Extract from CEQA Review

The following has been extracted from the Supplemental Information that we submitted with our CEQA documents as part of our application for a County Use Permit. It contains the results of our various cultural, biological, botanical, noise and traffic studies, as well as other information on how our propose biomass facility will effect the community.

The project is a nominal 2.4 MW (net) community based bioenergy facility which would be located in the Mariposa Industrial Park at 5673 Copper Leaf Rd as indicated on the Vicinity Map (Attachment A). The facility will utilize approximately 12,000 bdt (bone dry tons) per year of S.B. 1122 compliant, renewable forest biomass in a gasification process to produce a syngas. The syngas will be used to fuel two gas engine generators to produce electricity. In addition, the project will include two organic Rankine cycle heat recovery turbine generators to further increase the power output and make the facility more efficient. Power will be sold to PG&E under the State of California BioMat program. The project intends to enter into a 20 year power purchase agreement with the utility.

The project’s immediate goal is to help address effects of tree mortality by processing 36 bdt per day of dead and down trees from the High Hazard Zone in Mariposa County. In the long term, the facility will process biomass from forest thinning operations associated with maintenance of fuel breaks.  By purchasing woodchips, the facility will help offset the cost of fuel break maintenance and provide an alternative to prescribed burns.

The Mariposa Biomass Project (MBP) is a 501(c)3 nonprofit corporation established in 2014 with the primary purpose of developing a bioenergy plant in Mariposa County. MBP owns parcel 4 in the Mariposa Industrial Park and has lease option to purchase parcel 3. MBP also has an agreement with Cortus Energy, who will build, own and operate the facility. Cortus Energy is a clean technology company based in Sweden. Under the terms of the agreement with Cortus Energy, MBP will sell parcel 4 and its right to purchase parcel 3 to Cortus Energy upon successful development of the project.

The project is investigating the possibility of purchasing woodchips from the landfill to supplement the county’s need to divert more waste material away from the landfill in response to California’s 75% diversion goal. The county is also faced with the future possibility of having to close the landfill and haul garbage to another location such as Merced. The bioenergy project can utilize up to 2,400 dry tons per year of non-forest wood waste such as residential green waste. This material could be collected in Merced and back hauled to Mariposa and sold to the bioenergy facility.

Should the county go forward with the compost operation at the landfill, the project has been advised that the compost process needs approximately 1 ton per day of ash. The project might be able to support this requirement by providing wood ash from the bioenergy project.

The technology to be implemented is the WoodRoll process, a 2-state thermochemical biomass-to-energy conversion process. Cortus Energy, who will build, own and operate the facility, has successfully completed bench scale testing and pilot plant testing. Currently, Cortus Energy is moving forward with two commercial scale facilities, one in Japan and one in Sweden. The Mariposa project will be the first commercial facility in North America.

It is widely known that the biggest challenge facing small-scale bioenergy projects is financial viability. Scaling down of wood fired, conventional steam plants has not proven viable for several reasons including poor efficiency, high capital cost per kW and high labor cost per kW.  MBP believes the WoodRoll process developed by Cortus Energy which produces a clean syngas gas in conjunction with a high degree of automation, is the solution. The goal of this project is to demonstrate, deploy, and optimize a forest bioenergy technology and assess the performance characteristics and best practices of Wood Waste from Forest Management (WFM) feedstock. Project objectives are to:

• Successfully implement California’s first small-scale WFM bioenergy facility producing 2.4 MW (net) of renewable energy from forest biomass

• Reduce operational costs by using an indirect heating process to produce a cleaner syngas thus reducing engine maintenance costs and unscheduled outages

• Reduce fuel costs by demonstrating heat rates in the 12,000 Btu/kW hr range.

• Increase operating revenue by demonstrating capacity factors in excess of 90%

• Reduce operating staff by automation and remote monitoring

• Reduce greenhouse gas and particulate emissions by diverting biomass from burn piles and controlled burns and utilizing the biomass as an energy resource in a controlled environment

• Extract biochar to be tested for suitability as a substitute for activated carbon used in water treatment facilities. Biochar activation is to be accomplished at UC Merced and in situ testing is to be done at the Mariposa Water Treatment Plant


Parcel 3 will be graded in accordance with the Preliminary Grading Plan (Attachment E) to create a level space on which to store woodchips. Woodchip storage is governed by the 2013 edition of the California Fire Code, Chapter 28. The code limits the height, width and length of the piles as well as pile separation and fire truck access.

The project intends to limit the pile height to 15 ft, which results in approximately 24 days of storage. The project will implement a first in first out strategy to simplify the material handling process. Additional storage will be provided “in field”, where the material is collected and processed.

During its first years of operation, the project will likely provide year around employment for eight operators, one manager and one office administrator. In addition, the project will provide work for truck drivers, tree cutters, chipper operators and maintenance workers.

The facility will operate 24 hours per day, seven days per week and will initially employ a fulltime staff of 10. This assumes 2 operators per 8 hour shift and 1 additional maintenance worker and 1 administrator. As operation experience is developed staffing requirements may be reduced to 6 or 7.

During daytime hours, a maximum staff of 4 will be on site. A total of 5 parking spaces are proposed each 9 ft by 20 ft as indicated on the Preliminary Grading Plan (Attachment E). Public access is not anticipated.

The project will process approximately 37 bone dry tons of biomass each day. Truck deliveries will be limited to 7 AM to 5 PM, six days per week. The bulk of the material will be delivered in 45 ft long, 100 cyd self unloading chip trailers. These enclosed trailers have a conveying floor that automatically moves the woodchips out then back of the trailer. Each trailer can transport approximately 20 tons of woodchips (wet), which equates to about 12 tons (dry).

In addition, the project would accept woodchips from local chippers that would deliver chips in 8 cyd dump trucks. This would include suppliers such as the Fire Safe Council, Trees Inc., Goodman and Cole, etc. In all cases the wood material source of origin would need to be verified in order to be SB 1122 compliant as a renewable source.

The project will require monthly deliveries of propane, nitrogen, diesel fuel and other operation and maintenance materials. The project will need to truck ash to the landfill, which will average one truck load per week.

The project estimates an average of 3 to 4 chip trailers deliveries per day in addition to 8 to 10 small dump truck deliveries per day. There are no plans to allow residential disposal of material at the facility.

A complete traffic study was prepared by TKJM Consultants and is included as Attachment I.

Quote from the Traffic Study:

"The proposed Project would increase traffic through the intersection of CA-49 and Mykleoaks Road/Gold Leaf Road by seven trips during the a.m. peak hour and seven trips during the p.m. peak hour, a change of less than three percent. This is a small change in traffic volume and would have virtually no impact on the level of service of the study intersection. Simulations run using peak hour volumes indicated that the project would also have minimal impact on queueing."

The study concluded that the increased traffic will be insignificant. The study, however, recommended that the intersection of Gold Leaf Road and Highway 49 be improved to provide a better turning radius for trucks exiting Highway 49 south bound onto Gold Leaf Road. The project intends to implement this recommendation.

Several new structures would be constructed on the existing pad on parcel 4 as indicated on the Site Plan, Attachment C. No structures are planned on parcel 3. Weigh scale operation will be automated through a key card system.
The estimated square footages of the structures are as follows:

1. Gasification Facility Enclosure: 3,060 sf

2. Engine Generator Enclosure: 1200 sf

3. Biomass Pocket (Feed Conveyor): 1,250 sf

4. Control Room: 500 sf

5. Storage Building: 450 sf

6. Electrical Switchgear/Transformers: 360 sf

7. Fire Water Storage Tank: 450 sf

8. Ash Storage Bin: 150 sf

9. Nitrogen Tank: 150 sf

10. Propane Tank: 200 sf

11. Flare: 150 sf

A total of 8,600 sf of the property will be covered by structures, which equates to less than 4% of the project site.

Site access is from Highway 49 on to Gold Leaf Drive and then a right turn on Copper Leaf Dr. Copper Leaf Dr. is not a county maintained road. Delivery trucks will enter parcel 3 through a new driveway. The drive way will include a weigh scale. The trucks will be weighed, then directed where to dump their material and then use the turn around at the end of the driveway to exit the facility after they are again weighed. Truck access to the upper lot is over the existing driveway and is primarily for propane, nitrogen and diesel fuel deliveries as well as for staff parking.

It should also be noted that the line of site access onto Highway 49 from Gold Leaf Dr, is more than 600 feet in either direction.

The noise regulations applicable to the industrial park are 75 dBA at internal property lines and 55 dBA at Highway 49. The main source of noise from the bioenergy plant is the engine generator. The engine generators will be located in sound attenuating enclosures to ensure that the noise level at Highway 49 will not exceed 55 dBA and will not exceed 75 dBA at the property lines.

The other major source of noise is the frontend loader and chip trucks that deliver biomass to the facility. The feed system is designed to hold 16 hours of inventory, before it needs to be refilled by the frontend loader. This will insure that the frontend loader operation will be limited to 12 hours/day (during day light hours only). Truck deliveries will be limited to 7 AM to 5 PM, six days a week, Monday through Saturday.

A Noise Study was prepared by Bollard and Associates and is included as Attachment J. The study concluded that the noise generated by the facility will not exceed the noise limits applicable to the industrial park. In addition, the study evaluated the noise impact on the residences in Mykleoaks. Even though the night time noise levels measured at the nearest residences are very low (~40 dBA), the study concluded there should be no noticeable increase in noise levels as a result of the operation of the bioenergy facility.

Quote from the Noise Study:

"The noise generation of the proposed project is predicted to be satisfactory relative to both the noise standards of the Mariposa Industrial Park and CEQA guidelines during both daytime and nighttime conditions, for both onsite operations and off-site traffic. As a result, no adverse noise impacts are identified for this project, and no noise mitigation measures would be warranted at this time."

The following hazardous materials will be stored on site:
Propane: 20 tons or 10,420 gal
Nitrogen: 20 tons or 6000 gal
Diesel: 1000 gal
Engine Lube Oil: 700 gal (storage)
Engine Lube Oil: 342 gal (engine crankcase)
Misc. Lube Oil: 250 gal
Coolant (glycol): 250 gal (storage)
Coolant (glycol): 250 gal (cooling circuit)
Urea: 250 gal (for SCR)

There will be no underground storage of hazardous liquids on site.
Note: If total volume of petroleum liquid exceeds 1320 gallons, then it falls under APSA.


Ordinance 696 limits building heights to 45 ft and utility structures to 75 ft. The tallest building on the site is the gasifier enclosure, which is 40 ft high. The tallest utility structures are the safety flare, 23 ft and the main stack, which is 66 ft high. An elevation view of the facility as viewed from the north (Highway 49) is included as Attachment D.

The equipment will be painted an earth tone color to comply with Ordinance 696

The project is located approximately 6,500 ft from the east end of the runway serving the Mariposa County Airport.

The project will operate 24 hours per day and will therefore, require safety lighting around the plant. The exact location and wattage of the lighting will not be known until the plant is designed in detail and drawings are submitted to the Building Department for review.
There will be no lighting in the woodchip storage area. Lighting around the plant will be shielded and directed downward to minimize any impact on the neighbors. Lighting which may be required for maintenance or repair of outdoor equipment will only be turned on when necessary and only temporarily.

The safety flare pilot flame is shielded from view and will not be seen under normal operation. However, during plant startup, plant shutdown and during a safety situation that requires immediate shutdown of the gas engine generator, syngas will temporarily be bypassed through the safety flare and a flame will be visible on the top of the flare stack.

Water will be supplied to the project from an existing community well on parcel 1. The well’s capacity at the time of initial operation was 20 gpm. The well serves parcels 1 through 4. The project will use an average of 1.5 gpm of well water in the production of the syngas that fuels the gas engine generators to produce electricity. The project will include a condensate recycle system to collect the moisture that evaporates off the wood and minimize the water usage at the facility.

The condensate wastewater stream is limited to a small quantity of liquid (1 kg/hr) that is mixed with ash to create a sludge. A total of 60 lbs per day of sludge will be generated by the facility. The sludge will be disposed of at the landfill.

Sanitary waste will be disposed of through the existing community septic system on parcel 4. The septic system has a capacity of 20 people per day.

Parcel 3 has an area set aside for a septic system to serve parcels 2 and 3. The project proposes to connect parcel 2 to the community septic system on parcel 4. The project intends to install the piping to connect parcel 3 to the community septic system as part of this project.

The project will generate approximately 1.2 tpd (tons per day) of dry ash. The ash will be similar in nature to the ash generated by the curtain burners currently being used at the landfill. The project intends to dispose of this ash in the landfill.

It should be noted that the ash is high in minerals that are beneficial to plant growth. Therefore, alternate methods of disposal (compost additive) are under consideration. In Europe, it is common practice to return the ash to the forests.


The project has hired Natural Investigations to perform a botanical survey of the project site. The results of that survey are included in Attachment G. There were no significant findings as a result of the survey.

The project has hired Natural Investigations to perform a biological survey of the project site. The results of that survey are included as Attachment F. There were no significant findings as a result of the survey.

The project has hired Natural Investigations to perform a cultural resources survey of the project site. The results of that survey are included as Attachment H. There were no significant findings as a result of the survey.

To create level space on which to store the biomass, the project proposes to grade parcel 3 in accordance with the Preliminary Grading Plan (Attachment E). As indicated on the Site Survey drawing (Attachment B), there is a seasonal creek that runs along the north side of the property. The project expects that rip rap will likely be required along the base of the fill, which boarders the seasonal creek to ensure the stability of the fill material.
The estimated quantity of material to be moved and recompacted is approximately 10,000 cyds.

The Mariposa County Fire Department has jurisdiction over this site. The project includes a 100,000 gal fire water storage tank located in the southwest corner of parcel 4. Hydrants will be located as required by fire department.

Fire apparatus access to the wood chip piles is along the 30 ft wide driveway and turn around at the end of the driveway. Fire truck access to the bioenergy facility is along the existing driveway that services parcel 4 and a hammer head turn around between the nitrogen storage tank and the engine generator building.

By limiting the woodchip storage pile capacity to 24 days, the danger of spontaneous combustion of the woodchips is greatly minimized.

The project will file for an Authority to Construct with the Mariposa County Air Pollution Control District. The project has been advised that the BACT (Best Available Control Technology) will be applied to the project.

The project has 2 stationary point sources: The main exhaust stack which combines the emissions of the two gas engine generators and woodchip dryer and one safety flare stack.
The project intends to use GE Jenbacher, type 6 gas engine generators equipment with SCRs for NOx control and CO catalysts for increased CO emission reduction.

In addition, the air permit application will address greenhouse gas emissions as well as net emissions with and without the project. The air permit will also account for emissions associated with the construction of the facility as well as emissions associated with the collection, transport and processing of the wood chips.