Opower officially filed its S-1 on Monday signalling that it plans to go public. The document reveals an increase in revenue from $28.7 million to $88.7 million in 2013. More than 90 percent of revenue came from utility subscription, with the nation’s top utilities being its major source of revenue. The S-1 also shows that Opower recorded net losses of $21.3 million in 2011, $12.3 million ins 2012 and $14.2 million in 2013. Read more here.