Module title Blockchain Technologies
Module code COMP5125M
Assignment title Coursework
Assignment type
and description
It is a programming assignment where students are re-
quired to develop smart contracts for peer-to-peer en-
ergy trading.
Rationale
The aim of this assignment is to evaluate the students’
knowledge of blockchain based systems and smart con-
tract development skills
Word limit and
guidance
N/A
Weighting 60%
Submission dead-
line
02/05/2023
Submission
method
Student will upload their assignment on Gradescope
Feedback provision
Feedback will be provided online through Minerva and
Gradescope
Learning outcomes
assessed
Design decentralized applications and implement smart
contracts, Understand the context to which distributed
ledgers are applied
Module lead Evangelos Pournaras
Other Staff contact Rabiya Khalid ([email protected])
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1. Assignment guidance
Consider a smart community of electricity prosumers (electricity con-
sumers who also produce electricity). There can be a mismatch between
energy demand of a prosumer and the produced energy during a spe-
cific time interval. When a prosumer produces more energy than its
requirement, it can sell it to the other prosumers of the community who
do not have enough energy to fulfill their need. Traditionally, a third
party manages the trading of electricity between prosumers; however, a
significant cost is paid to the third party for its services and the system
is prone to security and privacy issues. To mitigate these challenges, a
blockchain based energy trading mechanism emerged as a promising so-
lution. In this coursework, you are required to design a smart contract
for peer-to-peer (P2P) energy trading between electricity prosumers.
Develop a main smart contract for energy trading for a local energy
market where prosumers send requests for buying and selling energy.
The smart contract should match the energy requests of buyers with
sellers and trade the energy. In the smart contract, the prosumers must
register before taking part in energy trading. When a new prosumer
is registered on the network, a smart wallet for the prosumer is au-
tomatically created by the smart contract. To purchase the energy, a
prosumer must have Ethers in his smart wallet (user can send ethers
to smart contract). A registered prosumer should be able to send en-
ergy surplus (sell) or deficit (buy) request to the main smart contract:
positive value for surplus energy and negative value for deficit energy.
On getting the request, the main smart contract should check if the
requester is buyer or seller and call the respective energy trading func-
tion of P2P smart contract (in case of buyer, main smart contract also
checks if the buyer has sufficient balance in his smart wallet to pur-
chase the required amount of energy, for instance, assume for 1 unit of
energy, a buyer needs to pay 1 Ether).
On getting the energy buying request, the P2P smart contract should
first find the available energy seller in the market who has sufficient
surplus energy to fulfill the energy requirement of the buyer. In case
no seller is available, the buyer’s request should be added to the queue.
Similarly, on getting the energy selling request, the P2P smart con-
tract should first find the energy buyer in the market (queue) whose
energy demand can be fulfilled by the seller; otherwise, the seller is
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added to the available seller’s queue. After energy trading, the infor-
mation should be stored in the blockchain (records of both buyer and
seller should be updated), and payment of energy should be added to
the energy seller’s account (smart wallet). For each prosumer, its ID
(address), energy status (how much energy it needs to buy or sell), and
balance (Ethers in smart wallet) must be stored in the blockchain as a
record and it must be updated after the prosumer takes part in energy
trading. A prosumer should be able to withdraw his Ethers from smart
wallet.
Traditionally, the electricity prosumers prefer to store the surplus en-
ergy in the local energy storage system (ESS) instead of selling it to
the buyers. They use this energy instead of buying energy from other
sellers when they are in energy deficit. Propose (and implement in
the smart contract) an incentive mechanism for the energy sellers and
buyers to encourage them to take part in energy trading.
2. Assessment tasks
The following functions must be the part of your smart contracts.
P2P smart contract
(a) A structure to store information of prosumers. The information
must include a prosumer’s ID (address), energy status (how much
energy it needs to buy or sell), and balance (Ethers in smart wal-
let). You can also add more information as per requirements. Note
that the data of buyers and sellers should not be stored separately,
it should be stored in the same structure named “prosumer”. The
data related to prosumers will only be stored in P2P smart con-
tract. No more than one struct shall be used to store information.
(b) A function to register a new prosumer (add information of a new
prosumer). Initially, only address of the user is added as its ID.
(c) Add functions to buy and sell energy.
Main smart contract
(a) Modifier function to make sure a prosumer is registered in the
system before sending any request.
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(b) Modifier function to ensure single registration of a prosumer (if an
already registered prosumer request for the registration again, the
function should send an error message saying the user is already
registered).
(c) A modifier function to check whether a buyer has deposited suf-
ficient funds (Ethers required to purchase the required amount of
energy) to buy energy in the smart wallet.
(d) A public function to register a prosumer. A prosumer only calls
this function to get registered (prosumer does not pass any value).
The function checks (using the modifier function) the prior reg-
istration of the prosumers. If prosumer is already registered, the
error message is generated (by the modifier function) to show that
prosumer is already registered; otherwise the address of the new
prosumer is sent to the P2P smart contract for storage (registra-
tion).
(e) A public function to enable a buyer to deposit some Ethers prior
to energy buying request. The prosumer dose not pass any value
to the function.
(f) A public function to accept prosumers’ requests and check if a
prosumer has sent an energy selling or buying request and pass
the data to the P2P smart contract. A prosumer passes positive
value if he is a seller and negative value if he is a buyer. For
example, if a buyer needs 3 units of energy, he will send -3 as
input. The negative sign shows that the buyer needs the energy.
On the contrary, if a seller wants to 3 units of energy, it will send
3 as an input. The positive 3 shows that the user has surplus
energy to sell.
(g) A public function to check the current energy status of a seller
or buyer (the amount of energy a buyer wants to buy or a seller
wants to sell). The function should not have any input arguments.
(h) A public function to check the balance of a prosumer. The func-
tion should not have any input arguments.
(i) A public function to withdraw the Ethers from smart wallets of
prosumers. The function should not have any input arguments.
(Note: funds can be withdrawn for a prosumer if his energy status
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is greater than or equal to zero, which means the prosumer does
not need to buy energy at the moment.)
Scenario to implement
Consider a scenario of a smart community with 20 electricity pro-
sumers with unique addresses. All of the prosumers are registered on
the blockchain. Suppose 9 prosumers are energy deficit and send the
energy buying request to the smart contract. For each prosumer, ran-
domly select energy deficit status (amount of required energy) between
(1-6) units. On the other hand, 10 prosumers have surplus energy and
choose their energy status (the amount of energy they want to sell)
between (1-8) units. Send the requests of prosumers to the smart con-
tract randomly and observe the behaviour of your system according
to the instructions given above. Create a table and add the following
information of all 20 prosumers in it:
(a) Address
(b) Initial energy status before energy trading
(c) Balance in the smart wallet before energy trading
(d) Energy status after energy trading
(e) Balance in smart wallet after energy trading
3. General guidance and study support
The reading list and study support materiel will be available on Minerva
and Gradescope.
4. Assessment criteria and marking process
The assessment criteria is provided at the end of this document in the
form of rubrics. Please refer to the point no 8 of the document.
5. Presentation and referencing
You are required to upload your code file of smart contracts on Grade-
scope along with a text file. In the text file, you will provide a brief
description of your proposed incentive mechanism (1 paragraph) and
table of your system’s behaviour (mentioned in point 2).
The quality of written English will be assessed in this work. As a
minimum, you must ensure:
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There are links between and within paragraphs although these
may be ineffective at times
There are (at least) attempts at referencing (if your incentive
mechanism is inspired from an existing work)
Word choice and grammar do not seriously undermine the mean-
ing and comprehensibility of the argument
Word choice and grammar are generally appropriate to an aca-
demic text
6. Submission requirements
It is an individual assignment (no teams). Submit your files on grade
scope and names of your files should be as follows:
code file: Name-Surname-SmartContracts.sol/PDF
Text file: Name-Surname-IncentiveMechanism.txt/PDF
7. Academic misconduct and plagiarism
Academic integrity means engaging in good academic practice. This
involves essential academic skills, such as keeping track of where you
find ideas and information and referencing these accurately in your
work.
By submitting this assignment you are confirming that the work is a
true expression of your own work and ideas and that you have given
credit to others where their work has contributed to yours.
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