Throughout the development of human society, especially the rapid progress since the Industrial Revolution, it is inseparable from the utilization of energy. However, the higher the degree of development, the higher the degree of dependence on energy. If we use fossil fuels as before, it is definitely not a long-term solution. First, this kind of energy is still abundant today, but it will always be exhausted one day. Second, the "side effects" such as pollution and climate change caused by the use of such energy are also It cannot be ignored, but to a certain extent, it restricts the pace of development.
▲ Picture from: pixabay
For various reasons, low-cost, clean and environmentally friendly renewable energy is becoming more and more important in the energy structure. In December 2021, South Australia, with a population of 1.77 million, was able to generate electricity from 100% renewable energy for almost a week.
During the six days identified, the state averaged 101 percent of its energy from wind, rooftop solar and solar farms, and only a fraction of its energy from natural gas to keep the grid stable, according to an analysis by energy analyst Geoff Eldridge.
According to clean energy website RenewEconomy.com.au, during the 156 hours of renewable energy operation, wind's share of total energy supply averaged 64.4%, rooftop solar averaged 29.5%, and utility-scale solar averaged 6.2% . Global energy consultant Wood Mackenzie also mentioned in the latest episode of the podcast "The Energy Gang" that Australia has successfully integrated renewable energy into 24% of its grid.
▲ Picture from: OpenNEM
At present, the most widely used and mature technologies of renewable energy are hydropower, wind energy and solar energy. Many countries and regions have actually started the utilization of such renewable energy, but it is not easy to practice.
The population of South Australia is not high, and the demand for electricity is not large, but electricity production is generally centralized, which means that a power plant needs to transmit electricity with little electricity over a long distance, and it cannot form a scale effect. In addition, due to various natural disasters, South Australia's power grid is often damaged, and frequent power outages also lead to high maintenance costs. The high cost of electricity has prompted the state government to promote the use of renewable energy.
About a third of homes in South Australia have had solar panels on their roofs over the past few years. There are also three industrial-scale solar power plants generating about 300 megawatts, so more than half of the state's electricity comes from wind and solar. According to PV technology consultant Pierre Verlinden, South Australia's renewable energy penetration rate has risen steadily over the past 13 years, with an absolute annual growth rate of 4.5%.
▲ Picture from: RenewEconomy
Although South Australia has achieved power generation with 100% renewable energy, in the power system, power generation and power consumption need to be balanced in real time. At present, wind and solar power plants cannot stably output power 24 hours a day. Therefore, in the state's energy structure In addition to wind and solar energy, a small part of natural gas is still needed to maintain the stability of the grid.
▲ Picture from: RenewEconomy
With four synchronous capacitors currently installed in South Australia, gas-fired generators may still be needed when there is not enough wind or solar to meet energy demand, but the amount of gas-fired power needed to maintain grid security will be significantly reduced, reducing the need for gas-fired power plants. peak demand.
However, natural gas in South Australia is expensive, and issues such as source diversity, energy storage and grid interconnection need to be addressed if the state government is to achieve a stable supply of 100% renewable energy by 2030.
▲ Picture from: ElectraNet
In Jamestown, South Australia, there is a large 150-megawatt Tesla battery pack next to the 315-megawatt Hornsdale wind farm, so this large battery pack is also the Hornsdale energy storage system ( HPR).
Common energy storage methods include batteries, energy storage flywheels, pumped hydro energy storage and compressed air energy storage, etc., but the current energy density of batteries (the total energy contained in each kilogram of energy material) is not high, so the main energy of this battery pack is. The function is not to be used as a backup power supply. Its main task is to quickly adjust the frequency to help the grid adapt to changes in renewable energy supply, and then "part-time" to absorb excess wind power.
▲ Picture from: Reuters
The use of renewable energy is one of the trends in the future development of society. There are still many areas to be improved, but the record of using 100% renewable energy in South Australia this time is a successful attempt. I hope to see more in the future. More such successes will allow renewable energy to promote the development of human society one step closer.
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