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Decentralized and immutable characteristic of blockchain has a possibility to change how the data is stored. Cryptocurrency is one example of successful blockchain technology implementation. The first cryptocurrency, bitcoin, was launched in 2009 and shortly afterwards followed by other cryptocurrencies, which are called alternative currency (altcoin). The blockchain system depends on a consensus mechanism to run. Most of cryptocurrency adopt the Proof of Work (PoW) consensus mechanism, which requires to run a computer program to solve a computational puzzle to verify the transactions and add the record into the blockchain, which called mining. Bitcoin uses SHA258 algorithm for its PoW. As an incentive, miners are then given some money on the currency. However, mining requires a lot of energy, alternatively, altcoins adopt different algorithm to run the system. This study aims to compare the energy used by various algorithms, which mined by four widely available, general purposes Graphic Processing Unit (GPU), and determine the profitability for each currency, given the mining share acquired for 24 hours. This is important because even the blockchain is not intended primarily for cryptocurrency, PoW-based blockchain system depends heavily on the mining process. Should the miners decided it is no longer profitable, they will easily switch to mine another, and without miners, the blockchain system will stop. The experiment shows that from 32 sets of experiment, only 15 sets (46.88%) are profitable. The result shows that among eight algorithms, Equihash, Ethash, and Cryptonight7 coins are the best performers, while Blake2b, Blake256, and Lyra2REv2 coins are the worst performers. Most the coins tested consume below than 1 TWh of annual energy consumption, except SiaCoin and Ethereum, and Decred.
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Journal of Theoretical and Applied Information Technology
15th March 2019. Vol.97. No 5
© 2005 – ongoing JATIT & LLS
ISSN: 1992-8645 www.jatit.org E-ISSN: 1817-3195
1623
PROOF OF WORK: ENERGY INEFFICIENCY AND
PROFITABILITY
1ANAK AGUNG GDE AGUNG, 2RIXARD G. DILLAK, 3DEVIE R. SUCHENDRA, 4ROBBI H.
1,2,3,4School of Applied Science, Telkom University, Indonesia
E-mail: 1agung@tass.telkomuniversity.ac.id, 2rixard@tass.telkomuniversity.ac.id,
3deviersuchendra@tass.telkomuniversity.ac.id, 4robbi@tass.telkomuniversity.ac.id
ABSTRACT
Decentralized and immutable characteristic of blockchain has a possibility to change how the data is stored.
Cryptocurrency is one example of successful blockchain technology implementation. The first
cryptocurrency, bitcoin, was launched in 2009 and shortly afterwards followed by other cryptocurrencies,
which are called alternative currency (altcoin). The blockchain system depends on a consensus mechanism
to run. Most of cryptocurrency adopt the Proof of Work (PoW) consensus mechanism, which requires to run
a computer program to solve a computational puzzle to verify the transactions and add the record into the
blockchain, which called mining. Bitcoin uses SHA258 algorithm for its PoW. As an incentive, miners are
then given some money on the currency. However, mining requires a lot of energy, alternatively, altcoins
adopt different algorithm to run the system. This study aims to compare the energy used by various
algorithms, which mined by four widely available, general purposes Graphic Processing Unit (GPU), and
determine the profitability for each currency, given the mining share acquired for 24 hours. This is important
because even the blockchain is not intended primarily for cryptocurrency, PoW-based blockchain system
depends heavily on the mining process. Should the miners decided it is no longer profitable, they will easily
switch to mine another, and without miners, the blockchain system will stop. The experiment shows that from
32 sets of experiment, only 15 sets (46.88%) are profitable. The result shows that among eight algorithms,
Equihash, Ethash, and Cryptonight7 coins are the best performers, while Blake2b, Blake256, and Lyra2REv2
coins are the worst performers. Most the coins tested consume below than 1 TWh of annual energy
consumption, except SiaCoin and Ethereum, and Decred.
Keywords: cryptocurrency, altcoin, proof-of-work, energy, profitability
1. INTRODUCTION
The first cryptocurrency, bitcoin (BTC) was
launched in January 2009 based on Satoshi
Nakamoto’s paper [1]. Ever since, other
cryptocurrencies have been emerged. Bitcoin (BTC)
and altcoins (alternate cryptocurrencies, community
name for cryptocurrencies other than BTC) are
gaining popularity, reached their peak in the end of
2017. At the time this article was written, there are
792 cryptocurrencies available in the market, with
the total market capitalization worth of
$232,993,580,527 [2].
One reason for bitcoin and other cryptocurrencies
popularity is that they require a much lower
transaction fee than credit cards and exchanges,
which charge 1% to 3% of the transaction value [3].
Cryptocurrency is also characterized by its
anonymous and decentralized processing of
transactions. Figure 1 shows the transaction volume
of bitcoin (BTC), which reach USD 48.35 billion on
December 13, 2017, while Ethereum (ETH) reach
USD 20.32 billion and Ripple (XLM), reach USD
6.33171 million on January 4, 2018.
Figure 1: Transaction Volume (USD) for Bitcoin (BTC;
red), Ethereum (ETH; purple) and Stellar (XLM; yellow)
Unlike traditional banking system, validation of
transaction in cryptocurrency does not rely on single
entity. It does not rely on central bank nor
government. Instead, transaction is verified using a
consensus mechanism involving multiple parties.
Every party (which is called a node) runs a specific
computer program in accordance of the mechanism
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15th March 2019. Vol.97. No 5
© 2005 – ongoing JATIT & LLS
ISSN: 1992-8645 www.jatit.org E-ISSN: 1817-3195
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adopted by the currency. In cryptocurrency system,
a node plays a very important role. They validate
transactions and record valid transaction into the
blockchain. In general, there are three mechanisms
to validate the transaction of cryptocurrency, the
Proof of Work (PoW), the Proof of Stake (PoS) and
masternode.
The PoW is used by 542 cryptocurrencies, or
roughly 68% of all cryptocurrency. In PoW
mechanism, a node runs a process called mining.
While mining is a mandatory process, it consumes a
great amount of electricity [4]. As an incentive,
miners are given shares in the form of the
cryptocurrency he or she mined. Bitcoin is an
example of PoW based cryptocurrency which uses
the SHA256 algorithm. Previous research on bitcoin
mining revealed a conclusion that in 2004, electricity
needed to mine bitcoin alone is comparable to
Ireland’s electricity consumption [5]. Figure 2 shows
electricity consumption for bitcoin mining annually
in January 1, 2018 had reached 36.79 TWh, and it
keeps rising [6]. This fact raises concern that mining
bitcoin will not be sustainable in the near future [7]
[8] [9].
Figure 2: Bitcoin Energy Consumption Index (BECI)
Chart
Cryptocurrency developers are trying to use
another algorithm rather than bitcoin’s SHA256. In
addition, to speed up the transaction, other purpose
is to reduce power consumption, because the simpler
algorithm uses less computing power and less load
on the hardware. By the time this manuscript was
written, there were more than fifty algorithm used by
cyrptocurrencies.
Cryptocurrencies use blockchain technology, but
the blockchain application is not limited to
cryptocurrency. While many argue that
cryptocurrency might not mature enough to replace
the current monetary system, the blockchain
technology has a potential implementation in many
fields. Research and implementation of blockchain
includes smart contract, logistics [10] [11], taxation
[12] [13], energy industry [14], also health and
medical [15] [16] [17] area.
Profitability is a major reason for miners to join
the mining process. For PoW based blockchain,
loosing miners could cause a problem, as the system
relies on miners to run the validate transactions. Less
miner also means the system becomes more
centralized. It is important to keep the mining
process profitable to attract miners.
This research compares energy used by GPU
mining. The obtained share then converted to fiat
money (USD) to determine if it is still profitable. We
also estimate how much energy needed and how
much it cost to run the network Eight algorithms,
represented by eight altcoins are used in this
research. This should provide an overview on how a
different consensus algorithm makes an impact to
mining profitability in actual condition.
2. DIGITAL MONEY
Money refers to anything, which generally
accepted, by a community, as a medium of
exchange. Money can have physical object, such as
coins or papers, which we know as cash. This type
of money has its value written on it. When it is
recognized by the legal system in a country, it is
known as legal tender. Digital money is the
electronic equivalent of cash. It exists in the form of
a data file, stored in a hardware or software. It
circulates in electronic network and transactions are
carried out electronically [18] [19]. Since digital
money exists in the form of data, it can be duplicated
at negligible cost. This is a problem known as the
“double spending problem”. To solve with the
double spending problem, digital money transaction
involves a central authority, which keeps track the
ownership of the money and verify the transactions.
This central authority is usually a bank or a
government agency. However, this centralized
system requires trust that the central authority will
not abuse the delegated power. Since there is only
one central authority, the system also vulnerable to
various problems, such as technical failure, hackers
attack on the database, or even malicious parties.
3. CRYPTOCURRENCY
Currency is money, which is acknowledged and
circulated in a specific boundary (such as country)
[20]. Currency can exist in physical and digital form.
Currency can be regulated by the government, or
unregulated (virtual). Virtual currencies usually
created and used by virtual communities. Different
from regulated currency, which has geographic
boundary, virtual currency has no geographic
boundary. In digital, virtual money, anyone
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© 2005 – ongoing JATIT & LLS
ISSN: 1992-8645 www.jatit.org E-ISSN: 1817-3195
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connected to the internet can be part of the
community, regardless his or her geographic
location. Cryptocurrency is a virtual, digital money,
which uses cryptography in its transaction and
creation. It has no intrinsic value, and their value
represents entirely on the expectation of the
currency. The first cryptocurrency is Bitcoin, which
was launched in January 2009. There are many
cryptocurrencies created after bitcoin, known as
alternate coin (altcoin) or simply called coin.
Cryptocurrency uses blockchain technology to store
its transaction data, which eliminate the double
spending problem of digital money.
4. BLOCKCHAIN
In distributed ledger system, the transaction
records are stored in a ledger, and duplicated and
keep by multiple entities or nodes. These nodes
communicate and update their ledger when a
transaction occurred, so every entity would keep the
same, updated ledger. Any disputes regarding a
transaction would be settled in a consensus way.
This means to successfully attack the system, one
must have at least 50% plus one of all entities. The
first known use of the system was practiced by the
people on the small island in the Pacific Ocean called
Yap [21].
Transaction records in the blockchain are stored
in a block, and cryptographically linked to the
previous block to form a chain (which is called
blockchain) as a security measure (Figure 3). The
bitcoin blockchain uses SHA-256 hash function to
secure its data.
Figure 3: Blocks in a Blockchain
The blockchain then is replicated across the
network. Entities which maintain the blockchain is
known as a node, a computer which runs a specific
program that corresponds to the type of consensus
mechanism being used. There are many consensus
mechanisms available, but the majority used are the
Proof of Work and the Proof of Stake. The use of
hash function means we can easily check if a
transaction record is changed, and since the hash of
a block is linked to the next block, any attempt to
change a transaction in specific block must be
followed by changing the hash of every block
afterward. Even if this is possible, the network will
easily detect this false blockchain because other
nodes in the network still have the correct
blockchain. This makes the blockchain immutable.
Despite its unregulated and their value depend
completely to supply and demand, cryptocurrency
has advantages, as they inherit the nature of the
blockchain. A blockchain is immutable, it is secured
by hash chain and every node in the network has its
copy. It also spread the authority among the nodes,
which means any data added should be decided by
consensus, eliminating single point of failure. It is
transparent, everyone can see every transaction from
the beginning, which also means users can easily
trace the transaction history.
Successful implementation of blockchain
technology in cryptocurrency opens the possibility
for other industry do adopt it. Transaction data could
be replaced with any other data, depends on its
application. The nature of blockchain can disrupt
security industry, financial sector, public services
industry, and Internet of Things we already know
[4].
4.1. Proof of Work (PoW)
In PoW based cryptocurrency, miners collect and
verify pending transactions. Pending transactions are
assembled in a block candidate. However, there can
be only one block candidate added to the blockchain
at a time. To choose which miner can add the block,
miners compete to solve a computational puzzle, to
hash value below a certain threshold, which is called
difficulty. Solving a puzzle prove that a miner has
made a contribution to the network, and not likely to
perform something malicious. This is a better
approach rather than randomly choose a miner [22].
Beside the pending transactions, a miner adds an
incentive transaction to its own account, makes
every miner start solving the puzzle with different
numbers. A random number, nonce, is included in
the calculation. In a simple way, mining is to find a
nonce which produces a hash lower than the
difficulty.
The computational power of a miner is denoted in
Hash per Second (H/s). The first miner to complete
the puzzle have the right to add the block candidate
to the blockchain, and receive an incentive, which is
meant to compensate the miner for his or her work.
The incentive mechanism is the major reason for
people to mine cryptocurrency. So in short, the main
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15th March 2019. Vol.97. No 5
© 2005 – ongoing JATIT & LLS
ISSN: 1992-8645 www.jatit.org E-ISSN: 1817-3195
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purpose of mining is to check transaction validity as
well as to create new money [23].
For most cryptocurrency, mining is
permissionless. Everyone can download the mining
software and the latest blockchain. More miner joins
the system will increase the probability to solve the
puzzle faster, however, only one block can be added
to the blockchain in certain time. To maintain a
constant block time, the network adjusts the puzzle
difficulty periodically, in which every miner must
find a hash number below the difficulty value.
If there is no miner, no one will verify the
transaction and the whole system will shut down
[24], so in PoW mechanism, the incentive share must
be profitable enough to attract miners and cover their
expenses.
The mining process itself involves computing
power to calculate the cryptographic hash, along
with the information of the transaction. The most
common way, it utilizes the Central Processing Unit
(CPU) or Graphic Processing Unit (GPU) computing
power. A miner runs the mining program either on a
Personal Computer or in special hardware called
Application Specific Integrated Circuits (ASIC).
Newer cryptocurrencies such as Electroneum (ETN)
is designed so it can be mined using mobile device
[25]. The ASIC produces a very high hash rate, but
they are very expensive, and the algorithm is limited
for every machine. The CPU is the least expensive
hardware, but the hash rate is very low compared to
the others. This is the reason most miners use GPU
for mining process. Here we will put forward brief
introduction the consensus algorithms, which are
used in the research.
4.1.1 Ethash [26]
The Ethash is the consensus algorithm of
Ethereum based blockchain. It is derived from
Dagger-Hashimoto algorithm, and designed to be
ASIC resistant. The Ethash is similar to bitcoin’s
algorithm, which is to hash a block candidate header
and the result should be below a certain number, or
difficulty.
Not only changing the nonce, this algorithm
requires miners to add pieces of data from a dataset
(DAG). Rather than hashing function, the algorithm
focuses on the input / output operation of a computer.
4.1.2 Cryptonight [27]
Cryptonight utilizes memory. In cryptonight, a
large area of memory is used to store pseudo-random
value. Then, a numerous read/write is performed at
pseudo-random addresses contained in the memory.
Final operation is to hash the entire memory. The
operation also involves Keccak algorithm.
Cryptonight7 includes two modifications to the
original algorithm.
4.1.3 Equihash [28]
Equihash is designed based on the generalized
birthday problem. The algorithm requires some
minimum amount of memory to solve the puzzle
efficiently, while the verification process is very fast,
and the solution is very small. The algorithm was
designed to be ASIC resistant.
4.1.4 X17
The X17 is based on X11 algorithm [29]. It
consists of 13 hashes cycle, each with different
hashing functions (Blake, BMW, CubeHash, Djb2,
Echo, Fugue, Groestl, Hamsi, JH, Keccak, Loselose,
Luffa, Simd, Shabal, Shavite, Skein, Whirpool). The
result of the first hash is calculated with the next
algorithm, and so on. The algorithm considered to be
safer than Bitcoin’s SHA-256. The first coin uses the
algorithm was the People (PPL) but the coin is
currently discontinued.
4.1.5 Blake2b / Blake256 [30]
Blake2b is a second generation of Blake family
cryptographic hash function, which is optimized for
64-bit platform, and the other, Blake2s is optimized
for the 32-bit platform. The algorithm focuses on
CPU computational power, and utilizes modern
processor architecture, such as instruction-level
parallelism, SIMD instructions, and multiple cores
CPU. The Blake2 algorithm initially created to
replace MD5 and SHA-1 algorithm.
Blake256 is the predecessor of Blake2s and
derived from the first generation of the Blake family.
Instead of 16 calculation rounds in the Blake2b, The
Blake256 only has 10. It uses 32-bit words and
produces a 256-bit digest.
4.1.6 Scrypt [31]
The Scrypt was originally created as a protection
for online backup service. Cryptocurrency adopted
the simplify version of the algorithm. The script has
memory intensive algorithm, which requires a
certain amount of memory to operate. The basic
operation is to complicate the solution of
cryptographic task with randomly generated
numbers.
4.1.7 Lyra2REv2
Lyra2REv2 is an improvement of Lyra2
algorithm, which is a key derivation function. In
Lyra2, the memory and processing power can be
tuned so users can specify the level of security [32].
The Lyra2REv2 is the second version of reduced
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efficiency of Lyra2. It consists of a six chained
hashes with five hash functions, Blake, Keccak,
Cubehash, Lyra2, Skein, Cubehash, BMW. Second
round of the Cubehash was added to reduce CPU
effectiveness, which was caused by bot mining.
4.2. Mining Pool
Early days mining did not require a lot of
computational power. As more people join the
process, it is harder to compete. People with higher
hash power will have better possibilities to solve the
PoW puzzle first, and will have better possibilities to
get the incentive. To achieve higher hash, miners
work together and combine their computational
power in a mining pool. Solo mining was unpractical
since it would take days to solve the puzzle.
However, by joining the mining pool, the incentive
has to be shared among all miners in that pool.
There are more than ten major mining pool, most
of them are located in China. Figure 5 shows mining
pool in the world. Percentages show total incentive
acquired within 48 hours [33].
5. RESEARCH METHOD
The overview of the research steps is presented in
Figure 4, which explained below.
First, we select eight altcoins (non-SHA256)
which have different algorithms. They should be
GPU mineable, and the coins should be listed in top
100 market capitalization, based on data from
CoinMarketCap website [34], March 13, 2018.
Figure 4: Research Flowchart
Figure 5: Bitcoin Mining Pool
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If there are cryptocurrency with the same
algorithm, the one with the highest market
capitalization is chosen. Higher market
capitalization means the coin is established and more
stable. Table 1 shows the complete list of the
cryptocurrencies in this research.
Table 1: Selected Coin
No Rank Coin Algorithm
1 2 Ethereum (ETH) Ethash
2 5 Monero (XMR) Cryptonight7
3 10 Bitcoin Gold
(BTG) Equihash
4 13 Verge (XVG) X17
5 12 Siacoin (SC) Blake2b
6 11 Decred (DCR) Blake256
7 20 MonaCoin
(MONA) Scrypt
8 57 Feather Coin
(FTC) Lyra2REv2
After the cryptocurrencies are selected, mining
pool, in which the mining program will connect to,
is selected. Table 2 describes mining pool for each
coin. The appropriate mining program for each
algorithm and GPU is selected, and the wallet
address for each currency is generated. The address
is used to save incentive of the mining.
The NVIDIA GeForce GTX 1080Ti and ATI
Radeon RX Vega 64 represent two high-end
consumer (general purpose) GPU available in the
market, listed at number one, and number seven on
the graphic card benchmark. Both are listed at the
top from their respective manufacturer. The nVidia
GeForce GTX 1070 and ATI Radeon RX570
represent much affordable GPU, listed at number 13
and 35 on the benchmark list [35]. All four GPUs are
listed as high-end graphic cards. The GPU is selected
because it is affordable enough for most people, and
widely available. They produce a better hash rate
than CPUs, and less expensive than ASICs.
Table 2: Mining Pool
No Coin Pool
1 Ethereum (ETH) asia1.ethermine.org
2 Monero (XMR) aus01.supportxmr.com
3 bitcoin Gold (BTG) asia.btgpool.pro
4 Verge (XVG) hashfaster.com
5 SiaCoin (SC) asia.siamining.com
No Coin Pool
6 Decred (DCR) dcr.coinmine.pl
7 MonaCoin (MONA) miningpoolhub.com
8 FeatherCoin (FTC) miningpoolhub.com
Table 3 shows mining program details used for
each currency. The mining program ran for 24 hours
for each currency. Configuration for each mining
program was set to default. Tweaking was
performed only if default configuration causes error
(system freezes, restart or shutdown). If the mining
program was interrupted more than five minutes, the
mining process was repeated, and new address was
generated.
Table 3: Mining Program
Coin Mining Program
nVidia Cards AMD Cards
Ethereum (ETH) ETH Claymore Miner v11.7
AMD-NVIDIA Windows
Monero (XMR) XMR-Stak 2.4.2 (April 19, 2018)
bitcoin Gold
(BTG)
EBFZec Miner
0.3.4.b
Claymore's
Zcash -
AMD GPU
Miner v.12.6
Verge (XVG) ccminer/alexis-
1.0
sgminer/5.5.5-
aeris
Siacoin (SC) ccminer-800-
x64-cuda75
marlin-0.9.0-
win32
Decred (DCR) gominer OpenCL v.1.0.0
MonaCoin
(MONA)
Ccminer x64
2.2.3 CUDA 9
Sgminer 5.6.1.
nicehash 51*;
Sgminer
5.5.4.3**
Feather Coin
(FTC) CCMiner 2.2.5
Claymore's
NeoScrypt
AMD GPU
Miner v1.2
* RX Vega 64, ** RX 570
Table 4 shows the complete specification of the
computer system. All mining programs are set to use
only the external GPU, while the on-board GPU
exclusively connected to display monitor to ensure
uninterrupted mining process.
Table 4: Hardware Specification
No Component Specification
1 Motherboard
Asus B250 Mining
Expert, Skylake-B250
chipset, Intel HD
Graphic 510
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No Component Specification
2 Memory 16GB (2x8GB) DDR4
1066 MHz dual channel
3 CPU Intel Skylake G4400 @
3.30GHz
4 GPU-0
Galax nVidia GeForce
GTX 1080Ti 11GB
GDDR5X @ 1630MHz
5 GPU-1
MSI nVidia GeForce
GTX 1070 8GB DDR5
@ 1582MHz
6 GPU-2
MSI Radeon RX Vega
64 8GB HBM2 @
1630MHz
7 GPU-3
MSI Radeon RX 570
4GB GDDR5 @
1281MHz
8 Hard drive Seagate ST3500418AS
500 GB, SATA 3Gb/s
9 Power Supply
Corsair HX1000 (1000
W) + Enlight ENP-
750HP (750 W)
All four external GPUs are connected using PCIe
riser, as shown in Figure 6.
Figure 6: GPU Configuration
The setup run on the latest Windows 10 Pro, set
to default configuration except for the Virtual
Memory is set to 400 GB and windows update is
turned off. All nVidia cards use the official v.388.71
driver, while the AMD cards use the official
v.24.20.11001.5003 driver. The computer is placed
in a 25oC temperature room.
The mining program runs for 24 hours for every
coin. A six-hour grace period is added after the
mining program finished to let all share completely
confirmed by the network before they are collected
at the wallet. Another extra time can be added to let
the ‘dust’ being collected. In some mining pool,
balance below a certain value (dust) can only be
transferred into the wallet in a specific period, for
example every three days or a week.
6. RESULTS AND DISCUSSION
Table 5 shows mining share in 24 hours for every
currency. These are the mining incentive for each
currency and each GPU card. These are net earnings,
and have been subtracted with mining pool fee,
transfer fee to the wallet, and other fees.
In high-end GPU section, the 1080Ti is leading as
the top earner for five coins, while the RX Vega 64
outperform the 1080Ti in Ethereum, Monero, and
FeatherCoin. However, this share is in its respective
currency and must be converted to USD using the
exchange rate valid for that time.
Both high end GPU consumes a lot of energy. The
RX Vega 64 consumes the most energy when mining
Ethereum (Ethash), Monero (Cryptonight), Bitcoin
Gold (Equihash) and Verge (X17), while the 1080Ti
consumes the most energy when while mining
Siacoin (Blake2b), Decreed (Blake256), MonaCoin
(Scrypt) and Feather Coin (Lyra2rRev2).
Table 6 shows the system energy used by each
GPU to mine specific GPU.
Table 5: Mining Share in 24hrs
Coin
Mining Share in 24hrs
GTX
1080Ti
GTX
1070
RX Vega
64 RX 570
ETH 0.00184 0.00156 0.00224 0.00102
XMR 0.0046576 0.003109 0.0077344 0.0022574
BTG 0.0642911 0.0402726 0.0416773 0.0271428
XVG 37.684888 24.368461 17.748841 6.6081782
SC 0.78 0.45 0.52 0.26
DCR 0.0008876 0.0005159 0.0006623 0.0003094
MONA 0.5055446 0.2833796 0.0020623 0.0150502
FTC 3.2072956 2.1852923 4.7615279 2.1000724
The system (main board, excluding the external
GPUs) consumes energy about 70 watts (1.68 kWh).
Electric cost was calculated using the Indonesia
electric rate, which equivalent to USD 0.11.
Revenue (Rev) for each cryptocurrency and each
GPU is calculated by multiplying shares in 24 hours
(S) and exchange rate of the coin (Ex). The result is
subtracted from energy cost, which is the energy
consumption of the system in 24 hours (Ws)
multiplied by the cost per kWh.
Rev = (S * Ex) – (Ws * 0.11) (1)
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Table 6: System Energy Consumption
Coin
System Energy Consumption in
24hrs (kWh)
GTX
1080Ti
GTX
1070
RX
Vega 64
RX
570
ETH 5.95 4.82 6.82 3.36
XMR 4.54 3.58 6.24 3.44
BTG 6.72 5.64 6.96 4.9
XVG 5.95 6.67 6.96 4.2
SC 7.58 5.98 6.94 5.4
DCR 7.63 5.78 6.96 5.41
MONA 7.85 5.52 6.84 3.17
FTC 7.68 7.2 6.94 6.3
Table 7 shows detailed revenue for each
cryptocurrency and each GPU.
Table 7: Revenue in 24hrs
Coin Rate
Revenue in 24hrs (USD)
GTX
1080Ti
GTX
1070
RX
Vega
64
RX 570
ETH $703.4 $0.64 $0.57 $0.83 $0.35
XMR $201.7 $0.44 $0.23 $0.87 $0.08
BTG $44.44 $2.12 $1.17 $1.09 $0.67
XVG $0.03 $0.30 ($0.12) ($0.32) ($0.29)
SC $0.02 ($0.82) ($0.65) ($0.75) ($0.59)
DCR $89.96 ($0.76) ($0.59) ($0.71) ($0.57)
MONA $3.30 $0.81 $0.33 ($0.75) ($0.30)
FTC $0.10 ($0.53) ($0.58) ($0.30) ($0.49)
Table 7 shows that from 32 sets of experiment,
only 15 sets (46.88%) are profitable. From eight
coins tested, the 1080Ti GPU is profitable at five
coins (62.5%), followed by the GTX 1070 at four
coins (50%), RX Vega 64 and RX 570 at three coins
each (37.5% each). Although the RX Vega 64 is
ranked above the 1070, the later GPU is more
profitable in more coins, since it consumes lower
energy.
Note that the revenue is calculated without
including air conditioning costs. Table 8 also shows
that all GPU generates heat more than 40oC, which
gradually raise the room temperature. In the long
time mining process, air conditioning would be
mandatory, not only to make the room comfortable
for people, but also such high temperature could
damage the hardware. The design of the Vega 64,
which only have one fan and closed heatsink design,
is also contributing to its highest temperature.
Table 8: Average GPU Temperature
Coin
Average GPU Temp (C)
GTX
1080Ti
GTX
1070
RX Vega
64
RX
570
ETH 57 58 70 58
XMR 50 50 65 58
BTG 61 59 75 59
XVG 62 57 60 57
SC 63 66 63 58
DCR 57 61 65 59
MONA 64 61 46 57
FTC 56 64 67 59
Table 9 shows best performer GPU for every coin,
which calculated by how much power consumption
needed to produce one mega hash.
Table 9: Best Performer GPUs
Coin
Best Performer
GPU in terms of
W/MH)
Power (W)
per hash rate
(MH)
ETH RX 570 4.837260728
XMR RX Vega 64 158333.3333
BTG GTX 1080Ti 313493.6629
XVG GTX 1080Ti 9.621621622
SC GTX 1080Ti 0.094506339
DCR GTX 1070 0.066276501
MONA GTX 1080Ti 4.644018793
FTC RX Vega 64 116.3506074
Given the global network hash rate for every coin at
the time, we calculate the power required to run the
network for each coin, and the estimated annual
energy consumption, as detailed in Table 10.
Table 10: Estimated Annual Energy Consumption for the
Coin Network
Coin Network Hash
Rate (MH/s)
Power
Required
(MW)
Est. Annual
Energy
Consumption
(TWh)
ETH 270,385,640.00 1,307.93 11.46
XMR 452.26 71.61 0.63
BTG 30.48 9.55 0.08
Journal of Theoretical and Applied Information Technology
15th March 2019. Vol.97. No 5
© 2005 – ongoing JATIT & LLS
ISSN: 1992-8645 www.jatit.org E-ISSN: 1817-3195
1631
Coin Network Hash
Rate (MH/s)
Power
Required
(MW)
Est. Annual
Energy
Consumption
(TWh)
XVG 551,700.00 5.31 0.05
SC 73,189,400,000.00 6,916.86 60.59
DCR 17,033,750,000.00 1,128.94 9.89
MONA 2,040,000.00 9.47 0.08
FTC 10,126.82 1.18 0.01
As a comparison, Bitcoin estimated annual energy
consumption in June 8th, 2018 was 70.842 TWh [6].
Most of the coins above have a significant power
consumption gap below the Bitcoin. However, in
cryptocurrency, mining is permissionless, and the
price of the coin depends entirely on supply and
demand. When a coin attracts too many miners (or
when miners use ASIC, which can produce a very
high hash rate at lower power consumption), the
blockchain automatically adjusts the difficulty to
maintain constant block time. High network hash
rate creates a barrier for miners. Miners with lower
hash rate will receive less incentive, and they will
likely exit the system because it is not profitable
anymore. Less miners in the system (also ASIC
owners) lead to less decentralized system, and it is
not desirable.
Table 11: Daily Energy Cost
Coin
Market
Capitalization
(MillionUS$)
DailyEnergy
Cost(Million
USD)
%Energy
Cost/Market
Cap.
BTC $130,256.22 $21.3496 0.016%
ETH $69,465.82 $3.4529 0.005%
XMR $3,237.59 $0.1890 0.006%
BTG $770.34 $0.0252 0.003%
XVG $381.54 $0.0140 0.004%
SC $574.99 $18.2605 3.176%
DCR $642.84 $2.9804 0.464%
MONA $197.69 $0.0250 0.013%
FTC $19.54 $0.0031 0.016%
Table 11 shows daily energy cost of running each
coin compared to Bitcoin. The data are taken from
the testing date, except the Bitcoin from June 8th,
2018. Energy cost is calculated based on Indonesia
electricity cost. From the table, we can observe that
even the energy consumed by the SiaCoin network
is lower than Bitcoin, but the energy consumption
proportion to market capitalization is 19,276% more
than Bitcoin. At some point, coin developers have to
take drastic actions. For example, the SiaCoin
decided to perform hard fork to reset its PoW
algorithm on October 31. The reset restricts ASICs
such as Innosilicon and Bitmain [36], and push down
the network hash rate to 932.70 TH/s by November
5.
For miners, calculating profitability can be
complicated, since coin price depends heavily on the
price of bitcoin, and the price of bitcoin is very
sensitive to cryptocurrency issues and policies.
During the testing period, Bitcoin price reaches its
peak at USD 8,454.75 on May 21, and drops to USD
5,954.43 on June 29 before climbing back to USD
7,000s. To describe its volatility, the Bitcoin highest
price was USD 19,747.87 on December 17, 2017
[37].
The use of blockchain in cryptocurrency may
significantly reduce the need for banks, which could
lower the transaction fee to a minimum, but the PoW
base blockchain runs on miners, and with the amount
of energy required, daily cost to maintain a coin
could reach millions of dollars.
7. CONCLUSIONS
The PoW system relies on miners to run the
system. Our experiment shows only 46.88% of 32
sets are profitable. Equihash, Ethash, and
Cryptonight7 coins are the best performers, while
Blake2b, Blake256, and Lyra2REv2 coins are the
worst performers in terms of profitability. Most the
coins tested consume below than 1 TWh
($110,000,000.00) of annual electrical energy
consumption, except SiaCoin and Ethereum, and
Decred.
Higher profitability means miner will probably
continue to contribute to the system. Profitability
also depends on the exchange rate of the currency,
which rely heavily on the BTC exchange rate. To
make it more complicated, cryptocurrencies price
solely depends on supply, demand and the
expectation of the holder. No central bank,
government, nor anybody can correct the price
should it rises or fall. Because the permissionless
nature of the blockchain, miners can easily switch to
mine more profitable coin. Actions such as hard
fork, switching algorithm or even switching
consensus mechanism is common in the
cryptocurrency world. This makes public,
permissionless blockchain which runs on PoW has a
high level of uncertainty.
Journal of Theoretical and Applied Information Technology
15th March 2019. Vol.97. No 5
© 2005 – ongoing JATIT & LLS
ISSN: 1992-8645 www.jatit.org E-ISSN: 1817-3195
1632
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This chapter provides an introduction to the distributed ledger technology of crypto‐currencies. It also provides a brief background discussion of payment mechanisms and describe crypto‐currencies in general. The chapter examines the 'monetary' properties of crypto‐currencies and considers some common uses. It describes some of the literature on the empirical properties of crypto‐currencies. The chapter explains the proof of work schemes used to maintain the integrity of Bitcoin ledgers. The empirical literature on crypto‐currencies, and Bitcoin in particular, is expanding rapidly. The chapter discusses the growth and usage of crypto‐currencies and describes a prototypical example of how transactions are facilitated using Bitcoin the first and most widely traded decentralized crypto‐currency. Proponents foresee an enduring role for crypto‐currencies. Regulatory and legal reform will need to account for the decentralized nature of most crypto‐currencies, and for their capacity to transcend national borders.
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Blockchain technology is a decentralized database that stores a registry of assets and transactions across a peer-to-peer computer network, which is secured through cryptography, and over time, its history gets locked in blocks of data that are cryptographically linked together and secured. So far, there have been use cases of this technology for cryptocurrencies, digital contracts, financial and public records, and property ownership. It is expected that future uses will expand into medicine, science, education, intellectual property, and supply chain management. Likely applications in the field of medicine could include electronic health records, health insurance, biomedical research, drug supply and procurement processes, and medical education. Utilization of blockchain is not without its weaknesses and currently, this technology is extremely immature and lacks public or even expert knowledge, making it hard to have a clear strategic vision of its true future potential. Presently, there are issues with scalability, security of smart contracts, and user adoption. Nevertheless, with capital investments into blockchain technology projected to reach US$400 million in 2019, health professionals and decision makers should be aware of the transformative potential that blockchain technology offers for healthcare organizations and medical practice.