Economic efficiency and CO2 assessment of selected biomass-based energy sources for Austria (BIOWERT)

The motivation for this project are the current environmental and energy policy efforts to decar-bonize the energy system (based, among other things, on the COP21 conference and the Austri-an government's Climate Neutrality 2040 programme) and its conversion to a sustainable one. In this context, the future energetic use of biomass as a largely CO2-neutral energy source plays an important role.

The core objective of this project is to evaluate selected biogenic primary resources and conver-sion technologies for biomass energy utilization, different conversion chains and different ener-gy sources (heat, electricity) and products (Synthetic Natural Gas (SNG), Fischer-Tropsch (FT)-Diesel) from the point of view of available potentials, CO2 intensity and economic efficiency. The starting point is that currently approx. 230 PJ of primary energy are produced from biomass, which is approx. 16% of the total primary energy.

The method of approach consists of a discussion of possible potentials up to 2040, an analysis of the CO2 factors of the chains under consideration, a static comparison of the economic efficiency of biogenic chains with fossil chains and a scenario analysis of the development of economic effi-ciency up to 2040.

The most important results of these analyses are:

The value initially depends on the available quantity. There is still possible additional potential in the areas of more efficient utilisation of forest resources, short-rotation coppice and miscanthus. Furthermore, individual potentials depend on the wood-processing companies. With regard to future potentials, the following insight is ultimately important: It is of course of interest to esti-mate as precisely as possible what quantities of biomass will be available (in absolute terms) for energy use in the future. More important than the calculation and documentation of detailed figures for specific future values is to understand the method of their development, especially the parameters on which the potentials (and their costs) and the resulting quantities on the market depend.

Concerning the CO2 factors of individual biomass fractions, it should be noted that these differ only insignificantly and essentially depend on how many additional processing steps are required up to energy conversion ("combustion").

With regard to the economic viability of biomass, it can be stated from a current perspective - around 2020 - that biomass is clearly economical for the heat fractions. For electricity, both with and without combined heat and power generation, the fossil alternative of natural gas is more cost-effective, primarily due to the better efficiency of natural gas power plants and the lower investment costs. For FT diesel, the fossil alternative is also slightly more cost-effective. The clearest difference is with SNG, where natural gas is more than half as cheap. This means that considerable subsidies would be necessary to make SNG economically viable. If sawmill by-products (SNP) were used instead of wood chips, slightly fewer subsidies would be necessary, and slightly more for short-rotation coppice. From a dynamic perspective up to 2040, the devel-opment of the CO2 price and the price of natural gas have the most important influence on the economic viability of biomass utilisation.

The major conclusions of these analyses are: The most important energy policy measure is a con-tinuously rising CO2 price. Already in a low CO2 price scenario, this means that most biomass-based applications/products will become economically viable by 2040. Furthermore, subsidies, e.g. feed-in tariffs for electricity or SNG production, naturally make the use of biomass more competitive compared to fossil fuels. Yet, the (subsidized) production of SNG (or FT diesel) only makes sense if this appears necessary from a political point of view, e.g. if there is no alternative to "green gases" for high-temperature processes in industry.

In an outlook the following aspects are important: 

1. How can the development of the CO2 price be modeled in scenarios?
2. Which scenarios are relevant for biomass prices?
3. How can the growth of the wood processing industry (and thus the available sawmill-by-products) develop?
4. Which areas will be available for energy use in the future, e.g. for short-rotation coppices?

Energy Economics Group (EEG), TU Wien

• Prof. Dr. Reinhard Haas
• Nadine Gürer, MSc.
• Dipl. Ing. Frank Radosits
• Prof. Dr. Amela Ajanovic
• Dr. Marlene Sayer