Growing doubts around the merit of burning wood and other solid biomass as a large-scale solution for cutting carbon emissions from power generation may see the renewable fuel dumped —in the same way diesel and liquid biofuels have lost favor as” low-carbon solutions” in transport.
Burning biomass to generate electricity is supported by some in the U.K. as a low-carbon renewable fuel with fewer carbon emissions than those produced by burning gas and coal. As a result, Britain’s tough carbon emissions targets have made the country a massive importer of wood. Drax power station, the biggest biomass power plant in the country, imported 6.5 million tonnes last year.
Flaws in the biomass-for-electricity-generation model should not be ignored just because wood is a renewable fuel, or because of claims that it is carbon neutral.
Biomass, in fact, is not carbon neutral, and there-in lies the risk. Wood-burning obviously emits plenty of carbon dioxide, and whether it is overall carbon neutral depends on sophisticated lifecycle analysis of the feedstock and on the type of wood burned, whether from whole trees or forest waste. In addition, biomass burning leads to particulate emissions, which affect air quality when burned at scale in cities.
Regulators do appear to be catching up with these questions about the environmental desirability of the fuel, which should sound alarm bells for investors. Rule changes that limit the use of these commodities, whether liquid biofuels in transport or biomass in power generation, will cut returns to investment, creating stranded assets.
For purposes of measuring climate impact, supporters of burning biomass base their carbon emissions estimates on rather selective accounting. Drax, for instance, reports its biomass carbon emissions at 34 grams per megajoule (MJ), a fraction of those produced by gas and coal electrification. But Drax assumes that all the CO2 coming out of its smokestacks is reabsorbed by trees growing on the plantations where the company harvests wood. The question as to whether all of Drax’s carbon emissions are really offset in this way, over several decades, is very complicated, and too important to ignore.
Nor should one ignore the impact of wood-burning on air quality. In addition to Drax, power plants at Wilton and Lynemouth burn biomass. Drax, Wilton and Lynemouth were the U.K.’s fifth-, sixth- and seventh-biggest point sources of very fine particulate matter (PM2.5), as of 2014, according to the latest available data from the U.K. National Atmospheric Emissions Inventory.
PM2.5 is one of the most dangerous types of air pollutants, according to the World Health Organization, and is responsible for triggering cardiovascular and respiratory diseases including lung cancer.
REGULATORY CHANGE IS AFOOT, as seen in part in the European Commission’s proposal last year to change the EU Renewable Energy Directive to require that, for the first time, new biomass installations achieve certain carbon emissions savings and meet other “sustainability criteria.”
These draft proposals are presently under scrutiny by European Union governments and the European Parliament. Last month, the environment committee of the European Parliament voted to phase out liquid crop-based biofuels for transport in a proposed amendment to the Renewable Energy Directive, a move that highlights similar risks faced by biomass power producers. And the mayor of London last month called for a reduction in word-burning emissions.
Those policy assertions followed new emissions data showing that every area of London exceeded World Health Organization guidelines for PM2.5 and that 7.9 million Londoners lived in areas exceeding the guidelines by at least 50 percent. (Of course, there are other sources of PM2.5, including tire wear and exhaust from diesel vehicles, once touted as a low-carbon technology.)
The recent regulatory activity—by the European Commission and the London mayor’s office alike—is common-sense change that will serve to draw attention to a fuel that has sailed mostly under the radar of emissions regulation until now.
The “dieselgate” scandal that engulfed Volkswagen two years ago stands today is an example to keep in mind here. Dieselgate demonstrated the all-too-real risk of ignoring well-understood problems—in that case, nitrogen oxide emissions associated with burning diesel — in favor of other policy priorities (superior fuel efficiency).
The particulate and carbon emissions associated with burning biomass are well understood, if complex, and regulators may be poised now to change rules that support its use as a clean renewable fuel.
Gerard Wynn is an IEEFA energy finance consultant.