* Q4 net loss $0.86/shr vs year-ago loss $0.64/shr
* Q4 revenue $22.7 mln vs $22.98 mln estimate
* Sees Q1 rev $25 mln-$31 mln, net loss $0.85-$1.05/shr
(Adds forecast, analysts' consensus, background)
LOS ANGELES, Feb 16 (Reuters) - Energy monitoring and efficiency company EnerNOC Inc (ENOC.O) reported a wider quarterly loss on Wednesday as revenue fell 15 percent and operating costs rose.
EnerNOC shares have been battered in the last week on concerns it booked power savings twice and covered up some customers' failure to meet agreed-upon electricity use reduction targets.
The fourth-quarter net loss was $21.2 million, or 86 cents per share, compared with a net loss of $15.2 million, or 64 cents per share, a year ago.
That was worse than the 83 cents per share loss that analysts had on average forecast, according to Thomson Reuters I/B/E/S.
Revenue fell 15 percent to $22.7 million from $26.7 million. Analysts were expecting revenue of $22.98 million, according to Thomson Reuters I/B/E/S.
For the first quarter, EnerNOC said revenue would be between $25 million to $31 million, with its net loss per share between 85 cents to $1.05.
EnerNOC works with power grid operators, utilities and large electricity consumers to reduce electricity use during expensive peak hours, cutting energy costs and alleviating pressure on the grid.
A statement issued by No. 1 U.S. grid operator PJM on Feb. 4 said companies that were double counting their savings "are engaging in market manipulation." It did not name any of the companies suspected of so-called double counting, but EnerNOC accounts for about 35 percent of PJM's demand response market.
The abrupt departure of Chief Operating Officer Darren Brady last week also fueled investor worries about the company's practices.
EnerNOC has said it was in full compliance with PJM market rules and that it was fully deserving of all payments for its services. It also said Brady's resignation was unrelated to the PJM statement.
Nevertheless, the Boston company's shares have lost nearly 20 percent of their value since Feb. 10, when it announced Brady's departure in a regulatory filing.
Shares in EnerNOC were up slightly in post-market trading at $19.43 after slipping 3.5 percent to $19.30 during the regular session. (Reporting by Nichola Groom and Matt Daily; Editing by Gunna Dickson, Phil Berlowitz)