Wednesday, May 26, 2010

A Latest Survey of State and Local Governments' Clean Energy Policies in the United States

The United States has been lagging in climate change policy development at federal level. It is not the same at state or local government levels.
The National Governors Association's "Securing a Clean Energy Future" initiative launched in 2007 was a wonderful proof of American people's serious concern about climate change.
Local governments' recent efforts to address the concern are well documented in the following report from three renowned organizations, Renewable Energy and Energy Efficiency Partnership (REEEP), Alliance to Save Energy, and American Council On Renewable Energy (ACORE).
I can call the report an encyclopedia of policies to improve energy efficiency and promote renewable energy at sub-national and local government levels.

The report, "Compendium of Best Practices: Sharing Local and State Successes in Energy Efficiency and Renewable Energy from the United States," is organized as follows:

  • Renewable Portfolio Standards
  • Energy Efficiency Resource Standards
  • Public Benefit Funds
  • Energy Code Implementation
  • Appliance Standards
  • Government Loan Programs
  • Property Assessed Financing Districts
  • Municipal Bonds
  • Direct Cash Subsidies- Rebates
  • Feed-in Tariffs
  • Tax Incentives
  • Commercial Methods- Power Purchase Agreements
  • Energy Service Companies (ESCOs)
  • Transmission Planning- Renewable Energy Zones
  • Net Metering and Interconnection Standards
  • Revenue Stability Mechanism
  • Leading by Example in Public Buildings and Facilities
  • Green Power Purchasing
  • Greening Fleets
  • Optimizing Traffic Signals
  • Wastewater Treatment
  • Austin, Texas
  • San Francisco, California
  • Seattle, Washington

Source: Ellingson, M., Hunter, L., Lung, R. B., Carey, K., & Plunkett, E. (2010). Compendium of Best Practices: Sharing Local and State Successes in Energy Efficiency and Renewable Energy from the United States. A collaborative report by: Renewable Energy and Energy Efficiency Partnership (REEEP), Alliance to Save Energy, & American Council On Renewable Energy (ACORE). [Full-text at]

Tuesday, May 25, 2010

The Most Comprehensive Review of Global Solar PV Industry to Date

The working paper from the Peterson Institute is too much depending upon authors' experts interviews. So cited numbers are rounded or ranged over big intervals. However, authors reviewed a vast amount of industry statistics and outlooks encompassing the entire global arena of the solar PV technology.

If you are interested in IEA (or OECD) member countries only, IEA PVPS's annual report was published in May.


Kirkegaard, J.F., Hanemann, T., Weischer, L., & Miller, M. (2010). Toward a Sunny Future? Global Integration in the Solar PV Industry. Working Paper 10-6. Washington, DC: Peterson Institute for International Economics. [Full-text at]

IEA PVPS (International Energy Agency Photovoltaic Power Systems Program). (2010). PVPS Annual Report 2009: Implementing Agreement on Photovoltaic Power Systems. Paris, France: International Energy Agency. [Full-text at]

Wednesday, May 12, 2010

Optimal Vehicle Speeds for Best Fuel Economy

I found an interesting figure. If this calculation is accurate, the potential oil savings by speed limit regulations on highways will be greater than have been thought.
The figure is from a master's thesis of an MIT student. The author simulated optimal fuel economy of four vehicle models using the Powertrain System Analysis Toolkit (PSAT) developed by Argonne National Laboratory (ANL).

Fuel consumption versus cruise speed for steady-speed driving is simulated as the following figure.

Maybe some of you are not familiar with the metric system (kph or l/km). When the figure is translated into mpg and mph, the optimal speed and fuel consumption of the four vehicles are (from a data table on page 65 of the thesis),
Model Optimal Speed Range (mph) Fuel Economy at Optimal Speed (mpg)
Honda Civic 34-39 71
Ford Focus 39-43 45
Honda Accord 30-39 59
Ford Explorer 40-47 35

It's amazing. It's too good to be true. However, even if the simulation overestimated Civic's 71 mpg, it is evident that vehicles' fuel-efficient speeds are well below most highway speed limits (55-75 mph).

I had better avoid highways, when I am not in a hurry.

Source: Berry, I. M. (2010). The Effects of Driving Style and Vehicle Performance on the Real-World Fuel Consumption of U.S. Light-Duty Vehicles. Masters thesis, Massachusetts Institute of Technology, Cambridge, MA. Retrieved from

Unit conversion:
1 mile = 1.609344 kilometers
1 gallon = 3.78541178 liters

Tuesday, May 11, 2010

UNEP: Biofuels' voracious invasion into natural habitats threats biodiversity

Secretariat of the Convention on Biological Diversity, presumably a subsidiary of the UNEP, published their third outlook of global biodiversity. Although it is a 'biodiversity' outlook, energy issues are deeply intertwined with this ecology issue.

In the report, a figure caught my attention. They nicely re-drew figures from a 2009 Science article (Its source is cited below.). Three figures are global land use projections according to three scenarios A, B, and C.
  • Scenario A: a business as usual scenario.
  • Scenario B: a scenario in which incentives, equivalent to a global carbon tax, are applied to all carbon dioxide emissions, including those resulting from land use change, to keep carbon dioxide concentrations below 450 parts per million.
  • Scenario C: a scenario in which incentives, equivalent to a global carbon tax, are applied to carbon dioxide emissions from fossil fuels and industrial emissions only, with no consideration of emissions from land use change, to keep carbon dioxide concentrations below 450 parts per million.

If there's no regulation on land use while greenhouse gas emissions from industries are restricted, most land areas which are covered with wild grasses, shrubs, trees will be converted to commercial cropland exclusively developed for biofuel production.

This very possible scenario, if realized, will be a major attack on global biodiversity conservation. Nobody exactly knows how catastrophic the biodiversity decline will be. However, that uncertainty cannot exempt us from the duty to ensure that future generations have at least as same natural endowments as what we have now.


Secretariat of the Convention on Biological Diversity. (2010). Global Biodiversity Outlook 3. Quebec, Canada: Secretariat of the Convention on Biological Diversity. Retrieved from

Wise, M., Calvin, K., Thomson, A., Clarke, L., Bond-Lamberty, B., Sands, R., Smith, S. J., Janetos, A., & Edmonds, J. (2009). Implications of Limiting CO2 Concentrations for Land Use and Energy. Science, 324(5931), 1183-1186.

Saturday, May 8, 2010

One of renewable energy's weak points to overcome: land use

Recently, two scientists have pointed out an important limiting factor of renewable energy sources, their use of land area. Each scientist use his own calculation.

1) Power density (W/m2; watts per square meter)
It was Vaclav Smil who has been a proponent of "power density", his own index of land use by energy sources.
To make a table from one figure in his 2008 book (on page 312), power densities of energy sources are:
Power Density
Energy Conversion Facilities
(Roughly in descending but overlapping order)
Oil fields
Coal fields
Thermal power plants
Flat plate solar heat collectors
Central solar towers
Hydro: upper-course (high heads, small-reservoirs)
Ocean heat
Hydro: lower-course (large reservoirs)
Compared to fossil-fuel energy conversion facilities, renewable energy conversion technologies have very low power densities.
(By the way, I hope he would provide exact numbers for each energy sources in his upcoming book, Energy Transitions: History, Requirements, Prospects (coming in June)).
* (Update on May 18, 2010) I think Dr. Smil made public specific numbers for energy densities of power resources in his latest series of contributions to MasterResource blog at

2) Land use intensity(km2/TWh/yr)
Robert I. McDonald and his colleagues published a controversial article that compared land use intensities of energy sources. As you have already noticed from its unit of measure, this index is somewhat an inverse of Smil's 'power density.'
Dr. McDonald's calculation is like this:

Here again, renewable energy sources are disappointing. And one reason this figure is controversial is nuclear power's great efficiency in land use.

Then what should we do?
If we want to make the catch-phrase of the Institute for Energy and Environmental Research "carbon-free and nuclear-free" come true, we need resolute policy measures and radical changes in people's mindset.


Makhijani, A. (2007). Carbon-Free and Nuclear-Free: A Roadmap for U.S. Energy Policy. Takoma Park, MA: IEER Press. [Full-text at]

McDonald, R. I., Fargione, J., Kiesecker, J., Miller, W. M., & Powell, J. (2009). Energy Sprawl or Energy Efficiency: Climate Policy Impacts on Natural Habitat for the United States of America. PLoS ONE, 4(8), e6802.

Smil, V. (2008). Energy in Nature and Society: General Energetics of Complex Systems. Cambridge, MA: The MIT Press.

Smil, V. (2010). Energy Transitions: History, Requirements, Prospects. Westport, CT: Praeger Publishers.

Wednesday, May 5, 2010

Why Air Pollution Control Is Important to Limit Global Warming Under 2 Degrees Celsius

A few people around me realize the importance of non-CO2 greenhouse gases (GHGs; CH4, N2O, CFCs, HCFCs, HFCs, O3) for climate change mitigation.
Fewer people around me realize the importance of non-GHG air pollutants (SO2, NOX (NO+NO2), CO, BC (black carbon), organic carbon) for the same purpose.
An amazingly well-written analysis by scientists from Scripps Institution of Oceanography clarifies how important they are and enlightens the ignorant majority (including me).

In the analysis, the authors show that the atmospheric concentration of carbon dioxide equivalent (CO2e; NOT CO2) greenhouse gases must be stabilized at 441 ppm by 2100 to limit global warming under 2°C above the pre-industrial temperature.
To achieve that goal, they propose three imperatives.

1) Reduce 50% of CO2 emissions by 2050 and 80% by 2100: However, it will NOT reduce the planetary GHG blanket thin enough within the 21st century due to the long lifetime of atmospheric CO2 (100-1000 years).
2) Offset warming from the reduction of aerosol masking: Reduce emissions of two major air pollutants: black carbon (BC) and ozone (and its precursor gases such as NOX, CO, and volatile organics (VOCs)).
3) Thin the GHG blanket: Reduce emissions of short-lived GHGs (methane and halofluorocarbons (HFCs)).

Then can I say that controlling air pollution is as important as reducing CO2 emissions reduction?

Source: Ramanathan, V., & Xu, Y. (2010). The Copenhagen Accord for limiting global warming: Criteria, constraints, and available avenues. Proceedings of the National Academy of Sciences, 107(18), 8055-8062. Retrieved from

New Country Rankings in Terms of Relative Environmental Impact

In a former posting, I looked into a ranking of countries by their ecological footprint. Today, I found more sophisticated and theoretically robust environmental impact rankings of nations than the ecological footprint one. (In fact, the authors of the cited article assert that their new rankings are overcoming some weak points of other well-known rankings such as the City Development Index (CDI), Ecological Footprint (EF), Environmental Performance Index (EPI), Environmental Sustainability Index (ESI), Genuine Savings Index (GSI), Human Development Index (HDI), Living Planet Index (LPI), and the Well-Being Index (WI).)

A research team lead by an Australian scientist published rankings of 179 countries in terms of their relative environmental impact. Data used for the analysis were population density (PD), population growth rate (PGR), governance quality (GOV), Gross National Income (GNI), natural forest loss (NFL), natural habitat conversion (HBC), marine captures (MC), fertilizer use (FER), water pollution (WTP), proportion of threatened species (PTHR), and carbon emissions (CO2).

In the article, two rankings summarize their primary findings.

1) In the "proportional" (relative to resource availability per country) composite ranking, small countries such as Singapore and South Korea were blamed for their intensive resource exploitation.
2) In the "absolute" (total degradation as measured by different environmental metrics) composite ranking, mostly large countries were ranked as worst. However, it is surprising that Brazil outranked USA or China.

Tables for the two rankings are as follows:

Table 1) Twenty worst-ranked countries by proportional composite environmental (pENV) rank

Table 2) Twenty worst-ranked countries by absolute composite environmental (aENV) rank

In their explanation of results, authors are specifically debunking the famous environmental Kuznets curve (EKC) hypothesis.

The EKC "predicts that wealthier societies can reduce environmental degradation beyond a certain threshold." However, their "tests of non-linearity in the relationship between per capita wealth and environmental impact supported only linear (proportional impact) or no relationship."
...This finding "suggests that any potential improvement resulting from higher per capita wealth is overwhelmed by the current necessity for economies to grow."

Source: Bradshaw, C. J. A., Giam, X., & Sodhi, N. S. (2010). Evaluating the Relative Environmental Impact of Countries. PLoS ONE, 5(5), e10440. Retrieved from

Sunday, May 2, 2010

9 Trends in Global Sustainable Development Indicators

The United Nation's Division for Sustainable Development published a summary of trends in sustainable development with two sets of relevant indicators: 1) indicators for sustainable consumption and production and 2) indicators for chemicals, mining, transport, waste management.
Each set of indicators are published in one volume report, respectively.

1. Trends in sustainable consumption and production
      1) Trends in Resource Use
      2) Stresses on Ecosystems
      3) Drivers of Changing Production and Consumption Patterns
      4) Policy and Voluntary Responses
      5) New Technologies and Finance

2. Trends in Chemicals, Mining, Transport, Waste Management
      6) Chemicals
      7) Mining
      8) Transport
      9) Waste Management

The database for these indicators can be found at

By the way, one figure I found interesting is this one. Authors say this figure shows us (generally; not absolutely) that resource- and energy-intensive activities are more and more concentrated in developing countries. (Ignore Canada in this case.)

Production-based emissions: all emissions produced within a nation’s border
Consumption-based emissions: all emissions resulting from consumption within a nation


Department of Economic and Social Affairs (DESA). (2010). Trends in Sustainable Development: Towards Sustainable Consumption and Production. New York, NY: United Nations Publication. [Full-text at]

Department of Economic and Social Affairs (DESA). (2010). Trends in Sustainable Development: Chemicals, Mining, Transport, Waste Management. New York, NY: United Nations Publication. [Full-text at]

Levelized Costs of Electricity Storage

Now we have some knowledge about the levelized costs of electricity generation.
Because the intermittency of renewable electricity, energy storage technologies are getting much attention nowadays.
So I googled this figure ("Ranges of levelized cost of output electricity for electricity storage systems").

FC/ aboveground: hydrogen fuel cell with aboveground storage
FC/ geologic: hydrogen fuel cell with geologic storage
CAES: compressed air energy storage

Last week, one person who has been working in an energy consulting company told me that the economics of compressed air electricity storage was not satisfactory to utility companies. His remarks conflict with this NREL analysis result.
Or, if both are right, none of the electricity storage technology is commercially viable.

Source: Steward, D., Saur, G., Penev, M., & Ramsden, T. (2009). Lifecycle Cost Analysis of Hydrogen Versus Other Technologies for Electrical Energy Storage (NREL/TP-560-46719). Golden, CO: National Renewable Energy Laboratory.