挖比特幣，碳排等同一個發展中國家！號稱更節能的「奇亞幣」誕生－商周頭條｜商周
比特幣價格近日向下修正，加密貨幣圈同時出現一新寵：奇亞幣（Chia），還未上市就吸引中港礦工，帶動其挖礦設備傳統硬碟、固態硬碟需求上升，預期價格也將上漲，供應也可能出現短缺。
特別的是，奇亞幣被稱為「綠色比特幣」（green bitcoin）。它的出現，反映外界以及圈內對比特幣等加密貨幣被批評過度耗能的反思，以及他們如何想出因應辦法。
《個人電腦雜誌》（PCMag）報導，比起比特幣的「工作量證明」（proof of work），奇亞幣則是使用「空間證明」（proof of space）作為共識機制。挖礦方式不同，比特幣依賴運算能力進行挖礦，而奇亞幣則依賴儲存空間，涉及大量讀寫動作。
廣告
比特幣如同其名稱，工作量證明需要大量的運算「工作」，由於需解開大量困難的數學難題，礦工的電腦耗費大量電力。
奇亞幣背後基礎在於，傳統硬碟和固態硬碟使用更少電力，更容易取得，購買價格也比挖比特幣所需的顯示卡便宜。
創造奇亞幣的團隊2月在白皮書中指出：「專門的挖礦硬體逐漸被少數幾個大型實體獨佔，分布於能夠取得便宜電力的專門資料中心…這種集中狀態降低了信賴感，也引發像是電力消耗、電子廢棄物、碳排放、地緣政治風險等難題。」他們相信奇亞幣能夠部分解決比特幣挖礦帶來的問題。
比特幣崛起，能源消耗問題成爭議中心
比特幣前陣子價格不斷攀升，其消耗巨量能源的現象也成為關注焦點。加密新聞網（Crypto News）報導，一位德國軟體開發者施密特（Moritz Schmidt）靠投資比特幣賺了近200萬歐元（約合新台幣6,480萬元），卻反過來把其中100萬歐元捐給可能封殺比特幣實用性的政黨綠黨（Greens），是德國史上最大筆政治捐款。
廣告
綠黨有機會在今年大選打敗現任總理所屬的基督教民主黨，他們考慮讓比特幣變得「可追溯」，與比特幣原本的匿名特性背道而馳。施密特表示，10年前他投資比特幣，但幾年前他開始意識到比特幣消耗大量能源，因此獲利了結後，決定反過來遏阻它的成長。
之前，微軟創辦人比爾蓋茲也曾坦言，他對比特幣「感到擔心」，因為比特幣非常耗能。
比特幣到底有多耗能？根據劍橋大學的比特幣用電指數，比特幣礦工的能源消耗量約是130太瓦時，大約是全球用電量的0.6％，碳排量與一個小型發展中國家如約旦相當。以人數相比較，約旦人口為1千萬人，活躍的比特幣用戶估計有100萬人。比特幣主力批評者德－弗里斯（Alex de Vries）表示，比特幣非常沒有效率。
另一加密貨幣以太幣的能耗程度也受關注。以太幣生態圈每年用電量相當於巴拿馬，而每筆以太幣交易的用電量，相當於2個美國家庭一天的用電量。
不過，一些比特幣支持者則認為，不應把比特幣的能耗與國家用量相比，這兩者並不適合相互比較。例如，持續投資比特幣的方舟投資（ARK Invest）研究指出，比特幣生態圈耗能不到傳統銀行系統的10％。當然傳統銀行可以服務更多人，但支持者認為，比特幣還處於早期發展階段，而早期是能源最密集的時期，等到基礎設施逐漸成熟，將變得更高效。
加密貨幣圈改革聲音，將採用新共識機制
撇開兩方不同聲音，加密貨幣圈內部其實也對此做出反思，試圖解決現行加密貨幣效率不高的問題。
除了奇亞幣，科技媒體TechCrunch指出，其中一個讓加密貨幣更環保的方式，是在某些能源未妥善使用的地區，支持當地鼓勵採礦的立法者。
3月，挪威第二大富豪羅科（Kjell Inge Røkke）成立一家名為Seetee的新企業，目標是把比特幣採礦中心設在再生能源農場，在電力需求低迷時吸收多餘的電力用於採礦。由此一來，比特幣將不是吃電怪獸，反而是善用現行電力系統的參與者。
然而，德－弗里斯說，這種方法存在致命的缺陷。它假定當電需要用在其他更有利於社會的目的時，採礦作業可以暫停。但是，挖礦需要24小時不間斷運行才有效；那是一場與時間的競賽，要在競爭對手中脫穎而出的唯一方法，是以最便宜的電力頻繁地運行更多的機器。
另一試圖根絕能耗問題的是跟比特幣同樣耗電的以太幣。以太幣的平台以太坊正努力把共識機制從「工作量證明」轉變為「權益證明」（proof of stake）。
在工作量證明機制中，數百萬個處理器同時處理相同的交易，所有參與者都競相爭取交易。因此，擁有的運算火力越多，獲利的機會就越大。這個機制是防止任何一個實體控制區塊鏈或進行竄改。
而在以太坊試圖建立的「權益證明」機制中，參與者被稱為「驗證者」，而非礦工，關鍵是要使他們誠實。權益證明用加密貨幣抵押量取代礦工算力比拚，節點不需要花大錢買礦機或繳交鉅額電費，取而代之的是，他們必須花錢買加密貨幣，並將這些加密貨幣抵押在智能合約中。
權益證明共識機制下，根據「幣齡」以偽隨機的方式，選擇下一個區塊的驗證節點，也就是說，抵押越多加密貨幣、抵押時間越長且距離上次獲得記帳權越久的節點，獲得下一次記帳權的機率越高。由於驗證者抵押的加密貨幣都是成本，作惡有可能導致幣價下跌，且抵押的代幣會被沒收，就像是拿石頭砸自己的腳。因此，理性的驗證者為了最大化利益，理論上不會選擇作惡。
以太幣創辦人布特林（Vitalik Buterin）認為，採用權益證明機制，可以將每筆以太坊交易所消耗的能源減少100倍以上。以太坊預計未來幾年將轉為採用該機制。（🍀延伸閱讀：共好！投資未來10年最重要的綠色商機）
參考來源：PCMag、South China Morning Post、TechCrunch、IEEE Spectrum、Quartz、Crypto News
核稿編輯：林易萱
Bitcoin will eventually hit ‘$1 million a coin,’ CoinDesk editor predicts
Bloomberg
(Bloomberg) – A week that could set in motion the eventual collapse of the 314-year union between England and Scotland is concentrating City trading desks on market disasters ahead.As Scots enter a May 6 vote pitched on whether there should be a second independence referendum, fund managers and sell-side strategists see potential for massive chaos across the U.K.’s economic landscape in the years to come. Yet in an echo of the early days of the Brexit poll, few are hedging for this disruptive prospect.While the stakes could hardly be higher, it’s not clear the U.K. government will agree to another referendum, even if pro-independence parties win a majority on Thursday. But with the vote stirring uneasy memories of Britain’s split from the European Union, fund managers are dusting off old playbooks for how to trade a binary risk event where timing is everything.“You’d have massive uncertainty, financial chaos and recession,” and a 10% devaluation of the pound, said Mark Nash, a money manager at Jupiter Investment Management.Nash isn’t hedging such a scenario yet – and neither is the market. The median of forecasts in a Bloomberg survey has the pound holding at $1.39 through June.Still, a handful of investment analysts have ventured forth bearish calls.Strategists at Credit Agricole SA recommend shorting the pound versus the dollar, with political risk over Scottish independence among the reasons.Barclays Plc abandoned a call to go long on the pound versus the euro on the potential for pre-election volatility.UBS Group AG credit strategists cut their outlook on a select group of U.K. bank bonds to neutral from overweight, warning that the “long U.K. trade” in credit could unravel on referendum risk.One thing is for certain: if things escalate, money managers will need to move fast. Odds show a repeat of the 2014 referendum, where Scotland voted to remain, would be too close to call.“Markets ignore things and ignore things and ignore and then suddenly panic. I have a feeling that is quite likely to happen with the Scottish independence issue,” said Jane Foley, head of currency strategy at Rabobank. “What I’m telling our clients is to be aware that even though this may not impact the pound right now, it’d be foolhardy to ignore it because it might suddenly come into the market’s agenda.”Consequences of secession would be huge. Negotiations would be necessary over what currency an independent Scotland would use, whether it would take a share of the British national debt, and what trade arrangements it would have with the remainder of the U.K. The Scottish National Party also harbors ambitions to bring Scotland into the EU, a situation that would create huge border and trade tensions, if the problem of ring-fencing Northern Ireland in Brexit is any example.“I wonder whether markets have actually considered the full ramifications of this election,” said Julian Howard, director of multi-asset solutions at GAM Investments, whose portfolios are strategically positioned for a decline in sterling. “It would be a lot worse than Brexit as Scotland is much more closely stitched to the U.K. than Britain was into Europe. We’re talking since the 1700s rather than the 1970s.”Mr. BrexitThe domicile of financial institutions could also be contested. If they were to remain based on Edinburgh, Scottish banks would miss out on the support of the Bank of England’s quantitative easing program and become less creditworthy, according to Charlie Parker, managing director at boutique investment manager Albemarle Street Partners.It’s the kind of tail-risk event that makes careers, for those with enough foresight to get it right.At Nomura Holdings Inc., strategist Jordan Rochester was part of a team that developed a money-spinning model to help the bank call the 2014 referendum result early. His political analysis on the split from the EU then led him to be nicknamed Mr. Brexit. Now he says the pound could fall up to 6% if Scotland voted to leave, depending on how priced it was prior to the result.But even he isn’t worried about the election on Thursday itself, and says the pound could even be in line for gains if the SNP fails to win more than half of the seats, as some polls suggest. Still, the independence cause could prevail once Green votes are counted, and an actual referendum date could trigger heavy hedging.Read: Why Scotland’s Road to Independence Vote Is Rocky: QuickTake“The market will look at polling in a new referendum and treat it much more like a tighter vote than 2014 – when it was only last-minute scares, not months in advance,” Rochester said.Westminster would likely mount resistance to any plans to seek an independence vote, refusing to grant the Scottish parliament the permission to make it legally watertight. That leaves the potential for a lengthy constitutional quagmire over whether the Scottish parliament can call a legitimate referendum on its own.Even though the prospect of an invigorated Scottish break-away movement is scary for traders, derivatives markets remain relatively calm. The term structure of sterling’s implied volatility has become inverted, signaling angst over events on Thursday – though the cost of insuring swings is still below its 12-month average. Over the longer-term, five-year risk reversals in cable trade near their average since Bloomberg began compiling data in 2005.“The difficulty with assessing the impact of these events on markets is that even if we know they are on the horizon, we don’t know when markets will react and if in the end the status quo will prevail,” said Sheena Shah, currency strategist at Morgan Stanley. Her firm sees a 30% chance of a referendum by the end of 2024. “There are so many unknowns and follow-up hurdles.”(Updates options pricing in penultimate paragraph.)For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.©2021 Bloomberg L.P.
How Much Energy Does Bitcoin Actually Consume?
Today, Bitcoin consumes as much energy as a small country. This certainly sounds alarming — but the reality is a little more complicated. The author discusses several common misconceptions surrounding the Bitcoin sustainability debate, and ultimately argues that it’s up to the crypto community to acknowledge and address environmental concerns, work in good faith to reduce Bitcoin’s carbon footprint, and ultimately demonstrate that the societal value that Bitcoin provides is worth the resources needed to sustain it.
How much energy does an industry deserve to consume? Right now, organizations around the world are facing pressure to limit the consumption of non-renewable energy sources and the emission of carbon into the atmosphere. But figuring out how much consumption is too much is a complex question that’s intertwined with debates around our priorities as a society. The calculation of which goods and services are “worth” spending these resources on, after all, is really a question of values. As cryptocurrencies, and Bitcoin in particular, have grown in prominence, energy use has become the latest flashpoint in the larger conversation about what, and who, digital currencies are really good for.
On the face of it, the question about energy use is a fair one. According to the Cambridge Center for Alternative Finance (CCAF), Bitcoin currently consumes around 110 Terawatt Hours per year — 0.55% of global energy production, or roughly equivalent to the annual energy draw of small countries like Malaysia or Sweden. This certainly sounds like a lot of energy. But how much energy should a monetary system consume?
How you answer that likely depends on how you feel about Bitcoin. If you believe that Bitcoin offers no utility beyond serving as a ponzi scheme or a device for money laundering, then it would only be logical to conclude that consuming any amount of energy is wasteful. If you are one of the tens of millions of individuals worldwide using it as a tool to escape monetary repression, inflation, or capital controls, you most likely think that the energy is extremely well spent. Whether you feel Bitcoin has a valid claim on society’s resources boils down to how much value you think Bitcoin creates for society.
If we’re going to have this debate, however, we should be clear on how Bitcoin actually consumes energy. Understanding Bitcoin’s energy consumption may not settle questions about its usefulness , but it can help to contextualize how much of an environmental impact Bitcoin advocates are really talking about making. Specifically, there are a few key misconceptions worth addressing.
Energy Consumption Is Not Equivalent to Carbon Emissions
First, there’s an important distinction between how much energy a system consumes and how much carbon it emits. While determining energy consumption is relatively straightforward, you cannot extrapolate the associated carbon emissions without knowing the precise energy mix — that is, the makeup of different energy sources used by the computers mining Bitcoin. For example, one unit of hydro energy will have much less environmental impact than the same unit of coal-powered energy.
Bitcoin’s energy consumption is relatively easy to estimate: You can just look at its hashrate (i.e., the total combined computational power used to mine Bitcoin and process transactions), and then make some educated guesses as to the energy requirements of the hardware that miners are using. But its carbon emissions are much harder to ascertain. Mining is an intensely competitive business, and miners tend not to be particularly forthcoming around the details of their operations. The best estimates of energy production geolocation (from which an energy mix can be inferred) come from the CCAF, which has worked with major mining pools to put together an anonymized dataset of miner locations.
Based on this data, the CCAF can guess about the energy sources miners were using by country, and in some cases, by province. But their dataset doesn’t include all mining pools, nor is it up to date, leaving us still largely in the dark about Bitcoin’s actual energy mix. Furthermore, many high profile analyses generalize energy mix at the country level, leading to an inaccurate portrait of countries such as China, which has an extremely diverse energy landscape.
As a result, estimates for what percentage of Bitcoin mining uses renewable energy vary widely. In December 2019, one report suggested that 73% of Bitcoin’s energy consumption was carbon neutral, largely due to the abundance of hydro power in major mining hubs such as Southwest China and Scandinavia. On the other hand, the CCAF estimated in September 2020 that the figure is closer to 39%. But even if the lower number is correct, that’s still almost twice as much as the U.S. grid, suggesting that looking at energy consumption alone is hardly a reliable method for determining Bitcoin’s carbon emissions.
Bitcoin Can Use Energy That Other Industries Can’t
Another key factor that makes Bitcoin’s energy consumption different from that of most other industries is that Bitcoin can be mined anywhere. Almost all of the energy used worldwide must be produced relatively close to its end users — but Bitcoin has no such limitation, enabling miners to utilize power sources that are inaccessible for most other applications.
Hydro is the most well-known example of this. In the wet season in Sichuan and Yunnan, enormous quantities of renewable hydro energy are wasted every year. In these areas, production capacity massively outpaces local demand, and battery technology is far from advanced enough to make it worthwhile to store and transport energy from these rural regions into the urban centers that need it. These regions most likely represent the single largest stranded energy resource on the planet, and as such it’s no coincidence that these provinces are the heartlands of mining in China, responsible for almost 10% of global Bitcoin mining in the dry season and 50% in the wet season.
Another promising avenue for carbon neutral mining is flared natural gas. The process of oil extraction today releases significant amount of natural gas as a byproduct — energy that pollutes the environment without ever making it to the grid. Since it’s constrained to the location of remote oil mines, most traditional applications have historically been unable to effectively leverage that energy. But Bitcoin miners from North Dakota to Siberia have seized the opportunity to monetize this otherwise-wasted resource, and some companies are even exploring ways to further reduce emissions by combusting the gas in a more controlled manner. Of course, this is still a minor player in today’s Bitcoin mining arena, but back of the envelope calculations suggest that there’s enough flared natural gas in the U.S. and Canada alone to run the entire Bitcoin network.
To be fair, the monetization of excess natural gas with Bitcoin does still create emissions, and some have argued that the practice even acts as a subsidy to the fossil fuel industry, incentivizing energy companies to invest more in oil extraction than they otherwise might. But income from Bitcoin miners is a drop in the bucket compared to demand from other industries that rely on fossil fuels — and that external demand is unlikely to disappear anytime soon. Given the reality that oil is and will continue to be extracted for the foreseeable future, exploiting a natural byproduct of the process (and potentially even reducing its environmental impact) is a net positive.
Interestingly, the aluminum smelting industry offers a surprisingly relevant parallel. The process of transforming natural bauxite ore into useable aluminum is highly energy intensive, and the costs of transporting aluminum often aren’t prohibitive, so many nations with a surplus of energy have built smelters to take advantage of their excess resources. Regions with the capacity to produce more energy than could be consumed locally, such as Iceland, Sichuan, and Yunnan, became net energy exporters through aluminum — and today, the same conditions that incentivized their investment in smelting have made those locations prime options for mining Bitcoin. There are even a number of former aluminum smelters, such as the hydro Alcoa plant in Massena, NY, that have been directly repurposed as Bitcoin mines.
Mining Bitcoin Consumes a lot More Energy Than Using It
How energy is produced is one piece of the equation. But the other area where misconceptions are common is in how Bitcoin actually consumes energy, and how that’s like to change over time.
Many journalists and academics talk about Bitcoin’s high “per-transaction energy cost,” but this metric is misleading. The vast majority of Bitcoin’s energy consumption happens during the mining process. Once coins have been issued, the energy required to validate transactions is minimal. As such, simply looking at Bitcoin’s total energy draw to date and dividing that by the number of transactions doesn’t make sense — most of that energy was used to mine Bitcoins, not to support transactions. And that leads us to the final critical misconception: that the energy costs associated with mining Bitcoin will continue to grow exponentially.
Runaway Growth Is Unlikely
Because Bitcoin’s energy footprint has grown so rapidly, people sometimes assume that it will eventually commandeer entire energy grids. This was the premise of a widely-reported 2018 study that was recently cited in the New York Times, making the shocking claim that Bitcoin could warm the earth by two degrees Celcius. But there’s good reason to believe this won’t happen.
First, as has become common in many industries, the energy mix of Bitcoin grows less reliant on carbon every year. In the U.S., publicly-traded, increasingly ESG-focused miners have been gaining market share, and China recently banned coal-based mining in Inner Mongolia, one of the largest remaining coal-heavy regions. At the same time, many organizations within the mining industry have launched initiatives like the Crypto Climate Accord — inspired by the Paris Climate Agreement — to advocate for and commit to reducing Bitcoin’s carbon footprint. And of course, as renewable options such as solar grow more efficient and thus more viable for mining, Bitcoin could end up serving as a serious incentive for miners to build out these technologies.
In addition, miners are unlikely to continue expanding their mining operations at the current rates indefinitely. The Bitcoin protocol subsidizes mining, but those subsidies have built-in checks on their growth. Today, miners receive small fees for the transactions that they verify while mining (accounting for around 10% of miner revenue), as well as whatever profit margins they can get when they sell the bitcoins they have mined.
However, the protocol is built to halve the issuance-driven component of miner revenue every four years — so unless the price of Bitcoin doubles every four years in perpetuity (which economics suggests is essentially impossible for any currency), that share of miner revenue will eventually decay to zero. And as far as transaction fees, Bitcoin’s natural constraints on the number of transactions it can process (fewer than a million per day) combined with users’ finite tolerance for paying fees limit the growth potential of this as a revenue source. We can expect some miners to continue operating regardless, in exchange for these transaction fees alone — and in fact, the network depends on that to keep functioning — but if profit margins fall, the financial incentive to invest in mining will naturally decrease.
Of course, there are countless factors that can influence Bitcoin’s environmental impact — but underlying all of them is a question that’s much harder to answer with numbers: Is Bitcoin worth it? It’s important to understand that many environmental concerns are exaggerated or based on flawed assumptions or misunderstandings of how the Bitcoin protocol works.
That means that when we ask, “Is Bitcoin worth its environmental impact,” the actual negative impact we’re talking about is likely a lot less alarming than you might think. But there’s no denying that Bitcoin (like almost everything else that adds value in our society) does consume resources. As with every other energy-consuming industry, it’s up to the crypto community to acknowledge and address these environmental concerns, work in good faith to reduce Bitcoin’s carbon footprint, and ultimately demonstrate that the societal value Bitcoin provides is worth the resources needed to sustain it.