In this video Jason Boone gives us a calculation and some apps we can use to calculate what we need to add to our invoice as the cost of capturing and storing the data.
This is not about what value your artistic eye is, but rather the cost of the hard drive space, and the cost of the data captured depending on the bit-rate and quality of the video format you're shooting at.
Often clients won't think about this and they'll be shocked that you actually add it to the estimate. They often think you're shooting digitally, so all you need is a camera. And there is some education needed. The video has some calculations, and you need to focus on how he gets to his final result, but when it comes to money, we shouldn't leave anything on the table, so it's worth spending the time and mind on.
I would recommend starting with a spreadsheet and entering all the data to get an end result. And, perhaps you should be charging for the back up drive and cloud storage too.
Do you know what your cost per minute of video is? Or, what your cost per photo is? If not, it'll be a good idea to run the numbers and see what you should be charging for the data throughput and storage alone.
It can be tedious to try to collect on all your costs. Best to figure them into one of your other rates or fixed charges. The customers are cost sensitive enough as it is.
This exercise yields numbers that are negligible in cost. I maintain a 4 drive, (24 TB) set-up plus online storage at $3.32 per 5 day week. For all my client and personal work. This is my cost of doing business and is reflected in my fees. While it may be interesting to know, perhaps you're set up is not as efficient as you believe. One big flaw in your idea here is that one should never fill up a drive in its entirety, always leave room for quicker read/write functions. This is basic computer practice.