Like the Maxim MAX4211 TI produces a (low side) current and voltage monitor with an SPI output, the LMP92064. Your processor will have to do the multiplication to get to power, but that's what processors are good for!
I believe TI has one or two others, but it will have to wait untll I get back to work on Monday.
I must apologize for not mentioning the Rogowski coil for AC current measurement. I have never had the opportunity to use one, so there is not much that I can add.
For completeness, I guess I should mention the rotating disc that used to be on all power meters. For the life of me I can't remember that name of the effect that produces the rotation and I don't know of any modern application that uses this approach.
What are the engineering and design challenges in creating successful IoT devices? These devices are usually small, resource-constrained electronics designed to sense, collect, send, and/or interpret data. Some of the devices need to be smart enough to act upon data in real time, 24/7. Are the design challenges the same as with embedded systems, but with a little developer- and IT-skills added in? What do engineers need to know? Rick Merritt talks with two experts about the tools and best options for designing IoT devices in 2016. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.