ABSTRACT
The global energy system is based predominantly on fossil fuels. Over the last decades the use of fossil fuels grew continuously until now, 2013. But more and more people start to realize that a continuous further growth in the use of fossil fuels will endanger the well-being of future generations, because the combustion of fossil fuels is the main cause of climate change. In 2011 according to the working paper 1 [1] of the Intergovernmental Panel on Climate Change (IPCC) 90% of the global CO2 emissions were caused by the use of fossil fuels and CO2 came up for 75% of all greenhouse gas emissions. In the meanwhile the concern about climate change is growing in many countries. The gathering of more than 100 heads of states or governments at the climate summit in New York on September 23, 2014, was a strong demonstration of the growing awareness of the climate problem. But the core message how to mitigate
climate change successfully did not reach the public audience. It will not be enough to provide several billion dollars to countries in development, it will not be enough to push for more e-mobility and better thermal insulation of buildings! If the industrialized countries have to reduce the greenhouse gas emissions by 90% within 30 years in order to achieve the 2°C target-and this is reality-they have to leave the fossil fuels in the earth’s crust and replace them by renewable energies. And this decision should be taken now to give the business community and financing institution clear signals on how to invest. It is not surprising: important and powerful parts of the busi-ness world and the public dislike this truth. They promote new technologies like carbon capture and storage (CCS) or bio-CCS to reduce CO2 from the atmosphere, because these technologies would allow us to go on with the combustion of fossil fuels as usual hoping that the next generation will collect the carbon from the atmos-phere and put it back into the earth crust (bio-CCS). But these con-cepts are not at all convincing. They are similar to the discussion of nuclear fusion that was seen as the golden key to all future energy problems fifty years ago. I remember the saying of a representative of Electricité de France (EDF) during a meeting in Brussels with respect to nuclear fusion: “C’est une energie de l’avenir, et la rest-erá.” The same will happen with CCS because nobody can explain convincingly why we should first dig out the carbon and then dig it back using 70%–80% of the energy in the fossil carrier. This is that inefficient and expensive as compared to the accelerated de-ployment of renewable energies that every decision-making body following rational arguments and not the pressure of the fossil in-dustry will favor renewable energy instead of CCS. Certainly improved energy efficiency in all parts of the energy system is an important part of the new energy strategy. But it will not be sufficient. In many parts of the world the energy demand will grow in the next years, because the consumption is still very low and the population is growing. The key strategy to mitigate climate change is the transformation of the energy system from fossil sources to renewable energies. Go 100% renewable should be the message of the century. But this is the long run goal that might divert the attention of the urgent steps needed in the next 20 years until 2035. Calculations of the World
Bioenergy Association (WBA) on the basis of IPCC reports illustrate that without relying on CCS the use of fossil fuels should be halved until 2035 in order to attain the 2°C target. This can be achieved if the majority of the countries on the globe starts a consequent policy in favor of all renewables such as wind, solar power, hydropower, geothermal energy, and biomass and curb all subsidies for fossil fuels. Which role will biomass have to play in an energy system using only 50% of the fossil fuels of today given an increased demand for energy in some parts of the world and a reduced demand in other parts? 3.1 Differences between Renewable Energy
SourcesIt is important to analyze the basic properties of different renewable energies and fossil sources. (a) Renewables without feedstock cost: Wind, solar power, solar-thermal power, hydropower, and geothermal power have no feedstock cost. They use the solar radiation in direct form (solar power, solar-thermal) or in indirect form (wind, hydropower). Geothermal is an exception using energy from the earth and not direct from the sun. All these energies have high capital cost but low running cost. As soon as the installations are constructed they deliver energy at low marginal cost. It is more economical to let them run, and shut down other generating units if there is an overproduction. These energies deliver mainly electricity. Their fast development explains partly why the transition of the energy system is frequently reduced to a transition of the electricity sector. The problem of these energies is the intermittence of the supply and the difficulty to store the excess electricity in a cheap way. Another aspect is the difference in the quantity of generated electricity from solar-and hydro-installations between the winter and summer seasons. Some publications promote the use of electricity for heating overlooking the fact that the peak demand for heat appears during the winter period, whereas the peak generation of electricity from hydropower and solar power occurs during the summer period. Only windmills
offer electricity all around the year in a more or less stable way. These renewables without feedstock cost cannot replace fossil fuels in the heating sector in the next 20 years. (b) Biomass (the renewable with feedstock cost): Biomass is chemical stored solar energy. The plants absorb carbon from the air in the form of CO2 and build up carbon hydrates via the photosynthesis. Solar energy powers this process and is stored in the carbon hydrates (biomass). This stored CO2and energy is released either by decay of the biomass as it happens in nature or by using it for food, feed, energy, or material purposes. Hence sustainably produced biomass is a carbon neutral energy source. Its use does not increase the carbon content of the atmosphere, as long as the production of biomass is equal or bigger than its use-this is one of the important criteria of sustainable biomass. The production of biomass as feedstock for energy is related to different cost elements such as the cost of land, production, collecting, transporting, storing, and processing biomass. Biomass can be converted to all forms of final energy such as heat, transport fuels, and electricity on the basis of a broad variety of conversion technologies. Bioelectricity is more expensive than electricity from hydropower or wind. In most countries of the Northern hemisphere bioheat is cheaper than heat from fossil fuels with the exception of those countries with subsidies for or a very low taxation of fossil fuels. Biofuels are at present the only available alternative to fossil transportation fuels for heavy trucks, big ocean ships, planes,
and tractors used in agriculture and long-distance traffic in individual cars. In any case the cost of final energy from biomass are always determined by the cost of the feedstock and the cost of the conversion-finance, depreciation, operation, and maintenance costs. These facts have to be considered when developing a bioenergy strategy. (c) Fossil energy carriers such as carbon, oil, and gas have also feedstock cost and conversion cost. As opposed to biomass the combustion of fossil fuels adds additional carbon from the earth’s crust to the atmosphere, blows up the natural carbon cycle, and causes climate change. In addition in many parts of the world the production of fossil fuels is declining, making
more and more countries dependent on the small group of producer countries. Climate change and the upcoming scarcity in many parts of the world are the main reasons why our societies have to leave fossil energies as fast as possible. 3.2 Development Goals for Biomass to EnergyThe underlying assumption of this text can be summarized as follows:
The global society-the citizens, the governments, the business community-is willing to achieve the 2°C target in this century and consequently to transform the energy system in a first step until 2035 accordingly, without relying on CCS. This requires us to reduce the use of fossil fuels by 50% until 2035. Even if electricity from wind, solar power, and hydropower grows rapidly until 2035, for generating more renewable electricity in 2035 than the total generation of electricity today biomass will also have to grow fast and deliver 140-150 EJ primary energy by 2035 [2]. The main target markets of biomass will be heat, transport fuels, and electricity generated in cogeneration units or in installations, especially biogas, that help to stabilize the electricity grid.
