It’s often said that the electric car industry is booming. But in actual fact, Germany is still in a cautious test phase. That's because up to now, few manufacturers have managed to produce batteries with a sufficiently long life at an acceptable price.That could all change with technological advance from the small town of Pfaffenhausen. This is where Porsche tuner Alois Ruf has developed a third-generation prototype that puts everything else in the shade. Introducing the "Greenster", or electro-Porsche: 250km/h, 370 hp, a range of 300km and 0 to 100km in five seconds - Our reporter Holger Trzeczak put it to the test.