How to design clean energy subsidies that work – without wasting money on free riders

The planet is heating up as greenhouse gas emissions rise, contributing to extreme heat waves and once-unimaginable flooding. Yet despite the risks, countries’ policies are not on track to keep global warming in check.

The problem isn’t a lack of technology. The International Energy Agency recently released a detailed analysis of the clean energy technology needed to lower greenhouse gas emissions to net zero globally by 2050. What’s needed, the IEA says, is significant government support to boost solar and wind power, electric vehicles, heat pumps and a variety of other technologies for a rapid energy transition.

One politically popular tool for providing that government support is the subsidy. The U.S. government’s new Inflation Reduction Act is a multibillion-dollar example, packed with financial incentives to encourage people to buy electric vehicles, solar panels and more.

But just how big do governments’ clean energy subsidies need to be to meet their goals, and how long are they needed?

Our research points to three important answers for any government considering clean energy subsidies – and for citizens keeping an eye on their progress.

Why subsidize at all?

An obvious first question is: Why should governments subsidize clean energy at all?

The most direct answer is that clean energy helps to reduce harmful emissions – both of gases that cause local pollution and of those that warm the planet.

Reducing emissions helps to lower both public health costs and damage from climate change, which justifies government spending. Reports have estimated that the U.S. spends US$820 billion a year just on health costs associated with air pollution and climate change. Globally, the World Health Organization estimated that the costs reached $5.1 trillion in 2018. Taxing and regulating polluting industries can also cut emissions, but carrots are often more politically popular than sticks.