No. 4, December 2000

Main articles in brief

They should not give way (Editorial)
Binding emission limit values applicable to all large combustion plants would not only drastically cut down the emissions of a number of air pollutants, but also those of the greenhouse gas carbon dioxide – because many of the oldest and least efficient power plants would be shut down instead of being fitted for flue-gas cleaning.

Too little required of them
There are already a very large number of large combustion plants, probably more than a hundred burning fossil fuel, that easily meet the emission limits proposed by the Commission for post-2003 installations.

Ships’ emissions
Lowering the content of sulphur in bunker oils would be an effective way of reducing ships’ emissions of acidifying substances, according to a study made for the EU Commission.

Auto-Oil II
Emissions from road traffic will in any case be coming down as a result of steps already taken, but if aims for the environment and health are to be attained, more must be done to traffic locally and to other sources generally.

Sulphur-free motor fuels
It will be beneficial both to the environment and health to reduce the sulphur in motor fuels. A question is whether the gains will outweigh the cost, and here the opinion is divided.

Replacing coal
Coal-fired power plants are among the worst offenders as regards effects on the environment. Although they can be bettered in some ways, it would appear cheaper as well as an improvement to change over to natural gas.

Forest damage
Great regional differences in trends are now appearing. While there has been a decrease in the number of damaged trees in central Europe, there are now an increase in the Mediterranean region.

Harvests affected
The extent of losses due to the effects of ground-level ozone in Europe have been estimated by a new method taking better account of the actual circumstances.

Air pollutants in Europe
Emissions of acidifying substances continue to decline in most European countries, although an increase has been noted in some parts of the south.

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EDITORIAL

They should not give way

It is at least beginning to dawn on leading policy makers that restricting the emissions from existing coal-fired power plants would have the double advantage of curbing not only sulphur and nitrogen oxides but also the greenhouse gas carbon dioxide.

The Moneypoint plant in Ireland is a case in point. This is a relatively modern installation with a capacity of 915 MWe, which was started up in the mid-80s. Nevertheless it lacks effective cleaning of the flue gases either from sulphur or nitrogen oxides. Seen in a European perspective, Moneypoint is no great "baddie," coming only twenty-third among the worst emitters of sulphur in Europe. But by the latest count this plant is responsible for almost two-fifths of all Ireland's emissions of sulphur, about a fifth of the nitrogen oxides, and a sixth of the carbon dioxide.

In a press release dated November 2, the Irish environment minister, Noel Dempsey, presented his country's strategy for dealing with climate change, saying: "In recognition of the reality that closure or conversion of Moneypoint would make the largest single contribution to reducing greenhouse gas emissions, the government has declared its intention to ensure that measures addressing the energy supply sector will be supportive of the ceasing of coal firing at Moneypoint by 2008."

Some of the shortfall in the electricity supply caused by the closing down of Moneypoint could probably be compensated by energy saving and a more efficient use of energy, and some by electricity from new, renewable sources, such as windpower. But even if the whole shortfall were to be made up by the electricity from new, modern gas-fired plants, that measure alone would cut down the country's emissions of sulphur dioxide and nitrogen oxides by almost 40 and 20 per cent, and those of carbon dioxide by about 10 per cent.

Which such enormous gains in prospect, one wonders why the Irish are choosing to wait until 2008 before stopping coal firing at Moneypoint.

But old, polluting coal-fired plants give rise to other problems too. In Germany the ministry of economics, in company with the country's generators, is puzzling how the electricity from Germany's relatively "clean" plants (at least as regards their emissions of sulphur and nitrogen oxides) are to compete on more or less equal terms with the electricity from much dirtier plants in other countries - a problem that is getting steadily more acute as the European electricity market becomes liberalized and more international.

The ministry is considering legislation as one means of preventing imports of "dirty" electricity from countries with a more lenient attitude as regards environment and safety. Among the other possibilities that are being weighed are voluntary agreements and/or ecolabelling of electricity.

But there is another solution, which would be more effective. In view of the revision of the EU directive from 1988, regulating the emissions of sulphur, nitrogen oxides, and dust from large combustion plants, which is now taking place, environmentalist organizations are supporting the proposal of the EU Parliament to make binding emission limit values applicable to all existing plants.

That would not only drastically cut down the emissions of a number of air pollutants, but also those of the greenhouse gas carbon dioxide - because many of the oldest and least efficient power plants would be shut down instead of being fitted for flue-gas cleaning. No matter what would be used to replace them - whether it would be more efficient use or new sources of energy, or new plants burning fossil fuels - the emissions of carbon dioxide would markedly fall off. Minimum emission standards would moreover make for much fairer competition in the market for electricity.

Unfortunately the vehement opposition of some of the coal-producing EU countries has induced the Council of Ministers to persist in allowing a number of exceptions and escape clauses. It will therefore be of decisive importance, when the directive now comes up for a second reading, for Parliament to stick to the demands it made at the first reading.

Christer Ågren

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LARGE COMBUSTION PLANTS

Too little required of them

The European power plants that are fired with fossil fuels let out enormous amounts of air pollutants. It is mostly sulphur dioxide that they emit, but also nitrogen oxides, particles, and heavy metals, all making trouble for health and the natural environment. They all emit, too, large amounts of greenhouse gases, notably carbon dioxide.

The revision of a directive dating from 1988, setting emission limit values for some of these pollutants from the largest plants (meaning those with a capacity of more than 50 megawatt) is now being considered in the European Union.

In its draft for a new directive, put forward in 1998, the Commission proposed a tightening of the limit values for new plants, which would mean those built after 2003. The new limits would be approximately twice as strict as the old ones, in other words, the values would be just about halved in comparison with those that have so far applied for plants built since 1987. The question is just how much tougher they really will be.

As much as four years ago (1996) we published a report¹ showing that there were a number of plants in operation in Europe that were not only easily meeting the current requirements for new installations (that is, the values for post-1987 plants), but also the new ones that might result from revision of the 1988 directive. The plants that were looked at in the report were of various ages (built between 1961 and 1994), of greatly varying size (100 to 5700 MWth) and fired with a variety of fuels (hard coal, lignite, oil, gas, and biofuels).

An updating of the list of the "best" plants fired with fossil fuels was made in connection with a recent survey of the largest sources of sulphur emissions in Europe (see AN 3/00). In this survey² the plants were ranked according to their combined emissions of SO₂ and NOx in relation to their output of useful energy (electricity and/or heat). Although this kind of assessment is somewhat unusual, it is better from the point of view of effects on the environment in that it rewards plants that use energy most effectively.

The best plants usually come in this order according to fuel type: those fired with natural gas (1), oil (2), and coal (3). Emission control techniques, such as flue-gas desulphurization or denitrification, may however change the order of ranking, which will also be affected if plants produce electricity only or heat as well. In combined heat-and-power plants the output of useful energy is typically 100 to 200 per cent higher, with a subsequent reduction of emissions per output.

At least five or six of the coal-fired plants on the list have such low combined emissions of SO₂ and NOx as to be comparable with gas-fired ones. (If the emissions of the greenhouse gas carbon dioxide are also taken into consideration, coal-fired plants will however be worse than gas-fired from the point of view of the environment.) All these coal-fired plants are producing both heat and power, and are equipped for desulphurization and denitrification of the flue gases. By and large all the best coal-fired plants among the 200 are located in Germany, Austria, the Netherlands and Sweden - in other words, those countries with the strictest laws concerning measures to control emissions in Europe.

In the EU directive, as well as in many countries' legislation, emissions are expressed as milligrams of pollutant per cubic metre of air (mg/m³) in the flue gases, and Barrett also gives a list of the best plants with emissions denoted in this unit. In this list plant performances are also compared when estimated a) according to the limit values in the 1988 directive, and b) the values that the Commission proposes should apply for new plants from 2003.

It should be noted that the emission figures for the best plants have been calculated from the available official statistics. Since such plants quite frequently burn fuel of varying quality - differing for instance in sulphur and energy content - and sometimes even use different kinds of fuel, and will be run at different loads from one year to another, performance may vary considerably over the years.

Be that as it may be, however, these new figures show that there are already a very large number of plants, probably more than a hundred burning fossil fuel, that easily meet the emission limits proposed by the Commission for post-2003 installations. There can therefore be no doubt as to the possibility of achieving emission levels, by the use of conventional technology, that are considerably lower than those proposed in the new EU SO₂ and NOx standards for such plants.

It is also a matter of interest that the requirements for stationary plants are still being formulated in such a way as to be "technology conserving." The emission limits that will apply for new plants for the next 10-15 years are being set so they can safely be met by using the same kind of commercially available techniques as will be in general use when the legislation is drafted.

The requirements for road vehicles have on the other hand come to act as "technology forcing," being set at levels that are considered possible of achievement within a few years. They are moreover being successively tightened up at much shorter intervals than those for stationary equipment.

At the time of the first reading of the directive in the European Parliament in the spring of 1999 attempts were made to better the requirements at least for emissions of SO₂. This idea found no place however in the common position adopted by the Council this last June.

The study of large point sources shows, too, that by far the greatest part of the emissions of SO₂ - about 90 per cent - comes from old plants (built before 1987). If the reductions that will be needed in the next ten years for fulfillment of the EU aims for acidification and air quality are to be achieved, something must obviously be done about the emissions from these plants. But there is nothing about this in the Commission's proposal.

The need to deal with existing plants has also been revealed in a study made by IIASA at the request of the Commission. In 2010, 85 per cent of the emissions of SO₂ from large combustion plants in the EU will, according to IIASA estimates, come from plants built before 1987, as well as 66 per cent of the NOx emissions. In coming to this conclusion, the IIASA assumed that the emission limit values proposed by the Commission for all new plants would be applicable from the year 2000.

This was why the European Parliament proposed that limit values for SO₂ and NOx should be made to apply to all existing plants - meaning all built before the year 2000. It was proposed to allow a period of transition until 2005, when the requirements would begin to apply. In its common position the Council did indeed make a small move in the same direction (AN 3/00), but with the inclusion of fewer plants and a start of application from 2008. It would also allow member countries great flexibility in carrying out the directive, and retain several exceptions, as for instance for plants burning indigenous lignite.

This winter, probably sometime between January and March, a second reading of the draft directive is expected to take place in the Parliament. It will then go to the Council for a final decision. Any disagreement between the two bodies will have to be settled through conciliation in accordance with the so-called co-decision procedure.

Christer Ågren

¹ Doing more than required. Plants that are showing the way. By A-K Hjalmarsson. APC Report No. 6, 1996.

² The worst and the best. Atmospheric emissions from large point sources in Europe. By Mark Barrett. APC Report No. 15, 2000.

Performance of some of the best coal-fired plants in respect of emissions of air pollutants.

Source: The worst and the best. Atmospheric emissions from large point sources in Europe. By Mark Barrett, 2000.

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The 100 largest sulphur emitters
- corrections

Some corrections need to be made in the table on page 5 of the last issue.

Two British power stations, Rugeley and Drakelow, were listed twice. The lower figures are the correct ones in each case: Rugeley 29,000 tons (72nd), Drakelow 19,000 tons (99th).

Maritsa in Bulgaria, placed at the top of the list, should be reported as two plants: Maritsa III, 220,000 tons per year, becomes second, and Maritsa I, 96,000 tons, is then fourteenth.

Maritsa North, properly Maritsa II, moves up to first place, with an annual emission of 291,000 tons.

The corrections have been made both in the web version of Acid News and in Mark Barrett's report.

It should be noted that the information dates from 1997-98, and that there have since been other changes. The two coal-fired stations at Thierbach, placed 6th in the table, and Lippendorf (35th) in Germany have for instance been shut down.

Mark Barrett will be glad to receive corrections or additions to the data or text in the report, as well as suggestions as to how it might be improved. Address: MarkBarrett@sencouk.co.uk.

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REPLACING COAL

Various options, one best

Although no ideal solution, natural gas combined cycle appears eminently possible.

If the worst coal power stations in Europe were replaced by new combined cycle natural gas plants, emissions of sulphur would be eliminated, and those of nitrogen oxides and carbon dioxide would simultaneously be cut, respectively, by 98 and 75 per cent. Taking all the costs into account, it would often be profitable too.

The worst power plants in Turkey, Bulgaria, and Spain let out more than 50 grams of sulphur dioxide for each kilowatt-hour of electricity. Emissions of 10 grams of SO₂ per kWh are common for coal-fired plants in the EU, and still commoner in eastern Europe. Each gram of SO₂ converts to about 1.6 grams of concentrated sulphuric acid. The average European uses some 6000 kWh of electricity a year - which means that if generated in these plants, it would give rise to more than 90 kilograms of sulphuric acid per person!

EU emission standard for plants built from 1987 on is 140-700 grams of SO₂ per gigajoule (g/GJ) of fuel,¹ depending on size, corresponding to 0.2-1 per cent sulphur without cleaning. There are no limits for plants built before 1987. In Spain plants are burning lignite with a sulphur content up to 7 per cent.

The best coal-fired plants with the most efficient flue-gas cleaning, such as the combined heat-and-power one at Västerås in central Sweden, emit about 6 g/GJ - in other words, a bare hundredth of what is permitted for certain plants according to the directive. Actually the best plants are even better, since they generate both heat and power and operate at 90-per-cent efficiency, as compared with 30 per cent for older plants producing only electricity. The emissions from Västerås amount to 0.024 grams of SO₂ per kWh of useful energy, which is 1/2000 of that from the dirtiest plants, or 1/400 from the kind of plant that is fairly common in the EU.

Still better however are new gas-fired plants. Since there is no sulphur in natural gas, such plants do not give rise to any sulphur emissions.

The situation is similar as regards emissions of nitrogen oxides, which in the case of the worst plants can exceed 700 g/GJ. The EU emission limit value for plants built after 1987 is 230 g/GJ fuel input. The best coal-fired plants now emit approximately 35-50 g/GJ.

The best natural gas combined cycle plants not equipped with catalyzers for reducing nitrogen oxides emit less than 15 ppm (8 g/GJ fuel input), corresponding to 50 mg/kWh of electricity. With the best flue-gas cleaning , the emissions of can be brought down still further, to about 2 ppm, or 1 g/GJ fuel input.

As can be seen from the table below, the combined cycle plants fired with natural gas are better in every respect than old coal-fired plants, and definitely better even than the best new ones.

There are other environmental effects from the burning of coal, besides those accruing from the emissions of sulphur and nitrogen oxides.

Since coal has a higher content of elementary carbon as compared to natural gas, when burnt it gives rise to significantly higher amounts of carbon dioxide. Moreover greater efficiency can be attained from the burning of a gas than from solid fuels. Coal contains large amounts of heavy metals, which are let out through the chimney or retained in the ash, thereby creating a disposal problem that does not occur with natural gas.

In the life-cycle aspect, natural gas has even further advantages over coal. More methane is let out from coal mining than from drilling for natural gas, and the mining, washing, and transporting of coal, as well as the production of lime for its desulphurization, add to the environmental debit of firing with coal.

Gas is however not always the best alternative. In Sweden for example environmentalists have always been against developing the use of natural gas because it would push aside biofuels. During the last fifteen years the use of biofuels, coming mainly from the forests, has greatly expanded in Sweden. Sweden is perhaps exceptional in being a rather sparsely populated country where 60 per cent of the land area is covered by forest, with forest-product industries forming a great part of the economy. Moreover district heating is well developed in urban areas, and emissions of CO₂ have been taxed since 1991.

But the Swedish example nevertheless shows that large-scale use of biofuels works in a modern country, from the technical, economic, and environmental points of view - at least for generating heat and to some extent for heat-and-power. In less forested countries there may be better conditions for energy crops, agricultural waste and solar heating.

Although renewables alone can not replace coal in the short term, they could well make a growing contribution to energy production alongside natural gas. Some such development will in any case obviously be necessary for attainment of the long-term aim of climate policy - namely, stabilization of the concentrations of carbon dioxide in the air at a lower level than the present.

Coal-fired power plants cause major environmental problems - especially the older ones with low efficiency and no modern equipment for abating pollution. A number of options are conceivable for dealing with the worst plants:

Let them continue to operate. This is untenable in consideration of the effects of their emissions on public health and their contribution to other environmental problems, such as eutrophication, acidification, and global warming. Stricter emission limits for the EU, which will apply to the candidate countries too, and emission caps in the Kyoto and Gothenburg protocols, will soon make this alternative either impossible or extremely expensive. Many of the plants are now technically worn out and dependent on nearby unprofitable coal mines as well as unsustainable subventioning.

Replace with efficiency and renewables. Efficiency is the best "source" of energy, since it would cut out all emissions of pollutants. Demand-side efficiency often makes economic sense, but it also calls for changes in attitudes, traditions, and institutions, which would all take time. The outlook is best in countries with the highest electricity consumption.

As for electricity from renewable sources, windpower is still quite expensive, and solar cells inordinately so. Modern technology for converting biofuels to electricity is neither technically nor economically mature. The potential for the production of heat-and-power from biofuels is limited, although best in industry. It needs to have a district heating network in place before it can be applied, since installing a new one would add too much to the cost.

Although it is possible to replace some of the more polluting plants with improved energy efficiency and generation from renewables, this cannot be done quickly in all cases.

Replace with nuclear power. Since 1990, no nuclear power station has been ordered in Europe other than two in France. In most countries no orders have been considered for 20 years or more. Many reactors have on the contrary been shut down. In an increasingly competitive market for electricity, new nuclear plants are out of the picture.

The possibility of keeping old plants in operation for a longer period than had been planned is also limited, since it would often require a lot of new investment, which would be difficult to recoup. Nuclear power will therefore in all likelihood continue to drop away.

Replace old coal-fired plants with new ones. What is known as Clean Coal Technology can certainly bring a great improvement in efficiency, and also result in greatly reduced emissions of NOx and SO₂ from coal-fired plants. But the emissions of carbon dioxide would still remain high in relation to the amount of energy produced. Being very expensive to build, new plants of this kind are in any case out of the question in most parts of Europe. One that has just started up at Lippendorf in Germany, burning lignite, with a capacity of 2x933 MWe, has for instance cost DM4.5 billion - almost US$2 billion, or more than $1000 per kW.

Fit flue-gas cleaning on existing plants. To date German legislation, for example, and to some extent that of the EU, has aimed at causing existing plants to be equipped for desulphurizing and de-NOx-ing the flue gases. Although that may be a workable interim solution for fairly good modern plants, it has distinct limits. For one thing it has no effect on CO₂, and for another it costs a great deal - around US$l00/kWe for desulphurization at a new coal-fired plant, and $50-70 for catching NOx. Although it has been forced down of late, the cost of such additional equipment can be very high if it has to be fitted to an existing plant. Not only can it easily amount to half the price of a new gas-fired plant (see below), but it will also take a long time from conception to a fully functioning plant. There would also be the extra operational costs and the risk of breakdowns.

Replace with the latest types of plant fired with natural gas. No ideal solution, but eminently possible. Most of the plants ordered of late have been natural gas combined cycle units. The capital cost of such plant, according to the US Department of Energy, is $449/kWe, as against $1102 for a corresponding coal-fired plant. Gas-fired combined cycle plants have several advantages over coal-fired ones. They are more reliable in operation, can be built quickly and in much smaller sizes. They can thus easily adjust to developments in the demand for electricity, without being too much affected by long-term forecasts. Gas is admittedly more expensive than coal, but the low capital cost of the plant makes it easier to adapt to changing operational conditions. Operators will not lose so much money, either, by running plants intermittently when electricity prices are lower, and making up for it when they are high.

The environmental advantages, which include relatively low emissions of CO₂, mean that gas is much less sensitive to changes in legislation, taxes, or the introduction of CO₂ permit trading. On the contrary, such moves would add to the competitive edge of combined cycle gas. All aspects considered, such plants would seem to be a highly realistic alternative to the continued operation of old, inefficient, and dirty plants burning fossil fuels. And then there are the environmental gains.

The next step, after it has been proved that some coal-fired plants could with advantage be replaced by gas-fired heat-and-power units, will be to squeeze the size of the replacement be ensuring a more efficient use of the energy soproduced, and adding a certain amount of energy from renewables. Many of the worst plants are in countries with a surplus of generating capacity, and in such cases shutting down without new investments in additional power-generating capacity would be best from the points of view both of the environment and the economy.

Fredrik Lundberg

Freelance writer specializing on energy and the environment.

Note. Nitrogen compounds affect the environment in much more complicated way than sulphur. Nitrogen oxides can contribute to acidification, eutrophication, and the formation of ozone and small aerosol particles. Nitrous oxide (N₂O) not only affects the ozone layer but is also a greenhouse gas. Whereas the emissions of N₂O from modern gas-fired plants are about 2g/GJ, from ordinary coal-fired power plants they will often be as much as 25-50 g/GJ (although they can vary markedly according to the type of plant as well as operating conditions). Moreover, some flue-gas cleaning arrangements may let out ammonia to the extent of 2 g/GJ of fuel. But gas-fired combined cycle plants do not let out any ammonia if they employ so-called Dry Low NOx technique, or catch NOx in an SCONOx reactor.

¹ For coal 1 g/GJ corresponds to 2.86 mg/m³; for gas 1 g/GJ corresponds to 3.70 mg/m³.

Emissions of SO₂, NOx and CO₂ from various types of coal-fired and gas fired plants.

^A At 30% efficiency. ^B At 34 % efficiency. ^C At 42,5 % efficiency. ^D At 60 % efficiency. ^E At 60 % efficiency.

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SHIPS' EMISSIONS

Lower the sulphur in bunker oil

In a report to the EU Commission, consultants make this proposal for cleaner shipping.

According to estimates in a study¹ made for the EU Commission, the emissions of nitrogen oxides and sulphur dioxide from shipping in European waters now amount, respectively, to 2.3 and 1.9 million tons a year. If nothing is done to check them, by 2010 they will be equivalent to more than a third of the emissions of NOx then expected in the EU and 40-50 per cent of the SO₂.

In order to be able to compare ships with large combustion plants on land, the consultants who made the study reckoned the power consumption of the shipping in all European waters to be approximately equivalent to that of 390 50-megawatt units running continuously every day of the year. In the terms of the directive (88/609/EC), large combustion plants are those with at least 50 MW thermal output.

The consultants therefore propose that the EU should pass legislation setting the limit for sulphur in bunker oils at 1 per cent for ships plying in EU territorial waters. At present there is no legislation on such oils. The sulphur content of other types of oil is regulated in directive 99/32/EC, setting a maximum of 1 per cent for heavy fuel oils used in emission sources on land, and 0.2 per cent for gas oils, including any used on ships.

It has been agreed within the UN International Maritime Organization that there should be a global cap of 4.5 per cent on sulphur in bunker oils. It is not likely however that this will have much effect, since the general average sulphur content has long been under 3 per cent. The IMO has moreover designated the Baltic and North Seas as low-sulphur-fuel zones, where the maximum limit would be 1.5 per cent. It is however highly uncertain when this will become effective, since IMO rules have first to be ratified by as many countries as represent half of the world's shipping.

With a 1-per-cent limit for the bunker oils used in EU territorial waters, the overall emissions of sulphur from shipping would come down by 700,000 tons, or 35-40 per cent. The consultants have put the cost of carrying out such a measure at US$1000 per ton of SO₂ so eliminated, which would mean approximately US$700 million a year. They note however that their estimate is greatly dependent on assumptions as to future oil prices and that there are other studies showing the cost to be only half as high.

The consultants also note that the emissions of nitrogen oxides from shipping could be reduced by as much as 50 per cent through the use of financial incentives such as differentiated harbour dues. They estimate the cost in that case to lie between US$800 and 1200 per ton of NOx thus eliminated. By using more far-reaching methods, the emissions could be reduced by two-thirds, but then the cost would also be higher.

As regards incentive schemes for controlling the emissions both of SO₂ and NOx, a nationally operated but port-administered system of levies is considered preferable to a scheme of harbour dues, and that such a levy system should be based on emissions rather than on gross tonnage.

Unfortunately it does not appear from the final report just how the new figures for the overall emissions from shipping have been arrived at - despite their being much lower than the corresponding EMEP figures based on calculations made by Lloyd's Register. Moreover the latter do not take into account the emissions from naval and fishing vessels or small craft, nor those from ships lying in port or at anchor awaiting a berth or further orders.

Christer Ågren

1 Study on the economic, legal, environmental and practical implications of a European Union system to reduce ship emissions of SO₂ and NOx. Final report for the European Commission (August 2000). By M.E. Davies, et al., BMT Murray Fenton Edon Liddiard Vince Ltd, UK. Available in pdf format at http://europa.eu.int/comm/environment/enveco/studies2.htm#27

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AUTO-OIL II

Results coming in better air quality

Emissions expected to drop despite increase in road traffic, but more is needed to achieve aims.

It is evident from the Commission's final report on the Auto-Oil II project that the measures already decided upon for reducing the emissions from road traffic will bring marked improvement in air quality during the next few decades. The proportion of pollutants coming from road vehicles is also expected to diminish. Nevertheless in 2010 great numbers of people will still be living in cities where the concentrations lie well above the desirable limits.

The first Auto-Oil program was a cooperative project in which the vehicle manufacturers and the oil industry were engaged, together with the EU Commission, between 1992 and 1996. Out of it came a number of proposals for directives, including three on emission standards for vehicles (private cars, light commercial and heavy duty vehicles) and another on quality requirements for motor fuels (petrol and diesel oil). These set down values that were intended to start applying in 2000 and 2005, although in the latter case they were only to be indicative.

The Commission wanted to have more research done before the indicative standards were finally adopted. It therefore started a wide-ranging program, Auto-Oil II, which was to differ from the first in that it should also look into possible non-technical measures for arriving at cost-effective solutions, and allow all those with an interest in the matter to participate from the beginning. The first program had been heavily criticized for its lack of openness.

But things did not turn out quite as the Commission had expected. The EU Parliament managed to ensure that the standards for 2005, instead of being merely indicative, should be definite. This rather upset the Auto-Oil II project. A final report was however issued this last summer, followed by a communication from the Commission in October.

In it the Commission notes that the directives emerging from Auto-Oil I will result in a considerable reduction of emissions. It estimates that despite the expected increase in the volume of road traffic, the emissions of several air pollutants will have dropped by 70-80 per cent or more by 2010, from their 1995 levels, and thereafter fall off still further (see chart below). Without these directives the emissions from road traffic would be 50-100 per cent higher in 2010, and then go on increasing in step with increasing road traffic.

The emissions of carbon dioxide are nevertheless estimated to increase by 10-15 per cent from 1995 to 2005, and then level off, since by that time the increase in road traffic is expected to have been offset by more fuel-efficient vehicles.

Further improvement will be needed in respect of pollutants that are damaging to health. Small particles in particular (PM10) will loom large. In 2010 between 50 and 75 per cent of the total urban population will still be living in cities that fail to meet accepted air-quality standards for particles (today it is closer to 90 per cent). In general there will be a great improvement as regards other pollutants, except for nitrogen oxides which will still exceed the standards here and there.

As a source of pollution, road traffic will decline in importance, according to the Commission, which points to the fact that there will be a need in future to direct attention to other sources as well - adding that the air-quality standards for particles, for instance, would not be met even if emissions from road traffic were entirely eliminated.

One thing that came out of the Auto-Oil II project was that two and three-wheel vehicles were "a key remaining area" where stricter emission limits would significantly improve air quality. The Commission recently presented a proposal for a directive setting stricter limits for such vehicles. A proposal for the technical updating of standards for all types of light and heavy vehicles is expected next year. Additions will also be made to the directive on fuel quality, which may be extended as a result of a review process initiated by the Commission (see article on opposite page).

In addition to the measures at EU level, the Commission urges individual action by the member countries, which it says should include promotion of alternative fuels for fleets of vehicles driving mainly in city centres (i.e. buses), the use of fiscal instruments, schemes to accelerate scrapping of old vehicles, and local, non-technical measures such as parking charges and road pricing.

Fiscal instruments and local non-technical measures are thought to have a significant potential. General increases in fuel duty or differentiated duties on fuel are predicted to have a "large net societal benefit" if revenues are used to reduce the "more distorting" kinds of taxes. Local non-technical measures could moreover provide "highly cost-effective" solutions.

Per Elvingson

To find out more: The Commission has a website for the Auto-Oil program, from which a number of documents can be downloaded, including the above-mentioned communication, entitled A Review of the Auto-Oil II Programme (COM(2000)626), as well as the main report on the project and a number of sub-reports from working groups. See http://europa.eu.int/comm/environment/autooil/index.htm or contact Peter Wicks, Environment DG, Unit ENV. D3, 200 Rue de la Loi, B-1049 Brussels, Belgium.

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SULPHUR-FREE MOTOR FUELS

Beneficial both for the environment and health

But will the gains outweigh the extra cost? The answers to a Commission questionnaire show opinion to be divided.

As from 2005, the sulphur content of petrol and diesel fuel will not be allowed to exceed 50 ppm (parts per million), a marked lowering from today's levels. The change is a result of pressure from the European Parliament when the present directive for motor fuels (98/70/EC) was being debated in l997-1998.

The question now is whether it should be lowered still further. The auto makers think it should, and when Germany joined in and supported them by proposing sulphur-free fuel, the Commission decided to take the matter up by sending out a questionnaire last May on certain points that all interested parties were invited to answer. The whole process has been kept public, and the replies can all be read on internet.

There can hardly be any doubt that it would be beneficial for the environment and health to have motor fuels with less sulphur, but here another question arises: Will the gains be sufficient to be thought to justify the extra cost?

The advantages of having sulphur-free motor fuels (defined as those with a sulphur content of less than 10 ppm) have been summarized by SENCO Consultants, in a report to the British government, in two main aspects:

• They reduce emissions from existing catalyst-equipped vehicles, particularly from the latest generation of petrol vehicles. For nitrogen oxides, the introduction of sulphur-free petrol may reduce fleet emissions by almost 50 per cent in 2010. There would also be lesser emissions of particles, especially from diesel-driven vehicles.
• They enable new catalyst technology to be introduced into the market. This is important for the introduction of more fuel-efficient cars to reduce emissions of carbon dioxide from road traffic.

Muddle over ceilings and standards for ozone

To judge from the common position on ozone (taken at the meeting of the Council in October) the EU environment ministers think it is quite in order to have a worse quality of the air than the Commission and the Parliament would like.

None of them has anything against the long-term aim of the directive, namely that concentrations should not exceed the level set by the World Health Organization for the protection of health, which is 120 micrograms/m³ (60 ppb) as an eight-hour average.

But it is on one part of the aim for 2010 that there is disagreement. The Commission had proposed that the level could be exceeded on no more than 20 days a year from 2010, in which it was supported by the Parliament at its first reading of the directive. But in order to bring round Greece, Spain, Italy, and Portugal, who wanted 40 days, the Council agreed on a compromise, making the maximum 25 days.

The Council also wanted the requirements to be weaker than the Commission proposed on two further points. For one thing it would somewhat lower the target for 2010 for the protection of vegetation. In addition it only wanted action plans to be set up when the threshold value of 240 micrograms/m³, averaged over three hours, had been reached. That would be aiming much lower than the Commission, with its proposal for starting as soon as the threshold level had been averaged over just one hour.

There is a close connection between the air-quality directive for ozone and that for national ceilings on emissions. It was under the assumption that its proposal for ceilings on the emissions of nitrogen oxides and volatile organic compounds, the substances that give rise to the formation of ozone, would be accepted by the member countries that the Commission reckoned its limit for ozone concentrations would be realized.

But taking the less ambitious ceilings agreed by the Council in June (see AN 3/00) as an excuse, a lot of countries are now out to get generally weaker standards for air quality.

Here however the European Environmental Bureau (EEB) points out an error in their reasoning - saying in a release to the press that "the shortfall in emission reductions expected as a result of the NEC directive can easily be made up by reducing shipping emissions and by implementing local measures, as transboundary emissions of ozone or ozone precursors are only part of the problem."

Several of the demands made by the Parliament at its first reading of the directive were found unacceptable by the Council. One was the desire to have the so-called target values for 2010 made binding, instead of being merely guide values. The Parliament also wanted the long-term aim, when there would be no exceeding at all of the threshold values, to have been reached by 2020.

The directive will now be going to the Parliament for a second reading.

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Benzene and carbon monoxide

Air-quality standards for benzene and carbon monoxide, which were agreed by the Council this October, will mean that as from 2010 the concentrations of benzene in the air may not exceed 5 micrograms per cubic metre, and those of carbon monoxide 10 milligrams after 2005.

It is expected that the measures already taken will cause the emissions of benzene, which come mainly from road traffic, in general to drop heavily. But unless further measures are taken, it will be difficult in 2010 to meet the standards in places where traffic is heavy. The directive allows member countries however to apply for an extra five years (at the most) in which to comply.

The standards for benzene and carbon monoxide forms a second daughter directive to the framework one on air quality dating from 1996.

Correction 
In our last issue it was wrongly reported that agreement was about to be reached on 10 micrograms per cubic metre as the limit for concentrations of benzene in the air.

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OZONE

Are levels decreasing?

Since the emissions of nitrogen oxides and volatile organic compounds, which do most for the formation of ozone, have dropped by 15-20 per cent in Europe during the last ten years, it might be supposed that ozone concentrations would follow. But from an analysis¹ of concentrations during the period from 1989 to 1998 they evidently have not.

One explanation is that they may have been less, but the drop has been masked by the great variations caused by the weather. Ozone is formed under the influence of sunlight, so the concentrations will usually be higher in warm summers than when the weather is rainy. Variations that are due to the weather will moreover be greatest in northern Europe, where emissions have dropped most.

Gaps in the network of monitoring stations also make it difficult to discern trends. In some places, particularly in France and southeastern Europe, the stations are too few to give a complete picture. In Spain many stations are located too close to the sources of pollution to be representative of a wider region.

¹ Transboundary Photo-oxidants in Europe. EMEP Report 2/2000. Available from Meteorological Sythesizing Centre - West, Norwegian Meteorological Institute, P.O. Box 43-Blindern, N-0313 Oslo, Norway. Internet: www.emep.int.

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EUROPE'S FORESTS

Every fourth tree damaged

The situation has worsened around the Mediterranean but improved in Central Europe.

Whereas forest damage has increased in the Mediterranean region during the last few years, there has been some recovery in central Europe. In Europe generally about a quarter of the trees are showing signs of defoliation.

In a Europe-wide program for watching the state of the forests which has been going on since 1986 a great number of trees are being observed for possible loss of leaves or needles every year. Thirty nations are engaged in the monitoring, now involving a regular scrutiny of 5700 sample plots in a l6xl6 km network, representing nearly 129,000 trees.

In the last survey 23 per cent of the trees in the sampling plots were assessed as damaged - meaning that they had lost more than 25 per cent of their leaves or needles in comparison with reference trees of the same species. That would be about 1 percentage point less than in the previous year.

But for Europe as a whole there were great regional differences.

There has been a sharp increase in the Mediterranean region of the mean defoliation of all species. Of the main tree species in that part of Europe the greatest increase was observed in common beech (Fagus sylvatica), Scots pine (Pinus sylvestris), and maritime pine (Pinus pinaster). Dry weather conditions have been given as the explanation, although the influence of ozone is also suspected.

On the other hand mean defoliation has dropped considerably in the subatlantic region, comprising Poland, western Slovakia, the Czech Republic, and eastern Germany. The improvement there was most pronounced for Scots pine, the proportion of trees that were classified as damaged having decreased from 46 to 25 per cent during the last five years. In this case the explanation was thought to lie in the favourable weather conditions. It is difficult however to separate the possible influence of the great decrease in sulphur pollution from the effect of such natural phenomena.

The regional variations can also be seen from the table, where the figures are from the national inventories.

Since 1994 intensive monitoring of 900 sample plots, spread over thirty countries, has become part of the all-Europe program. The aim is to get a better insight into the causes of defoliation. Among the findings so far are the following:

• Depositions of atmospheric nitrogen and sulphur do affect nutrient status and to a lesser extent tree vitality. In 30 per cent of the plots the nutrient status is either insufficient or unbalanced.
• Following the reduction of emissions, the depositions of sulphur have decreased much more than those of nitrogen on most plots during the last decade. On about 50 per cent of them, however, nitrogen deposition is more than 14 kg per hectare a year. Above that level adverse effects may occur, specifically on the ground vegetation.

It says in the annual report on the monitoring program that it is usually impossible to identify the causes of deterioration in stands or individual trees. Statistical evaluations indicate a complex system of environmental conditions and stress factors. The main factors that are statistically relevant for explaining defoliation are tree age, soil acidity, plant-eating insects and fungi, climatic extremes and/or water availability, as well as air pollutants such as sulphur and nitrogen compounds and ozone.

"Further reduction of emissions is still needed to guarantee the multiple functions of forests in Europe as a basis for a sustainable forest management," says the EU Commission in its presentation of the report.

Per Elvingson

Forest Condition in Europe. 2000 Executive Report and Intensive Monitoring of Forest Ecosystems in Europe. Technical Report 2000. Both available on the internet at the address: http://europa.eu.int/comm/dg06/fore/index_en.htm. Can also be ordered from Federal Research Centre for Forestry and Forest Products, ICP Forests, Leuschnerstr. 91, 21031 Hamburg, Germany (www.dainet.de/bfh/inst1/12).

Results from national forest-damage surveys, 1996-99. Percentage of trees with defoliation above 25 per cent.

¹ Until 1997 only trees older than 60 years were assessed. ² Excluding maquis.

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Crops

Harvest greatly affected by ozone at current levels

Although the effects of ozone at ground level have turned out to be somewhat less in Europe than previously supposed, they still remain considerable. High concentrations in the summer of 1994 are estimated to have reduced the wheat harvest by 12 per cent, corresponding to an economic loss of about 1.5 billion euros.

Since 1996 the accepted method of measuring the extent of the damage to crops caused by ozone has been to note total harmful exposure during the three months from May to July. To be considered harmful, exposure must have been more than 40 ppb (parts per billion) as an hourly average for at least 3000 so-called ppb-hours. The method is known as AOT40, where AOT stands for the accumulated exposure over a certain threshold, and 40 that the threshold value is 40 ppb.

The damage will not only depend however on exposure during these three months. The humidity of air and soil are also important factors. During dry periods the plants close their stomata, thus lessening the uptake of ozone. Much depends also on the stage of their life cycle at which plants are exposed, since sensitivity will vary.

In order to estimate the effects on crops more closely, scientists are now developing computer models that take humidity and phenology into consideration as well.

According to the usual method of calculation (AOT40), in the summer of 1994 the critical exposure for crops was exceeded over most of Europe. Values three times above the critical were noted in most parts of France, Belgium, Germany, and some of Italy.

But if consideration is also taken to soil humidity and phenology, the area of highest exposure moves further north.

The worst damage may then be expected in France, Belgium, the Netherlands, Germany, and parts of Italy, while the effects will be less in the south of Europe. In southern France, for instance, wheat ripens so early that ozone levels in June and July will have no effect on the harvest. In Spain, Greece, and a great part of Italy the climate is so dry that the plants' uptake of ozone is limited, and so also the damage. Here however the fact that some of the crops are heavily irrigated has not been taken into account.

All told, the new estimates suggest that the harvest losses for wheat in Europe must have amounted to 13 million tons in 1994, and that would be about 1.5 billion euros. Although the average drop in yield was 12 per cent, the variations from country to country were considerable. The highest harvest losses caused by ozone, 30 per cent, occurred in Belgium and Luxembourg. There was a loss of 15-20 per cent in France, the Netherlands, and Germany. The greatest part of the total loss occurred however in France, where the wheat harvest was lowered by 6.7 million tons. The next to suffer most were the German farmers, who lost 3.7 million tons, as against less than a million tons in any of the other countries.

A comparison of the effects on five different kinds of crop in France in 1994 showed sugar-beet growers to have suffered the most, losing 16 per cent of their crop. Wheat came only next, with 10 per cent, despite it being the more sensitive of these two crops. The reason was that the growing period for sugar beet happened to coincide with high concentrations of ozone in June and July, when wheat had already attained full growth.

The authors of the report from which these figure have been taken are careful to point out that the concentrations of ozone were relatively high in Europe in 1994 (they vary with the weather from year to year), and also that that there is still a great uncertainty in the estimates. Researchers will now be trying to hone their methods, and also to see if they can find out how the natural flora (biodiversity) is being affected by ground-level ozone.

Per Elvingson

Air Pollution and Vegetation. UNECE ICP Vegetation Annual Report 1999/2000. Obtainable from CEH Bangor, University of Wales, Deiniol Rd, Bangor, Gwynedd LL57 2UP, United Kingdom. E-mail: gmi@ceh.ac.uk. See also http://icpvegetation.ceh.ac.uk.

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EMEP

Total European emissions unchanged

Improvements in northern Europe is balanced by increased emissions in the south.

Since 1978 the movements of air pollutants around Europe have been registered by EMEP, the European Monitoring and Evaluation Programme. The centre for coordination of the information from a network of stations all over Europe is in Oslo, Norway, where a highly advanced computer model has been developed for calculating the transboundary travel of pollutants.

The model contains data on the manner in which various substances become transformed in the atmosphere and the length of their stay there. The latest figures for each country's emissions are fed in and run together with meteorological data for the year in question. Having the pollutants traced from their source to the place of deposition makes it possible to see whether the countries are fulfilling the commitments they have made in international agreements and also whether the overall aims of such agreements are being met.

The latest report from the EMEP differs in some respects from its predecessors.

Data on emissions from shipping in the Mediterranean has now been included, and the monitoring area exte