Solar has crossed a more interesting line than the one usually celebrated in release-day graphs. In 2025, it soaked up the bulk of the world’s extra electricity appetite. Ember’s Global Electricity Review 2026 says solar output rose by 336 terawatt-hours that year, up 40%, and covered roughly three quarters of net demand growth. Solar and wind together were close to the whole story.
I think that changes the game more than any tidy share-of-generation chart ever will. A technology does not need to dominate the existing stock of power plants to matter. It only needs to be the place new demand keeps landing. Once that happens, the next unit of electricity, contract, factory, and grid upgrade all start to bend around the same source. That is where solar now sits.
What Ember’s numbers actually say
Solar has become the first answer to new demand
The simplest reading of Ember’s 2025 data is brutal for the old order. When the world needed more power, solar supplied most of it. A 336 TWh jump in a single year is not decorative growth. It represents a very large slice of the entire global electricity system moving in one direction at once. The 40% increase makes the point hard to ignore. This was not a gentle drift.
Total share and marginal share are different beasts
I keep seeing people confuse solar’s overall footprint with its role at the edge of the system. These are not the same thing. Coal, gas, hydro and nuclear still account for the bulk of generation already online. Solar’s share of total electricity remains much smaller than its share of new demand. That distinction matters because markets do not care only about what is biggest. They care about what is being chosen next. Ember’s numbers say solar and wind met almost all of 2025’s demand growth. That is a stronger statement than “renewables are rising”. It says the growth market has already changed hands.
The old system is still huge, which is why this is subtle
The fossil and nuclear fleets did not vanish in 2025. They did not have to. Their size is the reason the shift is easy to underestimate. Old capacity can remain enormous while new investment quietly moves elsewhere. This is how structural change often looks before everyone admits it. The future arrives first as a bias in the next project finance decision.
Why solar keeps winning the next project
Speed and price beat grand promises
Solar wins new demand for dull reasons, which is usually how real transitions happen. It is fast to build, modular, and cheap enough to beat most alternatives on cost per unit of electricity in many markets. The International Energy Agency has said utility-scale solar has fallen by more than 80% in cost since 2010, and it remains the cheapest new generation option in most countries. That sort of number rearranges boardrooms. A gas plant can still look elegant on paper. Solar usually looks cheaper, quicker and less politically awkward.
Developers like projects that do not take years to become real
A solar farm can move from announcement to production far faster than a large thermal plant or a nuclear project. That matters in a world where demand is rising now, not in 2034. Utilities, governments and corporate buyers all prefer the thing that can be built before the political mood changes or the financing window closes. Solar is not winning because it is perfect. It is winning because it is available.
The result is a new default for capital
Once solar becomes the first viable option for incremental demand, money starts treating it as the base case instead of the niche case. That shifts the centre of gravity toward panels, inverters, land, interconnection, batteries and grid equipment. It also makes coal and gas expansion harder to justify unless the system is badly distorted or the political incentives are perverse. Some places will still choose gas for reliability. Fine. But the global default has changed, and defaults are where capital gets lazy.
What gets squeezed by the new pattern
Coal and gas lose the easy growth story
Power-sector coal demand now faces a ceiling that is harder to wish away each year. Gas still has a role, especially where grids are weak or flexibility is scarce, but solar makes daytime gas generation less valuable in markets with decent solar penetration. That means lower running hours and weaker economics for plants that were built to chase load growth. The problem is not immediate extinction. The problem is utilisation. A plant that runs less is a worse asset.
Copper, silver and batteries get pulled in the other direction
The winners are not only developers and utilities. They include the suppliers of the materials that make solar and storage possible. Copper demand rises with panels, cables and grids. The IEA has projected roughly a 50% rise in copper demand for clean energy and transmission by 2030. Silver remains embedded in photovoltaic cells. Battery metals such as lithium, nickel, cobalt and graphite get dragged in by the need to shift solar power from midday to evening. The commodity map is being redrawn by a technology that turns sunlight into balance-sheet pressure.
China sits in the strongest seat on the board
China’s manufacturing dominance in solar is still one of the most consequential facts in the sector. The IEA has said it controlled more than 80% of global manufacturing capacity across polysilicon, wafers, cells and modules in 2023. That is not a footnote. It is leverage. Whoever owns the supply chain for the technology that fills the world’s new demand gets to collect rents, shape prices and absorb scale advantages that rivals will struggle to match. The United States, Europe and India all know this, which is why they are trying to build domestic capacity. They are late, but not absurdly late.
Why the hour of the day now matters
Midday power gets cheaper, evenings get nastier
Solar changes the value of electricity across the day. Around noon, when output is abundant, wholesale prices get pushed down. In places with strong solar penetration, they can drop to zero or below. California knows this pattern well. Australia does too. Then the sun goes down and the grid needs a fast answer. That evening ramp is where flexibility earns its keep. Batteries, demand response and quick-ramping hydro or gas become more valuable even if they run less overall.
Storage is no longer a nice extra
If solar keeps dominating new supply, storage stops being an accessory and becomes a business model in its own right. Charge when power is cheap. Sell when the evening price spikes. That arbitrage is not a side show. It is the bridge that lets solar own more of the day. The same logic lifts transmission investment, because electrons are less useful when they are trapped in the wrong place at the wrong hour.
The open question is not whether solar will keep growing
The real question is whether grids, storage and market rules can catch up without turning the whole system into a mess of bottlenecks and perverse prices. Solar has already won the marginal contest. The next fight is over who gets paid to make that victory livable.