Based on the Basic Law for Establishing the Recycling-based Society, energy recovery from waste has been found to be an appropriate means for tackling burnable waste that cannot be put into the material recycling stream. While on one hand, the number of municipal solid waste disposal facilities has been decreasing, along with the total amount of waste nationally. On the other hand, the ratio of waste recovery facilities and the number of waste-generating facilities is on the increase. The Great East Japan Earthquake made it clear that municipal solid waste disposal facilities are vital regional energy centers due to the fact that they can contribute to preservation of the living environment and to sanitation improvements. Moreover, there is a need to take the appropriate measures for dealing with deterioration of municipal solid waste disposal facilities and reforms in electric power systems, as well as other systems.
With these movements of waste energy recovery in mind, the Ministry of the Environment is taking steps to support waste energy recovery, including waste power generation, through its Grant for Establishing a Sound Material-cycle Society and the Special Account for Energy-related Activities.
To actively promote WtE (Waste to Energy) plants with high power generation efficiency, the “Subsidy System for Promoting the Establishment of a Sound Material-Cycle Society” raised its subsidy rate up to 50%. This subsidy system, with 5-years validity, started from fiscal 2010 and ended in fiscal 2015. This article verifies how much the elemental technologies encouraged by the system have been adopted and to what level they contribute to the improvement of power generation. Technologies such as Starved Combustion, High Temperature and High Pressure Boilers and Condensing Extraction Turbines have been increasingly accepted since the subsidy system was enacted. However, technologies like abolition of the Zero-effluent Closed System, etc. have not been, due to social conditions and development of infrastructure on location. As a result, the average power generation efficiency rose from 14.1% to 18.5% ; changes particularly in those small-scale plants that were not emphasized in the past are remarkable. To make WtE plants contribute more to the realization of a sound material-cycle and low-carbon society, further improvements on power generation efficiency will be required under a new subsidy system in the future.
With regard to waste power generation in Japan, although average power generation efficiency for all existing facilities is currently only at approximately 11.9%, the rate for facilities planned for completion in the next five years is at 20% or higher, and the improvement in efficiency is definitely progressing. Given the scheduled completion of these facilities, which will combine incineration facilities with methane fermentation facilities and aim to be small-scale, high-efficiency power generation facilities with capacities of 100 to 200 ton/day, circumstances surrounding waste treatment are steadily undergoing change. In this paper, some of the contents of a manual for the preparation of energy recovery type waste treatment facilities, which started in FY2014 with the involvement of JEFMA, are introduced. These include EGR+SNCR, high-temperature high-pressure waste heat boilers, on-site catalyst denitrification regeneration, fly ash circulation, waste water recycling systems using membranes, and other technologies for further improvement in efficiency.
Power generation from waste incineration is a more stable power source than other renewable energy forms and is also a dispersed power source that is connected to the power demand area. For these reasons, it is expected to become an effective solution to the problem of global warming. Since 2010, Japanese waste incineration plant companies have merged with European companies in order to promote progress in the global technical reorganization of this field.
High efficiency power generation technologies used by European companies are little different from Japanese technologies. For example, use of low excess air ratio combustion, high temperature and high pressure steam conditions, adoption of water cooled steam condenser and installation of selective non-catalytic reduction. However, it is important to commercially benefit from waste management in Europe, so they actively work on recovery and supply of energy from waste and are operating many plants that have a steam condition of over 4MPa and over 400 deg C to supply not only power, but also heat as well.
This paper reports on high power generation efficiency using gasification technologies in Japan and Europe. Gasification has become one the great interests in Europe once again because of its possibilities for fuel production from waste and biomass and for alternative thermal treatment technologies.
In Japan, gasification suppliers focus on high steam parameters and low-stoichiometric combustion to achieve high power generation efficiency. In Europe, plasma and fluidized bed gasification technologies have been developed. Plasma gasification technologies reform the syngas from the gasifier by plasma, and introduce the reformed syngas to the gas engine in order to achieve high power generation efficiency. Fluidized bed gasification applies a combination of high-temperature ceramic filters with high boiler parameters.
Gasification suppliers have continued to develop and improve upon their technologies. Further development and new breakthroughs can be expected in the future with the aim of achieving higher power generation.
Initially, plans for municipal incineration plants simply meant developing hygienic facilities where waste processing could take place. In light of what we know from the viewpoint of global warming or what we have learned most recently from our experience of the Great Eastern Earthquake, there are now many reasons for developing municipal incineration plants that can also be used as energy recovery facilities and regional disaster prevention centers based on high-efficiency power generation.
This paper introduces such new trends in the development of incineration plants for municipalities.
This paper introduces the differing attitudes and methodologies about effective utilization of waste-generated energy with regard to pre-deregulation and post-deregulation of electric utilities. It outlines what deregulation actually means. Up to now the main topics talked about with regard to waste-generated power were selling power at the highest possible price and purchasing the public facility at the lowest price. Following deregulation, these new forms of energy took on the power to freely decide costing for waste-generated energy and pricing for supplying power to public facilities.
The “power” + “power distribution” (consignment of new energy) + “retail” method of general electric companies can now make the changeover to new enterprises that specialize in distribution of renewable power. The circulation of funds brings increased profits while at the same time, free energy pricing keeps funds from leaving the area, which can contribute to stimulation of the local economy. The paper elucidates on why cities, towns and villages should agree to take in companies providing new forms of power and why they should supply power to public facilities. It also explores what risks accompany starting up these businesses and explores the factors involved in such risks with regard to planning for the launch of renewable energy sources.