How does distributed energy integrate into the traditional power grid?

China Energy Storage Network : In recent years, distributed energy has grown rapidly, and related technologies have flourished, greatly facilitating consumers to establish connections with the power grid. Accelerating the integration of distributed energy and traditional power grids is also one of the hot topics at the 24th World Energy Conference held recently. This decentralized trend brings opportunities as well as some challenges.

The rapid popularization of distributed energy has gradually increased the impact on traditional power grids. In particular, the sudden increase in voltage has brought difficulties to management. This is the main problem faced by power operators.

Can distributed energy be accepted by traditional power grids?

In general, traditional power grids are mainly responsible for one-way transmission of electricity to consumers. As electricity is transmitted from power stations to consumers, the voltage gradually decreases, which means that traditional power grids mainly focus on preventing the voltage at the end of the wires from dropping and failing to reach consumers. Distributed power sources have changed the traditional power transmission mode, especially requiring the main grid structure to be stronger and more functional.

Distributed energy technologies such as solar and wind power that generate electricity for the grid also need to ensure that the voltage at the production end is higher than the voltage at the final transmission end. Therefore, at noon when the sun is at its highest, the photovoltaic power generation is the highest, and the solar transformer pushes up the voltage at the transmission end, causing the entire grid to be in an abnormally high voltage state.

The voltage fluctuates repeatedly, bringing many uncertainties to the operation of the power grid and also bringing technical challenges. With the promotion of distributed energy, the impact is still expanding and deepening. Studies have shown that when the solar energy coverage rate reaches 25%, the voltage anomaly will affect every consumer.

According to statistics, more than a quarter of distributed energy access to the grid has experienced high voltage beyond regulation. Once this happens, the transformer will automatically trip, affecting the stability of power supply. 12% of energy storage facilities will also be affected by abnormal high voltage.

Abnormally high voltage will bring many negative effects. For example, consumers' electrical equipment will age faster. The increase in electrical current will bring many problems, and consumers will have to buy more appliances. At the same time, due to poor energy production results, consumers' investment in distributed energy will also decrease. Excessive voltage will affect the ability of distributed energy to access the power grid, thereby affecting the subsequent development of distributed energy. Once the grid access capacity reaches the upper limit, consumers can no longer continue to access more distributed energy. In Hawaii and Australia, this situation has already occurred with the popularization of solar energy. If the power supply quality of the power grid is to be guaranteed, distributed energy must invest huge amounts of money, which will lead to higher electricity bills paid by consumers. It will not be supported by public opinion, and it is unfair to the homeless and the bottom of society.

If abnormally high voltage cannot be managed effectively, the cost of the entire power system will increase and end users will also be affected. Maintaining safe voltage at the consumer end is very important to ensure that power generation at the consumer end will not be damaged, efficiency will not be affected, or even abandoned directly.

A recent study of power systems showed that abnormal increases in grid voltage have occurred in Asia, Europe and America. Consumers can also see such problems through monitoring equipment.

Australia is the worst country for abnormal voltage accidents. From 2008 to 2011, driven by Australia's subsidy policy, domestic distributed energy has achieved great development, infrastructure construction has been rapid, and the monthly installed capacity in 2018 is still being refreshed. Since Australia's voltage itself is higher than the international standard, there are many uninhabited areas in the country, and the distance between villages is long, the growth of distributed energy has brought huge challenges to the stability of the power grid system.

Recently, Australian retailer AGL tried to build a new virtual power plant, using energy storage around southern Australia. However, the project failed because the voltage was too high, which greatly affected the operating efficiency and made the virtual power plant unfeasible.

It can be seen that only when the power grid adapts to the transformation of distributed energy can consumers participate in the supply and consumption of energy in a low-cost manner and become providers of clean energy, thus becoming truly more competitive than large-scale centralized energy production models.

If it fails to adapt, the global power grid system will be impacted, which will affect all parties. This requires the installation of smart technology on the infrastructure to ensure that the quality of power supply is improved at the lowest cost and consumers are protected.

The grid needs to improve the efficiency of distributed energy in the present and future, so that these challenges can be transformed into opportunities. The overall efficiency of the grid system will be improved, and consumers will be able to better connect with the grid. In order to achieve these goals, the grid needs to control distributed energy while protecting consumers.

To achieve this goal, it is necessary to deploy cost-effective and intelligent technologies that can manage distributed energy in real time and ensure the safety of consumers. Regardless of the technical route taken, the voltage performance of the original power grid must be improved accordingly.

Professor Toshihisa Takizawa of Nagoya University pointed out that intelligent technology must be compatible with the power grid, reflect care for end users, and understand the laws of energy production. In this way, technology can accurately simulate and predict changes in supply and demand. This technical capability is very important for improving the control of distributed energy.

In short, in developed countries around the world, many people habitually think that the power grid is reliable and stable. However, as distributed energy accelerates in the next 10 years, voltage control and grid stability will be the biggest challenges. The solution is not to restrict the development of distributed energy. The focus should be on how to improve the control of voltage, further invest in related technologies, and avoid consumers from being affected by abnormally high voltage. And let consumers have confidence that their investment in energy is worthwhile and that operators have sufficient capabilities to ensure the stability, safety and reliability of energy supply.