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A scientist’s opinion: Interview with Prof Michael Norton on burning wood as renewable energy

Interview with Professor Michael Norton, Environment Programme Director at the European Academies’ Science Advisory Council (EASAC) and Professor at Tokyo Institute of Technology, Shinshu University and Tohoku University.


According to a Joint Research Centre (JRC) publication, the global production of wood pellets reached 29 million tonnes in 2016, of which more than 50% was produced in the EU. Why is burning forest biomass considered a form of renewable energy? How did it end up in the Renewable Energy Directive (RED)?

Michael NortonAs you say, biomass is grouped with solar and wind as a renewable energy, and it’s renewable in the sense that a tree grows. But the real meaning of renewable in this sense is that the energy has to reduce atmospheric CO2 concentrations, because that’s why we’re subsidising renewable energies to combat climate change. And the scientific reality is that while solar and wind emit almost zero carbon when they’re generating electricity, biomass actually emits more CO2 per kilowatt-hour of electricity generated than coal and way more than gas. So it’s very questionable whether it should even be regarded as renewable from a climate point of view. We’ve looked at this from a scientific perspective in a number of papers, but I’ll try to explain in lay terms how we got to the current situation.

Now, if you look at the history of bioenergy, the original idea of including biomass came from a typical Scandinavian forestry policy, where there was residue which would otherwise be unused, and it made sense to try and get some energy out of it by burning it. But once that led to biomass being classified as renewable under any circumstances, it just set out an easy route to relabelling power stations as renewable by switching the fuels from coal to biomass. And that basically got us into the situation we are in today, where the majority of Europe’s so-called renewable energy comes from biomass.

Now, of course, there’s a lot of debate on how we should deal with biomass. The original idea of using forest biomass such as residue was that it came from sequestering CO2 from the atmosphere, and so was part of the natural cycle for which the carbon was, on the whole, neutral. In addition, as forestry residue was being used that would otherwise be left to rot, it made sense to encourage its use. So the idea of carbon neutrality became the principle underlying the original regulations and had the critical effect of allowing biomass combustion emissions to be treated as zero (because it was assumed to be compensated by the uptake of CO2 from the atmosphere through the photosynthesis of the regrowing trees).

Once this principle was established in the regulations, however, it expanded rather swiftly to large power stations without any limit on how much could be burnt. That is why large biomass power stations, such as Drax in the UK, can emit millions of tonnes of carbon dioxide each year from their stacks without those emissions being counted against the station or the country’s emission reports. Even though the current 15 million tonnes of emissions are fully absorbed into the atmosphere and contribute to the rising atmospheric concentrations of CO2.

The key question is whether this idea of carbon neutrality really applies in these cases. The argument remains that the carbon in the biomass will still be reabsorbed as the forest providing the feedstock regrows, but that’s too simple, because if you start harvesting a forest, you remove the carbon from the forest and put it into the atmosphere directly. But it takes a long time to regrow the forest to replace the trees that you have burnt.

So you have this time lag between releasing the carbon into the atmosphere and the compensating reabsorption from the atmosphere. And that’s what we call a carbon debt, because you initially put more carbon into the atmosphere than was the case before you converted to coal. The time it takes to repay that debt as the forest regrows is called the carbon payback period. And the payback period can be quite long for two reasons. Firstly, you have to emit more carbon dioxide from your power station to generate the same amount of electricity as you would have done with coal, and more than double the amount you would if you had used gas. So there’s a big carbon debt right at the start, which takes a long time to reabsorb, and that time can range from just a few decades to essentially never in some cases if you use very high carbon feedstock with effects on the carbon stocks in the providing forest. So you have this rather ironic situation that your so-called renewable energy actually increases CO2 in the atmosphere for periods which are now much longer than the time we have left to meet the Paris Agreement targets. So that brings us to the question of why on earth we would subsidise something which makes it more likely that we will overshoot the Paris Agreement targets?


According to Eurostat, between 2005 and 2016, the consumption of renewable energy in the EU increased by 79%. Nonetheless, the EU had to consider alternative forms of energy that could be cleaner and more sustainable. When and why did the idea of burning forest biomass start to circulate among EU policymakers?

There has been a big increase in the use of biomass to deliver renewable energy, and I think that has surprised many people. I’ve heard that when the original RED was being formulated, they were very much thinking in terms of reusing waste materials within a very short distance, like residue from local sustainable management where the main products were timber, pulp and so on. But once it was labelled as renewable, it actually became the easiest and cheapest way of contributing large amounts of renewable energy towards the national targets set by the EU. If you consider that solar panels and wind turbines were more expensive in the early days, and could only be installed at a relatively slow rate, it would have taken a large investment and a long time to actually deliver a 30% or 40% renewable target. But if you converted a large coal power station to biomass, you could produce a lot of electricity in one go and also avoid having to shut down that coal station as you tried to phase out coal. So there were a lot of political and economic reasons for doing this. The UK was one of the leaders, but other countries have since followed. Denmark is using biomass heavily. The Netherlands is in the middle of a big argument about how much they should use it, and it’s led to the situation at the moment where, as you pointed out, biomass is the most common source of energy in the renewable category.

Two things have changed since RED was adopted. Firstly, the subsidies offered for renewable energy have led to the rapid upscaling and industrialisation of the process. Large subsidies not only allowed the converted power stations to burn biomass, but also led to the evolution of long supply chains between Canada, the USA and even Brazil, all producing feedstock for EU power stations. These supply chains alone emit much more CO2 per kilowatt-hour than any of the other renewables, such as solar, wind and hydro, as well as nuclear energy. Their rapid industrialisation may not have been expected at the beginning, but once invested, there is a lot of ‘lock-in’, not just in the generators, but also in the sense that governments rely on the zero carbon accounting to reduce their declared emissions. So it’s become a bit addictive and it’s very difficult to actually change once you have put so much money into it. There are many powerful stakeholders now who wish to keep their subsidies, which, according to the Financial Times, are now worth around EUR 10 billion a year across Europe, including the UK, obviously.

Now we have a situation where biomass is more expensive than solar and wind energy, because their prices have come down very rapidly. For this extra cost, biomass also has this initial negative and adverse effect on the climate, unlike solar and wind energy, which have a net beneficial effect on the climate after just a few years. And it also has other disadvantages such as knock-on effects on biodiversity. Yet it’s still attracting more subsidies than the other forms of renewable energy, given the strong influence of the embedded stakeholder interests.


Several JRC researchers, along with scientists from the European Environment Agency, have stated that burning wood has a larger impact on the environment than burning fossil fuels. With this in mind, why do you think that the EU institutions promoted the idea of using wood as a form of renewable energy in 2009, even though they were most likely aware of the potential dangers?

Since the European Environment Agency’s statement in 2011, there have been many scientific publications reflecting these effects and letters signed by 800 scientists were sent to the European Parliament in 2018. There was a letter to the Commission earlier this year signed by 500 scientists, all pointing out the perverse effects of bioenergy and urging the Commission to include criteria for avoiding long payback periods in RED III. The current directive has sustainability criteria, but those criteria do not require any country to achieve net removal of CO2 from the atmosphere or to specify how quickly that should take place. So, the Commission has received substantial scientific input, including by my organisation, the EASAC, but this is countered by the sort of lobbying I’ve mentioned, concerns about energy security, and political concerns about what we would do if we couldn’t regard bioenergy as renewable and how we would meet our renewable energy targets.

It is fair to say that there has also been some debate over the science, including by some influential forestry scientists who say bioenergy is part of forestry management and a significant income stream for forestry. Questions have also been explored about whether the initial extra inputs into the atmosphere are significant in the longer term, whether subsidiary factors may reduce payback periods, about the difficulty of quantifying some of the effects on the atmosphere, and other matters. There has been quite a debate in the literature on this! The ‘pro-bio’ group has been very active in influencing the energy sections of the Commission and is also very active within the International Energy Agency. As we see it, many of these scientific arguments have some foundation, but are more detail-focused and do not change the fundamental weakness of bioenergy, which is that it makes matters worse before they can get better. And it’s really because of that major point that we’ve been emphasising that the regulations need to be fairly significantly revised, which is something that hasn’t happened yet.


In theory, the wood used in energy production should be inferior wood, which has to be harvested. Where does all the wood used in pellet factories come from?

As I mentioned, the initial carbon neutrality concept is typified by using forestry residue that was left over from harvesting wood for paper or timber or previous uses. But once you start needing to buy five million tonnes, you soon run out of genuine residue and you have to start cutting down trees, and that’s the point at which you incur this large carbon debt, because that carbon in the tree goes straight into the atmosphere in such an inefficient manner. So pellet manufacturers will certainly use residue from sawmills and other ‘waste’ wood, but this probably makes up no more than 10-20% of most of the pellet manufacturers’ input. The bulk is whole trees entering the pellet mills. The argument is that they are generally not good enough to be used for timber and may often therefore be classed as ‘residue’ – ‘residue’ being a very flexible definition, which includes tree thinning or clear cutting of a stand of forest, which just goes to bioenergy as the most financially rewarding route in that location.

The idea of just using inferior wood and talking about it as ‘residue’ may be used in public relations, but it doesn’t make much difference to the carbon budget calculations – the key is that extra carbon is being taken out of the forest stock and put into the atmosphere, and the compensating reabsorption of carbon from the atmosphere is too slow to help mitigate climate change in a timescale that can save us from catastrophic climate change.

Harvesting also affects biodiversity, which is why the EU’s biodiversity strategy document last year said that harvesting whole trees should be minimised. So again, we’ve been pointing out the conflict here, and so have many other people. But there’s a clash between what we are arguing on scientific grounds and the practical economic implications. This may be a growing problem since many future scenarios for meeting emission reduction targets envisage an increased reliance on biomass.


In British Columbia (Canada), the Forest Defenders Alliance has conducted an investigation proving that a lot of the wood that ends up in EU pellet power stations comes from Canadian primary forests. Are EU power stations also using trees from Canadian primary forests?

Well, the UK credits the south-eastern United States as the main source of its biomass supply, with the Atlantic side of Canada also credited as a significant source, along with other countries such as the Baltic States, Russia and even Brazil. The Pacific side of Canada represents a very interesting case, because the UK’s main biomass energy provider, Drax, bought Pinnacle Renewable Energy, a pellet company, earlier this year, whose operations are on the western side of Canada and whose goods are exported via British Columbia. I don’t know the detailed breakdown of the primary sources in British Columbia and Alberta, but I do know that some of it is shipped down the west coast, through the Panama Canal, across the Atlantic and to Europe, and then offloaded in Europe onto trains that deliver the wood to the power stations. And the biomass industry has announced this as a great achievement!

But if you think about that huge supply chain, it really doesn’t make any sense, does it? And it doesn’t make any economic sense without the very large subsidies that these organisations are receiving. So again, this is an example of how the subsidies that governments are prepared to pay in order to label these primary energy sources as renewable are large enough to underpin supply chains of thousands of kilometres, through the Panama Canal towards Europe.

On the Pacific side, the even more desirable market is across the Pacific, in Japan and South Korea. These countries are also increasing their consumption of wood pellets for the same reason: they can ignore the emissions from the stack and therefore that comes off their national emission figures.

As demand rises, pellet makers may continue to encounter difficulties in collecting sufficient forestry leftovers, and so logistics and economics will soon drive operators towards mass production through additional harvesting, which may well involve clear cuts on whole stands at the same time.


Is the European wood used in EU pellet power stations coming only from areas where logging is allowed? Or are we cutting wood down from areas that should not be logged?

It is very difficult to obtain accurate data on this topic and it is hard to quantify for the simple reason that statistics are not necessarily reported for illegal logging. But certainly in Romania, the general public is aware of the problems regarding illegal logging. I don’t have any information regarding how much of that is triggered or carried out to support bioenergy sources, but it is possible. But other major sources are not illegal. The largest European pellet mill, located in Estonia, is clearing many forests in Estonia and in its neighbouring countries, Latvia and Lithuania. But that is basically down to the local regulations and local zoning rules, which decide whether an area is to be conserved or access to it limited, or whether it’s up to individual landowners to decide what they do with their own forest. Until now, owners of forests that cannot be sold for higher value uses may be happy to have a market for their wood.

The Commission is aware of this problem and is refining its directive and rules on what we call land use and forestry, and has introduced a new scheme which would ultimately mean that if a country cuts down its forests for the purpose of bioenergy, for example, then the loss of carbon in the forest will have a more direct and obvious impact on its national emissions. And that, in theory, could act as a counterweight to burning. But at the moment, the main subsidies are for burning wood and there are no comparative subsidies or financial rewards for maintaining or improving the carbon stock in a forest. So from the point of view of income and economics, a standing forest represents a lesser value than a forest that has been burnt and put into the atmosphere. On our way to getting the balance right between improving carbon stock in the forest to keep it out of the atmosphere and making efficient and environmentally friendly use of the biomass, the economic subsidies are still distorting that decision and leading to the environmentally unsustainable burning of both European and imported wood.


What alternative means of energy production would you deem climate-friendly?

The ability to be climate-friendly depends on how much the greenhouse gases in the atmosphere can be reduced and how quickly. The latest report by the Intergovernmental Panel on Climate Change emphasised that we need immediate, large-scale and sustained reductions in emissions. So any technology which ends up increasing emissions for over 10 years is hardly helpful at the moment. So the priority has to be wind and solar, which have a fairly short payback period, and produce almost zero CO2 when they generate electricity. And even if you count the CO2 that was emitted in the construction and material production phases, their average lifetime emissions are of the order of 10 to 30 or 40 grams of CO2 per kilowatt-hour. In comparison, biomass power stations emit around 1 000 grams of CO2 per kilowatt-hour. So you’ve got a 50-fold or even larger increase in CO2 emissions between these two so-called renewable energies. Of course, some countries are stronger in wind and solar than others. And of course, you have to look for technologies that can deliver the energy you need.

So countries that currently depend on biomass do have to replace it with something, and the alternatives are mainly focused on demand reduction, i.e. reducing the need for energy so you don’t have to produce so much of it. Then you’ve got nuclear energy, which unfortunately had such negative effects at Fukushima that they then reverberated in Sweden and Germany and made the public there less willing to accept nuclear electricity. But I’ve lived in Japan for a while, including during that period actually. And the effect of the Fukushima disaster here was that all their nuclear power stations were shut down and replaced by coal, oil or gas power stations. So that had a direct effect on national emissions, which was quite substantial and is still being felt because it proved that it is difficult to restart many of those power stations. And of course, in Europe, we have this tendency to try and shut down existing nuclear power stations, which are then replaced with fossil fuels. So the key measure of effectiveness, I think, has to be focused on the basic CO2 emissions.

Biomass can contribute to that objective if feedstock is limited to those with really short payback periods and efficiency is maximised by using both heat and power, but that will mean that some of these large facilities that import from thousands of kilometres away no longer make any sense. Local plants using local sources of feedstock could still make some sense. Unfortunately, the regulations do not differentiate at the moment.

In terms of other technologies, geothermal has more potential than many people are willing to give it credit for at the moment. There are some interesting, innovative technologies coming from North America. And, of course, in some coastal areas, tidal power would make sense. And again, once they are installed, they would emit more or less zero CO2 when they generate electricity.


Why is burning forest biomass still seen as a form of renewable energy by the EU, when research has proven that it is damaging to the environment?

There is a widespread acceptance of the science. Even the pro-bioenergy scientists accept that you have to move backwards before you can actually make any progress and accept the issue of the payback period. The fact that science has not made more of an impact on the regulations may be due to the embedded resistance to change of large assets, large financial support, the political dependency of governments on biomass being treated as a renewable energy to meet their renewable energy targets and the fact that a lot of these facilities do have a very strong local political base and employ people. The supply chain is quite long and relatively inefficient as it employs a lot of people. There are ships, trains, ports and loading facilities. The harvesting areas give a boost to the local forestry industry. Thus, there are a lot of economic stakeholders involved. And of course, the economic stakeholders have a large political influence and the science can be an inconvenient truth that interest groups prefer to sweep under the carpet in order to carry on their business as usual. It is a classic case of science and facts only going so far and politicians bringing in other economic factors and employment factors, with their judgement sometimes being based more on those factors than on the basic science.


What can EU citizens do to remove burning forest biomass as a form of renewable energy from RED?

In the UK, every night on the TV, you are able to find advertisements from energy companies claiming they are climate-friendly or claiming that they are doing something for the climate. Some of them are genuine, but some are greenwash. Some of those claims are based on buying carbon offsets as part of their electricity, which comes from fossil fuels. But some of them are using biomass electricity as green energy and it is quite difficult for consumers to differentiate. But if you are concerned about that, the important thing is to ask the company that supplies you with electricity exactly where it gets its energy from. For instance, some electricity companies state that their source is wind, solar or nuclear, while others talk about the energy being ‘renewable’ without specifying how, and of course, that may well include biomass electricity, which is not contributing to climate change mitigation. So, it is a question of trying to cut through all the smoke and mirrors and find out the truth before you make a decision.

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