At this month's global climate conference, China, the world's biggest polluter, rejected a collective pledge for the world to triple renewable energy capacity by 2030.

But it's likely to achieve the target at home anyway, even though its renewables generation is already high for a developing country. Indeed, it may be reaching peak carbon-dioxide emissions right now.

And yet China has just thrown itself into a surge of construction of coal-fired power stations.

How to make sense of all this?

The likely answer is that China's leaders see even more reasons for shifting to renewables than politicians elsewhere do, but they don't like to pin themselves down with international promises. And they're building those coal stations mainly as standbys, for use when drought throttles hydro generation.

China produced 31 per cent of its electricity with renewable sources last year, equalling Australia's ratio and beating the US's 22 per cent by far, according to energy research company Enerdata.

A lot of China's renewable energy comes from water turbines - for example, the generators in the enormous Three Gorges Dam. But by the standards of developing countries, China is still doing well with solar and wind.

It got about 14 per cent of its electricity from those sources last year, almost catching up with the US's 15 per cent. It's well ahead of most developing countries in that field, though Australia is at 23 per cent and Germany 33 per cent.

China is building solar and wind capacity so fast that, even before this month's COP28 climate conference in Dubai, it was on track to triple its renewables generation by 2030, estimate analysts at BloombergNEF, another research organisation. European countries, the US and Japan so far don't look like they'll triple by 2030, though they did sign the conference pledge declaring that the world should (and, implicitly, that they would).

China has promised to reach peak carbon-dioxide emissions by around 2030, but analysts expect it to get there sooner. It may indeed have peaked this year.

So don't read too much into its refusal to sign up to the pledge. The country is not big on international accountability and probably hasn't completed its internal forecasts for 2030. Further, the pledge also called for an end to building coal-fired plants, whereas China is ramping up their construction.

It is an extremely selfish country, but its leaders are scientific in their outlook and can see as well as anyone that action is needed to avoid a global catastrophe, which would also be a catastrophe for China. They should have acted earlier and more strongly, but the same can be said, to varying degrees, for all countries.

They have had domestic reasons for foot-dragging - economic disruption, poverty in much of their country, and, formerly, the high cost of renewable energy.

But they don't have to worry about democracy. In particular, they're not held back by having many voters who browse the web for evidence of what they want to believe, that humanity isn't causing climate change.

China's leaders also try to direct their economy into what they reckon will be industries of the future, usually taking their cue from what's happening elsewhere, especially in the US. Renewable energy is the future, and China is good at manufacturing, so of course the government has promoted the making and local use of the solar panels and wind turbines. Now the country dominates global markets for them.

Its competitiveness in that field has been a boon to the world. The cheaper the equipment, the faster its global installation.

And the Chinese government knows that supply of domestically produced energy cannot be blockaded by the US Navy nor cut off by Russia. So they have a powerful strategic reason for pursuing renewables to replace oil and gas as well as coal.

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That also helps explain China's drive into making electric vehicles, which is another industry of the future and another area in which the country's manufacturing strengths are really helpful. In the past year, we've suddenly noticed that Chinese electric vehicles have become highly competitive, putting great and useful pressure on Western, Japanese and South Korean automobile makers.

Construction of coal-burning electricity stations is not an industry of the future. But in the middle of last year China began authorising new coal-fired generators left, right and centre. In the first half of this year, it started building plants with a combined capacity of 37 gigawatts while authorising another 52 gigawatts. Australia's most powerful electricity station, Eraring in the Hunter region, has a capacity of 2.9 gigawatts.

Note the timing. In the middle of last year China was suffering its worst heat wave since records began in 1961. Dam levels dropped and hydro generation had to be curtailed. Blackouts rolled across the country and factories suspended production.

Well, there's no way the Chinese Communist Party will put up with that again, which is obviously why those coal-fired power stations are being built.

Never mind. They won't be used much. Renewable energy is now so cheap that they'll be uneconomic from the day they're opened, and they'll fall further behind as production engineers in solar-panel, wind-turbine and battery factories work out ever-cheaper manufacturing processes.

China's leaders know all that, so we can be sure that the new coal plants are seen mainly as standbys for use in droughts or occasional transmission failures, and maybe to firm up supply if the sun isn't shining, the wind isn't blowing and local battery capacity is running low.

No doubt the coal projects are also supporting employment amid economic weakness. And they'll need to employ operators, who will presumably spend a lot of time playing mahjong.