The scientists analyzed how changes in the types of industries in Shanghai affect the amount of energy used. They found that improving how efficiently energy is used and changing the industrial structure helped reduce the overall energy needed. The decrease in energy usage for making things like equipment and goods (secondary industry) was the main reason for the drop in total energy use, but the energy use by businesses that provide services (tertiary industry) kept increasing. To lower the amount of energy used in future, it's crucial to focus on both developing the right types of industries and using energy more effectively.