Mega-what? Simplifying the size of renewables

In January 2023, an article suggested India’s corporate sector could deploy an extra 45 gigawatts (GW) of renewable energy by 2027.

And some of you might be like…

So we went ahead and worked out…

  • what 45 GW means and…
  • how it fits alongside other forms of energy

The Newton: Force

Let’s begin with the Newton, which measures force.

1 Newton is the force required to make a mass of 1 kilogram accelerate at a rate of one metre per second squared.

Is it also the force of Earth’s gravity applied to a mass of something weighing about 102 grams.

So if a 102 gram object (like an apple) sits on a flat surface, it is applying 1 Newton of force.

The joule: Work

A Joule is the amount of energy transferred to an object when a force of 1 Newton is applied to it over a distance of 1 metre.

In the graphic below, the 102g apple is lifted 1 metre. By doing so, 1 Joule of energy is used.

You can also think of a Joule as work.

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The watt: POWER

A Watt is a measure of power and is equal to 1 Joule being transferred per second.

In the graphic below, two apples are lifted. In each case, it spends 1 Joule of energy.

However, the hand on the left lifts the apple in 1 second. The apple on the right is lifted in half the time, 0.5 seconds.

Because 1 Joule is used over 1 second, we can tell that 1 Watt of power is generated.

Because the apple on the right is lifted in half the time, it generates twice as many Watts as the apple on the left.

bulb to Bhadla

To put the size of watts into context, we can begin with common items from the household.

We encounter watts in everyday life. For example, on lightbulbs, on our laptops and on other household appliances.

Global per capita energy consumption averages 2,500 watts, or 2.5 kilowatts (kW). This figure is higher in high-consuming, advanced economies such as the United States.

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As we move to larger sizes, we can see that 100 kilowatts would power many homes.

2500 kilowatts, or 2.5 megawatts (MW), is the capacity of an average onshore wind turbine.

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Offshore wind turbines are even larger, with one of the largest pushing 15 MW. A medium sized solar farm, like Limondale in Australia, is around 300 MW.

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Limondale is dwarfed by India’s Bhadla Solar Park, which has a capacity of 2,700 MW, or 2.7 gigawatts (GW). This is roughly the same capacity as many large fossil-fuel plants.

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The nameplate capacity of Palo Verde Nuclear Plant, the largest in the United States, is 3,937 MW. Yet this size appears tiny when viewed alongside humanity’s total power requirements.

Our future energy needs will increase due to three factors. These are population growth, an increase in standards of living across emerging economies, and greater electrification.

Electrification means switching to electricity as an input and moving away from incumbent fuels. For example, a car with a typical combustion engine can be switched for an electric vehicle. As clean energy is generated in the form of electricity, a switch to electric is often part of sectoral efforts to decarbonize.

Wedged between Palo Verde and India’s 2030 renewable energy target is the figure from the top of the page—45 GW.

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To this point, the graphics above have displayed one type of unit for energy—the watt. Using watts to measure energy assumes the facility generating it was operating at full capacity in ideal conditions.

To account for electricity being made and used irregularly, the kilowatt-hour is used.


A watt-hour (Wh) is a unit of energy that equates to 1 Watt of power sustained for 1 hour.

The kilowatt-hour (kWh) is more often used in practical settings. The formula remains the same: one kilowatt of power sustained for one hour is one kilowatt-hour.

The two animations below demonstrate how a watt-hour works.

In the first animation, a 10 watt energy source delivers power to a battery over an hour. This equals 10 watt-hours.

In the second, the same 10 watt energy source delivers power to a battery over two hours. This equals 5 watt-hours.

You could exchange watts for kilowatts and the formula would remain the same. A 10 kilowatt energy source delivering power over two hours would equate to 5 kilowatt-hours.

ItemGeneration (kWh)
5 hours of direct sunlight on a 300 watt solar panel1.5
Energy required to cool a refrigerator for 3 months1,000
Per capita energy consumption (India)7,000
Per capita energy consumption (USA)76,500
Enough energy to power around 250,000 homes1,000,000
IEA Net Zero Scenario: Renewable energy generation in 205064,500,000,000,000
IEA Net Zero Scenario: Total energy generation in 205073,000,000,000,000

A final word

This post has clarified what is a watt and the ways to explain the different scales of power. The article at the top of the page suggested India could add 45 GW of renewables in the corporate sector by 2027.

India’s current total installed capacity of electricity is over 400 GW. It is aiming for 500 GW of installed renewable energy by 2030. So, the extra 45 GW would be a welcome addition towards that target.

If the world is to meet the goals of the Paris Agreement, it must achieve net zero emissions by mid-century. A key part of this is building new renewable energy assets at a scale well beyond India’s domestic target.

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