evidence: The key policies include: Decision No. 2068/QD-TTg dated 25 November 2015 provides the following incentives: zero import duty for assets to form the fixed assets of a renewable energy project, and for materials and semi products which are unavailable in the domestic markets; corporate income tax exemption or reduction; land rental exemption or reduction; and government funding for research and technology of pilot projects. Decision No. 11/2017/QD-TTg dated 4 November 2017, as amended by Decision No. 02/2019/QD-TTg dated 8 January 2019, also provides incentives for solar energy projects, which are entitled to an import duty exemption for: goods imported to form the fixed assets of the projects; and materials, semi-products and fuel that are not available locally. Circular No. 02/2019/TT-BCT introduces notable changes to the regulations on wind power projects and the mandatory terms of wind power purchase agreements. Renewable energy projects rely on a number of legal contracts. One central contract is the power purchase agreement (PPA), which governs the sale and purchase of power: See also Key Features of Power Purchase Agreements. Other important contracts include land use agreements, supply agreements, installation agreements, O&M agreements and implementation agreements.