2006.08.29　 中國時報
巴西的燃料自足經驗
鄭天佐

巴西人口約為台灣的八點三倍，土地約為二四○倍，而人口密度則約為二十九分之一。兩國自然資源和土地人口非常懸殊，但經濟發展和成長率相差不多。巴西在一九七○年代石油進口率達九十％，現在台灣進口率接近百分之百。

近年來巴西之所以受到全球矚目，原因是當大家憂心石油價格上漲和地球表面溫室效應時，巴西卻達到百分百燃料自足，且四十％使用少排放溫室氣體的生質能──酒精。七○年代世界石油危機時，巴西政府鑑於對國外石油高依賴度威脅國家能源安全，他們一方面努力探測和開採國內石油，一方面推動前瞻性酒精替代能源計畫。不只獎勵農民種植甘蔗，也建立研究機構改良品種和釀造方法。

如今巴西酒精價格約為每公升台幣十八元，而汽油則為三十三元。雖然酒精能量低於汽油三十％，用酒精還是經濟實惠。他們多數的加油站充油管有一支充酒精，一支充酒精與汽油混合液，一支則充高檔汽油。混合液本來含二十五％酒精，但因酒精供不應求今年降為二十％。一般預測年底巴西國內出賣汽車百分百將是酒精和汽油雙用型。

巴西的酒精計畫並非一帆風順，一九八○年代全球石油價格下降，造成蔗農和酒精汽車擁有者極大損失。但是他們研發工作從未中斷，努力與堅持終於得到回報。如今很多先進國家的能源專家和投資企業家競往巴西取經，我們能源公司主管和政府能源政策制訂者應該仿效。

酒精並非解決能源短缺和溫室效應的唯一途徑。很多汽車製造廠和研發機構也同時開發電動馬達引擎，可利用氫氣電池把酒精能量轉換為電能，或用一般電源，後者需要輕便且容量大的蓄電池。生產酒精也非只限於甘蔗，環境考量我們政府計畫以甘薯替代，而美國農民則推動用玉米。很多國家正在研發分解植物纖維製造酒精的新科技，屆時甘蔗渣、修剪的草木，和廢棄木頭與紙張都可利用。我們推動生質能另有減輕失業人口和提升國家能源安全效益。

另一必須思考的問題是，地大人稀的巴西尚且遇到產量不足困境，台灣也很難避免。更加嚴重的是少數專家預測（正確性有待檢驗），即使我們把全世界不種植食物的土地全部利用來生產生質能，也僅能供應我們三十％的需求，但是食物的生產必會受到影響。以巴西為例，酒精的大量使用使得世界蔗糖價格上漲。全球人口逐年增加，我們必須評估大量使用生質能對糧食供應可能造成的衝擊。

世界本來就沒有白吃的午餐，自然資源補充速度有限，把資源用在某方面，另一方面就得節省。重要的是資源政策必須符合環境保護，並以永續發展作為最高原則。舉例說，種植稻米和甘薯，品種的改良、輪休耕、水土保持，肥料和農藥使用都需深入研究，而且不能違背永續發展大原則：想吃魚就不能大小魚一把抓，想收割米和甘薯，枝幹和葉子就不能全部用來釀造酒精。其實最好的永續發展策略，還是節省和善用地球有限的資源。

（作者為中央研究院院士）
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Brazil sets example on energy use

By Tsong Tien-tzou 鄭天佐

Taipei Times, Wednesday, Sep 06, 2006, Page 8

In terms of population and size, Brazil is 8.3 times and 240 times bigger than Taiwan respectively, while population density is only one-twenty-ninth of Taiwan's.

With regard to natural resources, size and population, there is a wide discrepancy between Taiwan and Brazil. However, both countries have fared about the same in terms of economic development and growth rates. In the 1970s, 90 percent of Brazil's crude oil was imported, while Taiwan today imports nearly 100 percent of its oil.

The reason Brazil has attracted the world's attention in recent years is that while the world is concerned about soaring oil prices and the worsening greenhouse effect, Brazil is now self-sufficient in terms of fuel supply and it has replaced 40 percent of its gasoline consumption with biomass energy -- ethanol.

During the 1970s oil crisis, the Brazilian government realized that its heavy dependence on oil imports would threaten its energy security, so it began to put great effort into exploring and exploiting domestic oil fields and pursuing a pioneering energy substitution project to replace gasoline with ethanol.

Not only that, it sought to reward farmers who were willing to grow sugar cane, while also establishing research institutes to improve sugar cane varieties and ethanol brewing procedures.

In Brazil today, a liter of ethanol costs around NT$18 and a liter of gasoline costs NT$33. Although a liter of ethanol contains about 30 percent less energy than gasoline, it is still a more economical fuel.

Most Brazilian gas stations offer three types of fuel: pure ethanol, a mix of gasoline and ethanol, and premium gasoline. The mix previously contained 25 percent ethanol, but that was reduced to 20 percent as the demand for ethanol outstriped supply. It is estimated that by the end of this year, all vehicles sold in Brazil will be the duo-fuel type, i.e. powered by both ethanol and gasoline.

Brazil's ethanol program has not been hassle-free. In the 1980s, when the world's oil prices were falling, sugar cane farmers and owners of ethanol-powered vehicles suffered tremendous losses. Nevertheless, the government never gave up on its ambitious project. Fortunately, its perseverance and hard work has now paid off.

Nowadays, energy experts and entrepreneurs from developed countries travel to Brazil to learn from its success. I believe that leaders of Taiwan's energy companies and government policymakers should follow their steps.

Using ethanol is not the only approach to solving energy shortages and the greenhouse effect. Therefore, carmakers and research institutes are developing electric cars that use hydrogen fuel cells that transform ethanol energy into electricity or use electric power from city power. The latter requires light and large capacity batteries. Ethanol production does not rely on sugar cane alone either.

Considering the different environmental conditions, Taiwan is planning to use sweet potatoes rather than sugar cane to generate the energy the country needs, while in the US, farmers are pushing to use corns. Many countries are also developing technology aiming to produce ethanol from plant fiber.

If the project is feasible, sugar cane bagasse, grass, discarded wood and scrap paper could also be used. Promoting biomass power in Taiwan could also reduce unemployment and enhance the nation's energy security.

Another issue to consider is that if a scarcely populated country such as Brazil has experienced inadequate yields of these energy substitutes, Taiwan is likely to encounter similar problems. Some energy experts even predict that if all land not used to produce food is used to produce biomass energy, that would still only supply 30 percent of world's energy needs, and it would affect global food production.

For example, Brazil's massive use of ethanol has led to soaring international cane sugar prices. As the global population continues to grow, the potential impact of the use of biomass power on the world's food supply must be considered.

There is no such thing as a free lunch. The rate at which natural resources regenerate is limited. When natural resources are consumed for one purpose, that means that there are less resources left for other purposes. The important thing is that energy policy is environmentally friendly and that sustainable development is the guiding principle.

If we want to continue to have fish, we cannot fish for both large and small fish, and if we want to continue have rice and sweet potato, we cannot use all the stems, branches and leaves to produce ethanol. The best policy for sustainable development is still to save on the limited global resources.

Tsong Tien-tzou is a research fellow in the Institute of Physics at the Academia Sinica.

Translated by Daniel Cheng