James Cirrone

In a move that’s sparked outrage from environmental groups, Stronghold Digital Mining is looking to continue burning tires to fuel its bitcoin mining data center in Nesquehoning, Pennsylvania.&nbsp;



StateImpact Pennsylvania, a reporting project of NPR member stations, <a href="https://stateimpact.npr.org/pennsylvania/2023/08/25/pa-crypto-plant-wants-to-burn-tires-environmental-advocates-ask-regulator-to-say-no/">reported</a> on Stronghold Digital’s plans last Friday, which led to the Clean Air Council issuing a public rebuke on X, formerly Twitter.



“We are calling on state regulators and [the Pennsylvania Department of Environmental Protection] with [Earthjustice] and [PennFuture] to deny a permitting request from Stronghold Digital Mining to burn tires as fuel for its bitcoin mining operations,” the non-profit <a href="https://twitter.com/CleanAirCouncil/status/1696224078602891401">wrote</a> on Monday.&nbsp;



Stronghold Digital told Blockworks that Pennsylvania-based environmental groups like PennFuture and Earthjustice “paint a really inaccurate picture.”



The Pennsylvania-based miner added that it already had a temporary permit from the state’s Department of Environmental Protection (DEP) to use tire-derived fuel, in other words, energy that is produced by burning tire scraps.&nbsp;



“The current application process with DEP is to obtain a permanent permit…to continue to burn the [tire-derived fuel] in the same manner and [in] limited quantity, given [that] several years of testing have proven no adverse effects,” a company spokesperson told Blockworks in an email.&nbsp;



Blockworks reached out to the DEP, PennFuture and Earthjustice for comment, but didn’t receive any responses before publication.&nbsp;



But how bad would burning tires for fuel be? To answer that question, let’s take a closer look at what happens when tires are melted down.&nbsp;



According to the US Environmental Protection Agency (EPA), in uncontrolled tire fires, tires will break down into hazardous materials including “<a href="https://archive.epa.gov/epawaste/conserve/materials/tires/web/html/fires.html">gases, heavy metals and oil</a>.”



That’s not the end of it though, because when burned, tires also produce emissions that contain “polycyclic aromatic hydrocarbons (PAHs), benzene, styrene, phenols and butadiene.” Earthjustice also pointed this out in an Aug. 21 <a href="https://earthjustice.org/press/2023/pennsylvania-residents-urge-dep-to-prevent-panther-creek-from-burning-tires-to-fuel-cryptomining#:~:text=The%20Panther%20Creek%20power%20plant,coal%20they%20use%20to%20produce">press release</a>.



Many of these chemicals have the propensity to cause cancer in humans. Benzene, in particular, has been <a href="https://emergency.cdc.gov/agent/benzene/basics/facts.asp#:~:text=The%20Department%20of%20Health%20and,of%20the%20blood%2Dforming%20organs.">definitively classified</a> as a carcinogen.



Stronghold Digital told Blockworks that random tire fires do not reflect its operations.&nbsp;



At the Nesquehoning location, dubbed the Panther Creek site, the company uses two circulating fluidized bed combustors (CFBs) — a type of boiler — to burn waste coal, a byproduct of coal mining, and tire scraps.&nbsp;



According to <a href="https://www.science.gov/topicpages/c/circulating+fluidized-bed+combustion">Science.gov</a>, CFBs have been known to completely vaporize ventilation air methane from the act of burning coal.



Stronghold Digital collects waste coal from polluted areas in the state with the help of the DEP, a spokesperson told Blockworks. That waste coal is then converted into energy that, in part, is used to mine bitcoin. Some of it is also transferred back to the grid.



Stronghold Digital wants to continue limited use of tire-derived fuel, which it says accounts for less than 7% of the burned material at its 80 megawatt power plant in Nesquehoning.&nbsp;



Additionally, the EPA does in fact <a href="https://nepis.epa.gov/Exe/ZyNET.exe/P1004TZU.TXT?ZyActionD=ZyDocument&amp;Client=EPA&amp;Index=2000+Thru+2005&amp;Docs=&amp;Query=&amp;Time=&amp;EndTime=&amp;SearchMethod=1&amp;TocRestrict=n&amp;Toc=&amp;TocEntry=&amp;QField=&amp;QFieldYear=&amp;QFieldMonth=&amp;QFieldDay=&amp;IntQFieldOp=0&amp;ExtQFieldOp=0&amp;XmlQuery=&amp;File=D%3A%5Czyfiles%5CIndex%20Data%5C00thru05%5CTxt%5C00000021%5CP1004TZU.txt&amp;User=ANONYMOUS&amp;Password=anonymous&amp;SortMethod=h%7C-&amp;MaximumDocuments=1&amp;FuzzyDegree=0&amp;ImageQuality=r75g8/r75g8/x150y150g16/i425&amp;Display=hpfr&amp;DefSeekPage=x&amp;SearchBack=ZyActionL&amp;Back=ZyActionS&amp;BackDesc=Results%20page&amp;MaximumPages=1&amp;ZyEntry=1&amp;SeekPage=x&amp;ZyPURL">support</a> tire-derived fuel as an alternative to fossil fuels. That’s because tires often end up in landfills, and if they catch fire, that could lead to even more disastrous consequences than if a third party had burned them in a controlled manner.



“Disposal of scrap tires in tire piles is not an acceptable management practice because of the risks posed by tire fires,” the EPA <a href="https://nepis.epa.gov/Exe/ZyNET.exe/P1004TZU.TXT?ZyActionD=ZyDocument&amp;Client=EPA&amp;Index=2000+Thru+2005&amp;Docs=&amp;Query=&amp;Time=&amp;EndTime=&amp;SearchMethod=1&amp;TocRestrict=n&amp;Toc=&amp;TocEntry=&amp;QField=&amp;QFieldYear=&amp;QFieldMonth=&amp;QFieldDay=&amp;IntQFieldOp=0&amp;ExtQFieldOp=0&amp;XmlQuery=&amp;File=D%3A%5Czyfiles%5CIndex%20Data%5C00thru05%5CTxt%5C00000021%5CP1004TZU.txt&amp;User=ANONYMOUS&amp;Password=anonymous&amp;SortMethod=h%7C-&amp;MaximumDocuments=1&amp;FuzzyDegree=0&amp;ImageQuality=r75g8/r75g8/x150y150g16/i425&amp;Display=hpfr&amp;DefSeekPage=x&amp;SearchBack=ZyActionL&amp;Back=ZyActionS&amp;BackDesc=Results%20page&amp;MaximumPages=1&amp;ZyEntry=1&amp;SeekPage=x&amp;ZyPURL">wrote</a> in a 2005 memo.



In a 2016 <a href="https://archive.epa.gov/epawaste/conserve/materials/tires/web/html/tdf.html">article</a>, the EPA added that “it is better to recover the energy from a tire rather than landfill it.”



And in the DEP’s copy of a general permit for the disposal of tires, it lays out exactly how tires ought to be used for energy production.



“The permitted beneficial use of whole waste tires, tire chips, baled tires, tire shreds, and crumb rubber is limited to use in recapping, as fuel in boilers or other combustion units,” the permit <a href="https://files.dep.state.pa.us/Waste/Bureau%20of%20Waste%20Management/WasteMgtPortalFiles/SolidWaste/Residual_Waste/GP/WMGR038.pdf">stated</a>.



Updated Aug. 30, 2023 at 3:24 pm ET: Additional context provided by Stronghold Digital regarding operations at its Panther Creek site



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Stronghold Digital wants to burn tires for fuel, environmental groups strike back

Shalini Nagarajan

<div id="highlights-block_62d5a0cee917b" class="highlights">
 <ul>
 <li>“The overall US crypto mining industry is likely to be problematic for energy and emissions,” lawmakers wrote</li>
 <li>They flagged that crypto miners have caused increased electricity costs for small businesses and residents</li>
 </ul>
 
</div>



Sen. Elizabeth Warren and other lawmakers have called on federal regulators to instruct cryptocurrency miners to disclose their emissions and energy use.



The Democratic lawmakers laid out “disturbing” findings from an investigation into the environmental impact of crypto mining in a <a href="https://www.warren.senate.gov/imo/media/doc/2022.07.15%20Letter%20to%20EPA%20and%20DOE%20Re%20Cryptomining%20Environmental%20Impacts.pdf" target="_blank" rel="noreferrer noopener">letter</a> to the US Environmental Protection Agency and the Department of Energy on Friday.



Seven companies including Riot, Bitdeer, Bit Digital and Stronghold have the collective capacity to use nearly the same amount of electricity required to power all residences in Houston, Texas — the fourth most populous city in the US — their data found.



“Our investigation suggests that the overall US crypto mining industry is likely to be problematic for energy and emissions,” the lawmakers wrote. They believe disclosing this information would support public policy decisions such as monitoring energy use and providing data on national and regional grid loads.



The letter highlighted lawmakers’ concerns that cryptocurrency mining in the US has <a href="https://www.nbcnews.com/tech/tech-news/us-becomes-largest-bitcoin-mining-center-china-ban-rcna2956" target="_blank" rel="noreferrer noopener">exploded since the crackdown in China</a> — once the world’s biggest mining hub — with the nation’s global mining share rising nearly ten-fold in the past four years.



They also raised concerns about how mining has triggered a jump in electricity costs for small businesses and residents. For instance, residents in Plattsburgh, New York saw prices <a href="https://crsreports.congress.gov/product/pdf/R/R45863/3" target="_blank" rel="noreferrer noopener">jump by $300</a> in the winter of 2018 after bitcoin miners found electricity there “abundant and cheap.”&nbsp;&nbsp;&nbsp;



Some miners have been struggling with the crypto market downturn. Compass Mining recently faced accusations by hosting firm Dynamics Mining over an alleged <a href="https://cms.blockworks.co/compass-mining-searches-for-direction-after-top-execs-resign/" target="_blank" rel="noreferrer noopener">failure to pay an electricity bill</a>, but the firm denied these claims.



The lawmakers also wrote that the total annual global electricity consumption associated with Bitcoin and Ethereum is estimated to be around 300 TWh (terawatt-hours) in May 2022, similar to the annual electricity usage in the UK.&nbsp;



“And this electricity usage has major emissions consequences: the energy used to mine Bitcoin and Ethereum in 2021 resulted in almost 80 million tons of carbon dioxide emissions,” they said.



The environmental impact of bitcoin mining is the subject of debate, with some miners <a href="https://cms.blockworks.co/crypto-mining-company-welcomes-sec-environmental-reporting-proposal/" target="_blank" rel="noreferrer noopener">welcoming further scrutiny</a>.



Ethereum’s energy consumption is expected to drop by 99.95% <a href="https://cms.blockworks.co/ethereum-ropsten-testnet-successfully-merged-to-proof-of-stake/" target="_blank" rel="noreferrer noopener">following The Merge</a>, as soon as September.



Democrats have <a href="https://cms.blockworks.co/cryptocurrency-mining-is-poisoning-our-communities-us-rep-says/" target="_blank" rel="noreferrer noopener">previously written</a> to the US environmental regulator in May, describing among other concerns how the amount of emissions produced by bitcoin mining is equivalent to that of a small country like Greece. But the lobby group Bitcoin Mining Council <a href="https://cms.blockworks.co/bitcoiners-protest-democrats-misleading-letter-sent-to-epa/" target="_blank" rel="noreferrer noopener">poked holes</a> in that letter, saying it held several inaccuracies — such as a claim that “a single Bitcoin transaction could power the average US household for a month.”



In June, the New York legislature <a href="https://cms.blockworks.co/new-york-passes-bill-restricting-carbon-fueled-crypto-mining-operations/" target="_blank" rel="noreferrer noopener">passed a bill</a> that would temporarily ban new bitcoin mining operations that use proof-of-work authentication methods for blockchain transactions. That bill could have been signed into law or vetoed by Governor Kathy Hochul, but she declined to commit and said her team would look at the proposal closely in the coming months.



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