Jabarkan Perbincangan kecekapan dan ekonomi dari Biodiesel dalam bahasa melayu

According to a study by Drs. Van Dyne and Raymer for the Tennessee Valley Authority, the average US farm consumes fuel at the rate of 82 litres per hectare (8.75 US gal/acre) of land to produce one crop. However, average crops of rapeseed produce oil at an average rate of 1,029 L/ha (110 US gal/acre), and high-yield rapeseed fields produce about 1,356 L/ha (145 US gal/acre). The ratio of input to output in these cases is roughly 1:12.5 and 1:16.5. Photosynthesis is known to have an efficiency rate of about 3-6% of total solar radiation

and if the entire mass of a crop is utilized for energy production, the overall efficiency of this chain is currently about 1% While this may compare unfavorably to solar cells combined with an electric drive train, biodiesel is less costly to deploy (solar cells cost approximately US$1,000 per square meter) and transport (electric vehicles require batteries which currently have a much lower energy density than liquid fuels).

However, these statistics by themselves are not enough to show whether such a change makes economic sense.

Additional factors must be taken into account, such as: the fuel equivalent of the energy required for processing, the yield of fuel from raw oil, the return on cultivating food, the effect biodiesel will have on food prices and the relative cost of biodiesel versus petrodiesel.

The debate over the energy balance of biodiesel is ongoing. Transitioning fully to biofuels could require immense tracts of land if traditional food crops are used (although non food crops can be utilized). The problem would be especially severe for nations with large economies, since energy consumption scales with economic output.

Jika hanya menggunakan tumbuhan makanan tradisi, kebanyakan negara tidak memiliki tanah yang mencukupi bagi menghasilkan bahanapi bio bagi kenderaan negara. Negara dengan ekonomi lebih kecil (dengan itu kurang penggunaan tenaga) dan lebih banyak kawasan pertanian berada dalam keadaan lebih baik, sungguhpun kebanyakan kawasan tidak mampu mengalih tanah dari oenghasilan makanan.

For third world countries, biodiesel sources that use marginal land could make more sense; e.g., honge oil nuts grown along roads or jatropha grown along rail lines.

Di kawasan tropika, seperti Malaysia dan Indonesia, minyak kelapa sawit ditanam pada kadar pantas bagi memenuhi permintaan biodiesel di Eropah dan pasaran lain. Ia telah dianggarkan di Jerman bahawa kos pengeluaran minyak biodiesel kelapa sawit hanyalan satu per tiga kos pengeluaran biodiesel rapeseed. Sumber langsung bagi kandungan tenaga biodiesel merupakan tenaga suria yang diambil oleh tumbuhan semasa fotosintesis. Berkenaan imbangan tenaga positif biodiesel:

Apabila jerami ditinggalkan di ladang, pengeluaran biodiesel amat tenaga positif, menghasilkan 1 GJ biodiesel bagi setiap 0.561 GJ kemasukan tenaga (pecahan hasil/kos 1.78).

Apabila jerami dibakar sebagai bahan api dan sisa oilseed digunakan sebagai baja, hasil/kos bagi pengeluaran biodiesel lebih baik (3.71). Dalam kata lai, bagi setiap unit kemasukan tenaga bagi menghasilkan biodiesel, output adalah 3.71 units (perbezaan 2.71 unit datangnya dari tenaga suria).