Final answer:
Domestic hot water can be heated more efficiently using natural gas at home, with an 85% efficiency, compared to using electricity generated by gas at a power plant, which is collectively less efficient at 38%. It would take 2.2 times more fuel at the power plant to produce the same heating effect.
Step-by-step explanation:
When calculating the energy efficiency of domestic hot water systems using natural gas versus electricity generated from natural gas, several factors are in play. A natural gas hot water heater has around an 85% efficiency at converting the energy into hot water. Meanwhile, electric hot water heaters can achieve nearly 100% delivered energy efficiency.
However, if the electricity is generated from a natural gas power plant which has a 40% efficiency at producing electricity, and there is a 95% transmission efficiency, the combined efficiency becomes 40% times 95%, which totals to 38% efficiency. Comparing the two systems, natural gas at home has a much higher efficiency than using electric heating powered by a gas plant.
To match the direct use of natural gas for heating water, the gas power plant would need to use approximately 2.2 times more fuel. It's important also to consider the source of electricity for your area when determining the most efficient and cost-effective method of heating water. As efficiency translates to energy and cost savings, understanding the local energy mix and technology such as heat pumps may offer additional efficiency that can counteract some of the wastage inherent in the production of electricity.