Biomass was once upon a time the totally predominant energy resource for humankind, aside from the direct sunshine. During the process of industrialization other energy resources like coal initially and later oil became very important. In Sweden a big project to harvest peat in a year-round production process started around 1912, but after the First World War the project was stopped, as the peat could not compete with coal. During the Second World War a similar project was started up again. Besides this, a major emphasis was placed on using wood as the basic resource for production of any kind of chemical to replace oil. After the war still the use of oil became too competitive to peat and wood for this purpose, so the projects were shut down again. Oil became the dominant primary energy resource. In Sweden nuclear power was instead seen as the replacement for oil in the future, and during the 1970s and 1980s 11 nuclear reactors were started up. Actually they did replace primarily oil, and the use decreased from 2/3 of the primary energy demand to only 1/3, roughly. Then the Three Mile Island incident occurred in the US, and the politicians said – no more nuclear power. After a referendum in 1980 it was said that we should not build new reactors after the existing ones had been “phased out” for technical reasons. The direction should be towards renewable energy instead. In 1992 after many discussions the politicians agreed on a carbon tax on fossil carbon. It meant approximately 1.6 €cent/kWh in extra tax. This really spurred on the introduction of bioenergy. Before this bioenergy use was 55 TWh/year, primarily in pulp and paper industry as spent black liquors. In 2012 the total use was approximately 140TWh/year, which should be compared to 400TWh/year total uses and approximately 130TWh/year oil use.As suchwehavebioenergy as the singlemost important primary energy in an industrial country. This historical outlook is quite interesting. In reality we should be able to take a similar course

also in most other countries in the world where we have agriculture and forestry. The biomass resources are not used as efficiently as they could be today, and a lot of it is just decomposing in the fields or in the forests, or even being combusted just to get rid of it. For those using biomass as the primary source for cooking food the efficiency is often not more than 10%, compared to 117% in many co-generation plants with exhaust condensation in Sweden. In this book and in a parallel book in this series on conversion of biomass we want to give

an overview of the existing and potential biomass resources, as well as the methods available today or in the near future for conversion of biomass to all our needs. This means looking back to the 1940s when the war made oil unavailable, and wood was used for everything. Today the reason is not the war-blockage but the worries about both global warming and the trend towards more limited oil resources available easily, and thereby increased prices. During the 1980s and 1990s the oil price was normally around 20 $/barrel while during the 2000s it increased to around 100-120 $/barrel. This of course means that alternatives become more interesting, and biomass is one of few resources that can be easily stored. This is why we believe it is worth writing these two books in the overall series of renewable energy. The combination of biomass, solar power and wind power, with the complement of hydro power, can easily replace all fossil fuel energy within the next fifty years, if only the right incentives are implemented, like the carbon tax in Sweden in 1992. So the problem is the political will, nothing else. If it had been economically disastrous to do Sweden would have been a very poor country in 2012, but this is not the case. This shows that if a political will and brave politicians take the right actions you can also develop the countries in a positive way generally. I am very happy that the interest for bioenergy is vast all over the world. It is my pleasure

to note that chapter authors come from all parts of the world, including the Americas, Africa,

China, India and Europe. It also shows that development and demonstration of new technologies is nowadays a global activity, and not something only for some chosen few. The books are intended for interested engineers, people working for authorities, researchers,

students at high schools and universities as well as for everyone interested in our future renewable energy systems. With that I wish you all pleasant reading. Enjoy the ride!