Calculate the number of 10 MW solar plants needed to match Nigeria's 4,300 MW capacity and the useful output of a 1000 MW coal plant operating at 35% efficiency.

$$
\text{Number of Solar Plants} = \frac{\text{Total Capacity}}{\text{Capacity per Solar Plant}}
$$
$$
\text{Number of Solar Plants} = \frac{4,300 \text{ MW}}{10 \text{ MW}}
$$
$$
\text{Number of Solar Plants} = 430
$$
Nigeria would need **430** 10 MW solar plants to match this capacity.
$$
\boxed{\text{430 solar plants}}
$$

2. To calculate the useful output from a coal plant operating at 35% efficiency with a 1000 MW input:

$$
\text{Useful Output} = \text{Input Power} \times \text{Efficiency}
$$
$$
\text{Useful Output} = 1000 \text{ MW} \times 0.35
$$
$$
\text{Useful Output} = 350 \text{ MW}
$$
The useful output from the coal plant is **350 MW**.
$$
\boxed{\text{350 MW}}
$$

Section D: Critical Thinking

1. Nigeria's prioritization of gas or renewable energy for future development involves a trade-off. Natural gas offers a relatively cleaner fossil fuel option than coal, with established infrastructure and dispatchable power, which can provide immediate energy security and support industrial growth. However, it is still a finite fossil fuel contributing to climate change. Renewable energy offers long-term sustainability, reduced environmental impact, and energy independence, but requires significant initial investment, grid modernization, and solutions for intermittency. A balanced approach, leveraging gas as a transition fuel while aggressively investing in renewables, might be optimal for both short-term stability and long-term sustainability.

2. Energy security significantly affects economic growth in industrial nations by ensuring a reliable and affordable supply of energy, which is crucial for industrial operations, transportation, and daily life. When energy supplies are stable and prices predictable, businesses can plan investments, maintain production, and foster innovation. Conversely, energy insecurity—due to supply disruptions, price volatility, or over-reliance on external sources—can lead to increased operational costs, reduced competitiveness, inflation, and economic instability, hindering growth and development.