Hidroelektrik yenilenebilir bir kaynaktır ama petrol, kömür ve doğal gaz değil.
- Hydropower is a renewable resource, but oil, coal and natural gas are not.
Kömür ve doğal gaz doğal yakıtlardır.
- Coal and natural gas are natural fuels.
Natural-gas prices.
... natural gas. And the proof is our oil imports are down ...
... to the lowest levels in 20 years. Oil production is up, natural gas production is up, and, ...