Category Archives: solar

The Gradual Death of Coal

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The economic case for coal is collapsing.

The only bid for the right to mine 167 million tons of coal on US federal land came from a Navajo tribe-owned company that bid $186,000, i.e. 1/10 of 1 cent per ton of coal. As Bloomberg NEF founder Michael Liebreich put it: “You can’t give coal away in the US’s most productive coal region.”

Meanwhile in Russia’s coal heartland region, the Kuznetsk Basin in southwestern Siberia, which mines about 60% of all coal in Russia, most coal companies are losing money on every ton of coal they sell, as it costs them more to dig up and ship coal to a Far Eastern port than foreign buyers in China or elsewhere would pay them for that coal.

Coal is losing out not just to fossil gas but also to renewables like wind and solar (combined with battery storage). In many countries, solar is now the cheapest source of power, followed by onshore wind. According to International Energy Agency (IEA) data, in 2025 for the first time, more electricity (in TWh) was generated worldwide from renewables than from coal, which had dominated output for at least half a century. The falling cost of renewables has been a main factor.

The biggest growth in renewables has been in China and in low income countries in the global South. China installs more wind and solar capacity per year than the rest of the world combined. Pakistan installed 17 GWp in 2024 alone, with a peak output of roughly 1/3 of its existing conventional generating capacity. From January to September 2025, India installed a combined 34 GW of solar and wind. It is targeting 500 GW of non-fossil power by 2030.

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Harnessing the Power of Osmosis

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The city of Fukuoka in Kyushu, Japan has announced a project designed to produce electricity from osmosis, a process involving two liquids with different concentrations of dissolved substances (“Japanese Power Plant Turns Saltwater Into Electricity—and It’s a Glimpse Into the Future“, Gizmodo, 2025-08-26). Water will seep through a permeable membrane from the less salty to the more briny side, creating a pressure difference that can drive a turbine and a generator. Here is a PDF of the Fukuoka area waterworks agency that describes it in detail.

In the case of this plant, on one side it uses clean treated sewage water from a nearby sewage treatment plant. On the other side, it uses salty brines from a reverse osmosis plant that extracts freshwater from sea water using pressure created by electric pumps — the exact opposite process of the osmosis power plant.

The osmosis power plant has an output of 110 kW. Working 24 hours a day, 365 days a year and with a conversion efficiency of 91%, this yields 880,000 kWh per year. This is the typical annual power consumption of 290 households. Sounds impressive? Let’s compare it to an alternative.

Looking at the building on Google Maps, the roof area of that plant measures 100 m by 160 m, or 16,000 m2. Covered with standard solar panels (1.4m x 1m, 280 Wp per module), a rooftop solar setup at that location would, according to the National Renewable Energy Laboratory solar calculator, produce 3,450,000 kWh per year, enough for about 1200 households vs. the 290 quoted in this article.

And that is before you take into account the energy losses for pumping brine and reclaimed cleaned sewage water that the osmosis plant will require for operation.

What this demonstrates is just how extremely mature a technology solar power is by now. There are no moving parts, no filters to clean, no pipes to replace, etc. You just install it and harvest electricity, year after year after year, for 25 years and more.