The Institute for Applied Ecology in Germany found that storing smaller amounts of data on network attached storage (NAS) devices will result in fewer greenhouse gases than stocking your information in a data center.
The organization estimates that storing 4.7 GB of data, or the data volume of just one DVD, online causes greenhouse gas emissions of 121.3 lbs of CO2 equivalents. Storing the data in an efficient home NAS would result in only 0.33 lbs of CO2 equivalents. In addition a 1 TB NAS would cost only about $130 per year to purchase and operate, while the same money would buy only 100 GB of storage space online.
The Institute also recommended to buy 2.5-inch NAS drives due to their lower power consumption, as well as network storage products with a network standby feature that does not consume more than 4 watts.