This confirms that the diploma thesis entitled "Development of a net metering system based on solar energy for domestic consumers" by Dr. By Imran Hosena (EEE Sohidul Islam (EEE Md. With the increase in world population and the rapid growth of the world economy) Economically, the demand for energy resources, especially electricity, has faced a tremendous increase Net metering is a policy whereby unused energy is fed into distribution network and is used by nearby consumers connected to the same distribution network.
Now, Bangladesh generates only 777.47 MW from renewable sources, which is about 3.52 percent of the total electricity generation. According to SEIA (Solar Energy Industry Association), net metering allows residential and commercial customers who generate their own electricity from solar energy to sell the electricity they don't use back into the grid.
Innovation
Worldwide Adoption
- Canada
- Australia
- Malaysia
- Pakistan
Ontario allows net metering for systems up to 500 kW, but credits can only be carried forward for 12 consecutive months. Net metering of up to 100 kW is permitted in areas of British Columbia serviced by BC Hydro. FortisBC, which serves an area in South Central BC, also offers net metering of up to 50 kW.
The City of New Westminster, which has its own utility, also allows net metering. The Malaysian Net Metering Guidelines distinguish between installed capacity limit and net energy export limit.
Worldwide Net-Metering Installation Capacity
In 2015, Pakistan introduced net metering regulations (“National Electricity Regulatory Authority Distributed Generation and Net Metering Regulations, 2015”) to encourage electricity generation from distributed renewable energy (RE) systems. However, the growth of net metering facilities has been slow, with only 815 permits issued till December 2018, adding 17.28 MW of installed power generation capacity in the country. Given Pakistan's renewable energy potential, especially from solar PV, the slow growth of net metering is a missed opportunity for the country.
In order to develop the net metering market in Pakistan and accelerate the spread of distributed generation (DG) technologies, this report provides an assessment of the regulatory and market barriers that limit the effectiveness of Pakistan's net metering program and recommends specific interventions to address this barrier. Here (Figure 1) shows a graph and data where the world state of Net-Metering was stated.
History of Net-Metering in Bangladesh
Innovation
Launching Date
Resources) has launched the Net Metering Guidelines-2018 which aims to stimulate the installation of rooftop solar PV systems on a massive scale. The main idea behind the net metering mechanism is that it allows consumers to become "prosumers" by connecting their RE systems to the distribution network via a bidirectional smart meter.
Current Status
Current Capacity of Renewable Energy and Net-Metering in Bangladesh
Share of Net-Metering in Bangladesh
To set up a complete network metering system, several installation rules and procedures must be followed step by step. PVs that generate electricity using solar energy also provide the IGBT-based inverter with maximum power tracking from the MPPT (Maximum Power Point Tracker). The DC power of solar PV panels is not stored in batteries; instead, it is converted to AC power by an inverter, which is then directly connected to the grid.
When there is a surplus of energy generation, it is supplied to the electricity grid, and when there is a shortage of electricity at the consumer, it is taken from the electricity grid. The net metering system with grid-connected inverter and bidirectional energy meter is shown schematically in figure (Figure 4).
Load Calculation
Load curve
A load curve or chronological curve is a graphical representation of the load (in kW) in the correct time sequence and time in hours. When the load curve is drawn for 24 hours in a day, it is called a daily load curve. If we then consider one year, this is called the annual load curve. The load curve of the power system is not the same throughout the day.
The Load Duration Curve
Here, from fig (Figure 6) shows the maximum total load demand is 2.57 KW and the minimum load demand is 0.4 KW.
Solar PV
Sizing Of Solar PV Panels
Voltage is plotted along the horizontal axis and power is plotted along the vertical axis in a power curve. When this is plotted on the I-V curve for the same cell, the peak power point becomes quite apparent.
MPPT
MPPT Code
MPPT Algorithm
Three Phase Grid Tie Inverter
Inverter Specification
Working System of grid Tie Inverter
Flow Chart of Inverter Mechanism
Inverters operate as a supplier when the load demand is less than the PV supply. When the PV supply cannot meet the demand of the load, the required power comes from the grid. When PV is not supplying electricity, the demand of the load is met through the power grid.
Inverter Switching
The table shows that at each 60° step only three switches operate, one from the higher group and two from the lower group, or two from the higher group and one from the lower group. During each step, only two IGBT conductors are routed for this inverter, one from the upper group and one from the lower group; but in the 180° mode converter three IGBTs feed in each step. The advantage of the 180° guidance over the 120° orientation is the number of switches that remain on at any given time.
Voltage and Current Transformation Blocks
Phase Locked Loop (PLL)
PWM Generation
Filter Design
Capacitor Sizing
Inductor
The filter or LCL filter is usually placed between the inverter and the grid to dampen the switching frequency harmonics produced by the inverter connected to the grid. The load AC voltage is used as a reference signal for the PWM pulse generator, which is also used as the required stage for sine wave generation. To obtain the AC output waveform, the obtained pulses are fed to a three-phase bridge inverter.
A PV array feeds an inverter, which feeds the utility grid (AC voltage) through an LCL filter. When we run the simulation, we notice that as the radiation level changes, the output current of the inverter also changes. As the PV industry has developed, so has the impact on the AC grid system, which is also expanding.
MATLAB Simulation Results
PV Output Voltage Curve
Inverter Output V-I Curve
Inverter Output V-I Curve in Different Irradiance
Net metering is a billing mechanism that gives solar system owners credit for the electricity they inject into the grid. Net metering allows them to export that power to the grid, thereby reducing their future electricity bills. And on the "sunny side," if the solar panel system is in full swing and producing more energy than the operation can use, the meter records how much electricity is being received by the utility.
The third reading on the meter shows the difference between the quantity delivered and the amount received, or the net energy used. A traditional net meter will only give the net power of the system, a negative power value specifies that power is injected into the power supply; in this case, the consumer gains money because power is injected into the power supply. A positive power value means that power is taken from the grid to meet the additional load requirements; in this case, the consumer has to pay extra money to the company to get the extra power.
Flowchart of Bi-Directional Energy Meter
Control signals C2, C3 and C4 are predefined control signals for the algorithm of the net metering control unit. Control signal C1 indicates whether the power available from the PV system is sufficient to meet the residential load when the system is first switched on. If the generated PV energy exceeds the required load, the control signal C2 is switched to a high level and the uniform excess energy model is used to calculate the remaining energy.
Similarly, a high control signal C3 indicates that there is enough power to meet the home load's PV energy shortfall. In case the utility grid is unable to meet the power difference, the local battery storage system is set up to compensate for the difference in PV energy. Finally, the cost of drawn and supplied energy to and from the supply is determined in order to estimate the Registered owner's monthly payment.
R1 is the amount received when excess PV array power is fed into the utility grid.
Control signal C1 is high
The energy generated from PV is not enough to meet the load demand, then the additional required energy comes from the grid to meet the load demand and the net energy must be imported or calculated as imported energy.
Control Signal C2 is high
Control Signal C3 Is High
Bi-Directional Energy Meter Circuit Simulation Using Proteus
Figure (Figure 26) shows the complete circuit diagram of a two-way energy meter called Net-Meter. The 1st source is considered the power coming from the grid and the 2nd source as the power coming from the PV side. Construction and all public and private industries for the installation of a rooftop solar system, including a Net-Metering system.
Since the power produced by solar energy using PV systems is difficult and expensive to store, this net metering allows the excess power produced to be supplied to the grid, and when solar power is insufficient or unavailable, power can be drawn from the grid, creating an opportunity for two-way supply and making solar energy more reliable. Energy and Mineral Resources Government of the People's Republic of Bangladesh," Master Plan for Energy Efficiency and Conservation to 2030, 2015. Nazmul, "Calculating Optimum Angle for Solar Panels of Dhaka, Bangladesh for Capturing Maximum Irradiation IEEE International WIE Conference on Electrical and Computer Engineering (WIECON-ECE), 2017, p.
34; Grid-connected energy storage system to take advantage of metering and variable-rate electricity." Control and Automation (MED), 2014 22nd Mediterranean Conference e. Khan, "Array-level optimization in solar systems Grid-connected PV to reduce partial shading loss", IET Renewable Power Gener., vol.
Shen, “A review of power decoupling techniques for microinverters with three different decoupling capacitor locations in PV systems,” IEEE Trans. Kwon, “Highly efficient microinverter with soft-switching upconverter and single-switch modulation converter,” IEEE Trans. 34;Net Energy Meter with Device Control and Two-Way Communication Capability."Advances in Computing, Communication and Informatics (ICACCI), 2016 International Conference on.
