A wireless 4g LTE gateway for RuuviTags is now available for various business cases where electric power supply and/or WiFi are not available. It can be installed indoors or out, such as in a factory, park, marina, construction site, shipping container, etc.
Typical battery life with external batteries (we provide) - 1 year.
The gateway can also be wired to grid power if it’s available, this is handy in a situation where there is electricity available but no wifi.
The gateway seller Kaltio Technologies Oy (hi!) serves organizations (businesses, public sector, etc) so this is not a product really intended for home use 
As part of the design to enable a gateway device to operate for months or 1+ years on battery power, the gateway sends data only to the Kaltio Technologies IOT system; it can’t send it directly to Ruuvi Station. However, data can be forwarded to other databases as needed.
Here’s more info (if external links are OK?): https://kaltiot.com/en/iot-devices/ruuvitag-gateway/