Electricity Production – Power – Energy Gap

We have seen the carbon intensity of the various national electric grids in the previous post. India is one of the countries with a reasonable growth of renewables – 40% installed power of non-fossil fuel-based electricity – yet with one of the higher carbon intensities in the group with 632 gCO2/kWh. We use that example to explain the difference between power and energy.

Power vs Energy

Power, defined as W, kW, MW etc., is the capacity of the generator to deliver the electric energy. And energy is what is delivered by the machine to do work. For example, if a one MW system runs for one hour, it produces 1 MWh of energy. In other words, a 1 MW system delivers 8.76 GWh of energy a year if it works full-time (1 x 24 x 365). But, if the same generator works only 10% of the time, it produces 876 MWh.

Capacity factor

We have encountered it before. It is the actual amount of energy obtained (in MWh) in an average hour of the year if you install a one MW plant. You can get it by dividing the exact electricity output by the maximum possible.

Let’s look at India’s electricity production (excluding utility and captive Power).

And the installed power,

You can see the issue: the installed power from non-fossil-fuel-based electricity production is in the 40s, whereas the energy contribution is only in the 20s. The capacity factors are estimated by dividing the power with the corresponding energy for a 24-running generator.

Note the low capacity factor for the gas generators. It is not an inherent problem of gas turbines but is likely due to controlled production as a flexible means to manage the peak load requirements.

Reference

CO2 Emissions in 2022: IEA
Electricity production: Enerdata
Carbon Dioxide Emissions From Electricity: world-nuclear.org
Greenhouse gas emissions: Our World in Data
Electricity Mix: Our World in Data
Electricity sector in India: Wiki
Renewable energy in India: Wiki