“The current status of the energy storage industry is much the same as that of the photovoltaic industry ten years ago”, is an opinion expressed by many professionals in energy storage. The reason why the PV industry is taken as a benchmark for the energy storage sector stems from the decline in costs and the speed of expansion over the past decade, which mirrors what is happening in the energy storage field. To achieve the goal of carbon neutrality, energy storage and new energy will need to serve as a combined solution to environmental and economic challenges and there is still some way to go in this regard.
At the same time, considering the high levels of common customers and channels across the two industries, an increasing number of PV companies have begun to launch energy storage products, from battery cells to integration services, and “PV+ESS” has become one of the key terms in the new energy field. According to statistics, almost all inverter manufacturers have introduced corresponding energy storage systems. In addition, leading module companies such as Trina Solar, Risen Energy, Jinko Solar and Canadian Solar have also launched their own energy storage solutions.
Energy storage has already become a term well-known by the public at large, presenting a potential platform for a significant number of ‘crossover’ providers, but can they really deliver when it counts? No final conclusion has yet been reached on this question. What does seem certain, however, is that it is not as simple as doing the mathematical calculation of 1 + 1 = 2 for a single PV power station to move towards PV+ESS integration. Instead, a synergy effect such as 1+1 > 2 is required during the integrated development process.
The “charm” of 1+1 > 2
According to Chen Sixiong, CEO of Kehua Data Co., an energy storage system is much more complicated than a PV system. “The photovoltaic system has only two ports, DC input and power grid. Relatively speaking, photovoltaic power supply only is unstable, but its power fluctuation is relatively controllable. However, a microgrid system with energy storage includes four ports: photovoltaic DC input, energy storage terminal, power grid and load terminal, among which there are three more volatile variables, demanding more complicated management of energy flows.
Due to its complexity, the same energy storage system may produce a drastically different effect. “There will be a significant difference between the actual result and the theoretical value for many energy storage or microgrid systems.” Chen takes a microgrid energy storage project on an island near the southeast coast of China as an example. The power supply mode of the island is complex, the power grid coverage is limited and it mainly relies on diesel generators for its power supply, thus problems such as tripping, power failure and unstable power supply often occur during the use of the original power system. Later, as one of the Golden Sun National Demonstration Projects, the island builds an off-grid solar system which, however, cannot achieve the expected goal due to its poor stability and efficiency.
At the end of 2019, in active response to the requirement of customers, Chen continues: “Kehua made a thorough investigation, taking into consideration the terrain there and climatic factors such as high humidity and high salinity and offered a customized microgrid ESS solution for the project, integrating the power supplies on the island into a system to form a suitable microgrid. This move completely solved customers’ problems. Stable power supply was guaranteed and, more importantly, annual on-grid power was increased by 37.1%, exceeding 1 million kWh for the first time.”
“Customer-orientation is the service tenet of Kehua, and every solution and technological innovation launched by the company will focus on solving a customer problem.Customerfeedback is that “Kehua solutions offer us practical assistance and will achieve everything they promise.”
Another case is the application of an oil well pumpjack power generation project. Previously, the project owner had always used a gas generator for power supply, but it fluctuated a great deal due to low POPM. A Fortune Global 500 company tried to optimize this project, but finally failed. Subsequently, backed by a strong technical platform, Kehua carried out in-depth research to fully understand the working characteristics of the gas generator and running characteristics of loads, solving problems encountered one by one and finally adopting multiple technological innovations to overcome the technical application difficulties of the microgrid ESS. These breakthroughs not only provided a stable power supply for the owner but also reduced a considerable electricity cost and wear and tear of the gas generator “.
Similar cases are numerous. Chen concluded: “Different from residential ESS, the microgrid system often has power above megawatt-level. With the increase of system scale, there will be system risks caused by problems such as IGBT damage.Without strong support from an experimental platform and sufficient accumulated experience, no organisation is able to respond to customer requirements for a rapid solution to engineering problems. Only powerful companies like Kehua, with significant accumulated power electronics technology and advantages of scale, have the strength to do this and do it well.”
Technology Accumulation in Power Electronics Field
Kehua has been working across energy storage inverters, energy storage systems and microgrid systems for more than 10 years, and has accumulated huge experience in power electronic technology over the 33 years of its existence, with countless application scenarios explored. Chen believes that, for Kehua, its biggest competitive advantage comes from two aspects. Firstly, the company attaches great importance to the continuous investment in products and technologies, which is the basis for innovation; secondly, the company’s internal management is scientific and rational. Regardless of the ever-changing market, Kehua is able to keep up with the pace of change from R&D to marketing, which is an absolute guarantee for long-term development.
Fundamentally, an energy storage system still relies on power electronics for energy exchange, which reveals a very important factor for inverter companies flooding into the energy storage field – technical homology. For Kehua, however, the technical homology merely lies in the accumulation of inverter technology.
It has so far been 33 years since KEHUA was founded in 1988 and the company has been ranked first in China for more than 20 years in two business sectors, those of uninterruptible power supply (UPS) and micro-module data centres. The two business sectors are also based on a power electronics technology background. “Both the inverter and the energy storage system are technically homologous to the UPS business and also classified as being in the power electronics field”. Based on decades of technological accumulation, Kehua’s current PV inverter has a cumulative installed capacity of over 18 GW around the globe, and is used in large-scale ground power stations, distributed power stations and PV composite projects.
In the microgrid field, the company’s energy storage systems have a cumulative installed capacity of over 1.1 GW around the globe, present in projects on the power generation, power grid and user side, and also microgrids. Project cases include:
- The highest substation energy storage project in the world – the Sanga and Zhongba 220kV Ali-Middle Tibet Plateau Power Grid Interconnection Project.
- The largest smart energy demonstration project in the world – Guangdong Power Grid DC Microgrid Smart Energy Demonstration Project.
- The first PV technology leader energy storage demonstration project in China – Shaanxi Tongchuan/Shanxi Changzhi PV Technology Leader Base Energy Storage Project.
- The SGCC’s first 100 MW grid-side distributed energy storage demonstration project – Henan Power Grid 100MW/100MWh Grid-Side Energy Storage Project.
- The first large-scale energy storage test demonstration project in the network domain approved by the National Energy Administration – Gansu 720 MWh Large-Scale Energy Storage Power Station.
Guided by the goal of carbon neutrality, Kehua is evolving toward “PV+ESS Solution Expert” status in the new energy field. The company considers energy storage as the development focus of its renewable energy business, making innovations in PV+ESS applications based on its technologies and implementing carbon neutrality in a scientific and efficient way.