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PO Box 1070, Frankfort, KY 40602  Phone 502.875.2428, Fax 502.875.2845

KRC Comments On Proposed Biodigester Zoning Revisions  Posted: August 3, 2016

August 1, 2016

Brian Mabry, Staff Case Manager
Planning and Design Services
444 S. 5th Street, Suite 300
Louisville, Kentucky 40202
By email only: Brian.Mabry@louisvilleky.gov

Dear Mr. Mabry:

These comments are submitted by the Kentucky Resources Council, Inc. on behalf of the many members of the Council that reside in Metro Louisville, and who will be adversely affected if the proposed revisions to zoning regulations are adopted without significant revision.

Before turning to the proposed regulatory changes, it is important to reflect on the current zoning ordinance and how it applies to biodigesters using anaerobic digestion technology. For while it is intended that the proposed changes would tighten regulation of biodigesters, the effect is instead to allow potential siting of such facilities in EZ-1 and other zones, while the existing ordinance would restrict such facilities to M-3 industrial zones unless they were converting wastes to gas for use at the facility site.

Chapter 4.2 of the Land Development Code lists the categories of conditional uses. Among them is 4.2.37, which is captioned “Non-emergency Generator and Non-accessory Alternative Energy System.” A biodigester that uses anaerobic digestion to create a methane-rich biogas for off-site use or sale is neither a “non-emergency Generator” nor a “non-accessory alternative energy system.”

A biodigester generating biogas for sale is not a “non-emergency generator,” since that term is defined as “[a] power generator used to provide supplemental power to a user requiring additional and/or sustainable power not normally available to the user from the local public utility. This type of generator does not include those used for emergency situations such as a loss of power due to unforeseen circumstances.”

A biodigester facility converting organic wastes to methane to be introduced into a gas pipeline for sale or use elsewhere is not a power generator, nor is it an “alternative energy system.” Instead, it is creating a fuel that can be converted to power or heat.

Nor does such a facility fit under the definition of a “non-accessory alternative energy system,” which is defined as “[a]ny facility or installation such as a windmill, hydroelectric unit or solar collecting or concentrating array, which is designed and intended to produce energy from natural forces such as wind, water, sunlight, or geothermal heat, or from biomass, for on-site or off-site use. The off-site use shall not be for public usage, which would be deemed a Public Power Plant.”

A biodigester converting waste to biogas for transport is not producing energy; rather it is generating and cleaning a fuel that would be introduced into the LG&E gas utility pipe system for sale and end use either for combustion in a gas turbine creating energy in the form of electricity or by combustion for space heating. It is clear from the distinction drawn in the definition of “alternative energy system,” which treats off-site public usage as a Public Power Plant, that the “alternative energy system” contemplated in the regulation is limited to alternative systems creating electricity and not those creating fuel that can later be combusted to generate electricity, since the definition of a public power plant is “[a]n electrical power generation facility that, regardless of fuel or energy source, is operated by a public utility or independent power producer and whose primary function is the provision of electricity to the electrical distribution system or transmission grid.”

The proposed revisions to the LDC would define a biodigester as an “alternative energy system” using anaerobic digestion for “the primary purpose of producing energy.” As such, the facility could be located in an EZ-1 zone regardless of whether it was producing electricity on site or generating pipeline-quality natural gas.

The proposed definition of “biodigester” should describe the process without introducing such vague terms as “primary purpose” and “secondary function.” For as written, a proponent of a project could state that their primary purpose was to produce soil amendments and secondary purpose was the production of a biogas, and that therefore the proposed facility was not a “biodigester” at all. It is unclear how staff or the Commission would determine what purpose is primary and what is secondary, and in truth, the question is irrelevant to how the location of a biodigester facility should be regulated.

KRC recommends that in order to eliminate doubts and ambiguities regarding the regulation of biodigesters, the definition of “alternative energy system” be revised to remove mention of biomass, and new definitions of “anaerobic digestion” and “biodigester” be adopted to read as follows:

Alternative Energy Systems: Any facility or installation such as a windmill, hydroelectric unit or solar collecting or concentrating array, which is designed and intended to produce energy electricity from natural forces such as wind, water, sunlight, or geothermal heat, or from biomass, for on-site or off-site use. The off-site use shall not be for public usage, which would be deemed a Public Power Plant.

Anaerobic digestion means one or more processes of controlled decomposition of biodegradable materials under managed conditions in the absence of oxygen, resulting in generation of a biogas for use or sale on- or off-site, and whole digestate. Biodegradable materials include, but are not limited to, food waste, sewage sludge, and wastes generated from fermentation processes.

Biodigester means a facility utilizing anaerobic digestion.

Under current regulation, a biodigester generating biogas for off-site use falls under Section 4.2.42 of the LDC as a “potentially hazardous or nuisance use” because of the accompanying hazards such as fire, explosion, noise, dust, or the emission of smoke, odor, or toxic gases.” The biodigestion process reduces the volume of solid waste by converting organic material into a gaseous form, and thus falls under the category of reducing wastes, which can only be located currently in an M-3 District and not an EZ-1 District. Additionally, the project will be creating a soil amendment that is a fertilizer and fertilizer can only be manufactured in an M-3 District under the current LDC.

Under the proposed ordinance, biodigesters, whether using the biogas fuel on site for generation of energy by combustion for heating or for electricity generation, or whether cleaning and introducing the gas into a pipeline for use elsewhere, could be sited in a C-M, M-1, M-2, M-3 or EZ-1 zoning district, thus substantially increasing the potential location for such facilities within Metro Louisville.

KRC opposes such an expansion of potential sites, and believes that the existing restriction on biodigesters to M-3 zones should be retained and clarified further by adopting the proposed definitional changes above, and by explicitly amending 4.2.42 of the LDC to read as follows:

4.2.43 Potentially Hazardous or Nuisance Uses

The following uses (manufacture, processing, treatment, or storage unless otherwise specified), having accompanying hazards such as fire, explosion, noise, vibration, dust, or the emission of smoke, odor, or toxic gases may, if not in conflict with other laws or
ordinances, be located in industrial zones as indicated below by Conditional Use Permit after the location and nature of such use shall have been approved by the Board of Zoning Adjustment. In reviewing an application for a CUP, the Board of Zoning Adjustment shall
review the plan and statements of the applicant and the following:
A. The Comprehensive Plan;
B. Environmental and health related concerns raised by the operation and the applicant’s proposal to mitigate any adverse effects to the public’s health, safety and general welfare;
C. The applicant’s site design, buffering, and security measures and their adequacy to mitigate any adverse effects to the public’s health, safety and general welfare;
D. Any other evidence submitted by the applicant and any other party addressing the issues.
A Conditional Use Permit under this section shall be issued only if the evidence shows the applicant’s operation and associated nuisances will be properly managed and the public’s health, safety and general welfare will be protected. The Board of Zoning Adjustment may impose additional conditions to protect surrounding properties. All
Conditional Use Permits under this section shall be issued subject to the applicant also receiving all necessary permits from local, state and federal regulatory agencies.
EZ-1 and M-3
Aluminum powder
Brick, firebrick, tile, clay products, including refractories: manufacturing, processing or
treatment but not including storage
Cement, gypsum, lime, and plaster of paris (but not storage)
Charcoal, lampblack, carbon black, bone black, and fuel briquettes, including
Chemicals, including acetylene, acids and derivatives, alcohol (industrial), ammonia, aniline dyes, carbide, caustic soda, cellulose and cellulose storage, chlorine, cleaning and polishing preparation (non-soap), dressings and blackings, creosote, dyestuffs, exterminating agents and poisons, hydrogen and oxygen, plastic
materials, and synthetic resins, potash, pyroxylin, tar products, turpentine and resin, and solvent-extracting
Coal, coke, or tar products including fuel gas, and coke-oven products
Distillation, manufacture, or refinement of coal, tar, asphalt, or asphalt products
Metal and metal ores, reduction, refining, smelting, alloying, including blast furnaces, cupolas, and blooming mills (but not storage of metal products)
Minerals and earths (including sand-lime products), grinding, crushing, processing or storage
Paint manufacture, processing, or treatment (but not storage)
Petroleum or petroleum products, refining, bulk storage, including gasoline or other petroleum products
Plastic, manufacture, processing, treatment, or bulk storage
Radioactive materials
Steel works and rolling mills (ferrous) for steel, structural iron and steel fabrication, and structural products, including bars, cables, girders, rails, wire rope, or similar products
Waste paper and rag operations
Wood pulp or fiber, reduction or processing (including paper mill operations)
M-3 Only
Anaerobic digestion / biodigester
Distillation of wood and bones
Explosives (when not prohibited by other ordinances) including ammunition, fireworks, nitrating of cotton or other materials, nitrates (manufactured and natural) of an explosive nature, and storage of latter
Exterminating operations where exterminating chemicals or agents are stored
Fertilizer (organic and non-organic), including fish, oils, manure, or peat
Glue and size (vegetable), gelatin (animal), and starch manufacture
Grain storage or grain elevators
Hair, hides, raw fur, leather, curing, dressing, dyeing, finishing, tanning, and storage
Match manufacture, processing, or treatment
Meat and fish products, including slaughtering of meat or curing of fish, packing, and storage
Ore dumps, slag piles
Rendering, incineration or reduction, and storage of dead animals, garbage, offal, or waste products (the entire operation to be performed within a building)
Slaughtering of animals or poultry
Stock yards and feed lots

With respect to the proposed setback of 1,320 feet, KRC believes that the setback should not be a fixed distance irrespective of the scale, capacity, design, operational history of the applicant and of the technology, and type and variability of composition of feedstock of the biodigester, but should incorporate a default setback distance of 2,640 feet from the digester to a sensitive receptor that can be adjusted upwards, or downwards to no less than 1,320 feet depending on those considerations, and the recommendations of local emergency response agencies. The overriding consideration should be one of assuring compatibility of the proposal with other land uses nearby, in terms of height, bulk, scale, intensity, traffic, noise, odor, appearance, and potential risks of pollution, fires or explosion during process upsets, malfunctions, or leaks.

For a limited-scale biodigestion process that is both utilizing only waste generated on-site and is utilizing the biogas in a closed-loop process to generate on-site electricity or space heating, the BOZA should have the flexibility to allow such processes only as an accessory use in C-M, M-1 and M-2 zones provided that the total tonnage of feedstock material processed on the site is less than 10 tons per day. The setback for a biodigester falling under this category would be set by BOZA to assure protection of sensitive receptors such as residential property, but in no case shall be less than 600 feet.

No process of converting organic wastes to biogas is without potential problems, whether from failed or clogged biofilters, from leaks or spills during product transfer, upsets in the digestion process, or from leaks of odorants that will be intentionally introduced into the gas prior to feeding the gas into a pipeline system. With every vent or stack to the outside air, with every valve, seal, and flange, there is a potential for odors, and typically there are several points in the process where venting to outside air of methane and other products and byproducts of the process could occur, including a flare for flaring off surplus gas and a discharge stack associated with a biofilter for odor control.

Adequate standards are needed to assure that all inputs of waste and outputs of products, byproducts, and impurities that are removed from the generated biogas are fully accounted for so as to prevent off-site impacts to other land uses, prior to issuance of a Conditional Use Permit.

With respect to proposed conditions B, C, D, E, F, G, H, I, and J, the conditions are good so far as they go, but the proposed requirements are missing several critical considerations. KRC recommends that these revisions be made to the list of conditions, and that all of the conditions be incorporated into 4.2.43 as a new subsection, rather than a separate section, so that the general language of 4.2.43 and the authority it provides BOZA to tailor conditions to the needs of the individual site and surrounding uses, is retained. Additionally, KRC proposes these conditions be added:

1. In order to assure that the proposed facility receives rigorous review, the LDC should be modified to provide that any proposal for a biodigester be reviewed by an independent consultant retained by the BOZA, and that the cost of that review should be passed to the applicant through a permitting fee.

2. All biogas condensate shall be discharged into a sealed drainage system or recirculated back into the digester. Liquids may be discharged into a sewer only as approved by MSD, or may be taken of-site in a closed tanker.

3. All bulking, transfer, and pre-treatment of waste shall be carried out in an enclosed building maintaining negative air pressure, with all waste storage and processing occurring on an impermeable surface with a sealed drainage system. Wastes shall be stored in enclosed containers or reactor vessels. The building shall be equipped with biofiltration sufficient to prevent ambient release of odor, bioaerosols, and microorganisms.

4. All storage and process tanks shall be bermed and shall have capacity at least 110% of the largest vessel or 25% of the total tankage volume.

5. All waste received shall be processed and introduced into the digester unit within 24 hours of receipt.

6. The exclusion of biodigesters as an agricultural land use should be limited to biodigesters located on the site of an agricultural operation and utilizing only feedstocks generated by the farming operation. Otherwise, the facility falls outside of the Chapter 100 exclusion and becomes a commercial facility that is subject to regulation under Chapter 100.

Thank you for the opportunity to presents these concerns and suggestions.


Tom FitzGerald

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