Hawaiian Electric Industries reported an increase in fourth-quarter net income that was largely the result of a one-time hit on earnings a year earlier that skewed the comparison on a year-over-year basis.

HEI earned $39 million, or 39 cents a share, during the October-through-December quarter, up from $13.8 million, or 14 cents a share in same period in 2012, the company reported Tuesday.

HEI operates the Hawaiian Electric Cos. and American Savings Bank.

The year-earlier quarter included a $24 million write-down related to rate relief the company granted to its utility customers as part of an agreement negotiated with the state Division of Consumer Advocacy. Excluding the write-down, HEI’s net income was $38.3 million in the fourth quarter of 2012.

For all of 2013, HEI earned $161.5 million compared with $138.7 million in 2012. After adjusting for the write-down, HEI’s earnings in 2012 were $163.1 million.

If you look at just the utility, Hawaiian Electric Co., which operates utilities on Oahu, Hawaii island and in Maui County, reported net income of $32 million in the fourth quarter, up from $4.2 million in the same quarter a year earlier. After adjusting for the write-off, net-income in the year-ago quarter was $28.7 million.

The improvement in HECO’s fourth-quarter adjusted net income was due mostly to lower operations and maintenance expenses, according to HEI. An increase in revenue was offset by increases in depreciation due to equipment investments to the utility’s grid, company officials said in a news release.

HEI Chief Executive Officer Constance Lau said HECO and its subsidiaries continued to make grid upgrades in 2013 to "ensure reliability and safety for our customers as we integrate more renewable energy."

A total of 17,609 solar photovoltaic systems with more than 129 megawatts of capacity were added to the Hawaiian Electric, Maui Electric and Hawaii Electric Light Co. grids in 2013. The 39 percent increase in capacity was the smallest annual gain since 2010.

The PV industry blamed the slowdown in part on new interconnection requirements put in place by HECO in September to address the high penetration of PV panels in some neighborhoods. Utility officials said they were concerned that extremely high levels of solar-generated power on some of its circuits were posing safety and reliability issues for HECO and its customers.

As a result, the PV industry is pushing for two bills in the Legislature that would require the state Public Utilities Commission to adopt rules for "improved accessibility to connect to the Hawaii electric system for any individual or business."

The HEI earnings included results from American Savings Bank, which were reported Jan. 30.

American Savings Bank showed strong loan growth in the fourth quarter, but net income fell 15.2 percent primarily due to lower gains on residential mortgage sales and less fee income the bank collected from debit card transactions.

The state’s third-largest bank said it earned $12.2 million compared with $14.4 million in the year-earlier quarter.

The financial results were released after the market closed. HEI shares closed down 2 cents at $24.46 on the New York Stock Exchange.