Tee Hee. Lord Drayson has been in the news today.
He suggested that the government cutting tax on diesel cars was a bad move and there should be scrapage scheme so people can buy an electric car.
It should be noted Lord Drayson drives electric racing cars and runs companies promoting electric vehicles so no conflict of interest here then. 
PS: Sorry should have done this on original post. Here is the comments from Arnaud about the solar panel:
Cheers
Mike
A 3S (11.1V) 8000mAh LiPo weights below 800grams and it will last you about 10 summit activations (spot + work all chasers, 20-30 QSO) with the FT-817 on 5W SSB, and I doubt anyone has ever done 10 summit activations in a row without reaching any place that has electricity (so you can recharge). Unless you are into very long hikes into completely isolated places, solar or wind systems are simply too heavy, fragile and inconvenient for the kind of energy they generate.
Razvan (YO9IRF)
PS: Quick calculation, a backpack covered in the newest thin-film solar cells would generate in one whole day the energy you are using in one activation (~10Wh, FT-817nd/5W/SSB as reference), and the solar cells weight by themselves as much as a 4000mAh/11.1V LiPo (without the required charge controller).
And I really don’t get it with the RF energy harvesting as it’s been around for a while. You can even buy commercial kit to experiment with. For IoT type stuff the main interest is in developing the protocols to run on a gnat’s breath.
As a more serious alternative how about a thermoelectric generator? And if that meant lighting a fire under it with sticks gathered on the summit would that be Ok by SOTA rules? I guess so as it’s not actually a fossil fuel. 
Good grief! I was joking but you can actually buy these things:
DIY version:
I use RF energy harvesting tens of times per day and have done for the last 15 years. These are 125kHz or 13.56MHz RF keytags to get in and out of the office.
But IoT! That’s the super buzzword of the moment. That makes it different.
Another problem is the lack of gearing. The rotation speed of the turbine props are too low for effective use of the generator.
A motor generator running on liquid fuel derived from compost might be a better option. I’ll leave the obvious gag to someone else.
R