Nic Carter is a general partner at the venture firm Castle Island Ventures and a co-founder of the blockchain analytics firm Coin Metrics. His own site listed both roles in November 2026. He's the crypto investor and writer known for his essays on Bitcoin's energy use and its quantum risk, and for his research on stablecoins.
In a May 2021 Harvard Business Review essay, Nic Carter put Bitcoin's yearly electricity use at about 110 TWh, or 0.55% of global production. Measured against the world's 2020 electricity generation, 110 TWh is closer to 0.41%. His two figures, both credited to the Cambridge Center for Alternative Finance, don't quite match each other.
Who Is Nic Carter?
Carter is a crypto venture investor who argues his views in public, mostly in long essays on his Substack and on the On The Brink podcast he co-hosts. His site also lists bylines in the Harvard Business Review, Fortune and Newsweek, among others. Three subjects come up again and again in his work.
Energy is one. Carter took Bitcoin's electricity use to the Harvard Business Review in May 2021 and later co-wrote a 2023 paper on Bitcoin miners as a flexible load for power grids. Stablecoins are another, the subject of Castle Island papers he co-wrote between 2020 and 2025.
Quantum computing is the third, and Carter has written about it at length since October 2025. The fear is that a large enough quantum computer could break Bitcoin's signatures, the same worry behind quantum-resistant crypto tokens. Carter wants Bitcoin's developers to plan the move to new signatures years before any machine can do it.
How Much Energy Did Nic Carter Say Bitcoin Uses?
Carter's figure was about 110 terawatt hours (TWh) a year, from his Harvard Business Review essay "How Much Energy Does Bitcoin Actually Consume?". A terawatt hour is a billion kilowatt hours. The essay opened on a question of values, how much energy an industry deserves to use. Its estimate came in one sentence, with two numbers that can be checked against each other.
Ember's yearly electricity data puts the world's total electricity generation in 2020, the last full year before the essay, at about 26,800 TWh. For his 0.55% to hold on that base, Bitcoin would have needed about 147 TWh a year, roughly a third more than the 110 TWh he gave.
Our World in Data's total for the same year, about 26,700 TWh, gives the same answer. Swapping in 2019 or 2021 barely moves the share, so the choice of year doesn't explain the gap.
|
Input
|
Value
|
Source
|
|
His figure for Bitcoin's yearly use
|
about 110 TWh
|
HBR, May 2021, citing Cambridge
|
|
His share of global production
|
0.55%
|
The same sentence
|
|
World electricity generation, 2020
|
26,803 TWh
|
Ember's yearly data
|
|
110 TWh as a share of 2020 generation
|
0.41%
|
Computed
|
|
What a 0.55% share would take
|
about 147 TWh
|
Computed
|
|
Our World in Data, 2020 generation
|
26,723 TWh, giving 0.41%
|
OWID energy data
|
|
110 TWh against 2019 and 2021 generation
|
0.41% and 0.39%
|
Computed from Ember
|
The essay doesn't name the world total behind its share, so the gap can't be pinned on either figure. The share appears once, and nothing in Carter's argument depends on it.
That argument was about where the power comes from. Energy use isn't the same as carbon emissions, he wrote, because the mix of sources sets the footprint.
Miners could also run on power other industries couldn't reach, he argued, such as wet-season hydro in Sichuan and Yunnan or gas that oil fields would otherwise flare. By his account, most of the energy went into mining new coins, not into processing payments.
What Is Nic Carter's View on Bitcoin and Quantum Computing?
Carter's view is that Bitcoin must start preparing for quantum computers years before one can threaten it. He opened his series on Bitcoin and the quantum problem in October 2025 with "Quantum computing is, in my opinion, the biggest risk to Bitcoin."
The worry is specific. Bitcoin relies on elliptic-curve cryptography, the math that makes it practically impossible to work a private key out from its public key, and a large enough quantum computer running Shor's algorithm could do exactly that.
In "Bitcoin developers are sleepwalking towards collapse", a December 2025 essay, Carter pointed to the money. "At least $6b was raised by quantum startups this year, the most in history by a large margin," he wrote.
His point was timing. Bitcoin changes slowly, "like steering an aircraft carrier" in his phrase, so a move to quantum-safe signatures would need years of work before any machine could break a real key.
He also noted that BIP-360 was the only listed Bitcoin Improvement Proposal on the problem at that point, and that a relative outsider led it.
By February 2026 Carter had ranked a list of Bitcoin developers by how influential he judged them, scoring how much concern each had shown about quantum risk. "The current verdict is simply that the most influential Bitcoin devs do not care," he concluded.
His April 2026 essay on two papers about what breaking that cryptography would take sounded more measured. The papers "accelerated my personal timeline for Q-day," Carter wrote, meaning the day a quantum computer first breaks a major cryptographic function. In the same essay he added that he wasn't calling a quantum break of Bitcoin's cryptography imminent, and knew of no one who was.
That essay opens with a disclosure you should know about. Castle Island was an investor in Project Eleven, a startup working on the post-quantum transition, and Carter sat on its board. Project Eleven's Q-Day Prize went to Giancarlo Lelli, who broke a 15-bit elliptic-curve key on quantum hardware in April 2026.
Read together, the essays make one argument. The break isn't imminent, in his telling, but Bitcoin moves so slowly that the fix must start years early. By his count in December 2025, Bitcoin had pushed through only two updates since 2017, both after long fights. That's the strongest part of his case, because it rests on Bitcoin's own record. Weigh the rest with his disclosed stake in mind.
Nic Carter's Career: Coin Metrics, Castle Island and Realized Cap
Carter studied philosophy at the University of St Andrews and took a master's in finance at the University of Edinburgh, his site says. His papers page says his 2017 master's thesis looked at governance across fifty tokenized networks and found it largely informal, with decision-making concentrated in few hands.
His 2021 HBR byline adds that he once served as Fidelity Investments' first cryptoasset analyst.
Carter co-founded Coin Metrics, and that's where realized cap comes from. His own list of blog posts includes "Introducing Realized Capitalization", a 2018 Coin Metrics post he wrote with Antoine Le Calvez. The entry describes a metric that "prices each unit of Bitcoin at the time of its last movement".
Subtract realized cap from market cap and what's left is the paper profit that Bitcoin's net unrealized profit/loss (NUPL) tracks, one of the on-chain gauges built on the metric.
Castle Island Ventures, where he's a general partner, has published his stablecoin papers since 2020. Carter's papers page runs from the 2017 thesis to a 2025 study of stablecoin payments, with work on Bitcoin mining and decentralized finance in between.
How to Trade Bitcoin Futures on Phemex
Carter's essays deal with Bitcoin's long-run questions, from its power use to its cryptography. If you'd rather trade on Bitcoin's price itself, Phemex lists a BTC/USDT perpetual futures contract, which closed mid-November at about $71,400.
-
Open a Phemex account and deposit the USDT you plan to use as margin.
-
Open the BTC/USDT perpetual on the futures page and choose your margin mode and leverage.
-
Pick long or short, set a stop-loss and check the order size before you confirm.
Futures use leverage, and a leveraged position is closed automatically if losses push its margin below a set minimum. A stop-loss limits the damage from one bad move, so size each position for a loss you can take.
Frequently Asked Questions
What is realized cap?
Realized cap values every bitcoin at the price it last moved on-chain and adds those values up. Market cap uses the latest price for every coin, so the gap between the two shows the paper profit or loss holders are carrying.
What does Castle Island Ventures invest in?
Public blockchain startups, as Carter's 2021 HBR byline described the firm. His site puts its focus at the intersection of blockchains and traditional finance.
What has Nic Carter written about stablecoins?
His papers page lists a July 2020 Castle Island paper on "cryptodollars" written with Matt Walsh. Later work includes a 2024 paper on stablecoins in emerging markets and "Stablecoin Payments from the Ground Up", a 2025 bottom-up estimate of stablecoin payment flows.
Disclaimer: This article is for informational purposes only and is not financial advice. Cryptocurrency trading involves substantial risk. Always do your own research before making investment decisions.
