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作者：Donella H. Meadows 05.10.99
二十五年來，能源專家阿莫里.羅溫不斷地深入尋找未來的能源。他曾被視為夢想家，但是現在他的事蹟已足以讓他夠資格稱得上是預言家。在最近一場國家氫學會舉辦的會議中，他與他在洛磯山研究院 (Rocky Mountain Institute) 的同事布略特.威廉在能源的拼圖加上了幾片新的元件，構成一幅以氫為基礎，不再遙不可及，並令世人振奮的經濟遠景。
若想了解全貌，沿著羅溫所點明這條的路徑走就對了。他一開始先為目前缺乏效率的能源科技點出一項天大轉機:
他堅信減少能源浪費與開鑿一個新油井或是建一個新電廠同樣有效，節約不但比較簡單便宜，同時對環境也較溫和。
在訂出「減少桶數」(negabarrels) 及「減少瓦數」(negawatts) 等節約單位後，羅溫換個方向重新思考汽車，並得到所謂「超級汽車」(Hypercar) 的概念: 「一部與富豪 (Volvo) 同樣安全、像保時捷 (Porsche)
同樣充滿活力的車」，一加侖的汽油就能讓它跑上一兩百英哩。沒有什麼簡單的方法可以達到如此驚人的效率，但羅溫提出大量的設計點子，彼此間還可以交互聯結，隨後他公開所有想法，使得汽車公司將彼此競爭，而能搶先製造第一部超級汽車上市。到目前為止，Toyota與Honda兩家公司已領先群雄。
只要可以將目前排氣量（或油耗量）減少1/4到1/8倍，就可以大幅地淨化空氣、減緩溫室效應，且降低對中東石油的依賴。但是石油終究會造成污染，並且總有一天會用完，許多人已經明白用氫來驅動我們的車子將會是比較好的方法。
若可以把氧從水中分離，或是從甲烷中分離碳，就可以得到氫；而分離所需的能源可以由風力或太陽能發電得到，氫則可以儲存、運送這些間歇性的可再生能源。還有很多方法都可以生產氫: 例如在沙漠中設置光電板列 (photovoltaic arrays)
或是從天然氣井的源頭開採，同時可以產生的二氧化碳打入井中以開採更多的天然氣，這也同時減少了溫室效應。氫就像天然氣一樣，可以利用管線來輸送，羅溫指出目前工業上常運輸大量的氫，較之於汽油顯得更為安全。
這個方案最棒的部分莫過於當你使用氫來當車子的燃料時，車子的排氣管除了水蒸氣之外，不會再排出也沒有其他廢氣。
羅溫不只想利用氫所產生的小型爆炸以推動內燃機，也想將它用於驅動電動車的燃料電池裡。燃料電池藉由受控制的化學反應產生電能，而再以補充氫氣來充電。
許多人曾夢想過車子可以使用燃料電池，事實上燃料電池已經用於太空載具之上，但正如羅溫所說的，那是「由一群博士手工打造出來的」，所以也很昂貴。必須要改變製程以大量生產，才能發展成為經濟商品，使一般民眾都有能力購買。而且目前要讓加「氫」站成為一個遍佈的網路仍有很多困難。
以上正是羅溫所新加入的幾片拼圖:
首先是超級汽車，不是現有的那些過重而拉力超強的車，而是以耗損較少能量的方法，例如小而便宜的燃料電池去達成這個目的。再來是要整合一些能相互補強的想法，造車的人通常以車子為本位思考，能源規劃者傾向專注在房子、工業、或是網格上；羅溫則考慮到整個系統，並且了解到先將氫能源利用於固定的能源需求最為容易，像是工作場所、家庭等地方，然後再將推展到交通運輸系統。
想像一下，當你一早起床，你所使用的電力是來自於你地下室中如冷氣機般大小的燃料電池，它所產生的熱能可以供給你洗澡所需的熱水，而所消耗的氫則是來自於管線、鄰近區域、或是屋頂上的太陽能收集板、或是來自於同樣位於地下室中，能把氫從天然氣中分離出來的「製氫機」。
你跳進你的超級汽車動身去上班，只有輪胎會發出聲音，你的身後只留下在空氣中的水。到了上班的地方停好車，把兩個接頭接到車上，一個是從你上班地點一具工業型的製氫機接出來，用來補充燃料電池，另一個是一條電線，它會整天從你的燃料電池接電出來並且計算你欠了多少電費。
如同羅溫所說：「當你坐在你的桌前時，你那如同發電廠的汽車正傳送超過二十千瓦的額外電力回到網格...，因此，原本你的第二大家產 (車子) 本來在閒置時都沒用處，現在卻可以自己償還本身租金中相當大的一部份，如果這種有好處的方法能被相當比例的駕駛人採用…，則大部分現存的火力、核能發電廠都將被取代，最後美國的超級汽車將會比國家發電網擁有四倍甚至更多的發電能力。」
羅溫表示：「這種方法提供了幾項策略優勢；它利用那些已經架好也付費了的天然氣及電力輸送系統離峰時期的發電能力；它依照你的需求製造，依照你的使用收費，需要的投資與需求的增加是同步的。這比起剛開始時要建構一個專門且集中的氫氣生產製造與傳輸的系統」要便宜數十到數百倍。而且存在於以天然氣分離氫與以電力分離氫兩種技術之間劇烈的競爭，將會促使硬體及氫的價格降低。」
是的，你現在還不能購買家庭號的燃料電池或是一具製氫機，或是超級汽車，儘管他們的原型都已經存在了。沒錯，目前來講這些技術都還相當昂貴，但就避免空氣污染與全球溫暖化、降低對中東石油及中央電廠的倚賴、以及不再需要建構長距離的纜線各方面所省下的花費來看，其實還不壞。沒錯，這套系統並沒有解決塞車及停車位的問題，但羅溫也有一些關於解決這些問題的點子。
想知道更多關於超級汽車(hypercar)的事，看看這裡
http://www.hypercar.com/
Donella H. Meadows是永續發展研究所(the Sustainable Institute )所長暨達特茅斯學院(Dartmouth)環境研究教授
全文詳見: http://www.gristmagazine.com/grist/
citizen/citizen051099.stm
版權歸屬 Earth Day Network，環境信託協會 (陳均輝 譯，徐怡德、朱敬平、陳中煌、蘇嵩棱審校)
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by Donella H. Meadows05.10.99
For 25 years, energy guru Amory Lovins has been seeing farther and farther into the energy future. He has been labeled a dreamer, but by now he's accumulated enough of a record to qualify as an oracle. At a recent meeting of the National Hydrogen Association, he (with colleague Brett Williams of Rocky Mountain Institute) put together some new pieces of the energy puzzle to picture an exciting economy, not far out of reach, based on hydrogen.
To understand it, you have to follow the trail Lovins has already blazed. He started by pointing out the tremendous opportunity in our current, inefficient energy technologies. Eliminating energy waste, he insisted, is just as useful as striking a new oil well or building a new power plant, and it is cheaper and easier and kinder to the environment.
Having established the value of negabarrels and negawatts Lovins moved on to rethink the automobile, coming up with what he calls the Hypercar, "safe as a Volvo, peppy as a Porsche," running 100 or 200 miles per gallon. No single trick accounts for the stunning efficiency, rather Lovins cascades dozens of design ideas that enhance each other. He makes the ideas public, so car companies will compete to bring them first to market. So far, Toyota and Honda are at the head of the pack.
Reducing the gas consumption of the car fleet by a factor of four or eight would do a lot to clean up the air, slow global warming, and reduce dependence on the Middle East. But oil is still messy and finite. It would be better, many people have realized, to run our cars on hydrogen.
You can make hydrogen from water by splitting off the O from H2O or from natural gas (methane) by splitting off the C from CH4. The energy to do that could come from wind or solar generators. Hydrogen could store and transport these intermittent renewable energy sources. Make it in the desert from photovoltaic arrays. Make it at the natural gas wellhead and shove the resulting CO2 back down the well to force up more gas and to bury the greenhouse effect. Transport the hydrogen in pipelines like natural gas. Lovins points out that large quantities of hydrogen are already moved around for industrial purposes and that it is safer than gasoline.
The best part of this scheme is, when you use the hydrogen to run your car, out of your tailpipe comes nothing but water vapor.
Lovins wants to use the hydrogen not in mini-explosions that drive an internal combustion engine, but in a nice quiet fuel cell that drives an electric motor. A fuel cell is essentially a battery; it generates electricity through a controlled chemical reaction. You recharge this battery by loading in hydrogen.
Many folks have dreamed of fuel cell cars. Fuel cells exist; they are the mainstay of space vehicles, but they are, as Lovins says, "hand-assembled by PhDs" and therefore expensive. It would take a massive scale-up to develop production economies that ordinary mortals could afford. Furthermore, it's hard to start up a network of hydrogen refueling stations.
So here are Lovins's new pieces of the puzzle. First, Hypercars. If we're not talking about our present over-heavy, draggy brontomobiles, we need way less power, therefore a smaller, cheaper fuel cell. Second, cascade some mutually enhancing ideas. Car people tend to think only about cars; energy planners tend to think mainly about houses, industry, or the grid. Lovins thought about the whole system and realized it would be easiest to start with stationary energy needs -- workplaces, houses -- and then expand hydrogen into the transportation system.
Picture this. When you get up in the morning, the electricity you use comes from your basement fuel cell, about the size of an air conditioner. The heat it generates gives you hot water for your shower. The hydrogen it consumes could come from a pipeline, from a neighborhood or rooftop solar array, or from a natural-gas fired "hydrogen appliance" also in your basement.
You hop into your Hypercar and go off to work. Only your tires make noise; only water remains in the air behind you. When you pull into your parking space at work, you snap two connectors onto your car. One reloads your fuel cell from the industrial-size hydrogen-appliance at your workplace. The other is an electric line that takes power all day from your fuel cell and calculates how much you're owed for the electricity.
As Lovins says: "While you sit at your desk, your power-plant-on-wheels is sending 20+ kilowatts of premium-quality electricity back to the grid. ... Thus your second-largest, but previously idle, household asset is now repaying a significant fraction of its own lease fee. If a modest fraction of drivers took advantage of this deal ..., most or all existing coal and nuclear power plants could ... be displaced. Ultimately the U.S. Hypercar fleet could have four or more times the generating capacity of the national grid."
Says Lovins: "This approach offers several strategic advantages. It uses idle off-peak capacity in the natural-gas and electricity distribution systems that have already been installed and paid for. It is build-as-you-need and pay-as-you-go, requiring investment only in step with incremental demand. It is one or two orders of magnitude cheaper than building a dedicated, centralized hydrogen production and delivery system from scratch. ... And vibrant competition between gas- and electricity-derived hydrogen, ... will exert downward pressure on the prices of hardware and hydrogen."
No, you can't buy a house-sized fuel cell yet, or a hydrogen generator, or a Hypercar, though prototypes do exist. Yes, right now the technologies are expensive. But factor in the avoided costs of air pollution, global warming, defense of the Middle East, central power plants, and long-distance electric wires and they don't look so bad. Right, this system still doesn't solve the problem of traffic jams and parking places. Lovins has some ideas about that, too.
If you'd like to learn more about hypercars, check out
http://www.hypercar.com/.
Donella H. Meadows is director of the Sustainability Institute and an adjunct professor of environmental studies at Dartmouth College. |
