user112448: Bitcoin mining will consume around 70TWh for 2020 (~3 nuclear power plants).
As far as I know, electricity is paid using fiat money. If 1 kWh costs 0.1 $, without counting hardware costs, that means that 1 year of mining costs $7 Billion for electricity.
At the moment, the Bitcoin capitalization is around 357 B$.
It follows that 2% (7/357*100) of the capitalization is used by electricity every year!
Who is paying for that (and how can it be sustainable)?

people who invest in Bitcoin using fiat money?
by Bitcoin deflation comparatively to fiat money?
people who lose money when/if Bitcoin goes down?
more generally: Mafia (an expensive laundry is not a problem if it is good)?
or I don't understand enough how Bitcoin works, and that's something else :-) ?


user30884: The other answers do a good job of explaining how miners are compensated for their electricity (and other) costs.  As the other answers point out, there are two ways that miners are compensated: block rewards and transaction fees.
In real terms, the block rewards (which halve approximately every four years) are paid for by everyone holding bitcoin, as the newly minted coins which comprise the block rewards have a deflating effect on coins already in circulation (by virtue of increased supply).
The transaction fees are paid by those that send coins to others.  Senders include transaction fees in their transactions, and these transaction fees go to the miners.  This incentivizes miners to include these transactions in blocks that they mine.
As the block reward decreases (with each halving), it is expected that transaction fees will have to increase, in order to incentivize miners to continue to mine.  So, the costs of keeping the blockchain going will gradually shift from holders to transactors.

user5406: The miners pay for the energy use directly, but the whole network pays indirectly. As @AndrewChow described, the miners provide a service to the network. They secure the ledger and provide the transaction ordering necessary for users to converge on a shared ground-truth. In exchange for this public service, the miners are reimbursed via block rewards.
The block reward consists of two parts, the block subsidy and the transaction fees. The subsidy consists of newly minted bitcoins. It doubles as both an incentive to miners as well as the initial distribution vector for bitcoins. It is financed via monetary supply inflation and thus a levy on all holders of bitcoins. The transaction fees are paid by the winning bids for the blockspace the transactions occupy in the blockchain.
You ask how this cost can be paid without anyone losing money. There is no such thing as a free lunch: the Bitcoin ecosystem pays an on-going maintenance cost for the network to continue running. There is no guarantee that the value of the overall Bitcoin ecosystem is stable or increases.

user48884: The people operating the mining hardware do. Mining hardware consumes electricity, so people who run the hardware receive an electricity bill from their electricity provider. They pay the bill using the proceeds from mining. Usually miners will sell some portion of the Bitcoin they earn for fiat, and pay for electricity using that fiat.

user13866: 
Who is paying for the running costs of Bitcoin?

The primary costs are almost entirely paid by miners.
Anyone else who runs any other sort of node (wallet etc) is likely to be also contributing by forwarding Bitcoin messages. They also pay a tiny amount of costs to sustain the network in terms of their own electricity costs, networking costs, capital assets (computers) depreciation etc.
Miners recoup their costs entirely from

In the form of fiat currency from people who buy from miners their mined Bitcoin (the inflationary block rewards subject to halving roughly every 4 years).

People using Bitcoin who include transaction fees in their Bitcoin transactions.

Appreciation in value of their Bitcoin assets (probably).


So in the end the costs are paid by people using fiat to buy Bitcoin and people who send bitcoin to others (e.g. to purchase goods, services or other kinds of assets).

112448: <p>Bitcoin mining will consume around <a href="https://digiconomist.net/bitcoin-energy-consumption" rel="nofollow noreferrer">70TWh</a> for 2020 (~3 nuclear power plants).</p>
<p>As far as I know, electricity is paid using fiat money. If 1 kWh costs <a href="https://www.globalpetrolprices.com/electricity_prices/" rel="nofollow noreferrer">0.1 $</a>, without counting hardware costs, that means that 1 year of mining costs $7 Billion for electricity.</p>
<p>At the moment, the Bitcoin capitalization is around <a href="https://bitcoinblockhalf.com/" rel="nofollow noreferrer">357 B$</a>.</p>
<p>It follows that 2% (7/357*100) of the capitalization is used by electricity every year!</p>
<p>Who is paying for that (and how can it be sustainable)?</p>
<ul>
<li>people who invest in Bitcoin using fiat money?</li>
<li>by Bitcoin deflation comparatively to fiat money?</li>
<li>people who lose money when/if Bitcoin goes down?</li>
<li>more generally: Mafia (an expensive laundry is not a problem if it is good)?</li>
<li>or I don't understand enough how Bitcoin works, and that's something else :-) ?</li>
</ul>
 30884: <p>The other answers do a good job of explaining how miners are compensated for their electricity (and other) costs.  As the other answers point out, there are two ways that miners are compensated: block rewards and transaction fees.</p>
<p>In real terms, the block rewards (which halve approximately every four years) are paid for by everyone holding bitcoin, as the newly minted coins which comprise the block rewards have a deflating effect on coins already in circulation (by virtue of increased supply).</p>
<p>The transaction fees are paid by those that send coins to others.  Senders include transaction fees in their transactions, and these transaction fees go to the miners.  This incentivizes miners to include these transactions in blocks that they mine.</p>
<p>As the block reward decreases (with each halving), it is expected that transaction fees will have to increase, in order to incentivize miners to continue to mine.  So, the costs of keeping the blockchain going will gradually shift from holders to transactors.</p>
 5406: <p>The miners pay for the energy use directly, but the whole network pays indirectly. As @AndrewChow described, the miners provide a service to the network. They secure the ledger and provide the transaction ordering necessary for users to converge on a shared ground-truth. In exchange for this public service, the miners are reimbursed via block rewards.</p>
<p>The block reward consists of two parts, the block subsidy and the transaction fees. The subsidy consists of newly minted bitcoins. It doubles as both an incentive to miners as well as the initial distribution vector for bitcoins. It is financed via <a href="https://bitcoin.stackexchange.com/a/37092/5406">monetary supply inflation</a> and thus a levy on all holders of bitcoins. The transaction fees are paid by the winning bids for the blockspace the transactions occupy in the blockchain.</p>
<p>You ask how this cost can be paid without anyone losing money. There is no such thing as a free lunch: the Bitcoin ecosystem pays an on-going maintenance cost for the network to continue running. There is no guarantee that the value of the overall Bitcoin ecosystem is stable or increases.</p>
 48884: <p>The people operating the mining hardware do. Mining hardware consumes electricity, so people who run the hardware receive an electricity bill from their electricity provider. They pay the bill using the proceeds from mining. Usually miners will sell some portion of the Bitcoin they earn for fiat, and pay for electricity using that fiat.</p>
 13866: <blockquote>
<p>Who is paying for the running costs of Bitcoin?</p>
</blockquote>
<p>The primary costs are almost entirely paid by miners.</p>
<p>Anyone else who runs any other sort of node (wallet etc) is likely to be also contributing by forwarding Bitcoin messages. They also pay a tiny amount of costs to sustain the network in terms of their own electricity costs, networking costs, capital assets (computers) depreciation etc.</p>
<p>Miners recoup their costs entirely from</p>
<ol>
<li><p>In the form of fiat currency from people who buy from miners their mined Bitcoin (the inflationary block rewards subject to halving roughly every 4 years).</p>
</li>
<li><p>People using Bitcoin who include transaction fees in their Bitcoin transactions.</p>
</li>
<li><p>Appreciation in value of their Bitcoin assets (probably).</p>
</li>
</ol>
<p>So in the end the costs are paid by people using fiat to buy Bitcoin and people who send bitcoin to others (e.g. to purchase goods, services or other kinds of assets).</p>
