Over the last few years, people have asked me several times why electric car manufacturers aren’t putting solar panels on their cars to charge the battery. It sounds like a logical thing to do, isn’t it? I always argued there might be two good reasons for car builders to shy away from this idea. First of all the surface area for solar cells on a car is limited and their orientation not ideal, hence a low energy production could be expected. Secondly, solar panels are not cheap. Pardon me, they were not cheap. Nowadays they are. And hence… things have changed lately.
The American Council for an Energy Efficient Economy, ACEEE, is a non-profit organisation aiming for a more energy efficient (American) economy. They’ve made an international scorecard, a ranking of energy efficiency of 16 large economies including Germany, the UK, China, Mexico, the US etc. Countries can earn a maximum of 100%, by scoring points in 31 metrics across four groups of important energy efficiency aspects: nation-wide energy aspects such as energy production and transmission, buildings, industry and transportation. The top three brings no surprises. On the first place comes Germany, followed by Italy and the European Union as a whole. Surprising result: China comes at the fourth place, while the US only comes only at the 13th place of the 16 economies investigated. But there’s still room for improvement: even Germany was rewarded a mere 62 on a scale of 100.
Seen as a bad omen by old cultures, the solar eclipse last Friday was enough reason to make some people worrying. Germany, highly reliable on solar energy generation, faced a serious challenge. The country has around 37gigawatts installed photovoltaic capacity -a typical nuclear reactor is 1gigawatt. In a timespan of 75 minutes, solar power output of 21.7 gigawatts dropped to a low point of 6.2 gigawatts. When the eclipse was over its apec, the output increased again with 15 gigawatts, according to TenneT (one of the four transmission net operators in Germany) this is triple the usual rate. This effect was enlarged because the eclipse started in the morning when insolation (amount of sun rays falling on earth’s surface) was not so high, but ended around 11:30 AM when insolation is much higher. The whole effect was amplified because of the bright weather that day. Thanks to careful preparations, the German grid didn’t experience any problems. They put alternative power sources including coal, gas, biogas, nuclear and hydroelectric energy pumped from storage in action to fill in the gap. Some big industrial facilities such as aluminium plants, which are very energy intensive, temporarily lowered their demand. The solar eclipse was a unique test which is relevant for all of us, since we’re going towards more sustainable energy generation which make us more vulnerable to changes in nature. But there’s nothing to worry about -the German engineers have shown we can handle it.