HomeMy WebLinkAboutFinal-Decommissioning-Plan.pdf
DRAFT 9/9/16
Black Oak Wind Farm
Decommissioning Plan
Anticipated Life of Wind Turbines
Megawatt-scale wind turbine generators available on the market today have a life expectancy of more than 20 years.
The tubular steel towers supporting the generators have a simple, rugged design and with basic routine maintenance
will serve many years beyond the life expectancy of the generators.
As the turbines to be installed for the Black Oak Wind Farm (the Project) approach the end of their serviceable life,
technological advances should make available more efficient and cost-effective generators that will economically drive
the replacement of the existing generators and thus prolong the economic life of the Project. In the event that this
doesn’t happen and the turbines need to be decommissioned, the following plan provides a description of the
decommissioning work and the estimated costs associated to perform it.
Estimated Cost of Decommissioning
Research in the US is lacking to support actual decommissioning costs of wind farms, since little decommissioning has
been performed due to the recent development of the wind industry. Estimates have been prepared by a range of
sources, with numbers between $40,000 and $170,000 per turbine proposed based on estimates of labor, materials,
and scrap value. (Falmouth, MA Mitigation Plan, 2011; Knauth, Ridgeline Wind 2011; New Grange Wind Farm DEIS,
2008).
Published research from Sweden in 2014 looked at actual decommissioning costs of two wind projects. One project
cost $21,141 per turbine to remove only the turbines themselves. The other project removed all foundations, roads,
crane pads, and cables, and cost $63,000 per turbine to perform (Giovannini 2014). No other published research is
available to the Applicant’s knowledge.
In reality, in the unlikely event that the Project had to be decommissioned it is more likely that turbines and associated
equipment would be sold to another power provider rather than sold for scrap for the value of the raw materials.
Individual rotors, generating equipment and towers would likely have value and demand on the open market. Ten to
twenty-year old turbines being decommissioned in Europe are commonly reconditioned and sold as operating
machines rather than for scrap.
Ensuring Decommissioning and Site Restoration Funds
According to the Town of Enfield Wind Energy Facilities Local Law, the Project will continuously maintain a fund, bond,
letter of credit, or equivalent financial security instrument payable to the Town of Enfield for the removal of non -
functioning wind turbines and appurtenant facilities, in a form and amount approved by the Town Board for the period
of the life of the facility. Prior to approval of the project by the Building Department of the Town of Enfield, the Project
will, in writing, provide a surety bond or financial security instrument in a proposed amount not less than
$180,000 per turbine, or a total of $1,250,000 (assuming 7 turbines), plus an additional $100,000 for assuring road
repair during decommissioning, renewable on an annual basis, for the removal of non-functioning turbines and
associated facilities. Per the local law, this amount may be periodically reviewed by the Town at its discretion, and the
amount altered accordingly for the estimated costs of removal, decommissioning, and restoration. The Project Sponsor
will fully comply with the local law concerning decommissioning and site restoration. As per a vote held on Aug ust 16,
2016, the Project will replace any surety bond with a letter of credit or cash escrow account by the time turbines are
commissioned, and letter of credit or cash escrow will be the financial instrument used for the life of the project, rather
than a surety bond.
Decommissioning Process
All decommissioning and restoration activities will adhere to the requirements of appropriate governing authorities, and
will be in accordance with all applicable federal, state, and local permits. The decommissioning and restoration process
comprises removal of above-ground structures; removal of below-ground structures to a depth of 36 inches; restoration
of topsoil, re-vegetation and seeding; and a two-year monitoring and remediation period. Access roads, fencing and
residual minor improvements will not be removed unless the landowner requests that they be removed. Above-ground
structures include the turbines, transformers, overhead collection lines, wind farm-owned portions of the substation,
maintenance buildings, and access gates. Below-ground structures include turbine foundations, collection system
conduits, and drainage structures. The process of removing structures involves evaluating and categorizing all
components and materials into categories of recondition and reuse, salvage, recycling, and disposal. In the interest of
increased efficiency and minimal transportation impacts, components and material may be stored on -site in a pre-
approved location until the bulk of similar components or materials are ready for transport. The components and
material will be transported to the appropriate facilities for reconditioning, salvage, recycling, or disposal. The presence
of Teet’s Scrap Recycling within the project boundary makes the recycling of all metal components an easy and cost
effective process.
Wind turbine removal
Access roads to turbines may be widened temporarily to sufficient width to accommodate movement of
appropriately sized cranes or other machinery required for the disassembly and removal of the turbines. High
value components will be stripped. The remaining material will be reduced to shippable dimensions and
transported off site for proper disposal. Control cabinets, electronic components, and internal cables will be
removed. The blades, hub and nacelle will be lowered to grade for disassembly. The tower sections will be
lowered to the ground where they will be further disassembled into transportable sections. The blades, hub,
nacelle, and tower sections will either be transported whole for reconditioning and reuse or dissembled into
salvageable, recyclable, or disposable components. Useable parts will be sold into the secondary market for
parts or installation elsewhere. The area will be thoroughly cleaned and all debris removed.
Wind turbine foundation removal
Topsoil will be removed from an area surrounding the foundation and stored for later replacement. Turbine
foundations will be excavated to a depth sufficient to remove all anchor bolts, rebar, conduits, cable, and
concrete to a depth of 36 inches below grade. After removal of all noted foundation materials, the hole will be
filled with clean sub-grade material of quality comparable to the immediate surrounding area. The sub- grade
material will be compacted to a density similar to surrounding sub-grade material. All unexcavated areas
compacted by equipment used in decommissioning shall be de-compacted in a manner to adequately restore
the topsoil and sub-grade material to the proper density consistent and compatible with the surrounding area.
The area will be thoroughly cleaned and all debris removed, and re-seeded to vegetation acceptable to the
landowner.
Underground electrical collection system
The cables and conduits contain no materials known to be harmful to the environment and will be cut back to
a depth of at least 36 inches. All cable and conduit buried greater than 36 inches will be left in place and
abandoned.
Substation
The Project substation is generally valuable to the local transmission owner. As per the interconnection rules
of the NYISO, the Project substation reverts to the ownership of the transmission owner and thus the Project
Sponsor does not intend to decommission the substation.
Site Restoration Process
To the extent necessary, topsoil will be removed prior to removal of structures from all work areas and stockpiled,
clearly designated, and separate from other excavated material. Prior to topsoil replacement, all rocks six (6) inches or
greater will be removed from the surface of the subsoil. The topsoil will be de-compacted to match the density and
consistency of the immediate surrounding area. The topsoil will be replaced to original depth, and original surface
contours reestablished where possible. All rocks six (6) inches or larger will be removed from the surface of the topsoil.
Any topsoil deficiency and trench settling shall be mitigated with imported topsoil consistent with the quality of the
affected site.
In accordance with guidelines provided by New York State Department of Agriculture and Markets, topsoil de-
compaction and replacement will be avoided after October 1, unless approved by the landowner in consultation with
the New York State Department of Agriculture and Markets since areas restored after October 1 may not obtain
sufficient growth to prevent erosion over the winter months. If areas are restored after October 1, provision will be made
to restore any eroded areas in the springtime to establish proper growth. Following decommissioning activities, the
sub-grade material and topsoil from all affected agricultural areas will be de-compacted and restored to a density and
depth consistent with the surrounding fields or to a depth of 18 inches. The affected areas will be inspected, thoroughly
cleaned, and all debris removed.
All disturbed soil surfaces within agricultural fields will be seeded with a seed mix agreed upon with the landowner in
order to maintain consistency with the surrounding agricultural uses. All other disturbed areas will be restored to a
condition and forage density reasonably similar to original condition. In all areas restoration shall include, as reasonably
required, leveling, terracing, mulching, and other necessary steps to prevent soil erosion, to ensure establishment of
suitable grasses and forbs, and to control noxious weeds and pests.
In accordance with the guidelines of the New York State Department of Agriculture and Markets, a monitoring and
remediation period of two years immediately following the completion of any decommissioning and restoration activities
will be provided. The two-year period allows for the effects of climatic cycles such as frost action, precipitation and
growing seasons to occur from which various monitoring determinations can be made. Any remaining agricultural
impacts can be identified during this period and follow-up restoration efforts will be implemented.
In addition, all Town, County, and State roads, impacted by Project decommissioning activity, if any, will be restored to
original condition upon completion of decommissioning. Funds for road repair after decommissioning will be included
in the total amount of the decommissioning bond or another financial instrument held by the town.
References
Tetra Tech. 2008. New Grange Wind Farm DEIS, Exhibit 9: Decommissioning Plan. Available at:
http://www.horizonwindfarms.com/northeast-region/documents/underdev/arkwright/Exhibit9_DecomissioningPlan.pdf.
Weston and Sampson. 2011. Town of Falmouth MA Wind Energy Facility Mitigation Alternatives Analysis. Available at:
http://www.falmouthmass.us/selectmen/falmouth%20turbine%20mitigation%20study.pdf.
Knauth, Jonathan. 2011. Knauth’s Analysis of cost to decommission turbines, Public commentary on the Ridgeline
Energy LLC Monticello Hills Application, Decommissioning estimate. Available at:
http://www.protectrichfield.com/documents/Decommissioning%20Estimate%20for%20Ridgeline%20Energy%20Monti
cello%20Hills%20Project.pdf.
Giovannini, Gabriele. 2014. Wind Farm Decommissioning: A Perspective on Regulations and Cost Assessment in Italy
and Sweden. Available at: https://www.diva-portal.org/smash/get/diva2:767553/FULLTEXT01.pdf