By Anders Lorenzen

As the UK and much of Europe prepare to move clocks forward for British Summer Time on Sunday, the twice-yearly ritual raises a familiar question with a modern twist: in an energy system increasingly powered by renewables, does daylight saving time (DST) still serve a purpose?

A policy designed for a different energy world

Daylight saving time was introduced to make better use of daylight hours, dating back to the birth of agriculture and at a time when artificial lighting was scarce. That logic made sense in an era where the majority of jobs were seasonal and depended on optimising natural light, and electricity was only just evolving, and artificial lighting was derived from burning whale oil.

But today’s energy systems look very different.

Heating, cooling, digital infrastructure and appliances now dominate electricity consumption. At the same time, solar and wind power are reshaping when and how electricity is generated—raising questions about whether shifting the clock still aligns with how energy is actually used.

A brief history of DST

The idea of daylight saving is nothing new, and it is only in fairly recent modern times that the majority of societies have followed a set 24 hour clock. Ancient civilisations modelled its socities based on the position of the sun.

In modern civilisation, the idea of daylight saving was first coined in 1810 and was adopted by different countries between 1906 and 1918.

Where DST still applies—and where it doesn’t

DST remains widely observed, but far from universal:

• Clocks move forward this weekend across most of Europe, including the UK under British Summer Time (BST), as well as parts of North America
• Partial adoption continues in countries such as Australia and some regions of South America
• No clock changes in most of Asia, Africa and parts of the Middle East

This patchwork reflects not only geography, but growing uncertainty about whether DST delivers meaningful benefits.

The energy question: shifting demand, not cutting it?

The central argument for DST has long been energy savings. More daylight in the evening, the thinking goes, means less need for artificial lighting.

However, the reality appears more nuanced.

• Lighting savings still exist, but they are smaller than in the past
• Morning energy use can increase, particularly in colder climates where darker mornings raise heating demand
• Cooling demand may rise in warmer regions, where longer evenings extend air conditioning use

Rather than significantly reducing overall consumption, DST often reshapes when energy is used, shifting demand peaks rather than eliminating them.

Regardless of the various benefits or disadvantages from moving to summer time, the reverse is the case when moving back to winter time, such asdarker afternoons means that children can do less outdoor activities and indoor activities such as watching TV, streaming, gaming and even putting the kettle on significantly increasing energy demand and usage.

Additionally, heating and artificial lighting will have to be switched on sooner at workplaces and transport.

Therefore, the real question appears to be what is the sweet spot? If one were to abolish DST, what would be used as the permanent time setting throughout the year, winter or summer time?

Renewables change the equation

The rapid expansion of solar power is adding a new dimension to the debate.

Solar generation peaks during daylight hours—particularly in the early afternoon. By extending evening daylight, DST can in some cases better align human activity with solar output, potentially reducing strain on electricity systems during peak periods.

But this effect is highly context-dependent.

• In solar-heavy systems, DST may slightly ease evening demand peaks
• In regions reliant on heating, benefits can be offset by higher morning energy use
• In winter-heavy climates like the UK, the overall impact remains limited

In other words, DST may interact with clean energy systems—but it is not a decisive factor in their efficiency.

Emissions impact: marginal at best

From a climate perspective, the evidence remains mixed.

Some studies suggest small reductions in peak electricity demand, which could lower reliance on fossil fuel generation at critical times. Others find that these gains are largely cancelled out by increased heating or cooling needs.

The broader consensus is that DST alone delivers only marginal emissions reductions, especially compared with structural changes such as renewable deployment, electrification and energy efficiency improvements.

Political action is stalling

The question of whether to keep or scrap DST remains unresolved in many regions.

• The European Union has previously backed ending seasonal clock changes, but implementation has stalled amid disagreements between member states
• In the US, the issue periodically resurfaces, with proposals to adopt permanent DST or standard time
• The UK has so far maintained the status quo, though the debate continues

What was once a technical adjustment has increasingly become a political and societal question—balancing energy, health, and economic considerations.

A symbolic shift in a changing energy system

As clocks move forward this weekend, DST highlights a broader transition.

Energy debates are no longer centred on saving a few kilowatt-hours of lighting. Instead, they focus on how entire systems—from grids to buildings to daily routines—adapt to a low-carbon future.

Against that backdrop, daylight saving time looks less like a climate solution and more like a legacy policy—one that may still offer small benefits, but is no longer central to the energy transition.

Not a game-changer either way

DST is unlikely to significantly reduce emissions or energy use in today’s world. At best, it fine-tunes the timing of demand.

But its persistence tells a deeper story: even as energy systems transform rapidly, some long-standing policies remain in place—not because they are highly effective, but because replacing them is more complex than keeping them.

And so, twice a year, the clocks change—and the debate continues.

Anders Lorenzen is the founding Editor of A greener life, a greener world.