Cloud-based apps can save businesses a bundle on energy costs versus on-site hosting according to new data from Nucleus Research. After comparing the energy consumption of Salesforce.com apps to their in-house equivalents, the research firm found that Salesforce.com beat out non-cloud app infrastructures with up to 91 percent in energy savings. And it saves money too.

Another interesting stat: “Salesforce.com customers saved the energy equivalent of 11 barrels of oil every hour.”

Nucleus’ findings somewhat mirror those of a study conducted by Accenture and WSP Environment for Microsoft. During their research, they found that mid-sized businesses could achieve energy and carbon savings of 60 to 90 percent.

How? In general, cloud infrastructures achieve high server utilization rates instead of traditional data centers and server closets where an app typically has a server to itself — many times with a lot of overhead that translates into wasted energy. Companies like Saleforce.com also load-balance in a way that they bring computing power to bear as user demand dictates instead of keeping servers fully powered up on indefinite standby. For its part, Salesforce.com has been making it easier for companies to get their feet wet when it comes to cloud computing. Last year, it began offering a free edition of its Force.com web app platform.

There is a catch to cloud-ifying apps, however. Nucleus warns that the cloud works best for standardized app suites. Apps that require deep customization don’t make the best candidates for the cloud, unfortunately. Nonetheless, that leaves a huge swath of applications that are primed for the cloud — and the energy and cost savings it offers — right now.