Eagle - Answers to Questions and Clarifications Raised at Greenburgh Town Board Meeting 12/9/20

1. Estimated Property Tax/Benefits to Town Supervisor Feiner and many other parties asked about the financial benefits to the town, and how much property tax the energy storage system would ultimately pay. Property taxes applicable to the project will ultimately be determined by the tax code and the judgement of the Town Assessor. Our team estimates that the project may ultimately pay $30k-$50k per year in property taxes over the life of the project (up to $1.5mm over 30 years). The actual number will be determined in coordination with the Town Assessor. 2. Storms/Trees Causing Line Outages A Town Councilperson asked what would happen if the lines between the battery and the Elmsford substation went down. We wanted to confirm that the battery project could in no way negatively impact the Town’s power supply. In the event of an outage between the battery system and the Knollwood substation the battery would safely be placed into a non-operational mode, and Con Edison’s grid would function (or not function) exactly the same as if the system were not present.

When the battery is operational, it should help to stabilize the grid and increase reliability on a grid-wide level.

The proposed overhead electrical lines will generally be located away from branches which could impact the lines. Where the project proposes to connect to existing poles, the branches will be trimmed, in-line with other local utilities. 3. Selling Energy to the Public A member of the Planning Board stated that “[the project] has no intention of selling energy to the public.” This is not accurate. The proposed project would sell energy into the NYISO energy, capacity and ancillary services markets. The public buys energy from these markets, either through Con Edison or through a third-party energy supplier. The proposed project would operate identically to virtually all power generating facilities in the state of New York which sell into the wholesale energy markets. The project would be regulated by the Federal Energy Regulatory Commission (FERC) in the same way as other wholesale power generators in New York State. 4. Availability of Other Locations A member of the Planning Board as well as other parties asked for additional analysis around whether the project could be located in another location that was not zoned residentially. The project must be located near the substation so that it can interconnect to the substation. Strata has been in discussions with all other landowners directly adjacent to the Con Edison substation (see diagram below; blue outline is the substation, red outlines are parcels of land that Strata approached). We were not able to reach agreement for the use of any of these other plots of land due to lack of interest from the landowner, previous engagements that precluded the landowner from leasing or selling the property to the project, or due to offers from other interested parties (e.g. the expanding car dealership). Many of

these other locations were located closer to residences than the proposed site at the Knollwood Country Club.

It should also be noted that the alternative locations that were reviewed and approached are closer to residential areas. Specifically, the Kimco Parcel is less than 400 feet to the nearest residential house with the other alternative locations situated even closer. The Knollwood Country Club was selected as it represented the only available and the best suitable site near the Elmsford substation which could accommodate the BESS Facility. While there may be available parcels outside of the area, they would be located significantly further from the Elmsford substation, making the Interconnection Route infeasible.

Figure 1 - Land Near Elmsford Substation 5. Conditions in the Planning Board’s Recommendation Chairperson Simon referenced a list of recommended conditions that the Planning Board included in their recommendation to the Town Board. As we have discussed with the Town Board and Town Attorney, we can accept almost all of the recommended conditions, including secondary containment and a decommissioning bond. Many of the concerns that have been raised have been previously addressed in memos and submissions to the various Town entities and review Boards. To simplify the collection of documents, please refer to the below list of documents, included in the Appendix to this document, which were previously submitted (or, in the case of the Viewshed Profile, are being submitted now). This list is not comprehensive. For further information, please reference the original application & submission submitted to the Town on 9/11/20, as well as the revised application materials submitted on 10/28/20.

• 9/29/20 – Letter of No Effect from SHPO • 10/28/20 – Planning Board Question & Answers • 11/18/20 – Letter of Review and Support from Fire Chief • 11/18/20 – Letter to Planning Board & CAC • 11/25/20 – Planning Board Letter & MSDS Sheets

• 12/17/20 – Viewshed Profile 6. Length of fire event A member of the Planning Board and other parties stated that Tesla claims that a fire could take a day or more to be extinguished. While Tesla may have stated this previously, it is not accurate for the Megapack system being proposed. The most recent emergency response guide is Tesla’s “Lithium-Ion Battery Emergency Response Guide, For Tesla Energy Products including Powerwall, Powerpack, and Megapack – TS-00004027 – REV 2.1 from August 28, 2020. This document states that “a battery fire may continue for several hours and it may take 24 hours or longer for the battery pack to cool.” (page 13 of 21). It does not state that a fire would continue for 24 hours and in fact explicitly states that the fire would continue for only “several hours”.

In fact, the fire would be extinguished in no more than 3.5 hours, though the system could remain hot for a full 24 hours. This is detailed in a separate document from August 2020 specifically applicable to the proposed Megapack (as opposed to the more general emergency response guide that also includes the Powerpack and Powerwall) which states “External suppression is not required as the system performs in a safe and controlled manner, fully consuming itself slowly over a period of 3.5 hours without explosive busts, deflagrations, or unexpected hazards.” This document can be shared under a Non-Disclosure Agreement (NDA).

In considering the , there are multiple benefits to the approach taken to allow the single enclosure to fully consume itself in a fire situation. An enclosure on fire is actually safer than one where potentially explosive gas is allowed to build up. The Megapack also has a sparker system that burns the gases before they can accumulate, thereby mitigating the danger of explosion. By allowing the enclosure to fully consume itself the danger of cell re-ignition cells hours after the system has stopped burning is mitigated. This has the added benefit of making decommissioning safer since the stranded energy remaining in the battery cells is removed during the fire. Nationally recognized testing according to the UL9540a method has shown that a fire in one enclosure will not spread to adjacent enclosures, even when they are only 6 inches apart. Tesla has tested the Megapack against the most rigorous version of the UL9540a test methods (Version 4). In sum, allowing the fire to burn itself out is the safest way to handle a fire event inside a Megapack container, and the system would burn itself out in no more than 3.5 hours. 7. Battery Safety Events A member of the Planning Board referenced an article in the Wallstreet Journal around a recall of Tesla’s electric vehicles. We believe that this comment was referring to an October 19th, 2020 article discussing a recall by Chevy of their Bolt electric vehicles1. We are not aware of any recall of Tesla’s electric vehicles.

A member of the public presented several safety incidents that have occurred at battery installations including an incident in Arizona and in South Korea. None of these safety incidents involved Tesla energy storage systems, which have never had an incident. The fires in South Korea are due to improperly integrated systems; the Tesla system comes fully integrated so that cannot be a problem.

1 https://www.wsj.com/articles/auto-makers-grapple-with-battery-fire-risks-in-electric-vehicles-11603099800

In addition, the incidents in Arizona and South Korea took place in Walk-In Energy Storage System Units, as opposed to the Tesla Megapack which is an Energy Storage System Cabinet. As per NYSERDA’s definition of ESS Cabinets it is a “cabinet containing components of the energy storage system that is included in the UL 9540 listing for the system. Personnel are not able to enter the enclosure, other than reaching in to access components for maintenance purposes.” Cabinet type systems are significantly safer than walk-in type systems. 8. Chemical-Based Fire Suppression A member of the Planning Board asked for data regarding why a chemical fire suppression system would not be effective in this type of system.

NFPA 855 – Standard for the Installation of Energy Storage Systems specifically addresses suppression methods to be used with lithium-ion BESS. Annex C-5 addresses firefighting considerations and states, “Fire-fighting dry chemical powders can eliminate visible flame. However, they also lack the ability to cool burning battery components. Quite often, even if visible flame is removed, the thermal runaway inside the battery will continue resulting in reignition. Carbon dioxide and inert gas suppressing agents will also eliminate visible flame but will likely not provide sufficient cooling to interrupt the thermal runaway process.

Tesla uses a different and more effective approach that addresses multiple hazards rather than addressing one component. These points are detailed in the response to question 6 of this document. 9. Systems in residential areas A member of the public asked about whether energy storage systems have been previously sited in residential areas. As of April 2020, Tesla had installed 100,000 of their PowerWall systems2, almost all inside homes (garages, basements, etc.). The PowerWall uses the same technology as the proposed system.

As for larger systems, Strata is aware of large-scale systems in the following towns that are located or will be located closer to residential buildings than the proposed project. Note that not all of these are Tesla systems. For reference, Eagle Energy Storage would be 20 MW and is 700’+ from residences.

• Folsom California – 62.5 MW system 384’ from residential buildings • Tecumsah, California – 25 MW system 147’ from residential buildings • Carpinteria, California – 10 MW system 131’ from residences • North San Diego County, California – 40 MW system 425’ from residences

Tesla has never had a safety event at any of its installations. 10. Electromagnetic Field Radiation

The proposed project would not cause any safety hazards due to electromagnetic field radiation. The system will be installed at 12 kilovolts (kV), which is the same as the Con Edison powerlines in the area.

2 https://electrek.co/2020/04/29/tesla-100000th-powerwall-home-battery-pack/

In fact, the above ground power lines in the area are carrying more energy at the same voltage than the proposed system would carry.

The battery itself will not emit any additional electromagnetic field radiation that would not be present in a normal power line. The transformers proposed for the project will be similar to the ones used by Con Edison which are commonly located at ground level throughout the town (including in residential zones). As such, the project will operate at a level similar to local electrical lines commonly seen throughout the Town. 11. Number and Type of Transformers The project will utilize seven 12kV/480VAC transformers, as shown on the Applicant’s site layout. The transformers will be pad-mounted and will be similar to Eaton Pad-Mounted Transformers as shown in the image below.

Figure 2 - Typical Transformer 12. Transformer Noise A member of the public asked about the noise from the transformers (as opposed to from the Tesla units themselves). Noise from typical transformers for this type of project are rated to produce no more than 64 dB, which would be reduced to less than background noise at the nearest occupied building. For more information about the project’s projected noise levels, please reference the letter that the Applicant sent to the Planning Board on November 25th, 2020. We have committed to the total noise emitted from this project being less than 65 decibels at the nearest off-site occupied building. 13. Fire Department having Jurisdiction A member of the public asked whether other local fire departments have been made aware of the project. The Elmsford Fire Department will be the primary first responders for this site. We have met with Chief Malone from Elmsford Fire Department on site, and he has submitted a letter supporting the project.

The second fire department who would be called to respond is the Fairview Fire Department. We are in the process of reaching out to Chief Reiss of Fairview Fire Department to offer information and training about this project. We have also offered to meet on site with Chief Reiss or any of his deputies.

Any other fire departments providing mutual aid would do so under the supervision of either Elmsford or Fairview Fire Departments. We have committed to offering training to both of these fire departments as often as they deem necessary. We are also able to offer training to any other fire departments who may provide mutual aid. Note that this was one of the recommended conditions sent from the Planning Board to the Town Board. 14. Battery Storage in Relation to Solar A member of the public was concerned that batteries may have the potential to decrease revenues from roof-top solar systems in the area that are also discharging into the electric system at the same time as the battery is. In actuality, battery storage like the proposed system will help keep the value of solar high over the coming years as more and more solar is interconnected to the grid. The charts below show California’s electric demand, net of rooftop solar, over time. New York’s current electricity demand is similar to California’s in 2012 and will progress towards California’s current duck-shaped profile as more renewables are added to the grid.

Figure 3 - New York Load Profile - Peaking During Non-Solar Hours https://www.nyiso.com/-/covid-19-and-the-electric-grid-load-shifts-as-new-yorkers-respond-to-crisis

Figure 4 - California Duck Curve Develops Over Time https://blog.aurorasolar.com/the-duck-curve-a-review-of-californias-daily-load-predictions/

On today’s grid in New York, demand net of solar peaks in the morning hours (6-10am) and in the evening hours (7-10pm). This is when the battery system would discharge, and these hours are not when solar is producing. The battery’s discharge would not negatively affect solar revenue today.

As more solar comes onto the grid, demand in the middle of the day net of solar will decrease, creating the “duck belly” (see 2020 California chart). This will drive down the revenue that rooftop solar systems can receive, and in some cases will preclude solar from being interconnected at all. Battery storage like the proposed project will follow price signals, which will increasingly show lower energy prices during the middle of the day and will encourage the system to charge during the day and discharge during the evening ramp. Storage tends to increase the value of solar and other non-dispatchable resources, and in no event will decrease the value of solar. 15. Battery Storage vs Renewable Energy While energy storage is not a source of renewable energy, it does increase the value of existing and future renewable energy and is an integral part of New York State’s energy plans moving forward.

Battery storage systems do not generate electricity, they store electricity for later use. However, battery storage increases the value of renewable energy sources like solar and wind and allows more renewables to be interconnected to the grid. New York State writes that “energy storage is critical to New York’s clean energy future. As renewable power srouces like wind and solar provide a larger portion of New York’s electicity, storage will allow clean energy to be available when and where it is most needed.”3

3 https://www.nyserda.ny.gov/All%20Programs/Programs/Energy%20Storage

Renewable sources of energy tend to be “non-dispatchable”. This means that grid operators do not have the ability to precisely control the output of wind and solar. As more and more solar and wind farms are interconnected to the grid, the overall power output becomes harder and harder to control. Battery storage is dispatchable and allows grid operators to keep supply and demand in balance, even with more solar and wind on the grid than ever before. The proposed project would help match supply and demand by following price signals in the energy markets as well as by participating in the public “frequency regulation” market, which allows the public grid operators to control the battery on a second-by-second basis to precisely match the supply and demand on the grid.

Furthermore, battery storage allows for the import of clean energy from upstate into the downstate region. The figure below, from NYISO, shows that the upstate grid is far more renewable than the downstate grid. Battery storage allows renewable energy from upstate to be imported downstate at times when the transmission lines are open, and then discharge into the downstate grid at times when the transmission lines are too full. On December 16, 2020 leading energy consulting firm Wood Mackenzie stated “…downstate New York is facing significant supply-demand imbalances that will require large-scale energy storage to manage. . . New York City and environs make up most of the state’s electricity demand but have less than one-third of the state’s current rewewable energy capacity, and there’s not enough transmission to carry all of new York’s ample upstate wind and hydropower to its downstate load centers”.4

Figure 5 – Constraints in New York State Transmission https://www.nyiso.com/documents/20142/2225293/2017-State-Of-Storage-Report.pdf

4 https://www.greentechmedia.com/articles/read/con-edison-contracts-new-yorks-biggest-battery-to-date

Finally, energy storage systems have the ability to replace dirty “peaker plants” that are only used a few hours a year but are among the dirtiest of all powerplants. This displacement of peaker plants is discussed in depth in “Dirty Energy, Big Money”5. 16. Visibility from Knollwood Road The project site was selected due to its unique location and surrounding topography. As discussed at several meetings, we do not anticipate that the site will be easily visible from Knollwood Road. To visualize, we developed a Viewshed Profile (included in the appendix to this document) using the existing survey and proposed site plans. Based on the analysis, it is unlikely that motor vehicle passengers will be able to see the facility. To further aid the screening of the site, we have committed to a security fence with earth-tone slats that will surround the site.

While we have made every effort to screen the site, if somewhere were to walk along the fenceline on Knollwood Road in the winter when there is minimal vegetation, a small portion of the site may be visible. See below for images taken December 16th, 2020 from Knollwood Road. The red rectangle indicates where the top of the BESS facility will be visible. The green box indicates where the proposed trees will be visible, blocking the current view of the Knollwood Country Club parking lot. Realistically, residents would need to exit their vehicles and approach the fenceline of the Knollwood Country Club’s property to notice the system, and even then, the view of the system will be offset by the additional trees blocking the current view of the parking lot.

Figure 6 - View of Proposed Project Site from Knollwood Road

5 https://www.cleanegroup.org/wp-content/uploads/Dirty-Energy-Big-Money.pdf