Utilities are one of the safest investment options given the regulated nature of business that gives their revenues a high level of certainty. They also benefit from their domestic orientation, which shields them from foreign currency translation issues that have been a headwind for many an industry lately.Utility is a mature sector that is not known for big surprises, but its ability to boost shareholder value through consistent dividend payments and share buybacks makes the sector attractive for yield hungry investors.The first quarter earnings season is well under way and this week appears to be one of the heaviest earnings release weeks. Nearly 37% of the S&P 500 members are expected to release their earnings this week. The utility sector is expected to perform better than the S&P 500. Utility earnings are estimated to improve 5.3% in the first quarter on a 0.9% improvement in total revenues. In contrast, the S&P 500 average earnings are expected to be down by 9.4% on a 0.8% drop in total revenues. For further details on earnings release kindly consult our Earnings Trend report.Evolving emission standards are posing new challenges for this industry. Utility operators are in response gradually shutting down old coal-based power units and are focusing on the use of cheap natural gas and other alternative sources to generate electricity. Let’s see how some of the utilities reporting earnings this week are dealing with this transition to a greener economy.Investors should also note that the dovish stance from the Federal Reserve on a much more gradual pace of rate hikes should favor this sector on two counts. First, they have a huge amount of debt to service and a low interest rate will obviously help. Second, for income-minded investors, their stable payouts in a low-rate scenario are definitely attractive.Here are the utility stocks gearing up for Q1 releases. SCANA Corporation SCG, a Zacks Rank #3 (Hold) stock, is expected to report first-quarter 2016 earnings on Apr 28, 2016. In the prior quarter, this utility company reported a positive earnings surprise of 7.79%. The company is well positioned in a positive regulatory environment, having a low-risk business with outstanding customer growth and operational efficiency. These, in turn, should favor cash flow growth in the first quarter (read more:Can SCANA Corp (SCG) Earnings Surprise Estimates in Q1?). The above chart indicates that SCANA Corporation delivered positive earnings surprises in three of the last four quarters. The average positive earnings surprise was 5.22%.Diversified utility, NextEra Energy Inc. NEE, a Zacks Rank #3 (Hold) stock, is scheduled to report first-quarter 2016 results on Apr 28, 2016. In the prior quarter, this utility company reported a positive earnings surprise of 5.41%. NextEra Energy is expected to benefit from the improving Florida economy, which is leading to the creation of new jobs. However, like other utilities, NextEra Energy is also exposed to the impact of El Nino. The unseasonably warm weather is expected to hurt utility output in the first quarter (read more:Can Utility Stock NextEra (NEE) Surprise in Q1 Earnings?). The above chart indicates that NextEra Energy was able to deliver positive earnings surprises in three out of the last four quarters. The average positive surprise was 4.28%.PPL Corporation PPL, a Zacks Rank #2 (Buy) stock, is scheduled to report first-quarter results on Apr 28, 2016. Last quarter, the company’s earnings met the Zacks Consensus Estimate. Favorable rate case outcomes in Pennsylvania and Kentucky are expected to benefit earnings through 2016. However, a milder-than-usual winter in its service territories could hurt the demand for the company’s services, thereby affecting its performance (read more:PPL Corporation (PPL) Q1 Earnings: Can the Stock Surprise?). The above chart indicates that PPL Corporation delivered positive earnings surprises in three of the last four quarters. The average positive surprise was 5.94%.American Electric Power Co., Inc. AEP, a Zacks Rank # 3 stock, will release first-quarter 2016 financial results on Apr 28, 2016. In the prior quarter, this utility company reported a negative earnings surprise of 4.00%. With unemployment rates falling significantly in the company’s service territories, American Electric expects loads to increase in 2016. The company anticipates an investment of $353.2 million in 2016 to meet environment regulation, which being an additional investment, could weigh on its finances (read more:American Electric (AEP) Q1 Earnings: What's in the Cards?). The above chart indicates that American Electric Power was able to deliver positive earnings surprises in three out of the last four quarters. The average positive surprise was 6.49%.CMS Energy Corporation CMS, a Zacks Rank# 2 stock, will release first-quarter 2016 financial results on Apr 28, 2016. In the prior quarter, this utility reported a negative earnings surprise of 4.00%. Last quarter, the company’s earnings met the Zacks Consensus Estimate. The ongoing investment to strengthen its operations and infrastructure will help the company to achieve its long-term earnings growth target. However, the milder-than-expected winter might adversely impact first-quarter 2016 sales ( read more:Will a Mild Winter Hurt CMS Energy (CMS) Earnings in Q1?). The above chart indicates that CMS Energy was able to deliver positive earnings surprises in two out of the last four quarters. Due to a large negative surprise in one quarter, the overall average surprise came down to a negative 1.37%.Pinnacle West Capital Corporation PNW, a Zacks Rank #3 (Hold) stock, will release first quarter 2016 financial results before the market opens on Apr 29, 2016. In the prior quarter, this utility company reported a positive earnings surprise of 37.04%. The ongoing improvement in economic conditions in its service territories is continuing to have a positive impact on Pinnacle West Capital’s performance. Increase in consumer spending and strength in the housing market will help the company to sustain this performance (read more:What's in Store for Pinnacle West (PNW) in Q1 Earnings?). The above chart indicates that Pinnacle West Capital delivered a positive earnings surprise in only one of the last four quarters. The average positive earnings surprise was 0.92%.Public Service Enterprise Group Inc. PEG, a Zacks Rank #2 (Buy) stock, is expected to report first-quarter 2016 earnings on Apr 29, 2016. In the prior quarter, this utility company reported a positive earnings surprise of 4.17%. Public Service Enterprise emphasizes on building reliable transmission and distribution infrastructure at its facilities. In Mar 2016, the company announced its plans to spend $16 billion over the next five years, marking an increase of $3.0 billion over its earlier projection of an investment of $13 billion(read more:Public Service Enterprise (PEG): What's Up in Q1 Earnings?). The above chart indicates that Public Service Enterprise was able to deliver positive earnings surprises in all of the last four quarters. The average positive surprise was 4.28%.Bottom LineThe utility heavyweights will start releasing first-quarter numbers from this week. This sector is expected to perform better than the S&P 500 this earnings season.Keep an eye on our full earnings articles to see how these stocks finally fared 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 AMER ELEC PWR (AEP): Free Stock Analysis Report CMS ENERGY (CMS): Free Stock Analysis Report PINNACLE WEST (PNW): Free Stock Analysis Report NEXTERA ENERGY (NEE): Free Stock Analysis Report SCANA CORP (SCG): Free Stock Analysis Report PPL CORP (PPL): Free Stock Analysis Report PUBLIC SV ENTRP (PEG): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research