Friday, December 10, 2010

European weather, Danish and Scottish power supplies

Denmark would like to get rid of the idea of using coal for its power stations and would like to have the five largest cities in the country “coal free.” Because Denmark still uses conventional, currently coal-fired, power stations for power this requires that they be converted to burning biomass instead.
Converting to biomass from coal is predicted to reduce the country’s carbon dioxide emissions by between three and five percent. It has been estimated that the conversion to biomass will cost the state some 900 million kroner annually through the loss of levies on coal.
The process has begun at the Amager Power Station which now includes a unit that burns straw and wood pellets.
The renovation process has taken more than five years and cost DKK 1.9 billion. In return, we have reduced emissions by as much as 630,000 tons CO2 per year.
The straw comes from farmers in Zealand, where it is pelletized before being shipped to the plant, which will burn about 100,000 tons a year of straw and 300,000 tons of wood pellets that will be imported from neighboring countries. The power company that runs these power stations, Vattenfall, has the stated intention of being CO2 neutral by the year 2030.

One of the other suppliers, Dong Energy which supplies more than 50% of Danish energy, has been criticized in the past because it planned on building new coal-fired power plants at Griefswald in Germany and at Hunterston in Scotland.
The company dropped out of the German power station plan a year ago. And it now appears that it may have struck out in Scotland also. The Hunterston station was scheduled to burn a mixture of coal and wood pellets, and aimed to be a demonstration site for carbon capture.
The 1.6 gigawatt plant, proposed by Ayrshire Power, is seen as a test of the Scottish government’s energy policy, which is fiercely anti-nuclear and pro- renewables but which critics say ignores the realities of future demand for power.

If permission is granted, the site, at Hunterston, will be the first in the UK to have an experimental carbon capture and storage facility. The company claims that this will capture 90 per cent of carbon from the plant and reduce consumption by up to 25 per cent.
However, within the last month, it appears that this plan has also died with the issue of a new policy statement from the Government.
“There is no current need for an increase in overall thermal capacity,” the policy statement says. “A huge increase in the potential of renewable electricity has led to a downward revision in the estimated requirement for new-build thermal electricity generation plant.”

Environmental groups say this spells the end of the Hunterston project, as well as another hotly disputed power scheme – ScottishPower’s plan to convert an old coal plant at Cockenzie in East Lothian to gas. It also confirms there is no need for any new nuclear plants.

“This would seem to signal a death knell for new coal or gas power stations such as those proposed at Hunterston and at Cockenzie,” said Duncan McLaren, the chief executive of Friends of the Earth Scotland. He pointed out that, according to the new policy, Scotland would need just 2.5 gigawatts (GW) of power from fossil fuel plants in 2030. This could easily be met by cleaned-up electricity from refurbished plants at Longannet in Fife (2.4GW) and at Peterhead in Aberdeenshire (up to 1.6GW), he argued.
As a basic point of reference,
Scotland produced in 2008 48.217 TWh of electricity (Scotland 2 2008), equivalent to 5.5 GW continuous power output. Of this:
27% was from nuclear power stations, 29% coal & combined cycle, 10% from hydro power, 27 % from gas/oil plants, and 7% wind onshore from approximately 800 MW capacity.
Scotland has already seen one station brought on line the 44 MW station at Lockerbie, that burns only wood.
The CO2 neutral plant is the UK's largest dedicated wood burning plant . . . . . It will burn 475,000t of sustainable wood fuel a year, including 95,000t of short rotation coppice. It will save up to 140,000t of greenhouse gas emissions annually. . . . . . . . Wood can have high moisture content, including Small Round Wood (SRW, 52–58%) sawmill co-products (54–62%), and Short Rotation Coppice willow (SRC, 35–55%). Besides freshly cut and old wood, Stevens Croft can burn different grades of willow.

The power plant can reach full output even with high-moisture fuels. It will burn a maximum of 20% recycled wood (limited by Planning and IPPC), and a maximum of 20% SRC (targeted by grant conditions for end 2011). Moisture content range for the plant is between 46% and 58%, with a design blend of 53%.
The majority of the fuel comes from sources within 60 miles of the plant.

Now this isn’t where this post was supposed to end up. I had started writing it because of a report that Denmark was restarting mothballed coal-fired power plants to meet the demand for energy in this colder-than-normal winter. As the post evolved it showed that Denmark isn’t having much luck in finding other sources for power outside the country, but that Scotland is becoming more self-sufficient by, among other sources, increasing their use of wood, which is also in the Danish plan. However, at present, Denmark has had a remarkably stable supply of electricity from coal for the last decade, judging by their coal consumption. (Note that the plot below shows the BP data, there are other sources which report that Danish demand is higher (at 7.8 million tons in 2009) although the shape of the curve is the same.)

Coal use in Denmark (Export Energy Databrowser )

A review of the Nordic power balance earlier this year showed that Denmark should have been more than self-sufficient, even with a 1 in 10 severity winter. However, and this is the confirmation of the story that I began looking for, Dong Energy has had to recognize that this winter is more severe and has, in fact, had to reactivate coal-fired stations.
DONG Energy has today decided to temporarily bring back into service Unit 4 at 
Studstrup Power Station and Unit 5 at Asnæs Power Station with effect from 9 
December 2010 and 3 January 2011 respectively. At the same time, Unit 2 at 
Asnæs Power Station will be taken out of operation on 3 January 2011. It is 
DONG Energy's intention to take the two power station units out of operation 
again on 1 April 2011 and 1 May 2011 respectively and to recommence generation 
at Unit 2 at Asnæs Power Station on 1 May 2011. 

Cold weather, coupled with low water levels, in the reservoirs that supply the 
Norwegian hydroelectric plants has created great demand for generating capacity 
in the Nordic energy market. At the same time, the cold winter is putting 
pressure on supply of heat in Aarhus and the neighbouring municipalities. By 
bringing Unit 5 at Asnæs Power Station and Unit 4 at Studstrup Power Station 
back into service, DONG Energy will thus be contributing to securing the 
electricity supply and the heat supply.


  1. "Scotland produced in 2008 48.217 TWh of electricity ... 7% wind onshore from approximately 800 MW capacity."

    Let's see now. 7% of 48.217 TWh is 3.375 TWh.

    800 MW wind capacity at 100% service factor could deliver 7.008 TWh in a year. Implied service factor would then be an eye-popping 48%.

    For comparison, well-sited trouble-free wind power installations typically deliver 30% of their rated output (setting aside the issue that some of this power will be useless since it will be generated at times when it is not required).

    Either onshore Scotland is 50% windier than the rest of the world, or we are looking at yet another example of arithmetically-challenged boosterism for wind power.

    "It has been estimated that the conversion to biomass will cost the state some 900 million kroner annually through the loss of levies on coal."

    Another fact the boosters of "renewable" Subsidy Sluts ignore -- in addition to the perpetual subsidies required by most "renewables", there is also the loss of taxes from fossil fuels. Since the Danish government is not willing going to shrink, those lost taxes on coal are going to have to be made up by additional taxes on the already heavily-taxed Danish people. Proper analysis would include those transferred taxes in the costs of "renewables".

    If self-decribed "renewables" are ever to be taken seriously, supporters first need to earn a reputation for honesty & accuracy.

  2. The only wind farm in Scotland that I am personally familiar with is the one outside Dalry in Kirkcudbright which I posted about earlier this year. I can say, knowing the location, that there is a considerable amount of wind there, but whether this is enough to give a 50% service factor is beyond my current ken.

    I am actually more intrigued by the use of straw, via pellets. Having heard some of the experience with burning switchgrass in Iowa, where they ended up with costs of close to $100 a ton,there are likely a whole lot of hidden costs in that operation that aren't seeing fresh air. it may be that there is a considerable social benefit that the Danes are willing to subsidize, but we have been running some tests (for a different reason) this week on switchgrass, and I can see pelletization being more expensive than the Iowa experience.

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