CO2 Benefits of Biomass Energy Vs. Solar and Wind Energy (Part 3)

Energy Policy

In Part 1 and Part 2 of this blog series on the benefits of biomass energy, we made three key points:

That biomass energy is carbon cycle neutral, just like solar and/or wind energy.

Biomass energy can be carbon cycle negative when it is developed in an environmentally sustainable way (e.g., soil building carbon sequestration, incorporating biochar).

Biomass energy is much more likely (especially in the Southeast and Midwest U.S.) to displace base load coal-fired electricity generation than either wind or solar power.

The reason for this is something called an "availability factor" (i.e., the number of hours a generating unit runs), where typically, solar and wind resources have low availability factors which are usually associated with natural gas or oil peaking and intermediate dispatch units.

Availability or Capacity Factors by Technology

This last point is important as coal fired power plants in the U.S. are responsible for 82% of CO2 emissions from total electricity generation.

Today, we will summarize these 3 key points by

Building on the previously cited EPRI paper on the avoided CO2 intensity of fossil fuel technology options (oil, natural gas, coal).

Incorporating empirical research on soil carbon sequestration from growing energy crops.

From carbon sequestration work performed with the University of Florida on fast growing trees, we found that a volume of below ground biomass equal to ~60% of the above ground mass was being created. However, we must note that our findings of terrestrial carbon sequestration are significantly higher than found in other research. Because of this, we include carbon sequestration rates derived from a U.S. Department of Energy study performed in North Carolina in the table below -- providing a range of .24 (DOE estimate) to .64 (our research findings estimate) tons per Mwh.

CO2 Displacement by Technology (ton/Mwh)

CO2 Displacement by Technology (ton/Mwh)

Conclusion: When biomass energy is developed in an environmentally sustainable way as base load power generation (displacing coal use), the CO2 benefits can be ~4 times greater than solar power displacing natural gas peaking technology.

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CO2 Benefits of Biomass Energy Vs. Solar and Wind Energy (Part 2)

Sustainability

In Part 1 of this series, we discussed the importance of viewing renewable energy technology options (wind, solar, geothermal, biomass) on a "big picture" (macro) basis using the integrated resource grid. The key concept under this view is that not all renewable energy options have the same impact in displacing fossil fuel use for electricity generation:

Typically, solar power and many wind power resources are considered "peaking units", which displace natural gas and oil fired generation.

Conversely, biomass and geothermal resources are often dispatched as base load units which would typically (especially in the Southeastern and Mid-Western U.S.) displace coal fired generation.

Today in Part 2 of our series, we will address the question: Is Biomass Energy Really Carbon Cycle Neutral? Hopefully, some pictures of our sustainable biomass energy efforts here in Florida will be better than a thousand words in answering this question.

The first picture below reflects what our land sources looked like before planting energy crops -- unused mining lands dominated by an invasive species plant of cogongrass.

The next two pictures reflect what our sites look like 1 to 2 years after planting energy crops (e.g., fast growing trees, sorghum):

As the above pictures reflect, our sustainable energy crop efforts CREATED a carbon bank that we then used for energy production.

In addition, when biomass energy resources are developed in a environmentally responsible and sustainable way -- biomass energy can exceed the CO2 benefits of other renewable energy sources and be "Carbon Cycle Negative":

Sequestering carbon below ground through energy crop root systems.

Incorporating a stable component of carbon (biochar, a waste product of biomass gasification) into soils.

Incorporating advanced recycling and composting methods for soil building using crop waste streams (e.g., sorghum bagasse).

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CO2 Benefits of Biomass Energy Vs. Solar and Wind Energy (Part 1)

Coal Use

In understanding the benefits of all renewable energy resource options, its important to understand the concept of the integrated resource grid. Under this concept, the renewable technology is viewed not as a stand-alone resource (i.e., a micro view) but how the resource is dispatched on the electricity grid (i.e., a macro view).

While there are some differences throughout the U.S., typically on the integrated grids of all resources (coal, nuclear, natural gas, oil, and renewables), biomass and geothermal units are often dispatched as base load and displace coal fired generation. Wind and solar units are generally dispatched as peaking units and displace natural gas.

The Electric Power Research Institute has an excellent technical paper explaining why CO2 emissions associated with coal-fired generation are significantly higher than the use of natural gas. EPRI's comparison basis is called the "carbon intensity" ratio and reflects:

The higher carbon content of coal versus natural gas and oil, and

The lower energy efficiency of existing coal power plants versus generation technologies that use natural gas (e.g., combined cycle).

Fuel Effect on Fossil Carbon Intensity

Technology Effect on Fossil Carbon Intensity

The efficiency of power plant technology is measured by the unit's heat rate (i.e., the amount of Btu's required to produce 1 kWh of electricity). For example, the higher a unit's heat rate, the lower its efficiency will be. Conversely, the lower a unit's heat rate, the higher its efficiency (thus using less fossil fuel and producing less air emissions of CO2, NOx, and SO2 to generate 1 kWh of electricity).

As the above EPRI data reflects, when biomass energy displaces coal use (e.g., such as in biomass co-firing at an existing coal unit, or in a State like Kentucky where 87% of electricity generation is from coal) the CO2 reduction benefits can be almost twice as great than with a solar or wind unit that displaces a natural gas generating unit's dispatch on the grid.

For more information on this topic, you can go to our Quick Facts on Biomass Energy.

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Google Friend Connect Webpage

Networking

The Biomass Energy Crop and Biomass Power Working Group has created a Google Friend Connect Web-page at:


While we will be adding more gadgets in the future, we would like everyone to use the "comments option" and let us know what specific types of stories (e.g., engineering, agriculture, environment, energy policy, etc.) you would like to see more of.

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Biomass Energy Is a Whole Lot More Than Just About Global Warming.

Sustainability

This past week the EPA issued notification that it is reviewing
water quality standards in Florida. This issue of water quality and management brings up a key agricultural talking point of biomass energy and energy crops that's not discussed in the main stream media.

With Biomass Energy, a key focal point in the Media will always be Global Warming -- we understand this reality. However, the story of biomass energy is much more than just greenhouse gas emissions. The complete story includes what we call the catalytic pro-active environmental impacts in developing biomass energy resources involving "best management carbon management" in agriculture.


Through our work with the U.S. Department of Energy's Oak Ridge National Lab (growing energy crops on marginal lands from phosphate mining), we achieved a dramatic increase in soil organic carbon (SOC) in the soils.

Soil Carbon Percentages Found Before &
2.5 Years After Energy Crop Planting
But our story doesn't just end with carbon sequestration, rather it is just the beginning of pro-active environmental benefits that can occur by implementing carbon management in agriculture which include:

The nature of soil carbon having multiple charges (+ and -), allowing for the "capture" of cations and especially anions of phosphorus and nitrogen that impact water quality (e.g., nutrient laden water run-off into lakes and streams).

The ability of soil carbon to hold and create "pathways" for increased hydrology in soils.

The ability of soil carbon to increase soil micro-organisms, free oxygen, and anion holding capacity (i.e., nitrogen)-- reducing the need for fertilizer inputs for crops.

The ability of Energy Crops to be an effective strategy in reducing/eliminating invasive species of plants (land and hydra-flora).

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