Coal's future is safe but what about the climate?
Does coal have a future? Climate change protesters and coal traders alike say it's a daft question, but agreement ends there.
For protesters, the shiny black lumps of fossilised wood and plants are contributing to drastic climate change. For traders, coal is an energy no-brainer which offers a ray of hope for 1.6 billion people living without electricity.
They're probably both right.
By the mid-21st century, the world may have an extra three billion people and four times the wealth but somehow it must also at least halve carbon emissions from its main energy source - fossil fuels - to rein in dangerous global warming, scientists say.
Power generation accounts for about two-fifths of global emissions, from burning fossil fuels, of the main man-made greenhouse gas, carbon dioxide, and coal for most of that.
"You've got to say - Right, here's the line in the sand, we're going to stop it here because it's madness to continue," said Connor O'Brien, spokesman for protesters against a proposed new coal-fired power station in southern England, which would be Britain's first for nearly 30 years.
The Camp for Climate Action in Kingsnorth, Kent, has so far recruited about 600 people, organisers say, and joins four similar protests worldwide this year, targeting the coal industry in Australia, Germany and North America.
The Kent camp protesters aim to try and shut on Saturday the existing coal-fired power station which is slated for replacement, owned by the UK arm of German energy service provider E.ON.
Despite environmentalists' concerns, energy companies say they are racing to meet demand for coal, especially in developing countries where the fuel is cheap and plentiful even in a year where coal price rises have outstripped those of oil.
"It doesn't paint a very good picture of the future for carbon emissions but there is no other real choice - coal is one of the few fuel sources which has a real capacity to expand," said Francisco Blanch, head of global commodities research at Merrill Lynch.
Meanwhile, industrialised nations want to avoid over-dependence on imported, cleaner gas, given security of supply concerns. Ukraine is a case in point, now switching to domestic coal after neighbouring Russia halted gas supplies in a price dispute two years ago.
Dilemmas of choice, to balance competing benefits and tradeoffs, have left the world's energy future wide open.
Nuclear energy for example, is hemmed in by public opposition in much of the developed world, while developing countries may be geologically unstable, or else, like India, face a political leap to sign a non-proliferation treaty which grants access to imported uranium.
Wind farms are growing rapidly but grid connection poses an extra expense, while in poorer nations antiquated networks struggle to handle the volatile power source. Solar power is booming, but only provides a tiny fraction of all power.
In the US utilities are building 28 coal-fired plants and another 66 are in early planning, as gas price hikes motivate new interest.