* Brazil plants to add 257,000 barrels/day of diesel output -source
* Petrobras plans to start two refining units by mid-2015, third in 2016
* Brazil diesel demand seen rising 4 pct to 5 pct a year -ANP (Adds detail of how much diesel new refineries will produce, adds ANP comment)
By Rodrigo Viga Gaier and Jeb Blount
RIO DE JANEIRO, March 12 (Reuters) - Refineries being built by Brazil's state-run oil company, Petroleo Brasileiro SA , may produce enough diesel to allow Brazil to stop importing the fuel in two to three years, a director of the country's oil regulator ANP said on Wednesday.
The comments by the ANP are one of the first signs from the regulator that Petrobras will be able to end Brazilian dependence on diesel imports soon.
The company expects to add 395,000 barrels a day of crude oil refining capacity between two plants by 2016, but government fuel price controls have prompted refining losses making it harder to finance its $221 billion five-year plan, the world's largest corporate spending program. It's also helped Petrobras' debt to soar.
"We have had significant advances in refining at Abreu e Lima and Petrobras' promise that it will start operations," Florival Carvalho, the ANP director, said at an event in Rio de Janeiro. "This is extremely important for the fuel sector because the new refineries will make up about 20 percent of our national diesel needs and reduce our imports to practically zero."
Petrobras' RENEST Refinery outside Recife in Brazil's northeast is expected to start operations by year-end and reach full capacity by mid-2015, and a second plant near Rio de Janeiro known as COMPERJ Refinery is expected to start operating in 2016.
RENEST and COMPERJ are both under construction. RENEST is also known as Refinaria Abreu e Lima, the name given the plant by late Venezuelan President Hugo Chavez before his state-owned Petroleos de Venezuela pulled out of the nearly $20 billion project last year.
Brazil imported 177,201 barrels of diesel a day on average in 2013, according to the ANP. That's nearly a fifth of Brazil's total diesel needs. Based on an ANP demand-expansion estimate of 4 percent to 5 percent a year, diesel imports could rise to more than 190,000 barrels a day by the end of 2015 if no new national capacity is added.
At RENEST and COMPERJ, Petrobras should be able to produce about 257,000 barrels a day of diesel fuel, a source with knowledge of the new refineries plans told Reuters. Diesel, Brazil's most-used vehicle fuel, will make up about 70 percent of the new refineries' output.
Assuming the new refineries will operate at 92 percent of capacity, face occasional maintenance shutdowns and that consumption will grow in line with the ANP estimate, the new refineries should produce enough diesel to close the import gap, the source said.
The source asked not to be named because he is not authorized to speak publicly about internal Petrobras refinery data.
Petrobras expects to have its first 115,000 barrel a day unit, or "train", operating at the RENEST Refinery by the end of this year and a second 115,000-barrel-a-day unit operating by the end of May 2015. RENEST alone should be able to produce about 150,000 barrels a day of diesel when both units are operating, the source said.
A 165,000-barrel-a-day train at COMPERJ is expected to start operating in 2016. COMPERJ will be able to produce an average 107,000 barrels a day of diesel. Few of Petrobras' refinery projects, though, have started on time and both RENEST and COMPERJ are years behind schedule.
Between the RENEST opening and COMPERJ start-up, Brazil will have to import at least 40,000 barrels a day of diesel, according to current demand and supply estimates.
Petrobras did not immediately respond to requests for comment.
The Rio de Janeiro-based company is Brazil's only major refiner of gasoline, diesel, cooking gas, naphtha, bunker fuel and natural gas. It produces about 2 million barrels of refined products a day in Brazil from 12 refineries.
Brazilian fuel demand has been rising faster than Petrobras has been able to expand refinery production, forcing an increase in imports and saddling the company with losses.
In an attempt to control inflation, Brazil's government has prevented Petrobras from raising domestic prices for gasoline and diesel to match world prices, forcing the company to sell its fuel imports at a loss. (Reporting by Rodrigo Viga Gaier and Jeb Blount; Writing by Jeb Blount; Editing by Jeffrey Benkoe and Meredith Mazzilli)