* Eneva shares rise 33 pct after bankruptcy protection ends
* Power producer says ready to invest in growth again
* Tycoon's Tweet on business matter first in nearly 2 years
By Jeb Blount
RIO DE JANEIRO, June 30 (Reuters) - Eike Batista, once Brazil's richest man whose empire's collapse heralded the end of the country's oil boom, re-emerged on Twitter on Thursday, plugging his business interests for the first time in nearly two years.
The former tycoon, whose one-time $60 billion fortune dwindled to nothing in the space of a year, sent a tweet singing the praises of Eneva SA, the electrical-power unit of his former energy-to-shipbuilding empire.
Referring to Eneva, which emerged from bankruptcy protection on Thursday, by its old name, MPX Energia SA, Batista praised the power generation and gas production company and its low costs.
"MPX is the jewel in the crown of thermal power generation for Brazil, 100 reais per MWH vs 500 reais MWH at other plants! Efficiency," Batista said in Portuguese.
MWH refers to megawatt-hours, a unit used to measure the amount of electricity generated by a power plant.
Eneva shares soared 33 percent on Thursday, although it was unclear whether Batista's social media comments had any impact.
With the exception of several personal, family and charitable tweets, the Eneva post was his first about business in 635 days.
When he was still Brazil's richest man, Batista was an avid Twitter user. Later, after his EBX holdings went bankrupt, some investors complained that he was Tweeting positive information while selling his own shares. (Reporting by Jeb Blount; Editing by Christian Plumb and Sandra Maler)