Hello.
I think that if it can send any information from far away, even at any frequency, it is actually telemetry... It's on you to judge its performance.
I understand your device charges its capacitors (is it a supercapacitor? or a bunch of common electrolytic capacitors in parallel? If not, you should consider supercaps) from the ambient energy. Is it solar? Is it thermal? is it from wind or uses a motor generator maybe? It should be good to know where you get the energy from, since maybe you can generate much more energy than you think, by de fact that you can get pretty little energy from these methods, but it's enough for low power applications such as temperature sensing.
I've worked in low power (battery supplied) devices, and I have to tell you that you must put at least one transistor to supply the external to MCU circuits (sensors, transceivers, LEDs, etc) when you need them, and turning it off when you don't... That will save energy for the MCU to keep working -even at sleep modes- and waking up every an amount of time to do the job. In this case, it could wake every hour, turn the external circuits on (take into account you could have to initialize external transceivers/modules if you turn them off) and measure to transmit data. Meanwhile, you harvest energy and charge your caps.
You've said that you send information every hour or half an hour... Have you thought about taking measurements every -to say- 5 minutes and send a larger data package (with all these measurements) at that hourly rate?
What exact transmission method are you using? ISM bands or GSM/mobile network? Modern transceivers use very little energy and can reach very good ranges, in good conditions (no rain, open areas, plain surface).