考量碳中和下之農企業最適經營策略分析－－以台糖公司造林地為例

目前仍少有實證研究探討農企業如何透過土地資源的最適規劃達到自身碳中和並獲取最大經營效益。本文以全臺最大農企業台糖公司為例，利用其於2003-2012年間配合政府平地造林政策於20年屆期後，來探討此議題。台糖十年造林面積達9,106.27公頃，遍及台灣10個縣市及種植上達50多種樹種。本文採國家及國際層級數據計算碳吸存量，並結合氣候資料及農業生產等多種資料來計算出台糖公司於在持續造林、太陽能光電及做為農業生產的最適選擇。實證結果顯示，台糖公司造林的碳吸存量於植林第18年時可抵銷其組織每年類別一及類別二所造成的碳排量23.2萬公噸CO_2e。結果也顯示台糖公司於十年間造林在2031年所有造林補助屆期後，平均每公頃碳吸存量為18.99公噸CO_2e。台糖公司在達碳中和後，僅需維持約6,020公頃繼續造林（約占總面積的66%），其餘面積轉為農租或將不利耕作之農地做太陽光電使用。其中，由於太陽能光電每公頃收35萬元最高，農租價格次之，碳滙每公頃收入僅有0.83萬元，所以台糖公司若無其他考量，最有可能將其不良農地做為光電使用，僅約28%的造林地轉為農租。在此選擇下，台糖公司最大年收益約可達341百萬元。各縣市的規劃亦呈現差異，台南發電效率及售電收入最高，故其每公頃單位收益可達約53萬元；而臺東較適合繼續造林，較少面積轉作農租也無不良農地，因此每公頃收益反而最低。以植林效率來看，以臺東縣和花蓮縣的碳吸存量為最高，尤以臺灣櫸木貢獻度最高，碳吸存量最差之地則為雲林縣，其光臘樹的吸碳能力甚差，僅有1.10公噸CO_2e∕公頃。敏感度分析結果顯示，碳價必須成長至每公噸3,500元時，農企業方選擇植林造樹方案來獲利。太陽能板發電效率每增加1%，各縣市的售電收益將成長5%，台糖公司總收益將成長3%。

There is still limited empirical research on how agricultural enterprises can achieve carbon neutrality and obtain maximum operational benefits through optimal land planning. This study takes Taiwan Sugar Corporation, the largest agricultural enterprise in Taiwan, as an example. It examines how, following the government’s flatland afforestation policy from 2003 to 2012 and the subsidy period ending in 2022 (the 20th year of afforestation), appropriate land planning can enable the company to achieve carbon neutrality while maximizing operational profits.
Taiwan Sugar’s afforestation over the decade reached 9,106.27 hectares, spanning across 10 counties and cities in Taiwan, with over 50 tree species planted. This study uses national and international data to calculate carbon sequestration amounts and employs various data, including single-tree volume equations, growth formulas, climate data, and agricultural production, to calculate how Taiwan Sugar, on its afforested land, can continue afforestation, utilize solar photovoltaic, and opt for optimal choices in agricultural production.
The empirical results show that Taiwan Sugar’s afforestation can offset its annual emissions of categories one and two by 232,000 metric tons of CO2e in the 18th year of afforestation. The study indicates that over the ten-year afforestation period, Taiwan Sugar’s average carbon sequestration per hectare is 18.99 metric tons of CO2e. The afforestation results enable Taiwan Sugar to achieve carbon neutrality after 18 years of afforestation (by 2020), offsetting its emissions by 232,000 metric tons of CO2e. After achieving carbon neutrality, Taiwan Sugar only needs to continue afforestation on approximately 6,020 hectares (about 66% of the total area), while the remaining area can be converted to agricultural leases or solar photovoltaic installations. Given that solar photovoltaic installations generate the highest revenue per hectare at 350,000 yuan, followed by agricultural leases, and carbon credits generate only 8,300 yuan per hectare in revenue, Taiwan Sugar is likely to convert all poor agricultural land into solar photovoltaic installations, with only about 28% of afforested land being converted to agricultural leases. Under this scenario, Taiwan Sugar's maximum annual revenue could reach 3.41 billion yuan.
Afforestation planning may vary by county and city, with Tainan having the highest electricity generation efficiency and revenue per hectare, at approximately 530,000 yuan. In contrast, Taitung is more suitable for continued afforestation, with fewer areas converted to agricultural leases and no poor agricultural land. Therefore, the revenue per hectare is the lowest. Looking at the efficiency of afforestation areas, Taitung County and Hualien County have higher carbon sequestration rates, with Taiwan beech contributing the most, while Yunlin County has the lowest carbon sequestration rate, with Chinese tallow tree having very poor carbon sequestration ability, at only 1.10 metric tons of CO2e per hectare. The sensitivity analysis results indicate that afforestation becomes a profitable option for agribusinesses only if the carbon price reaches NT$3,500 per ton. Additionally, a 1% increase in solar panel efficiency would boost electricity sales revenue by 5% across each county and increase Taiwan Sugar Corporation’s total revenue by 3%.