Battery energy storage is critical to the future grid, but it also has its limitations

MIT’s recent research stated that battery energy storage systems will play a key role in the grid in the future, but it still believes that the deployment of battery energy storage systems will also be affected by some power systems in which intermittent renewable energy dominates. limit. John Reilly, co-director of the Massachusetts Institute of Technology's Global Change Science and Policy Joint Program, explained the reason for this. The battery energy storage system is a combination of complex factors such as energy storage capacity, continuous discharge time, and cost. The battery energy storage system can store the electrical energy supplied by the solar power generation facility to meet the peak power demand at night. This is an ideal use mode for battery energy storage systems, especially in sunny places near the equator. Since the power demand during the day may be low, the power supply of the solar + energy storage project is predictable, which is not in line with the usage trend at night. In addition, its electricity supply throughout the year is balanced: enough energy storage capacity must be supplied from noon to meet the peak demand at night. In fact, the modeling of the battery energy storage system takes into account the installation cost, energy storage capacity, continuous discharge time, etc., which are the key factors for the deployment of the energy storage system. This energy storage technology can be a battery energy storage system, pumped storage or any energy storage system that meets its specifications. Pumped storage facilities can be used to save more costs because it is the lowest cost option today. No matter which energy storage method is used, cost must be considered. And its cost tends to add more capacity and longer energy storage time. But the problem is that almost no place in the United States is in this ideal state. Of course, the deserts of California and the southwestern United States are close to this ideal state, but even there, the winter days are shorter, the angle of sunlight is lower and the clouds continue to be cloudy. Therefore, take a TeslaPowerwall battery energy storage system user in Maine that has installed solar power generation facilities and an energy storage capacity of 12kWh on a housing project as an example. Its annual output is 10% to 15% lower than expected. Its battery energy storage system also faces the problem of uneven energy storage. In late spring or summer, the monthly power generation is 1.2 to 1.3 MWh, but only less than 0.1 MWh in January and February. This is due to the large roof. Part of the time was overturned by snow (as shown in the picture below). Residential solar power generation facilities and battery energy storage system users generate electricity each month (blue is solar energy, green is energy storage system) even though there are 31 days of sunny days in a month, but due to the shorter daylight hours and the different angles of sunlight Low, the best monthly electricity that can be generated in winter is about 0.5MWh. In winter, users use 1.3MWh of electricity every month. The user sets the Powerwall energy storage system to self-powered mode and hardly uses electricity from the grid in summer. This user's residential solar + energy storage system has a maximum annual generating capacity of 1.9MWh. If enough Powerwalls energy storage systems are to be installed to store the extra electrical energy processed in the summer, then 160 energy storage systems will be installed. If the price of each energy storage system is US$12,000, these investments will be close to US$2 million, which is impossible for home users. In order to better store energy, battery costs will have to be greatly reduced. The use of battery energy storage systems can prevent power outages for users because they can obtain federal tax credits, making battery energy storage systems more competitive with fossil fuel power generation facilities. Solar power generation facilities connected to the grid are still a good choice for users. It is estimated that their internal rate of return is between 4% and 6%, depending on whether the solar power generation facilities can be used for 25 years or 10 years. To be sure, Maine in the southwest desert region of the United States may be the other extreme. The grid-scale energy storage system has economies of scale, which is impossible to achieve through a small residential energy storage system. This is why when MIT constructs a model, it must carefully consider the hours of the day and the reasons for the real changes in demand and supply patterns in each season, and consider the needs of different renewable energy patterns and geographic patterns to connect to the grid. The supply is more reasonable. The cost of grid scale. The Massachusetts Institute of Technology pointed out in a study that if reliable, low-carbon, and dispatchable power generation methods are adopted, and the cost is reasonable, the cost of power decarbonization will be lower.