比特幣不是電池，而是水槽

比特幣不是電池，而是水槽

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不久前，Nick Grossman發表了文章《比特幣是電池》（ Bitcoin as Battery）。我喜歡這篇文章。行文很清晰，很吸引人，而且它對比特幣的巨大社會效益有一個樂觀的結論。可惜的是，我很確定它也是錯的。在本文中，我將解釋原因。要說明的是：這並不是在攻擊比特幣，攻擊比特幣消耗電力，或者它的社會效用；這篇文章純粹是對Grossman的論點進行批判，並邀請大家對比特幣的電力使用，和它的社會效用進行更仔細的經濟分析。

Grossman寫道：

「加密採礦將電力以加密資產(BTC、ETH等)的形式轉化為價值。這些資產[······]然後可以透過網路連接即時移動、轉移和轉換[······]。 」

這似乎表明，比特幣是一個電池：在一個地方和時間儲存能量，並在另一個地方和時間釋放能量。在本文中，我將解釋為什麼比特幣不是電池，而是水槽。這是以下兩個事實的簡單推論：

事實一：比特幣的價格是由貨幣市場決定的，也就是由比特幣的供求關係決定的。最重要的是，比特幣的價格幾乎不受電力供應，或者電力價格的影響。

事實二：比特幣的產生速度是固定的。大約每10分鐘就會產生6.25個新的比特幣。新產生的比特幣在所有礦工之間分配，按他們所消耗的電的比例分配。(這在技術上並不準確。我在這裡和這篇文章的其他部分做了一些大的簡化)

從這兩個事實中，我們已經看出，比特幣不可能是電池：無論向比特幣投入多少電，輸出的電量總是一樣的：每10分鐘6.25個比特幣。而6.25個比特幣的價值雖然不是固定的，是波動的，但這種波動與電價無關。在電池中，你投入的電越多，輸出的電就越多。在比特幣中，無論你投入多少電，輸出的電量都是恆定的。

事實上，把這兩個事實放在一起，給了我們很多關於比特幣用電經濟學的啟示：比特幣挖礦系統是介於套利和拍賣之間的東西。礦工如果能夠產生比某個閾值更便宜的電力，就可以有利可圖地開採比特幣。電價比這個閾值更貴的礦工，就不能從中獲利。這個閾值會隨著時間的推移而波動：它取決於當前部署在網路上的挖礦電力的數量，並且每兩週在一個叫做「比特幣難度調整」的過程中確定一次，這個過程有點像拍賣（我們在這裡不討論這個問題）。關於這些經濟行為，還有很多可以說的，但底線是這樣的：

必然的結果：比特幣網路激勵礦工將比門檻便宜很多的電投入其中。作為這些電力的回報，它產生了一個固定的經濟成果：每10分鐘6.25個比特幣。而這個經濟成果的價值與輸入的電量無關，它只取決於與挖礦無關的加密市場力量。比特幣經濟模型的經濟平衡如下：10分鐘內投入網路的所有電力總成本力爭等於6.25個比特幣的現時財務價值，如果電力變得更便宜，那麼就會有更多的電力投入到系統中，產生完全相同的產出。這就是為什麼比特幣不是電池而是水槽的原因：它的經濟產出是預先固定的，並不取決於投入的資源量。

現在，如果比特幣的價格上漲會怎樣？隨著比特幣價格的上漲，越來越多的能源在挖礦比特幣的過程中變得微利，所以更多昂貴的電力將被投入到網路中。無論是否有任何一種清潔或廉價的能源，都是如此：隨著比特幣價格的上漲，更多昂貴和浪費的電力也會被吸入其中。

當更多的廉價能源可用時，會發生什麼？它們將湧入比特幣網路，然後拍賣（即比特幣難度調整）將降低挖礦效率的門檻，這意味著更昂貴的能源將不再能為挖比特幣帶來利潤。但比特幣系統作為一個整體，最終會消耗掉這些廉價的動力源，所以它們將無法用於其他用途。比特幣的確是在激勵創造廉價的動力源，但它又迅速壟斷了這些動力源：這些動力源除了供養比特幣網路本身之外，不會被用於任何其他用途。這裡可能有一個微妙的論點：也許會有二次效應：比特幣的高價可能會激勵行為者，從長期來看，開發出更豐富的廉價能源的技術，這種技術可能會讓我們創造出更廉價的能源，用於非比特幣用途！但這是一個相當艱難的論證，可信度很高：這種二次效應通常比預期的要小。而且比特幣每天5000萬美元的賞金很可能不足以激勵真正的可持續廉價能源技術：它更可能激勵不可持續的廉價能源。而重要的是，廉價能源不等於清潔能源。比特幣激勵冷核聚變和更高效的太陽能電池板的發展，就像它激勵全球南方更積極的水力壓裂一樣。

與鋁冶煉廠相比：冶煉廠生產鋁，但比特幣網路生產網路安全

我們再來看看Grossman的論點。Grossman把比特幣比作冰島的鋁冶煉廠。他解釋說，鋁冶煉廠是一個電池：冶煉廠將廉價的電力轉化為商品，然後可以跨越空間和時間進行移動。（這個關於鋁冶煉廠的說法可能也是值得懷疑的，因為它再次包含了非內在化的外部性；但從理論經濟學的角度來看，我們可以把「冶煉廠=電池」作為冶煉廠的合理經濟模型）。

Grossman稱，比特幣的作用也是一樣的：把廉價的電力轉換成商品：比特幣。但這個類比並不成立。鋁冶煉廠的產品確實是一種商品：鋁。投入的電越多，產出的鋁越多。但比特幣挖礦的產品不是比特幣，至少和鋁冶煉廠的產品是鋁的意義不一樣。無論你是多放電還是少放電，無論如何，每10分鍾正好會產生6.25個比特幣。不，比特幣礦工的產品是安全感。如果你花更多的電，你就能得到更好的安全感，而可悲的是，安全感不是商品。它不能被再次出售，而且它不會隨著時間的推移而保持其價值。如果你把兩倍的電量轉換成比特幣，你並沒有得到兩倍的價值（記住，比特幣的價值是由無關的市場力量決定的！）；相反，你只是得到了同樣的價值，同時你為比特幣網路提供了兩倍的安全性。比特幣礦工是服務提供者。他們提供的服務是安全，他們提供的金額是「你能以每10分鐘6.25個比特幣的價格賣給我什麼安全」。

中本聰明確設計了比特幣網路，不是像冶煉廠那樣工作，而是作為拍賣，以最低的價格提供最大的安全保障。所以我們不應該驚訝於比特幣不像冶煉廠那樣工作，生產出來的不是商品。中本聰在設計比特幣網路時，有一個關鍵目標：安全。他們設計比特幣是為了盡可能的安全，而不是為了激勵社會尋找新的廉價能源：那隻是一個副作用，而且會產生不正當的激勵。

結語

總結一下，比特幣不是電池。比特幣是一個低成本電力的水槽。因此，它對環境的影響是相當負面的，而且隨著比特幣價格的攀升，它的負面作用會越來越大。不過，作為數位貨幣，比特幣還是有很多有用的社會屬性，而且還可能比銀行系統便宜很多（取決於你如何衡量）。比特幣還為開發有用的協議和基元提供了底層，這將構建Web 3.0，一個高效進行數據和價值交易的全球網路，具有不可估量的社會效用。比特幣對世界的貢獻（以淨現值計算）超過了它的能源成本。但我們不應該忽視比特幣的能源成本，這是一個微妙的話題，不應該一廂情願的看待。

資料來源：Bitcoin is not a Battery — it is a Sink

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.

Bitcoin Bounces Back to $55K as Yellen Backtracks on Rate Hike Comments

Bitcoin (BTC) has regained poise on Wednesday after U.S. Treasury Secretary Janet Yellen toned down comments suggesting interest rate hikes may be needed to stop the economy from overheating.

“It’s not something I’m predicting or recommending,” Yellen clarified during an online event hosted by The Wall Street Journal late on Tuesday, downplaying remarks made earlier in the day.

“If anyone appreciates the independence of the Federal Reserve, I think that person is me,” added the former Fed chief, according to a Bloomberg report Wednesday.

Bitcoin found a floor near $53,000 after Yellen’s clarification and was trading back above $55,400 at press time, representing a nearly 4% gain on the day.

Bitcoin daily chart Source: TradingView

Yellen had originally been discussing the scope for rate hikes in the context of U.S. President Joe Biden’s plans for $4 trillion of infrastructure and welfare spending over the next decade.

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“It may be that interest rates will have to rise somewhat to make sure that our economy doesn’t overheat, even though the additional spending is relatively small relative to the size of the economy,” Yellen said at an event organized by The Atlantic magazine.

Catching financial markets off-guard, the remarks intensified fears that an early unwinding of liquidity-boosting stimulus measures might push bitcoin, stocks and other assets lower. The Federal Reserve cut rates to a record low of 0.25% a year ago and has been buying bonds worth $120 billion every month to contain the coronavirus pandemic’s impact on markets and the economy.

Bitcoin, often touted as digital gold, has been one of the primary beneficiaries of the Fed’s massive inflation-boosting stimulus measures launched in March 2020. The cryptocurrency has charted a six-fold rally over the past 12 months.

Looking ahead

While the Fed recently reiterated its commitment to keep the liquidity tap open for a prolonged period, some experts fear the U.S. central bank would ditch its pro-easing bias and turn hawkish later this year.

“We think the market is starting to price a hawkish change in stance into the June and all-important September meeting[s] later,” QCP Capital said in a market update on its Telegram channel.

“We expect Fed speakers this week will now set the stage for this shift in domestic stance and outlook, although the worsening [COVID-19] situation will likely buy them some time,” the firm added.

The U.S. dollar is starting to show signs of life amid a growing debate over whether Biden’s massive spending, coupled with a vaccine-led economic recovery, would force the Fed to scale back stimulus earlier than expected.

The Dollar Index, which tracks the greenback’s value against major currencies, rose to a 2.5-week high of 91.44 earlier today, extending its recovery from the two-month low of 90.42 reached on April 29, according to data and chart provider TradingView.

A continued rally in the U.S. dollar could yield deeper losses for bitcoin. The two assets have moved mainly in the opposite direction since March 2020, courtesy of the Fed’s stimulus measures.

“The USD is now a big risk to the crypto market, and the USD is beholden to the Fed,” QCP Capital said. “The crypto-sphere is inherently and perpetually massively short USD (against crypto assets), and any spike in USD funding or appreciation in USD value will affect it greatly.”