probablyasocialecologist:

Traditional electricity generation has a thermodynamics problem: Burning fuel to generate electricity creates waste heat that siphons off most of the energy. By the time electricity reaches your outlet, around two-thirds of the original energy has been lost in the process.

This is true only for “thermal generation” of electricity, which includes coal, natural gas, and nuclear power. Renewables like wind, solar, and hydroelectricity don’t need to convert heat into motion, so they don’t lose energy.

Through the ages, the most common way to make electricity has been through thermal generation, with the process beginning by generating heat. That heat is then used to boil water and make steam, which spins a turbine that generates an electric current. The fuel source can be coal, natural gas, or nuclear fission, but the process is similar – and very inefficient. The majority of the energy that goes into a thermal power plant is vented off as waste heat. Additional minor losses come from the energy used to operate the power plant itself.

In contemporary thermal power plants, 56% to 67% of the energy that goes into them is lost in conversion.

[…]

What about the efficiency of renewables? A wind turbine is around 35 to 47% efficient. But wait, isn’t that the same low efficiency as coal and gas power plants? Well, yes…and no.

Comparing renewable energy with fossil fuels isn’t an apples-to-apples comparison, because renewables don’t use fuel.

A coal plant with 32% efficiency still burns 100% of its coal. The impact of burning coal is based on how much coal is burned, not how much electricity is generated at the end of the process. But a wind turbine that converts 32% of the passing breeze into electricity isn’t consuming anything.