Sunday, March 16, 2014

Tech Talk - Of wood, coal, the UK and Bangladesh

Ice and snow have returned to the central part of Missouri, so the warm heat from the tile stove is again keeping us comfortable. For many folk, however, this is not an option and they rely on a centralized power station to supply the electricity that is a fundamental part of current Western life. Yet there are moves to use more wood, even there. In an earlier post I had written that Missouri S&T was switching from a coal:wood mix to a geothermal network which, with the use of natural gas, is expected to provide a net saving of about $1 million a year on the fuel bill. Price, while important to a university, is not, however, always the controlling factor when governments get involved.

The rising prices and obscurity of future government policy has stopped progress toward a wood-fired power station in Northumberland. A plan to replace coal with wood at Blyth has reached an impass, with RES ceasing work on the biofuel plant. The $500 million, 100 MW plant had been scheduled to come on line in about two-and-a-half years but has been stopped due to “ongoing uncertainty in UK energy policy.”

On the other hand the largest UK coal-fired power plant, at Drax in Yorkshire, is in process of changing from being a coal-based plant to one that burns wood. But not just any wood, for as David Rose notes the new fuel will be wood pellets, grown and processed in North Carolina and then shipped at an ultimate rate of 7 million tons a year to the UK. The current wholesale market price for power is around $83 per MW/hr relying heavily on coal, but the agreed price for the wood-powered electricity will rise to $174 per MW/hr, higher than that of either onshore wind or the new nuclear power coming on line. (Using $1.66 per English pound). Retail prices are somewhat higher.

Price may not be that critical in the UK, but it remains critical in poorer parts of the world, such as Bangladesh, where the nation needs to infuse power into a country that has, at the moment, only a single power plant. Yet this is not a move without criticism. A recent Op-Ed in the NYT, protested the intent of the government of Bangladesh to begin a program that will develop their coal reserves. The article comes after the government appointed a new minister for Power, Energy and Mineral Resource who has pledged a new coal policy “within the shortest possible time” and it is this (and the existing 2010 policy) which has irritated Joseph Allchin who wrote the opinion.

The major concern at present deals with the Rampal coal plant which will consume some 4.5 million tons of coal a year and generate 1,320 MW of electrical energy. The coal is presently anticipated to come from either Australia, South Africa or Indonesia and is intended to address the acute shortage of power in Bangladesh, with the government aiming to raise power generation from 5,000 MW in 2011, through 7,000 MW in 2013 to 22,000 MW by 2016, that being on its way to a capacity of 39,000 MW by 2030. By 2021 it is anticipated that 14 GW will be generated from coal-fired power, with domestic coal producing 6 GW, and imports powering 8 GW of capacity. The concern comes from the nearness of the coal-fired plant to the Sunderbans mangrove forest, and the threat which this poses. But given that millions of folk live within ten miles of coal-fired power plants around the world (the closest the plant will be) the dangers seem overhyped and unrealistic.

Figure 1. Relative location of the proposed power plant at Rampal and the Sunderbans (Yale)

A second power plant of similar size (1,200 MW) will be built at Matarbari although that will also rely on imported coal, at least initially (sourced from Indonesia, Mozambique, Australia or Canada) and
The government has also a plan to implement three mega coal-fired power plants at Moheshkhali each having capacity to generate 1200MW electricity under private sector or joint venture deals.
. Domestic coal production will require considerable growth in production, given that it was only at around 800,000 tons per year in 2011. The coal coming from the thick seams of the Barapukuria coal deposit has some 200 M tons of reserves, and is being won using longwall top caving, which simplistically involves undercutting the coal thickness with a shearer, and then allowing the overlying coal to fall into the mining opening.

Figure 2. Schematic showing the idea of Longwall top caving, there is a second conveyor at the back of the roof support to carry away the broken coal as it feeds down over the back of the support (University of Wollongong )

Bangladesh has struggled for years with less than half the country having access to electricity and with the rest of the population relying on biomass and waste to provide fuel for heating and cooking. But just to keep up with current demand it must increase natural gas supplies by 35% to overcome current shortages, and thus, to meet the demand for those without power they have chosen to go with the coal-fired option.

It will be interesting to see how the politics of this unfold, given the obvious benefits that will arise as more folk in Bangladesh are provided with electricity, with all the benefits that this entails, and which is being held up by those that one might have thought would have wished to see such progress.

In passing it might be noted that China approved an additional 15 coal mines with a total output of more than 100 million tons last year.

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