Electrical Energy Generated in a Power Station

Electricity, a form of energy now indispensable in our daily lives, is generated in large-scale atomic, thermal or hydroelectric power stations and transmitted along power lines to our individual homes.
"Energy Saving" measures usually relate to reducing the amount of the electrical energy transmitted by these power lines that we use, or using it more efficiently. However, there are few opportunities to consider the energy inputted to create this electrical energy.
If you focus on this point, the efficiency of fuel cells should become apparent.

Energy Consumption in a Power Station

In, for example, a thermoelectric power station, electricity is produced by burning fuel (natural gas or oil) to create steam, which turns the turbines used for power generation. The electrical energy generated is then transmitted to users via power lines as electricity.

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The power station and your home are connected by power lines.
The power station generates electricity by burning fuel to turn turbines.
Exhaust heat, given off during generation, and transmission loss occur.
Not all of the energy inputted at the power station can be used in the home.

Of the energy inputted to generate electricity (the primary energy), exhaust heat at the power station accounts for some 60%, and transmission loss of several percent arises in the power lines between the power station and your home or in the power station itself.
In this case, for each 10kWh of energy needed in the home, some 28.6kWh of energy needs to be inputted at the power station.

The Efficiency of the Cogeneration System

Recently, consideration has been made of using exhaust heat from incineration plants to heat swimming pools, and using exhaust heat from transformer substations.
It would be best if exhaust heat emitted during the generation process from large-scale power stations could also be converted to thermal energy for heating or hot water, etc, using the inputted energy more efficiently. However, due to considerations of the conditions for locating large-scale power stations, this would involve sending hot water (thermal energy) from a far-removed location by pipeline, etc, and this is not considered practical.

In this connection, cogeneration systems⁽¹⁾ have become the focus of attention in that they carry out generation at the location where electricity is needed and use the exhaust heat that is emitted for room heating or to heat water.
For example, even if the efficiency of electricity generation is around 30%, if the efficiency in using exhaust heat is around 40%, 70% of the primary energy, inputted as fuel, can be used effectively, fuel efficiency is high and the generator can be used as an energy-saving system.