EUのバイオ燃料政策の過ち/新バイオ燃料を使用のハイブリッド都バス

 都の新バイオ燃料にはヤシ油が含まれているが、栽培のために熱帯雨林の伐採がされるとすれば大きな問題である。記事を書いた記者はわかっているのだろうか?
EUのバイオ燃料政策の過ち
 研究者の間から、バイオ燃料がCO2排出削減に寄与するか疑念がでている。
 EUが2020年までにガソリンとディーゼルの10%を再生可能資源から調達するという目標はCO2排出削減に有効な方法ではないという。英国科学者チームは森林再生と保護がより良い方法であるとしている。科学雑誌サイエンスによれば、同一面積ならバイオ燃料の生産よりも森林のほうがCO2吸収効果が9倍ある。さらに、バイオ燃料の栽培のために更なる森林伐採が必要とされてしまう。バイオ燃料への増加需要を満たすためにEU以外の国々で更なる森林伐採が起きてしまっている。化石燃料の代わりにバイオ燃料を使用することで得られるCO2排出抑制効果を同一面積を植林することによる効果とを、作物でも植林でも可能な耕地について比較した。また、バイオ燃料生産のために森林開拓をすることが及ぼすインパクトも計算したが、森林伐採はCO2サイクルに対して大きく急激な影響を及ぼす。森林のCO2貯蔵量は1ヘクタールあたり100-300トンあり、その3/4が伐採し燃やすことで最初の1年で失われる。この量をバイオ燃料の生産で取り返すには50-100年必要とされる。穀物やヤシ油よりもストロー、草、木材(lignocellulosic素材)といったいわゆる第2世代のバイオ燃料の方が良い状況をもたらす。
 文字通りCO2軽減をもたらす可能性があるのは1つの道のみである。土壌を壊すことなく森林から持続的にセルロースを取り出し、急速な森林再生が維持できることが可能ならば、ケーキを持ちつつ食べ続けられることが可能である。独英米を含む多くの国が第2世代のバイオ燃料を開発中だが商用「バイオ精製施設」の建造には資本コストが大きな障壁となっている。しかし、穀物価格の高騰によりこの問題もそう遠くない時期に技術的な解決がなされるという。トウモロコシのような穀物からのバイオエタノールプラントよりも第2世代のバイオ精製所は4-5倍高くつく。トウモロコシ価格が1ブッシェル(35リットル)あたり3ドル(£1.50)を越えれば同等となる。バイオ燃料生産のための穀物栽培が水供給の危機をもたらす可能性が議論され始めている。
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新バイオ燃料を使用 ハイブリッド都バス 来月10日から走行
http://www.tokyo-np.co.jp/article/tokyo/20070922/CK2007092202050673.html
2007年9月22日
画像来月からデモ走行を開始する新バイオ燃料を使ったハイブリッドバスのデザイン
写真
 都は二十一日、二酸化炭素(CO2)排出削減に向けて、都バスに第二世代バイオディーゼル燃料(BHD)を使ったハイブリッドバスのデモ走行を来月十日から開始する、と発表した。
 BHDはパーム(油ヤシ)や廃てんぷら油、動物の脂身などを水素化処理して造る。成分は軽油と全く同じ。従来のバイオディーゼル燃料は軽油に上限5%の混合しか認められていないが、BHDは高濃度での使用が可能で、CO2削減に大きな効果が期待されている。新日本石油とトヨタ自動車が、国内で初めて開発した。
 デモ走行に使用するのは、日野自動車製の最新鋭のハイブリッドバス二台。来年三月末まで渋谷-新橋間を営業運転し、普及に向けた課題を検証する。
 BHDの供給量はまだ少ないため、燃料にはBHDを10%混合した軽油を使うが、ハイブリッド技術と組み合わせることで、従来型のバスに比べてCO2は25%削減できるという。
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Last Updated: Friday, 17 August 2007, 15:24 GMT 16:24 UK
EU biofuel policy is a 'mistake'
http://news.bbc.co.uk/2/hi/science/nature/6949861.stm

Barley (Image: National Non-Food Crops Centre)
The researchers question whether biofuel can cut carbon emissions

画像The EU target of ensuring 10% of petrol and diesel comes from renewable sources by 2020 is not an effective way to curb carbon emissions, researchers say.

A team of UK-based scientists suggested that reforestation and habitat protection was a better option.
Writing in Science, they said forests could absorb up to nine times more CO2 than the production of biofuels could achieve on the same area of land.
The growth of biofuels was also leading to more deforestation, they added.
"The prime reason for the renewables obligation was to mitigate carbon dioxide (CO2) emissions," said Renton Righelato, one of the study's co-authors.
"In our view this is a mistaken policy because it is less effective than reforesting," he told BBC News.
Dr Righelato, chairman of the World Land Trust, added that the policy could actually lead to more deforestation as nations turned to countries outside of the EU to meet the growing demand for biofuels.
Carbon counting

画像Graphic showing carbon cycle
The scientific principle behind biomass is the carbon cycle
As they grow plants absorb carbon dioxide (C02)
The carbon (C) builds tissues and feeds the plant while the oxygen (02) is released
When plant material is burned the carbon re-combines with oxygen
The resulting carbon dioxide is released back into the atmosphere
The contribution of biomass to the greenhouse effect is therefore far less than for traditional fossil fuels

The study compared the amount of carbon absorbed by a forested area with the total of "avoid emissions" by using biofuels instead of fossil fuels.
The researchers examined arable land that could either be used for growing crops to produce biofuels, or replanted with trees.
"We looked at the amount of biofuels produced per hectare," Dr Righelato explained. "From that figure, we were able to calculate the amount of fossil fuels that could be replaced by biofuels.
"That gave a figure for avoided emissions, but then we had to subtract from that the carbon emissions generated during the production of the biofuels.
He said this calculation provided them with the "net avoided carbon emissions".
"This is the key factor, that is the amount of CO2 that is saved from being released into the atmosphere by using the biofuel."
The researchers then compared the net avoided carbon emissions with the amount of CO2 that would have been absorbed if forests were re-established on the land.
"In all cases, the amount of CO2 sequestered (by forests) over a 30-year period is considerably greater than the amount of emissions avoided by using biofuels," Dr Righelato revealed.
The researchers also examined the impact of clearing forests in order to convert land to grow crops used to make biofuels.
Dr Righelato said forest clearances had a large and immediate impact on the carbon cycle.
"Forest carbon stocks are in the region of 100-300 tonnes per hectare. Three-quarters of that is lost over the first year during clearing and burning," he said.
"It would take - in all the cases we examined - between 50 to 100 years to recover this carbon through the production of biofuels."
Second chance
However, he said that so-called second generation biofuels, which used feedstocks such as straw, grasses and wood (lignocellulosic material) rather than grains or palm oil, offered a much better opportunity.

Biofuels: the next batch
"It was the one route that seemed to offer some possibilities in terms of CO2 mitigation.
"If you can extract lignocellulosic materials sustainably from forests without destroying the soil and maintain a way that forests can rapidly regrow, it is quite possible you can have your cake and eat it, as it were."
A number of nations, including Germany, the UK and US, are developing second generation biofuels, but the capital costs needed to build commercial "biorefineries" have been seen as a major barrier.
But two US researchers, writing in the Biofuels, Bioproducts and Biorefining journal, say that rising grain prices could make the technology commercially competitive sooner rather than later.
Mark Wright and Robert Brown, from Iowa State University, US, said that a second generation biorefinery cost four to five times as much as a bio-ethanol plant that used grains, such as corn.
However, the overall cost of producing second generation biofuels would be similar to biofuels produced from food crops when corn prices exceed $3 (£1.50) per bushel, they explained.
The adoption of second generation biofuels would be welcomed by environmental groups and food agencies, who view first generation fuels as unsustainable.
Experts at the World Water Week conference in Stockholm have voiced concern that growing food crops to be used to make biofuels could jeopardise water supplies.
"When governments and companies are discussing biofuel solutions, I think water issues are not addressed enough," Johan Kuylenstierna, director of the annual conference, told AFP.

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Last Updated: Monday, 18 September 2006, 10:29 GMT 11:29 UK
Biofuels look to the next generation
By Mark Kinver
Science and nature reporter, BBC News
http://news.bbc.co.uk/2/hi/science/nature/5353118.stm
Sunflowers growing in a field (Image: AP)

Biofuels are being hailed by politicians around the globe as a salvation from the twin evils of high oil prices and climate change.

The boom in biofuels in the US stems from President Bush's drive to reduce dependence on imports of foreign oil; in Europe it has a more environmental dimension.

Transport is responsible for a quarter of the UK's total emissions; four-fifths of that quarter comes from road vehicles.

Realising this could threaten to undermine efforts to meet Kyoto Protocol commitments, the UK government announced earlier this year the introduction of a Renewable Transport Fuel Obligation (RTFO).

It requires fuel companies to add 5% biofuel to all petrol and diesel sold on their forecourts by 2010.

Environmental concerns

When the plant-derived biofuel is burned in an engine, the CO2 released is offset by the amount of the gas absorbed by the plants when they grew.

It is, in principle, approximately carbon neutral; though the energy needed to plant, tend, harvest, process and transport the finished product can make the equation less favourable.


Graphic showing the carbon cycle (BBC)
The scientific principle behind biomass is the carbon cycle
As they grow plants absorb carbon dioxide (C02)
The carbon (C) builds tissues and feeds the plant while the oxygen (02) is released
When plant material is burned the carbon re-combines with oxygen
The resulting carbon dioxide is released back into the atmosphere
The contribution of biomass to the greenhouse effect is therefore far less than for traditional fossil fuels

The two main players in the market, bioethanol and biodiesel, are made from crops such as cereals, soybean, rape seed oil, sugar cane and palm oil.

While governments embrace what they see as a key player in a low-carbon future, there are concerns over some potential unwanted consequences.

Demand for land to grow these crops could put pressure on valuable ecosystems such as rainforests, and reduce the area available for subsistence food crops in developing countries.

Jeremy Tomkinson, chief executive of the UK National Non-Food Crop Centre (NNFCC), shares these concerns.

"If you are chopping down huge areas of rainforest in order to grow palm oil, not only is the palm oil not very environmentally friendly, think of the damage to the area's biodiversity.

"This is a problem with some biodiesel, but the fuel we are using now is only a transitory thing."

The next generation

Mr Tomkinson predicts that within a decade, current biofuel production methods could be replaced by "second generation" fuels.

"To me, this is the answer," he says. "It opens up a whole new ball game."

"What we are calling second generation, when it comes to gasoline, is the use of lignocelluloses.


Farmer spraying a sugar beet crop (Image: BBC)
Because we are going to break everything down anyway, we can look at a whole new range of crops that really are energy crops
Jeremy Tomkinson, NNFCC
"Lignocellulose is a clever, technical way of saying biomass - it means anything that comes out of the ground."

Mr Tomkinson says it will more than double yields: "Instead of just taking the grain from wheat and grinding that down to get starch and gluten, then just taking the starch, we are going to take the whole crop - absolutely everything."

Second generation fuel will also have a smaller carbon footprint because the amount of energy-intensive fertilisers and fungicides will remain the same, he adds, for a higher output of useable material.

Because the technology will allow biofuel to be produced from any plant material, there would be no conflict between the need for food and the need for fuel.

"We can let the lads who grow wheat grow it for nutritional value, and we can have another sector that is growing non-food crops for fuel, chemicals and pharmaceuticals," Mr Tomkinson suggests.

"Because we are going to break everything down anyway, we can look at a whole new range of crops that really are energy crops, not short-rotation coppice crops that we are using now."

He says two possible energy crops are sunflowers and fodder maize.

Early days

Oil giant BP is investing $500m (£266m) in an "energy bioscience institute", which will be based in either the UK or US.

"There have been major improvements to food yields and productivity by applying plant science to agriculture," says spokesman David Nicholas, "but it has not been done yet in terms of applying that science to the yielding of energy crops."

BP is also investing money into research in India, where it is looking at whether it can derive biodiesel from plants that can be grown on soil not suitable for food crops.

"Biofuels are a reality and will become an increasing part of our industry, but we are at the early stages of what are the most efficient and advanced biofuels," Mr Nicholas observes.

A refinery (Image: EyeWire)
Second generation biofuel production is much more expensive

There are two sizeable barriers that need to be tackled before second generation biofuels arrive at the pumps - technology and cost.

"It is technically far more complicated than current production methods," says Mr Tomkinson. "All the different [sugars] in the plant need their own enzymes to break them down.

"A number of companies are looking at something called 'cellulose accessing packages' that will allow us to take a bag of enzymes and pour it on to lignocellulose and ferment the whole lot," he explains.

The NNFCC is about to carry out a feasibility study to find out whether the UK could have a Biomass-To-Liquid (BTL) processing plant, which can produce the fuel.

Mr Tomkinson believes a BTL plant will require a serious amount of investment: "For a world-scale BTL plant, you are looking in the region of £200m ($375m).

"Currently, a 250,000-tonne biodiesel plant costs about £50m ($94m), so that is a big difference for the same amount of fuel.

But because of its environmental advantages, Mr Tomkinson says governments all over Europe are paying close attention to this technology "because BTL really could be the way forward".

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