A CASE STUDY IN PLANNING A RENEWABLE …renewables.morris.umn.edu/biomass/staff/Tallaksen/...A CASE STUDY IN PLANNING A RENEWABLE ENERGY SUPPLY CHAIN ASEM 2014 INTERNATIONAL ANNUAL

A CASE STUDY IN PLANNING A RENEWABLE ENERGY SUPPLY CHAIN

ASEM 2014 INTERNATIONAL ANNUAL CONFERENCEOCTOBER 15‐19TH VIRGINIA BEACH VIRGINIA

JOEL TALLAKSEN, West Cen t ra l Re sea r ch & Ou t rea ch Cen te r, Un i ve r s i t y Of Minne so taTRICIA SIMO KUSH, PEM , I T Con su l t an t , Minneapo l i s , Minne so ta

Pictures morris campus and farming

Part II: Using Life Cycle Environmental Metrics To Select A Biomass Feedstock

TALLAKSEN & SIMO KUSH 2014

Typical Supply Chain Management•Decisions on technology purchased or built•Capital expenses•Understanding of points of failure•Operational requirements

•Decisions on personnel and training•Evaluation of potential outsource of activities

Material Production

• Technology• Staffing

Material Packaging

• Technology•Packaging

Transportation

• Equipment• Fuel

End Use

•Equipment•Disposal• Staffing

All of these are converted to a standard, easy to measure unit: DOLLAR$


Metrics for Managing Environmental Issues•Many potential environmental impacts, common areas:AirGroundWater

•Also need to consider:Impacts on the built environment (i.e. acid rain on stone buildings)Social impacts (i.e., communities and culture)

• Environmental impacts most frequently studiedFossil energy useGlobal warming potential

• A number of approaches for analyzing these impacts


Implementing Environmental Metrics• More difficult to summarize than economic metricsMany environmental impact concerns (air, water, soil, resources)Often several options for mitigate impactsOptions often involve tradeoff

• Part of the ‘Triple Bottom Line’ in project design

• Environmental management has more audiences to please

• Most environmental management decisions are based on the unique conditions of each project

• The following case study is used to illustrate one approach


Need to Diversify Energy Supply Chains•Transitioning from fossil fuels is difficultCosts of new infrastructureEasy use of fossil energy Existing infrastructure Energy dense fuel, simple logistics Current costs are cheap

•Natural Gas Cost Issues•Availability & Shortages•Environmental Issues

Pictures‐ Natural Gas Prices?


Morris Heating Facility as a Case Study• Constructed a biomass energy facility in 2011

• Key decision was which biomass fuel to use Corn most available biomass Corn Stover (leaves, stalks, and cobs)‐ higher volume, less dense Corn Cobs – Lower amount, but better handling and cleaner fuel

• Examined environmental metrics of these supply chains: Fossil Energy Footprint (MJ per MMBTU) Greenhouse Gas (GHG) Equivalents (kg CO2)

• Goal: Determine which biomass energy feedstock (corn stover or cobs) had the smallest impacts on the two environmental metrics selected

Insert picture of facility


Setting up the Environmental Metric Assessment•Limited life cycle assessment chosenThe information was not for regulatory, policy, or certification

•Farmer field to facility (cradle‐to‐gate)

•Used current technology• Infrastructure not includedNor background systems (i.e., energy to get diesel to Minnesota)

•Does not include factors related to soil carbon and CO2releaseAssumed harvesting was done sustainably


Methodology and Data analysis •Developed process flowIdentified areas of energy use

•Modelled process energy flowSpreadsheet based modeling

•Quantified energy useAlmost all is diesel fuelSome natural gas

•Calculated fossil energy footprint •Used fossil fuel emission factors for greenhouse gas data


Process examined in Biomass Supply Chain

Cultivation Collection Transport Processing StorageFertilizer added Stalks Chopped

Residues RakedMaterial BaledBales Loaded

Material Moved Via Flatbed Truck

Material Ground

Organized Stacks of Material

A) Corn Stover

B) Corn Cobs

Cultivation Collection Transport Processing StorageFertilizer added Cobs Sorted

On-site TransportOn-site StorageBulk Loading

Material Moved Via Self Unloading Bulk Materials Truck

No Processing

Bulk Piles

• Additional Fertilizer is needed when biomass is removed






Material Ground


A) Corn Stover

B) Corn Cobs




No Processing

Bulk Piles

• Stover Harvest Uses Current Equipment• Cobs Require Specialized Harvest Equipment






Material Ground


A) Corn Stover

B) Corn Cobs




No Processing

Bulk Piles

• Stover Transport Uses Commonly Available Flatbed Trailers• Cobs Can Be Moved Using Existing Grain Trailers






Material Ground


A) Corn Stover

B) Corn Cobs




No Processing

Bulk Piles

• Processing is Needed Only For Stover






Material Ground


A) Corn Stover

B) Corn Cobs




No Processing

Bulk Piles

• Outdoor Storage For both• Debatable whether investing in protected storage has a payback


Fossil Energy Use• Measured in MegaJoules of fossil energy per MMBTUMMBTU is a standard unit for natural gas (NG) in the U.S. Equals a decatherm which is a 1000 cubic feet of NGMorris campus heating needs peak at 19 MMBTU/Hour

• Cultivation energy (fertilizers) were higher for stover

• Harvest energy was greater for cobs

• The processing energy was very significant for stover

• Fossil energy for both biomass sources were considerably lower than natural gas

Stover Cobs NaturalGas

Cultivation 37.75 21.34 ‐Harvesting 8.55 33.81 ‐

Transportation 0.46 0.83 ‐On‐site energy ‐ ‐ ‐

Processing 25.15 ‐ ‐

Total Fossil Energy 71.91 55.98 1,054


Global Warming Potential•Measured in carbon dioxide equivalentsAll other compounds are tied to CO2 For example: 1 kg NO2 is equivalent to 22 kg CO2

•Trends followed fossil fuel pattern

Stover Cobs Natural Gas

Cultivation 1.90 1.08 ‐

Harvesting 0.60 2.36 ‐

Transportation 0.03 0.06 ‐

on‐site energy ‐ ‐ ‐

Processing 1.76 ‐ ‐

Total CO2 Equiv. 5.03 3.91 53.11


Sensitivity Analysis

Total Energy (MJ) CO2 Equivalents

Change in Factor Increase 35% Decrease 35% Increase 35% Decrease 35%

Factors stover cobs stover cobs stover cobs stover cobs

Processing Energy 12% 16% ‐12% 0% 12% 16% ‐12% 0%

Yield ‐3% ‐15% 5% 30% ‐3% ‐15% 5% 30%

Percentage of Farmers ‐0.1% ‐0.2% 0.2% 0.4% ‐0.1% ‐0.2% 0.2% 0.4%

Examination of which model variables had large effects on the results.

Based on results from a 35% increase and decrease in certain variablesGrain yield (which translates to biomass yield) was very critical for cobsCob harvest equipment uses significantly more fuel to collect the needed biomass


Overall Findings• Cobs had less of an environmental footprintRoughly 2/3 the GHG and Fossil Fuel Use

• Stover processing largest difference in metrics used

• Both Cobs and Stover had very significant reductions in environmental impacts than traditional fossil energy.

• When put in context of the existing fossil system, the relative difference in environmental metrics indicated that either cobs and stover would meet project goals.


Recommendation For Project• Corn cobs should be used. Implementation steps to pursue:(Partially based on the need to add the processing of stover)Contract suppliers who are willing to purchase/lease harvest equipment Establish storage sites that will accommodate cobs

• Areas of Concern:From sensitivity analysis: low yields could increase GHG and Fossil Use

• Major changes (increases) in biomass demand may increase GHG and Fossil UseLarger supply radius for cobs


Evaluating Case Study Methodology• Level of analysis supported goal of identifying supply chain impacts

• A low resolution assessment met the needs of this projectData was needed for an internal decision on the choices between supply chains.

• Need to balance the environmental choice with social and economic options

The next questions need to be:

Is the option with the least environmental impacts cost competitive?

Will the other actors in the supply chain (farmers, truckers, processors) be willing to support the proposed supply chain?


Acknowledgment• University of Minnesota Morris‐ Lowell Rasmussen, Vice Chancellor

• University of Minnesota, WCROC‐Mike Reese, Project Director

•Data and scenarios provided by projects previously funded by the Minnesota Corn Research and Promotion Council, the USDA SunGrant, and the University of Minnesota, Initiative for Renewable Energy and the Environment (awarded to staff at the U of MN)

• Image CreditsWikipedia, Tractors.wikia.com (Stream Tractor), National park service (Triple Bottom Line), John Deere (Green Tractor), AgCo (Grey Tractor)

Documents

A CASE STUDY IN PLANNING A RENEWABLE …renewables.morris.umn.edu/biomass/staff/Tallaksen/...A CASE STUDY IN PLANNING A RENEWABLE ENERGY SUPPLY CHAIN ASEM 2014 INTERNATIONAL ANNUAL