The Q1 earnings cycle is nearing its end. As of May 4, 2016, 81.3% of the market cap of the S&P 500 index have reported results. So far, overall first-quarter earnings have recorded a 7.5% year-over-year decline on a 1.9% slip in revenues.In the utility sector, 76.7% of the market cap have reported results as of yet. Overall sector earnings show a 5.1% decline during the quarter on a 9.1% drop in revenues.Taking into account companies that are yet to report quarterly numbers, earnings are estimated to fall 4.8% on a 1.7% dip in revenues. For more details, you can go through our Earnings Trend report.Majority of utility earnings in the first quarter were, to some extent, hurt by warmer-than-expected temperatures this winter. However, a gradually declining unemployment rate, low interest rate and the sector’s investment initiatives put the companies in a better position than most of the other S&P 500 index members.Let’s take a look at some utilities that are scheduled to report first-quarter earnings early next week.The AES Corporation AES, a Zacks Rank #4 (Sell) stock with an Earnings ESP of 5.26%, is set to report first-quarter 2016 results before the market opens on May 9. Last quarter, the company posted a positive earnings surprise of 3.03%. On its fourth-quarter 2015 earnings call, AES Corporation had lowered its 2016–2018 adjusted EPS expectations to reflect a major impact from macroeconomic factors such as devaluation in foreign currencies, changes in commodity prices, and lower demand and higher interest rates in Brazil.However, the company has maintained a flexible liquidity position. In 2016, it expects to generate approximately $1.3 billion of proportional free cash flow, which translates into 90 cents per share. The company also projects parent free cash flow of about $675 million. (Read more: AES Corporation Q1 Earnings: Stock to Disappoint?).The above chart indicates that AES Corporation was able to deliver positive surprises in two of the last four quarters. However, due to larger negative surprises in the other two quarters, the overall average surprise was a negative 3.85%.CenterPoint Energy, Inc. CNP will release first-quarter 2016 financial results before the market opens on May 10. Last quarter, the utility reported a positive earnings surprise of 8.33%. CenterPoint Energy is focused on upgrading its infrastructure and improving reliability. It has set a capital outlay of $6.2 billion for the 2016–2020 period, including an allocation of $1.4 billion for 2016.This Zacks Rank #2 (Buy) company has an Earnings ESP of -9.38%. For this quarter, the company expects earnings in the range of $1.12 to $1.20 per diluted share. It aims to achieve bottom-line growth of 4–6% on the back of its existing businesses and investments through 2016. An investment of $363 million in Enable Midstream preferred security and expansion of the company's non-regulated Energy Services business should accelerate bottom-line growth further. However, due to warmer-than-normal temperature in winter, household expenditure on heating was lower, which is expected to dent its revenues in the first quarter. (Read more: CenterPoint Q1 Earnings: What's Ahead for the Stock?). The above chart indicates that CenterPoint Energy was able to beat earnings estimates in two of the last four quarters. The average positive earnings surprise was 0.64%.Xcel Energy XEL will release first-quarter 2016 financial results before the market opens on May 9. Last quarter, the company’s earnings were on par with estimates. It carries a Zacks Rank #4 (Sell) and has an Earnings ESP of -6.25%. Xcel Energy’s first-quarter earnings are expected to benefit from rate increases approved in various jurisdictions in the previous year. However, unseasonably warm weather dented fourth-quarter 2015 earnings by 7 cents and is expected to continue doing so in the first quarter. (Read more: Will Xcel Energy Q1 Earnings Disappoint Expectations?).The above chart indicates that Xcel Energy was able to deliver a positive surprise in only one out of the last four quarters. This led to an average negative surprise of 1.38%.Bottom LineGiven a number of S&P 500 earnings releases scheduled for next week, investors should keep an eye on the earnings releases by these utility companies.Stay tuned for our full earnings articles to see how these stocks finally fare this season.Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report CENTERPOINT EGY (CNP): Free Stock Analysis Report XCEL ENERGY INC (XEL): Free Stock Analysis Report AES CORP (AES): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research