(示意圖/圖片來源:Pixabay)

在上一篇文章中(美國生質能使用:政策與地理的決定性影響),我們提到了有關美國在生質能的成長,以及政府如何將技術支援與再生能源配額制度(RPS)結合起來,以降低各州電廠使用再生能源的進入障礙,鼓勵各州使用生質能。在美國,生質能發展的主要動力來自農業政策,在其相關政策下補助農民、森林所有者及其他木質生質能提供生質料源,如:生質能作物援助計畫(Biomass Crop Assistance Program,簡稱BCAP)及其他直接、間接補貼,使得美國生質能成本可以在短期內下降。

在2008年以前,生質能已被廣泛應用於美國本土,尤其是電影「不願面對的真相」後,政府對氣候變遷意識逐漸增強,聯邦政府規劃用一個較為緩慢的方式來減少化石燃料使用。本文將不涉及以玉米為原料之生質酒精或生質柴油,著重討論生質能中另一部分固態能源。當時化石燃料價格相較於今日仍屬於相對高點,對生質能來說,其最大成本來自於將料源由各地收集至電廠所產生之運輸成本(2016 Billion-Ton Report),而生質能料源本身屬於廢棄物,通常來自林業或農業。

(資料來源:2016 Billion-Ton Report)
圖1 2040年美國潛在森林、農業與廢棄物生質能料源(基礎情境)

由上圖Billion Ton報告中的分析可以發現,經濟規模能夠降低生質能成本,基於這個邏輯,催生了2008年農場法案(Farm Bill),及生質能作物援助計畫(BCAP),以降低森林與廢棄物在農業部門的成本。

生質能作物援助計畫(BCAP)補貼農業或林業土地所有者,將木質原料賣給政府,且規範只有經過認證之能源或加工廠才可收取上述乾生物質廢棄物。該措施當時被認為解決農林部門三個潛在問題:(1)大量農業廢棄物、(2)植被留在森林之潛在火災風險、及(3)作為發展生質能之料源。目前該計畫每年花費2,500萬美元,其中10%-50%成本,透過政府配套措施,用來支付生質能收集與運輸成本,利用此方式,政府不須直接支付予未經認證之設施,並可要求土地所有人承擔責任。該計畫最初並未設定補貼上限,但由於2010年該計畫補貼金額達到2,500萬高峰後,政府最終應設定補貼上限之限制(註1)。另外,美國國內對於森林剩餘資材之清運仍有部分爭議,部分團體認為林地生態健康與碳封存之目的而需要剩餘資材,另有部分團體則認為剩餘資材堆置,恐會增加火災或外來物種之風險。

(圖片來源: wiki )

生質料源之收集解決了一半的挑戰,而現在他們所需要的是一個地方來負責生質能生產過程。由於擔心品質問題,Farm Bill法案為生質能轉換設施(Biomass Conversion Facilities,簡稱BCF)制定認證標準,BCF可自BCAP收到料源,但無法直接獲得支持,相反地,他們可以透過取得更便宜之燃料而受益,他們也可以收取BCAP以外之其他生質燃料來源。除了乾性的木質生質能外,政府也為生質柴油設立單獨的租稅抵免制度,2006年,美國有20%玉米產量用於生產生質酒精,當年透過BCAP對玉米所獲得之農業補貼合計為88億美元。2011年,估計約18億美元用於補貼生產生質酒精之玉米。請注意,這些並非是來自玉米之廢棄物。該計畫仍存在很大爭議,且面臨對環境效益之質疑(註2)。儘管這些方案有潛在缺點,但均大幅降低成本並改善生質能生產之過程。

表1 2014年生質能消費量及能源產量(million bioenergy equivalent dry tons per year)
(Source: 2016 Billion-Ton Report)

對亞洲的啟示

顯然地,從美國的情況看來,若補貼一種能源將會增加使用量,然而當伴隨著政府干預增加,可能無法總是產生最好效果。當天然氣價格開始下滑,石油價格下跌,生質柴油計畫與生質能計畫皆在2012年左右結束。截至目前為止,隨著其他能源的蓬勃發展,風力與太陽能發電價格持續下跌,美國生質能發展已逐漸進入高原期,全球對生質能投資也逐漸減少。

當時BCAP與生質柴油之稅收抵免等政策同時滿足實際需求與感知的需求。實際需求來自對農業廢棄物與森林剩餘資材之清運、外來物種之控制與火災預防,這些計畫有助於其他政府計畫能夠得以施行。大眾感知的需求來自能源獨立及碳減排,因此無法使用相同方式去施行。當亞洲在推動生質能計畫時,在展開新計畫前,若能認知並釐清到什麼需求是生質能可以解決的,可以避免浪費政府寶貴的資源與政策。

(責任翻譯:吳周燕)

 


Lowering the Cost of Biomass: The US Experience

In the previous article we went over the growth of biomass in the US and how government technical support combined with renewable portfolio standards lowered the barriers to entry for state power authorities to use biomass. A boost to biomass came from agricultural policies that paid farmers, forest owners, and others with woody biomass to bring their material for collection. This program, the Biomass Crop Assistance Program (BCAP), along with other direct and indirect subsidies drove down the cost of biomass in the US.

Prior to 2008 biomass was used extensively in the United States, but after government awareness of climate change began to increase, especially after the film An Inconvenient Truth, the federal government wanted a way to move slowly towards using less fossil fuels. This article won’t touch on corn ethanol or bio-fuels, yet they make-up half of the energy generated under “biomass”. At the time, fuel prices were relatively high (compared with today). For biomass, the largest cost comes from transporting the materials from the resource site to the point of power generation (Billion Ton Report). Mainly because the materials themselves are waste, from forestry or agriculture.

(Source: 2016 Billion-Ton Report)
Figure 1  US potential forestry, agriculture, and waste biomass resources at the roadside in 2040 (base case)

As you can see from the above graph this analysis from the Billion Ton Report shows how economies of scale can reduce the costs of biomass substantially. However, forestry and waste have high costs regardless. Understanding this context, the Farm Bill of 2008 created the Biomass Crop Assistance Program (BCAP).

The Biomass Crop Assistance Program paid landowners, either agricultural or forestry, to remove woody material and sell it to the federal government. Only certified energy or processing facilities could receive this dry biomass waste. At the time, this was believed to solve three issues, the large amounts of waste in agriculture, the potential fire risk of vegetation left in forests, and the development of biomass fuel sources. Currently the program covers $25 million USD per year and covers10-50% of costs to cover harvest and transportation of biomass through matching payments from government. In this way the government does not pay directly for uncertified facilities and requires landowners to take responsibility. The program originally had no cap, but in 2010 when the program peaked at $250 million matching payments the government finally set a limit.[1] The removal of forest residues remains somewhat controversial with some groups saying forests need the residue for ecosystem health and carbon sequestration, others say it represents a fire or invasive species risk.

(Source: wiki )

Collecting solved half of the challenge, now they needed responsible sites to process the biomass. Fearing issues in quality, the Farm Bill also set standards for certified Biomass Conversion facilities (BCFs). BCFs receive material from the BCAP, but do not receive direct support themselves. Instead they benefit by processing cheaper fuel, yet they can also utilize other biomass fuel sources not only from the BCAP program.

Besides dry woody biomass the government also created a separate tax-credit system for biodiesel. In 2006, 20% of the U.S. corn harvest was used for ethanol production. The total agricultural subsidies through the BCAP for corn that year totaled $8.8 billion. In 2011, an estimated $1.8 billion went to subsidize corn destined for ethanol production. Note that this was not waste products from corn, this program remains highly controversial and is of questionable environmental benefit. [2] Despite their potential drawbacks, all of these programs taken together substantially reduced the cost and improved the logistics of biomass for energy production.

Table 1  Total Current Consumption of Biomass (2014) for Energy and Energy Products (million bioenergy equivalent dry tons per year)
(Source: 2016 Billion-Ton Report)

Lessons for Asia

Clearly, if you subsidize a form of energy it will receive increased usage. However, when it comes to government intervention, that may not always work best. Both the biodiesel program and the biomass program ended around 2012 when natural gas prices began to drop crushing the price of oil. Fast forward to the present, wind and solar prices continue to drop with biomass in the US plateauing and global investment for biomass decreasing as these other forms of energy move ahead.

At the time the BCAP and the biodiesel tax credits filled a real need and a perceived need. The real needs came from removal of agricultural waste, forestry residue, invasive species control and fire prevention. These programs helped enable other government programs and generated cleaner energy as a result. The perceived needs of energy independence and carbon reduction did not materialize in the same way. When developing biomass projects in Asia, understand what needs biomass can solve before beginning new projects to avoid “wasting” government support and policy.

 

Note

  1. http://nationalaglawcenter.org/wp-content/uploads/assets/crs/R41296.pdf
  2. https://www.scientificamerican.com/article/biofuels-might-hold-back-progress-combating-climate-change/

【延伸閱讀】

美國生質能使用:政策與地理的決定性影響
Biomass Use in the United States: Policy and Geographic Impacts

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