Showing posts with label London. Show all posts
Showing posts with label London. Show all posts

Friday, April 22, 2011

Drought, renewable energy, Texas, London and Florida

The Governor of Texas has asked the denizens of the state to pray for rain. The state has not had serious rain for months, and the drought conditions have turned severe.

The current drought conditions in Texas.

Conditions are not anticipated to get any better in the next few months. The recent predictions are that the conditions will persist in the area through July.

Predictions of the weather changes through July (NOAA )

Droughts around the world are one of the unfortunate consequences of changing weather, in much the same way as we have seen high snowfalls in other parts of the country this past winter. There will likely be cries about the underlying causes (with folks forgetting that droughts have occurred throughout history), but this post was started because of a potential event-changing occurrence.

This week Thames Water, which supplies 687 million gallons of water a day to the inhabitants of London and the immediate vicinity, was running its first water desalination plant. The region has faced droughts in the recent past as have other regions of the United Kingdom. Earlier solutions included building large water reservoirs, that at Kielder is the largest man-made reservoir in Europe. There is, however, only a certain limited amount of land that can be made available for this use, and so desalination proves an alternate way of supplying the increasing global demand for water.

In the United States droughts have threatened the viability of nuclear power stations, since the shortage of cooling water (as we recently learned again in Japan) is essential to safe plant operation. And therein lies one of the rubs to the situation. As the spokesman for Thames Water noted, the intent is not just to run the plant when there is a drought, since that is going to be too late. Rather at times of lower rainfall the plant (which can produce up to 150 million gallons a day) will pump clean water into the reservoirs, maintaining their integrity, and building up a reserve that will reduce the drought impact if it occurs. The plant was apparently completed last June at which time it was expected that it would just be used in times of drought. Within the last year that thinking has changed, and the plant is now running intermittently, partly to train operational staff, partly potentially also to help meet demand.
According to the Environment Agency, average water use is 148L per person per day in the UK and in the south-east of England it’s as high as 170L (far higher than the government target of 130L). Despite the popular perception of London as an overcast, rain-soaked city, its rainfall rate is, in fact, on a par with Rome, Dallas and Istanbul.

Schematic of the flow path through the desalination plant.

One question that I had relates to the amount of power that will be needed at Beckton. A calculation assuming that it takes 4 kWh to produce a cubic meter of fresh water, suggests that it will need a 21 MW plant. In 2009 the company CEO noted
The (20 MW) plant will be the first in the world to generate all its energy on-site, from renewable sources, including recycled cooking oil.
However the plant has been controversial, not least because although planning to use rapeseed oil, it could also burn palm oil, which is apparently cheaper. That is much more controversial. Planning permission for a second plant nearby at Southall, was refused in June 2010.

Biofuel powered stations in the UK, which includes that in the Tees Valley, where a plant burning 300,000 tons of recycled wood and specially grown wood from plantations, have had a somewhat mixed reception.

But to get back to the original idea of desalination, the largest plant in the United States is in Tampa with a maximum projected size of 35 million gallons/day, though it currently only produces some 25 million, sufficient for 10% of the region’s water needs. It went on line in 2008.
The plant uses about 44 million gallons per day (mgd) of seawater from a nearby power plant’s cooling system, which is pretreated with sand filters and a diatomaceous earth filtration system to remove particles. Reverse osmosis filters then separate 25 mgd of freshwater from the seawater. The unused concentrated seawater is diluted with up to 1.4 billion gallons of cooling water before it is discharged to the bay and that dilution is why environmental studies show no measurable salinity change in Tampa Bay related to plant production.
Which brings us back to Texas. In the latest report on desalination in the state, two possible developments are cited. There is a plan to install a 2.5 million gallon a day plant at Brownsville and a 1 million gallon a day facility on South Padre Island. Unfortunately the South Padre Island initiative failed in a bond election last year, and its future is considered doubtful. Meanwhile the Brownsville Public Utilities Board is considering combining a renewable energy source (shades of the UK) into the plant, in order to leverage funding, and possibly qualify for DOE funds.

But in the meantime, as the discussion continues, the drought gets worse. The discussions started with an initiative in 2002. As those in Texas may find out the hard way, waiting until the crisis is upon them makes it too late to construct the solution that might have helped. It appears that those in the UK and Florida were just a little more prescient. It might be noted that the initial planning for the Florida plant started in 1996.

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Monday, January 19, 2009

P20. Pick Points

Half-a-dozen or so stories of interest.

So is the Russian:Ukrainian story over for another year, or ten? Certainly it has lost the press coverage, but there will remain caution until the gas finally arrives. But one part of the deal is that RosUkrEnergo will be cut out of the action. Gazprom is reported to have set 0700 on Tuesday to resume supplies However it is estimated to take another 36 hours before gas will make it to Western Europe. The domestic situation in Ukraine is a little more complicated, since the coal and steel plants (that heavily use Russian gas) are in the east of the country, which has been a strong Russian supporter. But the gas problem has alienated some of the region, even though it is leading to a potential increase in the use of coal, which is locally mined. (pdf). The mines also contain natural gas, and this can be recovered as a separate fuel. (pdf), and such work appears to be under way.(pdf)
Here is the beginning of my post.
The British – oops! – Scottish coal industry has started to move into profit, after having been in the red a year ago, Scottish coal mining has become profitable. This occurred as sales dropped from 3.1 million tons to 2.9 million, and is encouraging the firm to open new and some old sites, though all will be surface mines, or opencast. The market will now be able to use 4 million tons/year, and so the prospects for a new deep mine at Canonbie are looking up. (Small personal note – back over a hundred and twenty years ago my ancestor was blacksmith in that village. It is a beautiful setting).

Speaking of coal there is a strange story up in Alaska about the power plant and a utility company.

I had mentioned the other day that CNG prices had gone up in Pakistan, the result has been that out of 250 stations in Rawalpindi and Islamabad that sold the fuel, over 150 were not in the cities and some 400 were out in the region, and those who had CNG were only working limited hours . It freed taxi drivers to raise rates. But it also appears that there were differences in the rates in different cities, and though the lack of supply was blamed on low gas pressure price may have also played some part. The current situation seems to be getting worse.

Speaking of reviews of the situation Energy Shortage points to a broad review of the problems that Nepal are having with hydro-electric power generation.

Investors seem to be pulling back from wind power investments, just as the plug was pulled in Maine, so it appears that the large London Array project, some 341 turbines which would generate some 1,000 mW of electricity, and which Shell backed out of, is now being reconsidered by the Abu Dhabi State owned Masdar company, again because of questionable economics. Though the drop in steel prices might help. Apparently wind driven power generation is still costing three times that of a conventional gas-fueled station, though how long that will last is likely a Russian decision.

As usual there are more stories at the Energy Bulletin and Drumbeat at The Oil Drum.

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