MFR Rednet Energy Cables will convert it, but I've not had good luck with them personally. I find it easier to set up basic EU power generation than to worry about how to convert RF. Use steam (as it can be used for both power systems) into a RC Turbine. If you need more power than that puts out, you should be looking at making more stable infrastructure in the IC2 side of things. Or you could just spam Turbines, but that's a lot of iron.