment, Adnoc declined to comment.

The three sources declined to be named because they were not authorised to speak publicly.

DLE technology is in its infancy and its economics are far less certain than those of oil.

But Saudi Arabia and the UAE can draw on expertise in handling oil brine and wastewater at oil production sites.

An advantage of filtering the ultralight battery metal from salt water is that it avoids the need for costly and environmentally challenging open pit mines or large evaporation ponds, as employed in the world's leading producers Australia and Chile.

China is the biggest processor and consumer of lithium, needed for electric and hybrid vehicles.

CONCENTRATION AND PRICE COLLAPSE

For now, global economic weakness has depressed buying of new vehicles and led lithium prices to dive.

Lithium prices have fallen by about 80% since touching a peak in November 2022 as a slowdown in EV sales exacerbated a supply glut.

Leading carmakers, however, are among those looking for new lithium supplies in anticipation of future demand.

Analysts have said the EV industry will depend on lithium for years to come, even though cheaper battery technology alternatives using less or no lithium are being studied.

An issue with extracting lithium from brine is that concentration levels can be very low, making already uncertain economics less favourable.

One of the people said Aramco was working on using new filtration technology that seeks to solve the issue of concentration, while another person said Adnoc was also addressing that.

Saudi Arabia's oil wealth means it can afford to take a financial risk and its diversification plans include establishing itself as a hub for EVs to make use of whatever lithium it produces.

The kingdom has established its own EV brand Ceer, and built an EV metals plant. Its sovereign wealth fund, the Public Investment Fund (PIF), has a goal to produce 500,000 EVs annually by 2030.

Saudi Arabian Mining Company (Ma'aden), the Gulf's largest miner, is working to extract lithium from seawater.

"There is good research in the kingdom with Ma'aden ...and Aramco because the discharge of the oilfields have good salinity and good traces of minerals," Saudi vice minister of industry and mineral resources Khalid bin Saleh Al-Mudaifer told Reuters on the sidelines of a press conference in Riyadh in December.

"They have done good work, they have done good extractions of sodium, magnesium, and traces of lithium. The technologies are in the early stage, but there is good work and good investment," Al-Mudaifer added.