Traditional vs. modern biomass: the transition

The plot presented in this post, made with Gapminder (thanks to Hans Rosling), is a comparison of use of solid biomass for energy purposes (expressed as % of TPES*, on the y-axis) among different selected countries.

This comparison is made including a United Nations’ indicator, called Human Development Index, HDI (on the x-axis). The HDI is “a composite statistic of life expectancy, education, and per capita income indicators”, and is used to rank countries in terms of human development” (Wikipedia). Countries with a HDI > 0,85 are considered with a very high HDI, countries with a HDI < 0,50 are considered with a low HDI.

From the plotted data, we note that:

  • Countries with a low HDI (e.g. <0,50) evidence a high use of solid biomass for energy purposes (> 30% of the TPES). For some African countries, most of the produced energy is coming from solid biofuels.
  • Countries with a medium/high HDI, evidence a lower use of solid biomass for energy purposes (<25% of the TPES).
  • Over time, the use of solid biofuels to produce energy is decreasing in countries with a low HDI in the time frame 2000-2010 (but there are some exceptions!). The use of solid biofuels to produce energy is increasing in countries with a very high HDI  (HDI>0,75) in the time frame 2000-2010.

This trends might be explained looking at:

  • The progressive reduction in the use of traditional biomass (non commercial by-products, animal dung burned for cooking and heating purposes, in developing countries). The World Health Organization estimates that 1,5 M premature deaths per year are directly attributable to indoor air pollution from the use of such traditional biomass and charcoal.
  • The investments, e.g. in the EU countries, to increase the share of energy produced from “modern” solid biomass, as an increasing share in their TPES.

The trends of the points representing the countries, moving along the timeline, draw a “hockey stick” shape. Based on such representation, some interesting questions arise:

  • How quickly traditional biomass can be substituted by other renewable energy sources (including modern biomass)?
  • Is it possible to convert traditional biomass in modern bioenergy technologies (reducing e.g. indoor air pollution)?
  • How to calculate the maximum possible contribution of energy from solid biomass in the TPES for each country? Can all countries with high values of HDI, follow the “hockey stick” trend?

What is your opinion? Comments are welcomed.
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*Total primary energy supply (TPES) is the “total amount of primary energy that a country has at their disposal and it is made up of: indigenous production +  imports –  exports –   international marine and aviation bunkers +/- stock changes.” (IEA, 2017).

 

Bioenergy state-of-the-art: 10 reports from 2016-17

  1. IEA, Roadmap development and implementation, 2017
  2. IEA, Bioenergy balancing the grid, 2017
  3. IEA, Work programme 2016-2018, 2017
  4. IEA, The status of large scale biomass firing, 2016
  5. IEA, Small Scale Energy from Waste: Drivers and barriers, 2016 
  6. IEA, Status overview of torrefaction technologies, 2016
  7. IEA, State of Technology Review – Algae Bioenergy, 2017
  8. IEA, Biorefinery Optimization Workshop Summary Report, 2017
  9. IEA, Status report on thermal biomass gasification in countries participating in IEA Bioenergy Task 33, 2016
  10. IEA, The European wood pellet market for small-scale heating Data availability, price developments and drivers for trade, 2016

Operational excellence in biomass energy plants

Operations costs, in biomass energy plants, depend on input feedstock quality. To optimize operations and find economic optima, three preliminary steps could be considered.

1) Fuel costs [€/MWth], how do they vary depending on the fuel quality?

Fuel Such as Cost variation (average)
Easy Sawdust, whole tree chips 100%
Average Bark, stumps, forest residues 67%
Challenging Demolition wood, plywood residues 56%
Very challenging Agrofuels, SRF 44%

Note: figures, averaged for solid fuels (Europe).

2) O&M costs [€/y]: chemicals (~20%), electricity (~20%), maintenance (~60%), how do they vary depending on the fuel quality?

Fuel Such as Cost variation (average)
Easy Sawdust, whole tree chips 100%
Average Bark, stumps, forest residues 124%
Challenging Demolition wood, plywood residues 154%
Very challenging Agrofuels, SRF 194%

Note: Values averaged for thermal energy generation (50-500 MWth, fluidized beds boilers), including data from virtual.vtt.fi/virtual/combust.

3) Evaluate the economic feasibility balance including the reduction of fuel costs and the increased O&M costs for the specific installation.


As a summary, first, it is necessary to classify fuels according to operational risks (not a trivial task: even the same fuel type could be Easy/Average/Challenging/Very challenging depending on its origin and properties). It might be smart to use predictive analyses (e.g. BIOFACT-C) and previous return of experience.

Second, based on such 3-step preliminary analysis (and the technical constraint of the specific installation with its components), it is possible to assess with which new fuels it would be possible to operate the energy plant.

How do you perform your operational excellence analyses? Are you expanding the capabilities of your technologies? Any considerations is welcomed.

Bioenergy technologies role in the 2°C Scenario: how the market could change in the next 15 years?

The Energy Technology Perspectives (ETP) is the International Energy Agency’s publication which estimates how technologies impact the objective of limiting the global temperature rise to 2°C.

The 2°C Scenario (2DS) of the ETP 2016 lays out an energy system deployment and an emissions trajectory consistent with what at least a 50% chance of limiting the average global temperature increase to 2°C, up to 2050. The 2DS sets the target of cutting CO2 emissions by almost 60% by 2050, compared with 2013.

If jumping to the conclusions of the study, current clean energy technologies deployment is still behind what is required to meet the 2DS Scenario, even though recent progress on electric vehicles, solar PV and onshore wind is promising. But what shall be the role of bioenergy in order to pursue this 2DS scenario?

  • Firstly, biomass becomes the largest energy source in 2050 in the 2DS (the share of fossil fuels in primary energy is in the 2DS, 45%, almost halved by 2050 compared to today, 81%).
  • Secondly, according to the authors and referring to Fig. 1, if looking at the primary energy consumptions (for production of secondary carriers such as biofuels and electricity), a rapid increase in the total supply of energy from biomass sources is required. The sectors which will be consuming the most are refineries (sharply increasing demand) and, to less extent, power plants. On the contrary, direct consumption of biomass energy is expected to remain constant.
  • Thirdly, if focussing on the final energy consumption, even if the total use is kept constant (see direct consumption), the industrial and residential sectors will behave differently. A decrease in residential use of biomass energy, mainly driven by the further decrease of traditional biomass used for cooking, is expected. Hot water production shall become the most important application for residential direct use. An increase of the industrial deployment of bioenergy is expected, mainly in relation to the direct production of chemicals and its use in the cement industry.

Fig. 1 – Author’s elaboration of Energy Technology Perspectives 2016 bioenergy technologies data.

To conclude, the report suggests that bioenergy technologies shall contribute to the developments to limit the average global temperature increase to 2°C, with the use of biomass in refineries, power plants and industry (cement, chemicals), cutting CO2 emissions and improving the sustainability of our energy system. All data of the study, including the ones to produce the Fig. 1 can be downloaded and explored dynamically at www.iea.org/etp/explore.
Lucio De Fusco, PhD

 

Torrefaction of biomass: does it reduce the risks of fuel ash slagging, fouling and corrosion in combustion?

Introduction

The torrefaction of biomass is a thermal process performed at 240-300°C to upgrade a raw material to an output solid with increased energy density (MJ/kg), more homogenous and less vulnerable to biodegradation. The fuel obtained after torrefaction has properties which allow an easier handling and improved thermal performances in combustion. Beside physical properties, the fuel chemical composition is changed. Such changes influence the inorganic matter content, composition, association, and therefore the operational risks in combustion due to inorganic matter.

Methodology

With this brief work, the potential of torrefaction to reduce the risks of fuel slagging, fouling and corrosion in combustion (due to the changes in the inorganic matter), by using a fuel characterization tool called BIOFACT, is verified. The analysis only refers to fuel composition. Specifically, the module to characterize the fuel for combustion BIOFACT-C is used. This module considers (v. 1.2): fouling, agglomeration/slagging, corrosion (high temperature), HCl emissions, particulate matter (PM10), SOx emissions. For each of such risks considered, the tool computes a semi-quantitative evaluation from 0 (lowest risk) to 100 (highest risk).

Two fuel samples are analyzed, considering the properties of the fuels before and after torrefaction, at different temperatures:

  • Eucalyptus wood, raw and torrefied at 220, 250, and 280°C
  • Birch wood, raw and torrefied at 240 and 280°C
Results

The results are presented below.


Depending on the fuel, torrefaction could influence the risk of operational issues related to the fuel ash. Emissions (SOx, HCl) and high temperature corrosion might be reduced, depending on Cl and the other ash constituents. Nevertheless, based on the preliminary analysis – valid for those specific fuels – fouling and agglomeration/slagging are not reduced. PM10 emission risk could increase, due to the higher relative concentration of some PM forming inorganic matter in the fuel (on weight).

This preliminary analysis shall be confirmed by experimental results. The interested reader could look at the related working paper (which includes references), accessible here.

 

MWh from solid biomass in Europe (2000-2016): who produced the most?

According to the Renewable Electricity Capacity and Generation Statistics 2016 by the IRENA [1], in brief:

  • (2014) Germany, UK, Sweden, Poland and Italy are the first 5 countries ranked in terms of energy produced from solid renewable fuels
  • (2014) Sweden, Denmark, Estonia, Austria and Belgium are the first 5 countries ranked in terms of energy produced from solid renewable fuels per million inhabitants
  • (2000-2015) In the last 15 years, Poland, Estonia, Hungary and UK invested the most in new capacity from solid renewable fuels (evidenced also in the variation in the total energy produced) with respect to the year 2000 (>10 times)
  • (2012-2015) At country level, in the last three years, a relative reduction in new capacity built is registered (according to the IRENA [1]) for Belgium, the Netherlands and Austria


All data available in [1], elaborated by the author.
[1] International Renewable Energy Agency (IRENA), ‘Renewable Electricity Capacity and Generation Statistics 2016‘, data available at http://resourceirena.irena.org/, accessed 8/04/2017.