汽车界可承受之“氢”

工作人员,在此过程中,对于氢能是否能成为汽车未来能源的最终极解决方案这个问题,你也许会找到答案。

科学家告诉我们:为什么需要氢能动力汽车?

Gareth: Hydrogen! We’ve heard it all before. All that talk last 2)millennium, all this stuff about the hydrogen economy. The media may have left the topic alone, but the scientists, engineers, and now car companies, certainly haven’t.

Well, what’s new and where next for hydrogen? And for a glimpse of that, Germany’s a pretty good place to start. It’s considered to be one of the leaders in Europe when it comes to hydrogen technology. Klaus Bonhoff is head of the country’s National Organisation for Hydrogen and Fuel Cell Technology.

Klaus: We had a big hydrogen 3)hype some ten years ago. People were thinking, “Well, here’s the solution for future mobility, here’s a zero-4)emission mobility based on 5)renewables”. These were the advantages, but these still are the advantages. It then became obvious that it would take some more time to actually get this into the market. Public side is sometimes not as patient as that, so there was another hype that came up. So we talked about bio-fuels. And we’re now talking about battery technologies. So people tend to believe that future mobility will be based on just one solution. And this is just not the case. We do need bio-fuels. We do need battery technologies. But we also need hydrogen and fuel cell technologies.

Gareth: Which part of that 6)portfolio does it fit into? Which areas of transport would you say hydrogen is best suited to?

Klaus: When you look at the urban areas and the CO2 emissions related to public transport, hydrogen and fuel cells really offer the best potential to provide zero-emission buses in…in 7)metropolitan areas. Within road transportation, around 70% of the CO2 emissions is from passenger cars and light duty vehicles, so this is the segment you have to really address if you take CO2 emissions seriously.

Heavy duty has also a role to play. Probably options like bio-fuels are, at least short-term, a better option for that segment, but let’s 8)stick with the passenger cars and light duty vehicles for a minute. And within this you see different segments: you see compact cars, mid-size cars, large cars. Everybody today is talking about batteries, and batteries are best suited for compact vehicles with short range, and this is where they actually offer huge advantages and, you know, besides that they’re fun to drive, offer environmental benefits and they’re zero emission. When it comes to larger vehicles with longer range that can be refueled in, you know, minutes, as what we’re using today. This is where we are really in the arena of hydrogen fuel cell technologies.

汽车工程师向我们证明:氢能动力运用在轿车中有完美表现。

Gareth: Bring a load of designers from car companies together and they like nothing better than looking under each other’s 9)bonnets, especially when the kit within is still so novel. One of those “10)kicking the tires”,to use an industry phrase I’ve only just learned, is Sabina Flantz. She’s an engineer at Ford.

Sabina: The fuel cell is not under the 11)hood. The fuel cell sits underneath the driver and the passenger seat. And then there’s another box with 12)accessories: its compressor, its

13)valves, its knockouts, its all that stuff that makes the fuel cell happy. That’s behind the rear seat bank.

Gareth: And because there is less to look at, and there are certainly fewer moving parts, does that mean there’s less to go wrong?

Sabina: We can say that these cars have been more reliable than we’ve ever thought that they would be. So those cars are designed for three years of a lifetime. A regular car is still designed for ten years of a lifetime, so those were the cars they built in 2004 designed for three years and we’re beyond this. And we can still have them in the field because they’re better than we expected. Now, are they comparable to the regular combustion engines? Not quite. We’re not quite there. But think about the past 100 years that we spent to 14)refine the 15)combustion engine car. In the past ten years that we’ve been using those (that) type of cars...

伦敦试验者为我们剖析:氢能作为公共交通工具能源的可行性。

Gareth: Well, from cars to buses and from Berlin to London, I’m back in London, actually on the bus along the RV1 bus route going on the south bank on the Thames. Now, if you are a Londoner, then I know what you’re thinking, “Didn’t we once have hydrogen-powered buses on this route?” Well, you’re right. We did. So what happened? We’re back to

16)diesel now.

Well, those hydrogen buses were actually just on a 24-month trial that started in 2004. London was one of nine cities on that study aimed at establishing the viability of hydrogen as a fuel for public transport. Overseeing it all in the capital was Mike Weston. He’s operations director for buses at Transport for London. And I’m on my way to his office right now. I’m very keen to find out what that trial revealed.

Mike: We learnt it was viable. It was reliable. It had some limitations. The main limitation being around operating range of the vehicle. And so, in coming up with our next project, we were…we…we set some…ourselves some clear objectives. The next demonstration had to move the technology forward; it couldn’t just be a case of buying some more buses, more similar buses that performed in the same way and did the same job. So we…we went out to a competitive tendering process, to the market. And we said that the next hydrogen buses must have an operating range of about 18 to 20 hours a day and must be able to run on the RV1 for the whole duration of the operating day.

Gareth: How do you manage to extend the distance they can travel?

Mike: Okay. The main way in which we’ve managed to extend the operating range of the buses is…is by combining the fuel cell technology with hybrid technology. We already have in London a number of diesel hybrid buses, and the hybrid system is an on-board energy system that…you stores excess energy from the…from the engine and also from the braking system. That allows more efficient use of the vehicle.

Gareth: Storage is an issue, isn’t it? I mean, how big is the…the hydrogen tank on the bus?

Mike: The hydrogen is stored on the roof of the vehicle in…in six circular tanks about two metres long each. And…and the bus will carry about 45 kilograms of hydrogen, which actually becomes a bit of a challenge in the future, because actually we…we’ve struggled to find that storage space on…space on double-deck vehicles.

Gareth: So do you see London as a bit of a leader, I mean you’ve been part of this kind of pan-European project? But London, as a city, are you…are you proud of what you and London have achieved in bringing these buses onto the streets of London and making them work?

Mike: Yeah. I mean certainly…certainly this next project is…is fairly unique, because it will be one of the first cities in the world to have buses that can…can have the operating range and perform very…on a very similar basis to diesel. But we are working with … we…we have an alliance with a number of other worldwide cities. We’re working very closely with about a dozen other cities around the world, who are also trying different types of hydrogen bus technology. And the challenge is ultimately that the…the…probably the next barrier to the roll-out of this technology is cost. Still relatively expensive—these buses cost about four or five times the cost of a conventional single-deck bus. So it’s still a big barrier. And the one thing that will help change that is volumes (volume). So we need more cities around the world to be buying hydrogen buses and to increase the volume so that we can get the cost down and make them more economical.

Gareth: I have to say I’ve had a lovely time on this program with the believers and those hydrogen evangelists. But back here in London it’s pretty much down to earth. I mean, yes, there are quite a few hybrid cars around these days, but for the most part, the streets remain choked with petrol and diesel vehicles. It’s a reminder that, whilst they’ve cracked fuel cell technology, the costs really need to come down, and designs need to be refined. Hydrogen isn’t hype anymore, but then neither is it everyday reality. Well, not quite yet anyway.

格瑞斯: 氢动力!我们早有听闻。上个千禧年炒得火热的概念,什么“氢能经济”的。媒体或许已不再关注了,而一众科学家、工程师,还有当今的各大汽车公司却绝对还没放弃这一议题。

那么,关于氢动力,有什么新发现新路向呢?要一探究竟,德国是个不错的门户。说到氢能科技,德国在这方面的发展被公认是欧洲多国中的佼佼者。克洛斯·波恩贺夫是德国“国家氢能及燃料电池组织”的头儿。

克洛斯: 大概十年前,有一阵子,氢能概念给炒作得很厉害。大家都觉得“好了,将来出行运输的能源问题找到解决方案了。基于可再生能源、零排放的动力就在眼前了”。氢能的这些优势,过去如此,现在依然不变。但是显然,把氢能概念化为实际应用推出市场得花上好一段时间。普罗大众有时候没这个耐性,所以,另一股热潮抢滩兴起,我们转谈生物燃料,而现在,我们又开始谈电池驱动科技了。就是这样,人们习惯上以为将来的动力来源只能依赖唯一一种方式,而实际上并非如此。我们既需要生物燃料,也需要电池科技,同时,还需要氢能及燃料电池科技。

格瑞斯: 在能源应用的组合体中,氢能适用在哪方面?你认为氢能最适合用在哪些运输领域上?

克洛斯: 看看那些城市区域和公共交通工具的二氧化碳排放量,氢能及燃料电池的确具备最佳潜力为大都市打造零排放公车。在道路运输方面,大约70%的二氧化碳排放量源于轿车及轻型货车,所以如果真要解决二氧化碳废气排放问题,就得好好往这一运输类别着手处理。

重型货车当然也是个问题,生物燃料也许是这类汽车的一个更好的选择,至少短期而言如是。但是我们还是稍微再谈谈轿车及轻型货车吧。在这个领域里,还可以细分成不同车型:有小型车、中型车、大型车。今天人人都在说电池,而最适合采用电池动力的是跑短途的小型车。电动的优势在这一车型上得到明显的发挥,除了提供独特的驾驶乐趣,还具备环保性能,零排放无污染。而说到跑更远距离的大型车,也就是我们现在用的那些可以在几分钟内加满燃料的汽车,则是氢能燃料电池科技应用的大舞台。

格瑞斯: 把各大汽车厂商的设计师请来集聚一堂,他们最喜欢的就是揭开别人的车头盖往里审视,尤其是当那套发动设备还那么新的时候。其中一位来“踢车胎”的——套用一句我刚学到的行话——是福特汽车的工程师莎宾娜·弗兰兹。

莎宾娜: 燃料电池并不在车头引擎盖下,而是设在司机及乘客座椅下。另外还有一个内有空气压缩机、阀门、分离器等辅助燃料电池正常运作的配件箱,安装在后座储存室后面。

格瑞斯: 既然要看的东西没那么多,运动机件当然也少了,那是否意味着问题也随之变少?

莎宾娜: 我们可以说这种(使用燃料电池的)汽车比我们当初想象的要更可靠实用。那些车的使用寿命设计是三年,而一部普通汽车设计的使用寿命依然是十年。那些是2004年制造的车,本来设计只能用三年,而现在我们已经超越了这个年限。到目前我们还在用那些车是因为它们的表现超乎了我们的预期。那现在它们的性能可以比得上常规的内燃机驱动汽车吗?还不怎么行。我们还没达到那个水平。但要想想,过去一百年我们一直在发展完善内燃机驱动汽车的制造工艺及性能,那类汽车是我们过去十年间都还在一直使用的……

格瑞斯: 谈完小车我们来谈谈大巴,去完柏林,来伦敦看看。我现在回到了伦敦,正坐在公车上,是沿伦敦泰晤士河南岸行驶的RV1线路公车。如果你是伦敦本地人,那我知道你一定在想:“本来不是有氢动力公车走这条路线的吗?”嗯,没错,曾经是有的。我们现在又用回柴油机驱动的大巴了,这是怎么回事呢?

其实,那些氢动力公车只是试运行了两年,从2004年开始的。当时有一个项目旨在研究以氢能作公共交通工具能源的可行性,伦敦是九个试验城市之一。在英国首都监理这一项目的是迈克·韦斯顿,他是伦敦交通局的公车服务营运总监。现在,我就是坐车往他办公室去。我很想知道那次的试运行得出了什么结论。

迈克: 我们了解到,氢动力巴士作为公车是可行的,是可靠的,但也有一些局限,最大的局限主要是巴士的可行驶里程。所以,在进一步的项目规划中,我们订下了一些清晰的目标。下次的试验必须把科技再推进一步;不能仅仅是购置更多的巴士,不该购置表现和功能都大同小异的巴士。因此,我们把项目推向市场,进行公开竞标,要求下一批氢动力公车必须每天能跑18至20个小时的路,而且必须能按RV1线路营运日的全程时数行驶。

格瑞斯: 那你们是怎样延长这些氢动力巴士的行驶里程的呢?

迈克: 我们延长这些巴士的行驶里程主要是把燃料电池技术跟混合动力科技结合起来。我们已经有一些柴油混合动力公车在伦敦营运。混合动力系统是一种车载能源系统,引擎和刹车机件产生的剩余能源会通过这一系统被储存起来,让汽车实现更节能高效的运作。

格瑞斯: 贮存空间是个问题吧?我意思是,那些巴士上的液氢储罐有多大呢?

迈克: 氢燃料贮存在车辆的顶部,有六个分别长两米的圆柱状储罐,共装有大约45千克的液态氢。这对氢动力公车将来的发展的确是构成了一定的挑战,因为在双层巴士上,我们一直很难找到足够的空间来放置那些储罐。

格瑞斯: 你参与过这样一个覆盖欧洲多国的试验项目,伦敦作为一个城市而已,有此成果,你觉不觉得伦敦是这方面的领头羊?能成功引入这些公车在市内道路上行驶,你会为自己和伦敦在这方面的成就感到骄傲吗?

迈克: 会的,这个新计划绝对是相当无可比拟的,因为伦敦将会一马当先,在全球率先拥有里程性能可媲美柴油机驱动汽车的氢动力公车。而我们也跟世界其他一些城市保持着研发同盟关系。现时,我们跟世界各地的十几个城市紧密合作,它们也在努力尝试不同类型的氢动力巴士技术,最终的挑战……普及推广这一技术过程中要解决的下一个障碍很可能就是成本的问题。这些巴士的成本是一般单层巴士的四到五倍,花费仍相对高昂,所以始终是一大障碍。有助改变这一现状的就是这类巴士的增量应用,因而我们需要全球更多的城市继续购置这些氢动力巴士,量的提高会使成本降低,使其变得更经济适用。

格瑞斯: 我得说,很高兴在这次的节目上跟各位氢动力的传道先驱和信徒们高谈远景,但回到伦敦这里,还是要老实面对现实。我的意思是,没错,最近是有那么一些混合动力汽车在城中行驶,但街道上大部分还是充斥着汽油及柴油车辆。这提醒着我们,虽然他们在燃料电池技术方面有所突破,但成本确实需要降下来,设计也需要进一步改良优化。“氢动力”已不再是概念炒作,可惜也未完全融入我们的日常生活,还挺有点距离呢。

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