EEET 5012 - Renewable and Distributed Power Generation - Practical 2 – Annual Energy Cost of a Grid-Connected Residential Home
EEET 5012 - Renewable and Distributed Power Generation Practical 2 – Annual Energy Cost of a Grid-Connected Residential Home
Aim: The aim of this practical is to determine the energy/electricity cost of a residential household with and without Photovoltaic systems using Excel/MATLAB coding.
Objectives: Familiarise with the energy cost calculations of a residential home
Develop a rigorous model of a grid-connected household and rooftop Photovoltaic (PV) system
Investigate the impact of a PV system and various tariff structures on energy cost Familiarise with MATLAB coding environment and plotting functions (optional)
Background: The annual energy/electricity cost of a grid-connected household mainly depends on two factors: 1) imported energy to meet household load demand, 2) retail price at which energy is imported (RP) from the grid. Eq. (1) determine the annual energy cost of a household without a PV system. If the rooftop PV system is installed, the power generated by the rooftop PV system meets the load demand of the house during the day. This reduces the cost of importing energy from the grid. Moreover, the house owner earns revenue by exporting excess PV energy to the grid at the feed-in-tariff (FIT). In this case, annual energy cost is given by (2), and the power balance equation at the point of common coupling can be expressed by Eq. (3). When the PV generation is higher than the load demand then Pexp(t) > 0 and Pimp(t) = 0. When the PV generation is lower than the load demand then Pexp(t) = 0 and Pimp(t) > 0.
???=(??×∑? (?)∆?) (1) ???
???=(??×∑? (?)∆?)−(???×∑? (?)∆?) (2) ??? ???
? (?)+? (?)=? (?)+? (?) ?? ??? ?? ???
(3)
Figure 1 Configuration of a grid-connected home with a rooftop PV system
Procedure:
- The load and PV generation data are given in the excel file (Data.xls). Import the data to MATLAB. Hint: Command to import data: dtin=xlsread('FileName')
- The energy price factsheet from a retailer X, Y and Z are given in Fig. 2, 3 & 4. X retailer offers standard/ flat tariff, however Y and Z offer time of use tariffs. Calculate and plot a bar chart of the annual energy cost of the household under these rates and find the most beneficial tariff structure. Include the daily supply charges in your calculations. Assume there is no PV system.
Figure 2 Energy price factsheet by retailer X
0600-0959 1000-1459
Figure 3 Energy price factsheet by retailer Y
Figure 4 Energy price factsheet by retailer Z
- Assume the studied house already has a PV system of 3 kW. Determine the annual energy cost considering the feed-in-tariff given in Fig. 2, 3 & 4. Compare the annual energy cost for three cases with and without PV system. Change the value of feed-in-tariff from 3 cents/kWh to 23 cents/kWh in the step of 5 cents and record the corresponding annual energy cost of the household. Plot the obtained annual energy cost against specified feed- in-tariff values for all three cases and discuss its characteristics.
- Assume the house owner is installing a 3 kW PV system, which is financed by a bank at a 2% p.a. interest rate for five years. The installation cost for a 3 kW PV system is $2500. Calculate the CRF and then the annual installment of the PV system. Recalculate the annual energy cost for the most beneficial considering the annual installment of the PV system.
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Report:
• Results of step 2 to 4 with critical analysis and discussion.
• Plot the load and PV curve of 1st January on the same graph and discuss its characteristics.
• State other ways to minimize the annual energy cost of the household
Note:
Don’t forget to upload your Excel/MATLAB file with the report.
