Sustainable Energy

A reality check on renewablesFollowing in the footsteps of the late Sir David MacKay, this website provides updated figures and back-of-the-envelope calculations on the viability of achieving a fossil-free future.

If you're unfamiliar with David MacKay's work, do yourself a favor and watch his excellent TED talk. For a deeper dive, read his (free) book "Sustainable Energy - without the hot air". It brings great clarity to any discussion about renewables and the energy transition at large.

Why?

Basics

Energy Consumption vs. Land Area

How many kWh of energy does the average person in a given country consume per day? How many people live in one km² in that country? How has this changed over time?
Bubble size is proportional to land area. Numbers show the primary energy consumption (electricity, transport, heating). The actual energy consumption per country is higher because of the embodied energy of food and imported goods. Source: HYDE (2023); Gapminder (2022); UN WPP (2024); UN FAO (2024); U.S. Energy Information Administration (2023); Energy Institute - Statistical Review of World Energy (2024); Population based on various sources (2023) – with major processing by Our World in Data, CC BY

Surface Power Density

How much power does one unit area of land yield for each type of energy?
Numbers show the mean surface power densities of utility-scale energy systems in the US. With the exception of solar and wind, whose potential varies with geography, these numbers generalize to other countries (although some energy sources may not be available there). Source: van Zalk, Behrens - "A review and meta-analysis of power densities and their application in the U.S."

Energy Consumption vs. Renewables

What portion of primary energy consumption is covered by renewables for a given country? What portion of electricity demand is covered by renewables? How has this changed over time?
Biofuels are mostly used for transport. Geothermal consumption is estimated assuming 90% utilization of installed capacity. Source: Ember (2024); Energy Institute - Statistical Review of World Energy (2024); IRENA (2024) – with major processing by Our World in Data, CC BY

Required Land Area

If a country obtained all of its primary energy from renewables by 2050, what percentage of its land would be needed for that? How much more land is that in comparison to today?

2023
2050
Land area estimates are derived from the energy mix percentages of renewables and their respective mean surface power densities and may deviate from the actual land use in 2021-2023. Future primary energy consumption is estimated from the OPEC projection. Sources: OPEC World Oil Outlook 2050, UN World Population Prospects 2024World Bank, ESMAP, Solargis - Global Solar Atlas, CC BY, World Bank, ESMAP, Vortex - Global Wind Atlas, CC BY, van Zalk, Behrens - "A review and meta-analysis of power densities and their application in the U.S."  – with major processing by sustainable-energy.info, CC BY

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