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Old King Coal is making a comeback, and the merry old soul is trying to clean up his act.

Last week, we had UK Energy Secretary Ed Miliband announcing a new generation of coal-burning power plants, with the replacement of Kingsnorth in Kent already established as an environmental battleground.

Why coal? Because it's plentiful, easy and relatively cheap.

Compared with nuclear, oil, gas and renewables, it has the benefit of being cheap, easy, secure, with stable supply, a less volatile price, fewer political downsides, and there's lots of it still under Britain.

But it's dirty. Very dirty.

The key to having coal as part of our electricity generating future is to capture the emissions and get them out of harm's way.

That's why CCS, or carbon capture and storage, is very popular with politicians.

The science makes a lot of sense, but it hasn't yet been proven commercially, and there's a lot riding on making sure that it does.

Ed Miliband said Kingsnorth and others getting planning permission will have to ensure at least 25% of its emissions are captured and stored, which has met criticism for lack of ambition.

The latest development is in Edinburgh this morning, with publication of research by academics and industry experts showing the North Sea may have the capacity to store all of Scotland's industrial carbon dioxide output for the next 200 years, then keeping them under (what we are told is) a safe cap of rock for the foreseeable future.

As First Minister Alex Salmond has been keen to stress at the publication, the capacity under Scottish waters is reckoned to be greater than the Netherlands, Germany and Denmark combined.

The research has been backed by the Scottish Government and Scottish Power, which is keen to see its Longannet coal-burning power plant in Fife as one of the pilot projects being funded by the UK Government.

In last week's Budget, Chancellor Alistair Darling announced there would be up to four such projects, and the one by the north bank of the Forth has the attraction of lots of emissions already ready to treat.

It also has easy access to the pipeline network that has brought oil onshore for the past few decades, and is now facing redundancy as the mature oil fields deplete.

The same network could take liquefied emissions out to the oil fields, to be pumped into deeply-buried porous sandstone filled with salt water, known as saline aquifers.

It's a mixed picture, though.

Only an eighth of the 80 saline aquifers studied have shown the rock is suitable for storage, and of those ten, there's a very wide range when calculating the potential - of between 4600 tonnes and 46,000 tonnes.

Of the 200 oil wells surveyed, only 29 were found to be suitable for storage.

Some have had sea water pumped in at high pressure to remove oil, and there are problems with using those.

The clever bit is if they can use the technology to boost oil production.

By pumping the liquid down, it should help displace the remaining oil from porous rock, improving the return on the North Sea's older fields and making CCS more financially attractive.

If all that works, Longannet would take six years before the pilot project could be pumping liquefied carbon dioxide.

And if that works, three or four storage and pumping hubs would have to be built along Britain's east coast, at a cost for each one with its pipeline network estimated between £700 million and £1.7 billion.

A whole lot more pipelines could bring liquefied carbon from continental Europe.

Norway is also interested in developing this technology, and is hosting an international conference on it later this month. Indeed, this is highly competitive stuff.

There are rich rewards for the companies and countries that get ahead in the race to make the science into engineering and technology and then show it can be commercial.

The recent Scottish Council for Development and Industry, (SCDI)/ Wood Mackenzie research report into Scotland's energy future estimated the replacement of Longannet could be £2.2 billion, with the cost of fitting on a CCS plant at £2 billion.

SCDI reckons there are around 50,000 coal-burning plants around the world, with China in recent years opening them at a rate of roughly one every week, so fitting scrubbers to all or even most of them is going to mean a lot of manufacturing.

Fast-developing economies including China, India, South Africa and in South America are relying on coal to plug the large shortfalls in power supply.

And in the United States, coal remains very important to keeping the lights on.

The recent stimulus package from the administration in Washington DC includes a whopping $777 million (£522m) for low carbon energy research.

The Advanced Research Projects Agency for Energy is being set up on the model used for the USA's efforts in the 1950's space race.

The European Union's stimulus package has also earmarked £340 million for clean energy, with an emphasis on avoiding over-reliance on Russian fossil fuels.

Polish coal-burners are keen to get their hands on that money from Brussels, with the biggest polluting plants on the continent and today seeing an important new step in Europe's polluters being brought into the carbon trading system, meaning the economic incentives to avoid emissions are getting ramped up.

The race to capture carbon is on.