Australian state government has approved the world's biggest single-tower solar thermal power plant, a _______ structure that is planned to be built in South Australia by the year 2020. Which capacity option correctly completes this statement?

Introduction / Context:
Australia has been investing heavily in renewable energy projects, especially large solar installations in sunny regions such as South Australia. This question tests knowledge of a famous announcement about the world's biggest single-tower solar thermal power plant, along with its planned power generation capacity measured in megawatts. Understanding such facts is useful for general awareness, competitive exams, and discussions on clean energy transitions.

Given Data / Assumptions:

• An Australian state government has approved the world's biggest single-tower solar thermal power plant.
• The plant will be built in South Australia by the year 2020.
• The missing information is the planned power capacity in megawatts.
• Available options are 150-megawatt, 200-megawatt, 250-megawatt, and 300-megawatt.

Concept / Approach:
To answer this type of current affairs and general knowledge question, candidates need to recall key figures related to major projects, especially when they are highlighted as record breaking or world leading. The project referred to in this question is the Aurora Solar Thermal Plant near Port Augusta in South Australia. Its planned capacity in the announcement was a specific megawatt value that became widely reported in the news. The correct strategy is to remember that value and match it to the options given in the problem.

Step-by-Step Solution:
Step 1: Recognise that the project described is the solar thermal power plant to be built in South Australia by around 2020. Step 2: Recall from current affairs that this plant was promoted as the world's biggest single-tower solar thermal facility at the time of approval. Step 3: The announced capacity for this project was 150 megawatts of power generation. Step 4: Among the options, match this remembered capacity value to the choice that states 150-megawatt. Step 5: Therefore, the correct completion of the sentence is that the structure is a 150-megawatt solar thermal power plant.

Verification / Alternative check:
A quick verification method is to think about realistic capacity ranges for large solar thermal power plants. While 200 or 300 megawatts might sound plausible, the project was specifically highlighted at 150 megawatts in many government and media reports. Remembering that it was a 150 megawatt plant that aimed to supply a significant fraction of South Australia's electricity demand confirms that the correct answer is 150-megawatt. This consistency with multiple sources of information supports the final choice.

Why Other Options Are Wrong:
The 200-megawatt option suggests a larger capacity than what was officially announced and does not match the known figure for this specific project. The 250-megawatt and 300-megawatt values are even higher and would make the project larger than what was approved. Since the question refers to the exact capacity used in the official description of this world leading plant, any number other than 150 megawatts is inaccurate in this context.

Common Pitfalls:
A common mistake is to assume that bigger numbers are automatically correct for record breaking projects, leading candidates to choose 200, 250, or 300 megawatts without recalling the exact figure. Another pitfall is mixing up different solar projects or confusing solar photovoltaic capacity with solar thermal capacity. Careless reading of similar questions in study material can also cause confusion if one does not memorise the precise number associated with the Aurora plant.

Final Answer:
The correct capacity of the approved single-tower solar thermal power plant in South Australia is 150-megawatt.