Renault has completed a staggering challenge by having an electric car travel from John O'Groats to Land's End using only solar power.A Renault 4 E-Tech was able to make the 1,000-mile journey, despite only being powered by solar energy in a staggering technological display.The "Plein Sud" variant aimed to follow the sun during the summer solstice along the length of Great Britain.Along the journey, the Renault 4 E-Tech made use of solar power a…