Green power is electricity that is environmentally friendly. Generally refers to energy that never run out and non-toxic and it called in various name in renewable energy or clean energy such as biomass energy, geothermal energy, wind energy, solar energy, hydro energy, etc.
Solar thermal energy in general term is electricity generated by concentrates the light from the sun in focus to create heat, and then used heat is used for make electricity.
Direct Normal Irradiance (DNI) is the amount of solar radiation received per unit area by a surface that is held perpendicular. It is measured in (W/m²) or kilowatt-hours per square meter per day (kW•h/(m²•day)).
For solar thermal power plant in case when Direct Normal Irradiance (DNI) is less than 250 W/m2, it cannot be able to generate electricity - unless there is a built-in backup heat source such as heat storage system.
Other types of solar thermal power are limited by technical and return on investment. For example, Solar Tower can be limited by solar intensity because there is not sufficient in Thailand. Moreover, the intensive capital investment provides an un-feasible return on investment.
Parabolic trough power plants use a curved mirrored trough which reflects the direct solar radiation onto a glass tube containing a fluid (also called a receiver) and this system can track by GPS. The receiver may be enclosed in a glass vacuum chamber. The vacuum significantly reduces convective heat loss. A fluid (also called heat transfer fluid) passes through the receiver and becomes very hot then used heat transfer fluid in next step.
Common fluids are synthetic oil and water.
Under its long-term power development plant (PDP-10) and to reduce the investment burden of the government. According to the plan, it encouraged private sector investment in electricity generation. Under the power purchase agreeement from the Electricity Generating Authority of Thailand (EGAT) and Provincial Electricity Authority (PEA).

By having renewable energy, the government is not only fulfill its long-term plan, but also its burden in building sources of alternative electricity generation will be lessened, thus can further its investment in other required infrastructures.

Initial Environmental Examination is the public hearing for the preliminary environmental impact. Every solar power projects are required to be approved with IEE award considering the importance of community opinions.
"Carbon credits" is a Green House Effect gas that plant can be reduced. The amount will be revalued before selling and being credited to the developed countries which under the Agreement.

The Agreement is under the terms of the Kyoto Protocol that the developed countries (Annex1) to reduce emissions that cause global warming. In this way, they can buy "Emissions trading" or "carbon credits" from developing countries (Non-Annex1).