The Eyjafjallajokull volcano in Iceland began erupting a few weeks ago, but a combination of factors is now wreaking havoc on European air-travel. The interaction of the molten lava with an ice-sheet 100m thick is sending a thick plume of "ash" high into the atmosphere, which is being driven to the south-east by unusual winds and has caused the grounding of all flights in the U.K. and most flights across Europe. Ryanair has suspended all flights until 13.00 on Monday, which concerns me as I am scheduled to fly to Bratislava by Ryanair on Wednesday for a small lecture tour in Slovakia and it is debatable whether all will be resolved by then.
It is what insurance companies used to call an "act of God" and we are held at the behest of the weather conditions. The volcano last erupted 200 years ago, but continued to do so for more than a year. Now in the jet-age, the risk of ash (in reality finely divided volcanic rock) being drawn into the engines of an aircraft pose the real threat of taking-out all four engines within minutes. The engine itself will be trashed by the glass produced by fusion and subsequent solidification of the ash, and the fuel-flame extinguished, thus risking aircraft literally falling from the sky should they fly through the ash-cloud.
Consequently, the inhabitants of villages and parts of London under the Heathrow flight-path can hear the birds singing on these beautiful spring days, not obscured by the cacophony of planes overhead, in a foretaste of life in the post jet-age era which will come when there is insufficient fuel to put into planes. It seems bizarre to talk of building a third runway and a sixth terminal at Heathrow and treble the number of flights by 2020, when the world is at the tipping-point of oil production, and rising demand, and all evidence is that perpetual growth is a fallacy and we are probably witnesses to the end of Capitalism.
Without cheap, plentiful oil the world will have trouble producing enough food to sustain its burgeoning population, and plane-travel will be the least of our concerns. I will probably get to Slovakia all right, but meanwhile it is worth contemplating how we might manage in the post-oil, post global-transport era.
Saturday, April 17, 2010
Tuesday, April 06, 2010
Report Says, Algal Biofuels May Not Cut Carbon Emissions, but Read it More Closely.
A new study suggests that overall the CO2 emissions attendant to producing biofuel from algae may be worse than those from corn, canola (rape-seed) or switch grass. The main problem is the use of carbon dioxide brought from elsewhere in "gas-bottles" and inputs of fertilizer, particularly nitrogen and phosphorus. According to a Life-cycle analysis, the land-based crops all were found to sequester more carbon than that incurred in growing them, while the contrary was true for growing algae, meaning that replacing fossil fuels by algal fuels could cause an overall increase in carbon emissions.
Not surprisingly, the report just published in the prestigious American Chemical Society journal, Environmental Science and Technology, has put the cat among the pigeons, since there are many companies gearing-up to produce algal biofuels. The US Algal Biomass Organisation has claimed that the study contained "faulty assumptions" and was based on "grossly outdated data".
Now, I am a fan of growing algae not the least of which because to do so means that far more fuel might be produced per unit area than is the case from the above mentioned land-based crops, as algae have a better photosynthetic yield; there is no need to use freshwater since algae grow well (even better) on saline waters or wastewaters, thus preserving an already endangered resource; you can put the tanks on any land (even deserts), so there is no need to compromise food-production in a competition over the same arable land to grow food-crops or fuel-crops; they might be used to clean CO2 from the smokestacks of power-stations fired from e.g. gas or coal; they might be used to clean wastewaters of nitrogen and phosphorus.
On closer inspection, the report is in fact very positive about growing algae, particularly in the latter two respects. Read positively, the data are only in opposition to making fuel from algae if nitrogen and phosphorus nutrients are added in their mineral forms, and if the CO2 has to be injected into the system (transported as a compressed gas) as made mainly by the process of steam reforming methane, along with most of the world's available hydrogen:
(Overall) CH4 + 2H2O --> CO2 + 4H2.
That H2 is used to make nitrogen (ammonium sulphate and nitrate) fertilizer by reacting it with N2 via the Haber Bosch process to make ammonia (NH3), and so there is in a way a symbiosis between the production of CO2 and NH3. The phosphorus would likely come from mining "rock phosphate", which requires energy too.
However, the figures in this "cradle to farm gate" analysis (i.e. they do not include the energy costs of processing the algae or other biomass into fuel per se) show that if the production of algae is combined with a wastewater treatment strategy, so that N and P are removed from it by the algae (an otherwise energy intensive procedure), and fed with CO2 from smokestacks, most of the environmental burdens attendant to growing algae are offset (i.e. an algae production plant, a power station and a sewage-works should all be placed in mutual proximity). Of three possible municipal wastewater effluents evaluated as a source of N and P, the most effective was source-separated urine with a very high content of these elements, in which case growing algae became more environmentally beneficial than the land-based crops.
Even if there remains some dispute over the exact figures used, what the study does highlight is the importance of developing an integrated paradigm of production and recycling for algal fuel production as I stressed before in the context of rare metals such as are required to maintain the electronics and solar power industries.
Related Reading.
"Environmental Life Cycle Comparison of Algae to Other Bioenergy Feedstocks," By Andres F. Clarens, Eleazer P. Ressurreccion, Mark A. White and Lisa M. Colosi, Environ. Sci. Technol., 2010, 44, 1813.
Not surprisingly, the report just published in the prestigious American Chemical Society journal, Environmental Science and Technology, has put the cat among the pigeons, since there are many companies gearing-up to produce algal biofuels. The US Algal Biomass Organisation has claimed that the study contained "faulty assumptions" and was based on "grossly outdated data".
Now, I am a fan of growing algae not the least of which because to do so means that far more fuel might be produced per unit area than is the case from the above mentioned land-based crops, as algae have a better photosynthetic yield; there is no need to use freshwater since algae grow well (even better) on saline waters or wastewaters, thus preserving an already endangered resource; you can put the tanks on any land (even deserts), so there is no need to compromise food-production in a competition over the same arable land to grow food-crops or fuel-crops; they might be used to clean CO2 from the smokestacks of power-stations fired from e.g. gas or coal; they might be used to clean wastewaters of nitrogen and phosphorus.
On closer inspection, the report is in fact very positive about growing algae, particularly in the latter two respects. Read positively, the data are only in opposition to making fuel from algae if nitrogen and phosphorus nutrients are added in their mineral forms, and if the CO2 has to be injected into the system (transported as a compressed gas) as made mainly by the process of steam reforming methane, along with most of the world's available hydrogen:
(Overall) CH4 + 2H2O --> CO2 + 4H2.
That H2 is used to make nitrogen (ammonium sulphate and nitrate) fertilizer by reacting it with N2 via the Haber Bosch process to make ammonia (NH3), and so there is in a way a symbiosis between the production of CO2 and NH3. The phosphorus would likely come from mining "rock phosphate", which requires energy too.
However, the figures in this "cradle to farm gate" analysis (i.e. they do not include the energy costs of processing the algae or other biomass into fuel per se) show that if the production of algae is combined with a wastewater treatment strategy, so that N and P are removed from it by the algae (an otherwise energy intensive procedure), and fed with CO2 from smokestacks, most of the environmental burdens attendant to growing algae are offset (i.e. an algae production plant, a power station and a sewage-works should all be placed in mutual proximity). Of three possible municipal wastewater effluents evaluated as a source of N and P, the most effective was source-separated urine with a very high content of these elements, in which case growing algae became more environmentally beneficial than the land-based crops.
Even if there remains some dispute over the exact figures used, what the study does highlight is the importance of developing an integrated paradigm of production and recycling for algal fuel production as I stressed before in the context of rare metals such as are required to maintain the electronics and solar power industries.
Related Reading.
"Environmental Life Cycle Comparison of Algae to Other Bioenergy Feedstocks," By Andres F. Clarens, Eleazer P. Ressurreccion, Mark A. White and Lisa M. Colosi, Environ. Sci. Technol., 2010, 44, 1813.
Subscribe to:
Posts (Atom)