Germany and Japan and other developed countries have taken the lead in the use of solar energy. With the development of photovoltaic roof plans and photovoltaic building integration, the ratio of solar power generation in Germany and Japan to their total energy use will increase dramatically.

The rapid development of solar photovoltaic power generation in Germany and Japan is inseparable from the active guidance and incentive measures taken by the government. In Germany, two major incentives were used: First, high-priced acquisitions of residential solar power were imported into the main grid (0.53 euros/kWh), while residents used solar power at the same price as ordinary electricity (0.21 euros/kWh). It stimulated residents' consciousness of installing solar power generation equipment on their own roofs and patios. Second, loans were given priority, and loans were discounted by 3%. Residents were encouraged to purchase and install solar power generation equipment.

In order to encourage the use of solar power, Japan has adopted a similar subsidy method. The investment spent by residents on installation of solar power generation equipment is subsidized by the government by 50%. The electricity generated by solar energy is integrated into the power grid and acquired by the government at a high price; the price of residential electricity is lower than the purchase price. The incentives of the policy have greatly increased the enthusiasm of residents in using solar power. In the past year alone, Japan has installed 80,000 rooftops with new solar power equipment.