Despite all of the bad news and share-price drops that have happened in the energy sector lately, not everything was doom and gloom this past quarter. Not only were there several companies that beat Wall Street's expectations, but some also give some relatively promising signs that better times are ahead. 

So we asked three of our energy contributors to highlight one company that really impressed them this past quarter, based on both its performance and what management had to say about the future of the business. Here is what they had to say.

Matt DiLalloHalliburton's (NYSE:HAL) second-quarter earnings report surprised a lot of people, especially its chief rival Schlumberger (NYSE:SLB). In fact, it was in listening to Schlumberger's second-quarter conference call that we can see just how impressive Halliburton's earnings really were.
 
After Schlumberger delivered its own surprisingly strong results, an analyst on its call wondered aloud how its rivals, namely Halliburton, must be feeling: "I think you're going to make it a difficult weekend for some of your peers as they ponder what they're going to say next week." While Schlumberger CEO Paal Kibsgaard only thanked the analyst for the compliment, he too must have wondered if his chief rival would be able to match his company's stronger-than-expected quarter. 
 
Well, it turned out that Halliburton did even better, as it crushed earnings expectations. In fact, for comparison's sake, Schlumberger earnings were just 10% higher than estimates while Halliburton beat the consensus by a whopping 52%. This fact was not lost on analysts or Halliburton's management team on the conference call. Instead, there were some jabs going the other way, as the first analyst on the call said, "It looks like contrary to, I guess, popular belief on Friday, you guys did not have to work all weekend to change what you were going to say today, so congratulations on a good quarter" -- to which Halliburton CEO David Lesar joked that he "had a stress-free weekend, that's for sure." 
 
Driving this result was the company's ability to really kept its costs in check, helping it to overcome the weak market and offset pricing pressure. It also continued to move forward with several initiatives that will strengthen its business in the future, putting it in position to really drive strong gains once oil and gas activity level improves. Needless to say, Halliburton's report was very impressive.

Tyler Crowe: The fact that Core Laboratories (NYSE:CLB) was able to beat expectations this past quarter shouldn't come as a huge surprise. After all, sentiment for energy companies lately is so bearish that it's almost harder to miss Wall Street's expectations than beat them. What was actually impressive about the company's earnings was that it was able to maintain such strong margins in this down market. As producers cut back on capital expenditures, the general assumption is that they would renegotiate prices with their service contracts for lower rates. This hasn't been the case thus far with Core, though, for a couple of reasons. 

First, Core has a very diverse client base, ranging from the world's largest oil company -- Saudi Aramco -- to the little mom-and-pop operations in the U.S. with just a small handful of wells. Some of its largest clients are the national oil companies in the Persian Gulf region, which have maintained activity throughout the price collapse and are employing Core for some major oil recovery projects to maintain production at their supergiant fields. These long-term projects are a much more steady revenue stream.

The second reason Core can maintain margins and pricing power is that the work it does in many cases saves companies several millions of dollars in development costs. By rolling out a slew of new technology designed to generate better well economics in shale wells in the past several months, it is allowing producers to spend less on the more costly processes like hydraulic fracturing and drilling. Since it is able to generate aggregate cost savings for the producer, it can command a higher price and force other oil services companies that do the grunt work to bear the brunt of the cost savings. 

These are two examples of what makes Core's offering in the oil and gas space so unique, and its ability to use those strengths to produce bottom-line results in a down market is truly impressive, 

Travis Hoium: It wasn't long ago that I thought First Solar (NASDAQ:FSLR) was one of the worst companies in the industry. Its cost advantage over competitors had evaporated, its efficiency was behind even commodity solar panels, and it's had so little demand that it started shutting down production lines despite the industry's overall growth.

Oh how times have changed. First Solar acquired some thin-film manufacturing technology from GE in late 2013, and as it's rolled that technology into its own plants, efficiency has shot through the roof. In the second quarter of 2015, the company had an average fleet efficiency of 15.4%, up 1.4% from a year ago, and its best line was at 16.2% efficiency. The new record module is at 18.6%, so there's more upside in coming years.  

This has turned First Solar's competitive ability around extremely quickly, and now it is reopening shuttered manufacturing lines and winning bids for projects around the world. With a surprisingly strong second-quarter profit and full-year guidance, fast-improving efficiency, and its new yieldco 8point3 Energy Partners, First Solar has made an amazing transformation in a short amount of time.

Matt DiLallo owns shares of Core Laboratories. Travis Hoium has no position in any stocks mentioned. Tyler Crowe owns shares of Core Laboratories. The Motley Fool recommends and owns shares of Core Laboratories and Halliburton. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.