Net Zero & the Grid

Electrify Everything

A quick look at the impact of switching away from fossil towards clean electrical energy.

In our last post, we talked in brief about the role of the electrical grid in the pursuit of a decarbonized future. According to the IEA, the path to Net Zero relies on "electricity .. [as].. the linchpin of the global energy system".

In this post we look at how electrification makes such a difference.

Electricity is more efficient

Electrification is the low hanging fruit of the energy transition. Devices that run on electrical power are far more energy-efficient than combustion devices. According to the US Dept of Energy¹, Electric vehicles convert over 77% of the electrical energy from the grid to power at the wheels. Conventional gasoline vehicles only convert about 12%-30% of the energy stored in gasoline to power at the wheels."

One of the biggest problems with combustion devices, whether in large fossil fuel generating stations or small units like internal combusion engines that drive gasoline cars, is the proportion of otherwise useful energy that ends in unrecoverable thermal loss. A large thermal power plant might have some potential for heat recovery if co-located with a district heating scheme, but as those power plants are typically located well away from urban areas, such use-cases are rare. Think about the impossibility of capturing the thermal emissions from a fleet of cars, buses, trucks.

The diagram below, drawing on IEA data², illustrates the scale of the problem globally — roughly 40–45% of all primary energy is lost as waste heat in electricity generation alone, almost entirely from fossil thermal plants. Switch to the efficiency tab to see how that loss compares end-to-end with an EV charged on clean electricity.

Where Does Global Energy Go? Input, Transformation & Useful Work

Global primary energy supply ~620 EJ (2023). Hover any block for detail. Switch tabs to compare fossil vs clean energy efficiency.

Energy Flow

Fossil vs Clean: Efficiency

Primary Energy Input

160 EJ

Coal

26%

190 EJ

Oil

31%

145 EJ

Natural Gas

23%

50 EJ

Wind & Solar

37 EJ

Hydro & Geo

26 EJ

Nuclear

37 EJ

Bioenergy & Other

~6%

→

Transformation

~250 EJ

Conversion Losses

Fossil thermal generation

lost as waste heat

~110 EJ

Electricity Generated

~29,900 TWh

~200 EJ

Direct Fossil Use

Transport, heat, industry

~30 EJ

Renewables Direct

heat pumps, solar thermal

→

Energy Services

~250–270 EJ

Rejected Energy

Waste heat from fossil power generation

~100 EJ

Useful Electricity

to homes, industry, transport

~80–100 EJ

Useful Direct Services

transport, heat, industry

~28 EJ

Useful Renewable Services

near-zero conversion loss

Of every 100 units of primary energy consumed globally, roughly 40–45 units are lost as waste heat in electricity generation alone — almost entirely from fossil fuel power plants. Electrification powered by renewables eliminates this loss at source. That is why an EV charged on clean electricity uses 3–4× less energy than a petrol car doing the same journey.

Fossil Fuel Power Generation

Input energy (coal / gas)100%

Electricity out of plant~35–40%

After transmission losses~33–37%

Wasted as heat~60–65%

ICE VEHICLE (petrol/diesel)

Fuel energy input100%

Reaches wheels~20–30%

Wasted as heat~70–80%

Clean Energy Generation & Use

Input energy (wind / solar)100%

Electricity out of plant~98–100%

After transmission losses~90–92%

Conversion loss<10%

EV (charged on clean electricity)

Electricity input100%

Reaches wheels~77–85%

Wasted as heat~15–23%

A petrol car wastes ~75% of its fuel as heat before the wheels turn. An EV charged on solar or wind wastes less than 20% end-to-end. This efficiency gap — not just lower emissions — is a primary economic driver of electrification. Fewer units of energy purchased means lower running costs, even before the fuel price difference.

Electricy is cleaner

In 2016, almost three quarters of GHG (Greenhouse Gas) emissions came from energy use³. Buildings, transportation and industry represented most of that load. As that energy was predominantly drawn from fossil-fuel devices, the argument for electrification is obvious.

Global GHG Emissions by Sector, 2016

Share of total GHG emissions (49.4 billion tonnes CO₂e). Click any sector to expand sub-categories. Hover segments for details.

100%

All sectors

Progress is underway in each of these segments. Carbon intensive devices are being replaced by attractive and economical electrified alternatives. The encouraging pace of development in heat pumps (HPs) and electric vehicles EVs offers the promise of widespread replacement of gas/oil/solid-fuel boilers and internal combustion engine (ICE) vehicles. A significant contribution to NZE occurs if the energy powering these devices comes from decarbonized sources.

Device electrification alone delivers meaningful carbon reductions. Say 1,000 EVs were charged with energy sourced from combined cycle gas generation units (arguably the least polluting of fossil fuels in use today). Compare this in aggregate with 1,000 ICEs doing the same mileage while burning gasoline.

Reduced engine idling alone delivers carbon reductions per mile travelled. Far superior energy conversion from a large efficient power station compared to 1,000 individual ICE engines boosts the equation further.

Nonetheless, it remains a carbon emitting (or Carbon Positive) transaction in aggregate (albeit comparably less polluting). The full impact of the transition from ICEs to EVs is only realized with a Decarbonized Grid. The same holds true with HPs.

✅

It's easy to grasp the allure of renewable energy - it's objectively more economical than legacy energy sources and has no emissions. However, there are real technical challenges in the transition to an energy system that progressively retires fossil fuels from our generating capacity.

Read about those challenges in our next post - Decarbonizing the Grid