Sempra Energy reported second quarter net income of $62 million, down 88 percent from the like quarter of 2011 when it generated $503 million in net income.

The company said the decline was due to a $179 million write-down on its investment in the Rockies Express natural gas pipeline.

In the prior year’s second quarter, Sempra’s profits included a $277 million accounting gain on its investment in two South American utilities it controls.

Sempra said it re-evaluated its 25 percent ownership stake in the Rockies pipeline after Kinder Morgan decided to sell its 50 percent ownership in the pipeline, and that the impairment charge reflects existing weak conditions on the pipeline’s value.

Sempra’s six month earnings were $298 million, or $1.21 per diluted share, compared with $757 million or $3.14 per diluted share for the first half of 2011.

Excluding the Rockies pipeline write-down, the company said it would have reported $477 million in earnings for the first half of 2012, compared with $480 million in adjusted earnings for the like period of 2011.

San Diego Gas & Electric Co., a Sempra subsidiary, reported second quarter net income of $95 million, compared with $71 million in net income for the like quarter of 2011.

The increase was due mainly to higher profits related to the Sunrise Powerlink transmission line that was energized in June.

Sempra reaffirmed its 2012 earnings per share guidance at $3.46 to $3.76.

In midday trading, shares of Sempra were down $1 from the Aug. 1 closing price to $69.08. Its 52 week range is $44.78 to $72.32.