Renewable Energy Systems & the National Electricity Transmission Grid

This report analyzes the impact of renewable energy systems, particularly solar PV and wind energy, on the national electricity transmission grid, focusing on the case of South Australia's power grid failure. It examines the factors affecting solar PV system output, the role of wind energy in grid stability, and the implications of reduced rotating inertia. The report also discusses the potential of local distributed generation and energy storage in preventing or minimizing loss of supply, and the broader implications for interstate electricity ties as renewable energy systems expand. The analysis covers the technical challenges and opportunities associated with integrating renewable energy sources into the national grid, emphasizing the need for adjustments in protective settings and enhanced grid management strategies.

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1. Perform analysis of the capital cost given the following,
Payback= 25 years
Cost= 3 per peak
Cost of solar PV=0.1 per kWh
The total amount of energy in kWh= System peak kW X System % average output X Average hours per
year x number of years of system lifetime.
25 years’ x 0.1 per kWh x 0.1per kWh
= 0.25kWh
Melbourne and Alice Spring
The first electricity to be supplied in Melbourne was generated and distributed by a number of
private companies and municipal generators. At first, the electricity produced in Victoria using simple
technology and transmission was done over short distance hence it was being used for public events. In
the current situation, most electricity is generated by burning coal brown in color and the major
consumers of electricity in Victoria is aluminum smelter at Portland. The high water content in coal
makes it less suitable for combustion unless a specialized technology is used and Victoria has a limited
hydroelectric generation system due to limited water resources. There is a wind farm in Victoria having
250 wind turbines and producing 8000GWh of electricity which represents 18% of the power used in
Victoria
The first electricity to come to Alice Springs was in 1872 in the form of 120 volts’ batteries that was
being used in operating the Overland Telegraph Line. The first Alice Spring was situated in Bath Street
and the second station was in Sadden Range. Alice Springs receives a solar radiation of about 6.16-
kilowatt hours per square meter daily. The following are reading from the weather station report
 Wind speed in Alice Spring: 4.56m/s
 Solar radiation: 6.16kWh/sq. m/day
 Humidity: 39.42%
 Air temperature: 20.86 degrees Celsius.
 Air pressure: 95.29kPa
Using the 6 X 265 Watt Solar panels (1.59kW) the following are the results obtained)
o 8.8128kWh is the average output produced by the system daily.
o The minimum output on a daily basis is 5.8374 kWh.
o The maximum daily output is 11.043 kWh.
o The value of electricity annually is $ 965.

Factors affecting Output of Solar PV System station and coal station
There are factors that affect the output of solar PV system for example;
 The thickness of the cable since in case a cable of 6 sq. mm cross section cable will now be 0.06
ohms and the voltage drop, o.6V which is 2.5 % voltage drop for a 24V system which might be
acceptable. The size and thickness of the cable need serious attention starting from the planning
stage. System voltage can also be raised in order to reduce the resistance loss.
 Temperature also affects the output of solar PV since solar perform better in cold rather than in
hot climate. Panels conventional at 25 degrees Celsius and the rise in temperature above 25
degrees’ Celsius decays the output but in hot summer days, the temperature of the panel reach
70 degrees and this means the panel will put out up to 25% less power compared when rated at
25 degrees.
 Battery efficiency also determines the output since they are needed for charge storage.
The additional facilities required if the grid were to the solar-PV dependent are
 Photovoltaic panels ( PV panels)
 Inverters
 Meters
 Charge controllers
 Disconnect switches
 Battery banks to store the solar power
 Fuse
 Surge protection that the government requires being installed

1. Were the political leaders justified in blaming wind energy and renewable energy generally for
the total grid failure
According to the report released by the AEMO on the blackout which occurred in South Australia; It
was justified that the blackout was a result of wind which blew over the transmission line but has
nothing to do with the South Australia wind turbines. In the report, it has been well articulated that on
the day of total grid failure, two electrodes having a speed of wind of 190 and 260 kilometers per hour
tore through a single circuit 275kV transmission line around 170km apart. The damaged of the three
transmission lines tripped resulting to six voltage dips on the South Australia grid in a short period of
time (Ackerman, 2012, p. 345).
A sustained power reduction was experienced in nine wind farms situated in mid-north of South
Australia as the fault on the transmission network grew. The protection settings allowed the wind
turbines to withstand a preset number of voltage dips within a period of two minutes. The output of the
wind farm fell by 456 megawatts immediately the protection feature kicked in (Belyaev, 2010).
The reduction of output in the wind farm made the Heywood Interconnector from Victoria to try to
make up the shortfall. After the powering down of the last wind farm, the interconnector flow attained a
level that it activated a special protection scheme which tripped it offline. The generation remaining was
much less than the connected load resulting to the collapsed in the entire system. The power system of
South Australia then became separated from the national grid. In relation to the statement made by
political leaders, AEMO reports show that there is no doubt the protection settings on some windfarms
also contributed to the chain of events which resulted in a statewide power blackout.
2. What is regarded as the primary reason for the complete collapse of South Australia power
grid
According to the report presented by the AEMO, the blackout was caused by overprotective wind
turbine settings being triggered thus causing a reduction in power generation. The primary reasons
which caused loss of power in South Australia were (Dong, 2016, p. 123);
 Two tornadoes damaged 275kV transmission line and a double circuit 275kV transmission line
simultaneously.
 The damage made transmission line to trip resulting in six voltage dips on the South Australia
grid within grid-connected two minutes.
 The number of voltage dips triggered a protection feature to be activated on eight wind farms in
South Australian.
 The activation of these features resulted in significant sustained generation reduction of 456
megawatts over a period of seven seconds (Hordeski, 2008, p. 223).
 The rapid increase in flow through the Victoria-South Australia interconnector activated a
protection scheme which tripped interconnector offline.

 South Australia became separated from the National Electricity Market and the generation
which remained was outweighed by the loads connected and therefore the frequency of the
island could not be maintained thus all supply to South Australia was lost (Luis, 2013, p. 432).
3. Could adjustment of protective settings on the wind farm assisted in maintaining supply and
preventing total grid collapse.
Adjusting potential settings in wind turbine assist in preventing shocks which occurs in case of bad
weather. Potential settings assist in the wind farm assist the wind farm to override the voltage
disturbance in case of a storm.
In the South Australian power failure, there were issues with Synchronous generators and they included;
 It was expected that all generators should have been able to ride through the transmission
faults caused by the storm.
 It was noted that the five thermal generators operating as transmission lines fell, remained
connected and operated up until the South Australia system disconnected from the rest of the
National Electricity Market.
 The operation of these generators relying on the system faults experienced during these events
(Moore, 2017, p. 345).
4. Was there an issue an issue with the level of rotating inertia in South Australia power grid
There were numerous issues in the level of inertia and they include;
 At the present, there was enough inertia available for conventional generators which is
accessible to all the areas connected synchronously in order to assist in maintaining the security
of the system and attaining the set frequency standards.
 The reduction in the operation of synchronous generation became more likely as a result of low
level of inertia. This included the areas during the time of low demand and high renewable when
the conventional generation is offline.
 The material technical difficulties for the power system microgrid generally resulting from the
changing generation mix (Plimer, 2017, p. 47).
 South Australia will need to run as an islanded system, replying to local generations to provide
the needed services.
 Tasmania cannot access mainland inertia whereby low inertia is more likely occur in case of low
demand. Hydro generation is likely to be withdrawn from the market as a result of the capability
of their flexible operation and renewable status, unlike conventional gas and coal, fired
generation.
 The electrical frequency stays the same across the whole grid while the national grid stays stable
and intact. The generators synchronized to the system contribute to the inertia found in the grid
in general
The level of inertia plays numerous role in the operation of power system. Inertia is just a function of
the mass of the rotors of conventional generators. The inertia of conventional generators acts to resist
changes taking place rapidly in power system frequency. Inertia acts to dampen the act at which
frequency can change on the whole power system. The power system frequency is slowed if the amount

of inertia in power system is greater and the response to a particular disturbance for example trip of
generating unit depend on it (Wang, 2015, p. 97).
What roles does rotating inertia play?
There is an implication in power system security resulting from an increase in the rate of change of
frequency because traditional control system for example under frequency load shedding and
contingency frequency control ancillary services might not respond quickly enough to arrest and contain
a frequency disturbance. Under normal and abnormal circumstances, reduced power system inertia
becomes difficult to manage and that is why there is need to carry out a technical analysis. The
conventional generators were provided so the availability of the services are affected by the operational
generators. The shortage of power system in South Australia may come as a result of the withdrawal of
conventional generations (Spoehr, 2009, p. 100).
What ways can inertia be provided?
Inertia can be provided by the traditional synchronous generators, for example, hydro generators, coal
and thermal gas.
5. The possible supporting role could local DG and local distributed energy storage had in
preventing or at least minimizing loss of supply.
Role of Local Distributed Generation
The Distributed Generation (DG) is a new concept in electric market and it has been used for decades in
electricity in the electricity market. It is simply powered generation built near consumers and its sources
include small-scale, environmentally –friendly such as wind and photovoltaic installed and designed to
preserve a single end users site. Distributed Generation mostly comprises traditional fuels fired
reciprocating engines or gas turbines. The Distributed generation plays numerous roles in minimizing or
preventing loss of supply for example;
 The size of the turbine is increased while the marginal cost of production of electricity is
decreased as a result of advert of the steam turbine. In simple terms, DG has an advantage on
economies of scale point of view (Luis, 2013, p. 23).
 The Distributed Generation enable transmission of electricity. The alternate currents are used
unlike direct current and they are allowed to transmit over long distances without a significant
reduction or loss.
 High efficiency and this was achieved via larger facilities which are capable of withstanding a lot
of pressure from the steam and the temperature used in the generation of electricity.
 The environmental constraints. The generation facilities outside the city center were relocated
by the use of network transmission and this led to the removal of pollution due to coal fire plant
exhaust.
 Distributed Generation increase reliability of the electric system
 It supplies the power demanded urgently.
 It reduces the effect of using the land.
 It assists in the reduction of vulnerability.

 It assists in peak power reduction.
Role of local distributed energy storage
Energy storage has played a Microgrids role in the electricity industry known and the most
commonly used type of energy storage in Australia is the use of pumped hydroelectricity storage with
1490MW of operation within Australia. The local distributed energy storage plays the following roles in
Australia;
 Ensuring the electricity produced is stable and of quality.
 Reducing the need for new transmission power plants and lines.
 Smoothing the supply of the generated electricity from variable renewable energy sources.
 Decreasing the reliance on combustion power plant to meet peak demand.
 Providing security to the grid where there are transmission and distribution interruption.
 Enhancing grid efficiency by dispatching energy in case the electricity is needed rather than
when it was originally generated.
 Managing short-term differences caused by demand for energy and fluctuation in the
generation.
 Distributed energy storage can be used to defer or offset the need for new generation capacity.
 They can be used in providing the backup source of power supply.
 Local distributed energy sources can be used in Australia to dampen fluctuations of voltage on
the distribution lines.
 They can be used in shifting energy through time to reduce the cost of generation by storing
excess electricity at off-peak times and discharging during peak periods.
 They are used also in case of line outage.
6. The role played by micro the grid in minimizing loss of supply
Microgrids also are known as hybrid generation systems or remote power systems or mini-grids are
self-contained electricity which is capable of operating independently of it and they range in size from
kilowatts to megawatts. Microgrids are the outcome the massive changes taking place in the electricity
market including, distributed energy resources, energy storage system and plug-in electric vehicles.
Example of electricity microgrid applications include;
o Research facilities such as campuses
o Military installation
o Remote, island or rural communities
o Industrial or commercial facilities such as data centers
Microgrid plays an important role in minimizing the loss of supply by;
 Microgrid assists in technology cost reductions because according to electricity market in
Australia the cost of monitoring and controlling renewable energy technology are reducing.
 It enhances clean and affordable energy for economic development.
 Use of microgrid promotes the use of renewable energy and acceptance of localized energy
solutions.

 The microgrid provides a cost-effective solution to promoting system resilience in the face of
Australia by increasing vulnerability to environmental hazards
7. Implications of national transmission grid as regards further spread of renewable energy
system and local DG
As a result of the national transmission grid, South Australia leads the nation in terms of
renewable energy commercialization with 8% of the nation's population. It captures 90% of its
geothermal developments, 30% of solar power and 56% of the grid-connected wind power. South
Australia is also considered to be the target for green energy investors. South Australia and Tasmania
are the granite basement rocks are suitable and they are main locations where geothermal energy is
being developed in Australia The geothermal energy has been utilized commercially at two locations in
South Australia that is Birds Ville which generates geothermal electricity from hot water from the great
artesian basin and also geothermal district heating scheme at the Portland. Implications of national
transmission grid resulted in many companies in Australia engaging in developing geothermal energy in
full scale for full-scale commercial deployment (Kariniotakis, 2017, p. 87).
The implication of national grid has led to the spread of Distributed Generation (DG) locally such
that currently, the lithium-ion battery installation is taking place outside Horns dale wind farm in South
Australia. South Australia is also planning to build a 250MW virtual power plant which will entail
thousands of solar panels and battery running software that decides when the batteries charge and
discharge in order to maximize the value and efficiency of the grid (Hordeski, 2008, p. 17).

Bibliography
Ackerman, T., 2012. Wind Power in Power Systems. s.l.: OLMA Media Group.
Belyaev, L., 2010. Electricity Market Reforms. s.l.: Hauffe Gruppe.
Dong, Z., 2016. Emerging Techniques in Power Systems Analysis. s.l.:Informa.
Hordeski, M., 2008. Emergency and Backup Power Sources. s.l.: Thomson-Reuters.
Kariniotakis, G., 2017. Renewable Energy Forecasting. s.l.: Adventure Works Press.
Luis, D., 2013. The Australia & New Zealand Grapegrower & Winemaker. s.l.: Ridders Digest.
Moore, T., 2017. Urban Sustainability Transitions. s.l.: McGraw-Hill Education.
Plimer, I., 2017. Climate Change Delusion and Great Electricity Rip-off. s.l.:HarperCollins.
Spoehr, J., 2009. The Electricity Crisis. s.l.: Wolters Kluwer.
Wang, N., 2015. Large- Scale Wind Power Grid Integration. s.l.: China Publishing Company.
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