Liquid fuels can be produced from biomass by any of the following processes:
Ethanol is currently produced from starch and sugar based products which are fermented to form a dilute alcohol. Various grades of industrial, beverage and fuel grade ethanol are then distilled from the initial dilute solution.
Biodiesel can be produced from any non mineral oil or fat through transesterification, a reaction with alcohol and a catalyst. The products of the reaction are and ester (biodiesel) and glycerol. A variation of the transesterification reaction has been used for centuries to produce soap but modern biodiesel production plants use a very fast, high pressure and temperature continuous process.
Interest is currently growing in the use of biomass gasification products to produce Fischer-Tropsch liquids (FTLs). These liquids may eventually be produced at similar prices to petroleum-based diesel. FTL formulations tend to be cleaner burning than petroleum-based diesel.
Pyrolysis processes provide greater flexibility and higher conversion efficiencies compared to combustion, but capital costs are also currently excessive and technology is in the early stages of development. The product, pyrolysis oil, which can be used in turbines and other heat plant, can be easily transported and thus allows separation of the resource location from the site of use.
Advances in the hydrolysis/fermentation of ligno-cellulose to produce ethanol/methanol and lignin are promising, with future cost reductions claimed. The alcohol fuels can be used in present designs of internal combustion engines, new micro-turbines, or as a source of hydrogen for fuel cells.
Parliament has passed legislation to require the sale of liquid biofuels in New Zealand. Information on the obligation can be found here.
The full legislation for the Energy (Fuels, Levies, and References) Act can be sourced online here.
The new biofuels obligation legislation contains sustainability principles which will make sure biofuels sold towards the obligation will:
- Emit significantly less greenhouse gas over their life cycle than fossil fuels
- Avoid negative impacts on food production
- Do not reduce indigenous biodiversity or adversely affect land with high conservation values
The New Zealand government is currently drafting the regulations necessary to achieve these sustainability principles. These will be specified through an Order in Council by 30 June 2009.
New Zealand government officials note that New Zealand's may be the first mandatory requirements in the world.
The relevant section from the Act is copied below.
Part 3A: inserted, on 1 October 2008, by section 9 of the Energy (Fuels, Levies, and References) Amendment Act 2008 (2008 No 60).
|34H||Minister must recommend Order in Council under section 34G(2) providing qualifying biofuels must be sustainable biofuels|
|(1)||The Minister must recommend the making of an Order in Council under section 34G(2) as soon as practicable after this section comes into force.|
|(2)||The Minister must be satisfied, before making the recommendation, that the Order in Council will -
(a) provide that qualifying biofuels are sustainable biofuels; and
(b) be consistent with the principles of sustainable biofuels in subsection(3); and
(c) appropriately consider the indirect effects of biofuel production
|(3)||The principles of sustainable biofuels are as follows:
Principle 1: Less greenhouse gas
Sustainable biofuels emit significantly less greenhouse gas over their life cycle than obligation engine fuel. In relation to this principle, the Order in Council must -
(a) specify a methodology for life cycle assessment of greenhouse gas emissions from obligation engine fuels; and
(b) specify minimum levels of no less than 35% green- house gas emission reductions for qualifying biofuels in comparison to obligation engine fuel.
|Principle 2: Food production
Sustainable biofuels do not compete with food production and are not grown on land of high value for food production. Without limitation, the following biofuels do not contravene this principle:
(a) byproducts of food production described in the Order in Council;
(b) ethanol from sugarcane grown in circumstances and in areas described in the Order in Council;
(c) rotational oilseed crops grown not more than 12 months in any 24-month period on the same land or as otherwise specified in the Order in Council.
In relation to this principle, the Order in Council must -
(a) specify a methodology for assessing the effects of the production of a biofuel on food production and for assessing whether those affects amount to competition; and
(b) specify a mechanism for recognising particular land (including land outside New Zealand) as being land of high value for food production.
|Principle 3: Biodiversity and land with high conservation value
The production of sustainable biofuels does not reduce indigenous biodiversity or adversely affect land with high conservation value. In relation to this principle, the Order in Council must-
(a) specify a mechanism for recognising particular land (including land outside New Zealand) as having high conservation value; and
(b) specify a methodology for assessing the affects of the production of a biofuel on indigenous biodiversity and land of high conservation value.
|(4)||If the Minister has not recommended an Order in Council referred to in subsction (1) by 30 June 2009, the Minister must report to the House of Representatives about the following:
(a) the reasons why the Minister has not recommended that such an Order in Council be made; and
(b) any alternative methods to the method set out in this section of ensuring qualifying biofuels are sustainable biofuels; and
(c) the time when the Minister intends to make such a recommendation.
|Section 34H: inserted, on 1 October 2008, by section 9 of the Energy (Fuels, Levies, and References) Amendment Act 2008 (2008 No 60).|
- From 1st to 2nd Generation Biofuel Technologies - An overview of current industry and RD&D activities (extended Executive Summary), November 2008