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生物氣體
利用生物廢料來產生能量已經證明是一種實用且經濟的回收再利用大量有機垃圾的方法。來自家庭、農業、商業、以及工業的垃圾被微生物所消化，產生出一種甲烷和二氧化碳的混合氣體，然後就可轉變成能量。甲烷是無毒、無煙、並且可燃的氣體。1立方米生物氣體所產生的燃料足以供一個5、6個人的家庭煮三頓飯，同時還可以使一個60瓦燈泡點7個小時，或者供應1臺1馬力的內燃機運作2個小時。
生物氣體技術具有很多益處。它能消化掉人類垃圾，並且減少垃圾中的病原體而引發疾病傳染，其中包括造成傷寒、龍線蟲症、霍亂、痢疾、鉤蟲病、血吸蟲病等病菌。雖然「生物氣體」在中國、泰國、印度及尼泊爾等地得到廣泛應用，但在非洲的南部地區還需加以推廣。
在很多發展中國家裏，大多數有機廢料，諸如牲畜的糞便、農作物殘渣等被當作燃料直接進行燃燒（稱為「生物量」能源產生），但是這些廢料的燃燒往往造成空氣污染，導致呼吸道疾病。根據世界衛生組織（WHO）1992年的資料，在發展中國家裏有7億婦女因生物量的燃燒而面臨著越來越嚴重的健康問題。如果一部分廢料是透過生物氣體技術而加以利用，此類健康類問題就能減少。
海洋能量
從海浪中產生的能量也許不會成為電力的主要來源，但是它持續在經濟和技術上展現出越來越多的可行性。根據《新科學家》雜誌（1998年5月16日發行本）的報導，利用波浪發電目前的平均成本是1982年的十分之一。該雜誌的報告說，現在可供使用的六種波浪發電裝置中的三種具有商業競爭力，而且其中一種裝置在英國的發電成本，比起燃煤發電便宜了三分之一。《新科學家》雜誌進一步指出，英國政府目前正在認真考慮，將波浪發電列入此一目標：英國將在2010年之前減少二氧化碳排放量10%。
另一項試驗性的能源利用正在夏威夷島（美國）、日本、巴里島（印尼）其他一些地方進行研發。該項技術是利用海洋表面與海面下1,000米深兩處海水的溫差來產生能量。
版權歸屬 國際河網IRN，環境資訊協會（陶俊 譯，吳國玢、李瑞玉 審校）
中英對照全文：http://e-info.org.tw/issue/water/2001/is-water-irn01120301.htm |
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Biogas
The use of biological waste to generate energy has been proven to be a practical and economical means of recycling large volumes of organic wastes. Waste from domestic, agricultural, commercial and industrial sources is digested by microorganisms, which produces a mixture of methane and carbon dioxide, which is then turned into energy. Methane is non-toxic, smokeless and flammable. One cubic metre of biogas produces enough fuel to cook three meals for a family of five to six people, running one 60-watt electric light up to seven hours, or running a one-horse-power internal combustion engine for two hours.
Biogas technology has a number of benefits. It can digest human waste and decrease the spread of disease from pathogens in the waste, including organisms that cause infections such as typhoid, Guinea worm, cholera, dysentery, hookworm and bilharzia. While biogas has been widely used in China, Thailand, India and Nepal, it has yet to be encouraged in Southern Africa.
In many developing countries, most organic wastes such as dung and agricultural residue are burned directly for fuel (referred to as "biomass" energy production). The combustion of these wastes often creates air pollution and causes respiratory diseases. According to the World Health Organization (1992), 700 million women in developing countries are at risk for developing serious health problems from the burning of biomass. These problems would be reduced if a portion of these wastes were used in a biogas process.
Ocean Power
Creating energy from ocean waves may never become a major source for power, but it continues to become more economically and technically viable. According to New Scientist magazine (May 16, 1998), the average cost of wave power is now 10 times lower than it was in 1982. The magazine reports that three of the six wave-power devices now available can produce power that is economically competitive, and one device produces power that is one-third cheaper than coal in the UK. New Scientist reports that the British government is now seriously considering including wave power as part of its goal to reduce carbon emissions by 10 percent by the year 2010.
Another experimental energy source is being researched in the US island of Hawaii, Japan, Bali and elsewhere. The technology uses the difference in temperature between ocean surface water and water up to 1,000 metres deep to create energy.
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