Monday, June 28, 2010

Sequestered Carbon Dioxide Is NOT Different from Nuclear Waste

A long-term simulation of the environmental effects of sequestered carbon dioxide ends up with a conclusion that CO2 stored in either deep sea or underground is not different from nuclear waste.

There are two places we can store the captured CO2: deep ocean or underground.
(1) If we sequester CO2 in deep ocean, ocean acidification and oxygen depletion will inevitably endanger the ocean ecosystem. In addition, we cannot avoid leakage from the ocean carbon reservoir.
(2) If we sequester CO2 in underground, the "leakage" of the stored CO2 will impose unanticipated burdens on our offspring. Therefore, the author asserts that sequestering CO2 underground is in essence the same as storing nuclear waste under Yucca Mountain.

I think the message from this research is:
"The carbon capture and sequestration (CCS) cannot be any way to mitigate anthropogenic climate change. Burying CO2 is just another way of hiding our mess from our children."

Source: Shaffer, G. (2010). Long-term effectiveness and consequences of carbon dioxide sequestration. Nature Geoscience, doi:10.1038/ngeo896. [Full-text at]

Wednesday, June 23, 2010

Costs and Emissions of Unconventional Liquid Fuels

I found an interesting chart from a latest paper published by the Resources For the Future (RFF).

Finding 1:  Biofuels are costly.
Finding 2:  Unconventional oils are dirty.
Conclusion: None of them are an alternative to conventional oil.

Question:   Am I saying we'd better stick to conventional oil?
Answer:     No. Neither unconventional nor conventional liquid fuels are a desirable option for our sustainable energy future.
Suggestion: Hm.... Firstly, less travel. But people won't like it. Secondly, more public transportation. Come on, it's acceptable. See Asia or Europe! Thirdly, drastically more efficient homes and buildings. I hope governments can help poor people retrofit their houses.

P.S.:       I know my suggestions are naive. But their direction is right. Let me study more and give you more persuasive solutions to free ourselves from liquid fuel addiction.

Source: Darmstadter, J. (2010). The Prospective Role of Unconventional Liquid Fuels. Washington, DC: Resources for the Future. [Full-text at]

Sunday, June 13, 2010

Forest Carbon Sequestration Is Not Recommended Yet: A Massachuestts study

A lifecycle study of woody biomass smashes another blow to biomass energy proponents.
The study, prepared for Massachusetts' Department of Energy Resources, found biomass energy from forest management cannot reduce greenhouse gas emissions compared to continued fossil fuel energy consumption.

For the report, authors introduce a concept called 'carbon debt' of biomass energy. Before the carbon sequestration occurs by forest re-growth, forest biomass emits more greenhouse gases than fossil fuels per unit of energy produced. This carbon debt will be paid off by the re-growth over time. The following table shows how long it will take for forest biomass to pay off its carbon debt to its replaced fossil fuel energy.
Fossil Fuel Technology Replaced
 Carbon Debt Payoff (yr)
Oil (#6), Thermal/CHP
Coal, Electric
Gas, Thermal
Gas, Electric

This information is very disappointing to many policy makers, most of whom set target years in 2030 or 2050. In terms of net carbon sequestration, forest biomass cannot reduce greenhouse gas emissions by 2050. Forest biomass cannot compete with natural gas electricity until 2100.
Biomass Cumulative % Reduction in Carbon Emissions (Net of Forest Carbon Sequestration)
Oil (#6) Thermal/CHP
Coal, Electric
Gas, Thermal
Gas, Electric

Source: Walker, T., Cardellichio, P., Colnes, A., Gunn, J., Kittler, B., Perschel, B., Recchia, C., & Saah, D. (2010). Biomass Sustainability and Carbon Policy Study. Brunswick, ME: Manomet Center for Conservation Sciences. [Full-text at]

Wednesday, June 9, 2010

World's fossil-fuel CO2 emissions in 2009: China is No. 1 three years in a row

BP released its latest annual "Statistical Review of World Energy". This year, they calculated fossil-fuel CO2 emissions of countries. China is the world's most emitter far away from No. 2, the United States.

The following chart is a record of CO2 emissions changes in top ten dirtiest countries over the past 10 years.

Surprisingly, even in the global economic recession, the emissions in five countries (China, India, South Korea, Iran, and Saudi Arabia) increased from 2008 to 2009. (Annual change percentages the table below differ from BP's numbers in their original Excel spreadsheet. I cannot figure out the reason.)

Table: Annual Changes in Fossil-Fuel CO2 Emissions

2005 2006 2007 2008 2009
China 10.2% 9.8% 7.8% 6.8% 8.8%
US 0.3% -1.2% 1.8% -3.0% -6.7%
EU 0.1% 0.6% -1.5% -1.9% -6.7%
India 4.9% 4.2% 8.4% 8.8% 6.7%
Russia -0.8% 2.7% 0.8% 1.9% -8.7%
Japan 1.0% -1.3% 1.0% -0.2% -12.0%
South Korea 2.1% 0.6% 5.5% 1.8% 1.5%
Canada 2.0% -1.1% 2.3% -1.0% -6.1%
Iran 12.3% 4.1% 2.0% 5.2% 4.3%
Saudi Arabia 6.2% 4.1% 5.2% 8.4% 5.1%

Source: BP. (2010). BP Statistical Review of World Energy 2010. London, UK: BP. [Full-text at; Excel spreadsheet at]

Monday, June 7, 2010

Satisfying 79% of Global Electricity Needs by Renewable Sources

The 3rd edition of the Greenpeace International's flagship 'Energy [R]evolution' report is out. Although there's a more aggressive scenario (called 'Advanced E[R]' scenario) simulated in this report, I'll focus on their main scenario here.

Their main targets based on the 'Energy [R]evolution' scenario are to reduce energy related CO2 emissions by 50% from their 1990 levels, phase out global nuclear energy by 2050, and produce 79% of the worldwide electricity from renewable energy sources.

The following figures explain how those targets are achieved step-by-step from 2007 to 2050, while the targets are compared with reference and advanced scenarios.
  • Targets 1 and 2: Reduce energy related CO2 emissions by 50% from their 1990 levels and phase out global nuclear energy by 2050

  • Target 3: Produce 79% of the worldwide electricity from renewable energy sources by 2050

According to the report, the main energy [r]evolution scenario can be achieved by five principles:
  • Implement renewable solutions, especially through decentralised energy systems
  • Respect the natural limits of the environment
  • Phase out dirty, unsustainable energy sources
  • Create greater equity in the use of resources
  • Decouple economic growth from the consumption of fossil fuels
The assumptions and data used in the report are quite reasonable, reliable, and persuasive. Whether you agree with the Greenpeace or not, you'd better read through this 260-page-long report before reaching at your own conclusion.

Source: Teske, S., Zervos, A., Lins, C., Muth, J., et al. (2010). Energy [r]evolution: a sustainable global energy outlook (3rd ed.). Amsterdam, The Netherlands: Greenpeace International; Brussels, Belgium: European Renewable Energy Council (EREC). [Full-text at]

One of renewable energy's weak points to overcome: Intermittency

Limited land areas are one weak point of renewable energy, as I wrote in

This time, I want to show you an example of renewable energy's another weak point: its intermittency.
Yes, geothermal energy is exempt from this weakness.
Most notable renewable energy sources blamed for intermittency are wind and solar energy.
Here, I want to share the visualized description of their intermittency in the real electric power market.
Data comes from California ISO. The California ISO has been recording hourly power output of renewable energy sources every day on their website at

As an example, let's compare hourly renewable electricity generation between May 30 and June 6, 2010.

(1) Renewable generation across May 30, 2010

(2) Renewable generation across June 6, 2010

How can we solve this problem? Energy storage ( is one good solution, though it is not enough to assure operational reliability in power systems. Finding a better solution is what I want to do....

Comparison of Subsidies to Energy Sources

The Global Subsidies Initiative made a table summarizing subsidies to major energy types.

Table: Estimates of Global Subsidies to Energy Sources in 2007
Energy type  Subsidy estimate (US$ billion/year)  Energy produced (2007)  OECD share of production (2007) Subsidies per energy unit (US$/kWh) 
Nuclear energy   45      2,719 TWh electricity 0.84      1.7     
Renewable energy (excluding hydroelectricity)  27        534 TWh electricity 0.82      5.0     
Biofuels   20         34 Mtoe            0.68      5.1     
Fossil fuels  400      4,172 Mtoe            n/a       0.8     

Some people might think,
'Renewable energy is receiving more subsidies than fossil fuels per unit energy produced!'
But we have to take into account the economy of scale effect. Global subsidies to renewable energy (27 billion US dollars) were less than 7% of non-OECD subsidies given to fossil fuels (400 billion US dollars).
In addition, there are the rapidly increasing 'learning by doing' effects in reducing renewable energy's dependence on subsidies. (Subsidies are endowed in the forms of feed-in tariffs and renewable portfolio standards.)
To understand the 'learning curve' prospects for renewable energy sources, the International Energy Agency's low-carbon energy technology roadmaps might be helpful. (Find them at

Source: The Global Subsidies Initiative. (2010). Relative Subsidies to Energy Sources: GSI Estimates. Geneva, Switzerland: The Global Subsidies Initiative. [Full-text at]