HEAT & POWER Green Energy from Mount Iizuna A FAMILY OWNED COMPANY, Miyazawa Wood Working Industry Co., Ltd (Miyazawa) recycles wood at the base of Mount Iizuna. Miyazawa together with other six companies in the Hokushin area, including a forestry company, a waste service company and a construction company, together founded the Cooperative Business Association in 2003 to focus on new utilisation of wood biomass for power generation. The 1.3 MW plant, the first of two plants operated by Miyazawa, started operation in 2005 and is located in a mountainous region. However, infrastructure including high-voltage cables and roads was already well established thanks to the nearby Nagano Olympic Stadium, reducing the initial investment. The main fuels used at this power plant are construction and demolition wood waste. Since the FIT system was introduced, thinning timber increased in availability while demand for pulp materials decreased. So Miyazawa built a second 1.5 MW plant beside the first, based on the same model, and operation began in January 2014. The second plant mainly runs on unused thinning wood. The power plants have stoker furnaces installed, which are able to burn materials with a moisture content of up to 55 percent. Raw chips are fed in without controlling the moisture content. Miyazawa manages its own fuel supply, producing some materials and buying unused materials from other companies. They also accept waste wood with a so-called “inverse onerous contract” under the Waste Management and Public Cleansing Act and supply chipped wood to the power plant. Crushed chips from waste wood construction waste wood – considered “recycled wood” under the FIT scheme — are mainly used at the first power plant, while woodchips from forest thinning — “unused wood” under the scheme — are mainly used at the second plant. Wood in the “general wood” category is not used, because it is difficult to obtain certification from the FIT system. Green Circle Co., Ltd., one of the cooperative members, sells the electricity from the first plant to facilities such as ski resorts, and from the second plant it sells to local facilities to promote local energy generation for local consumption. Before the FIT system was introduced, waste wood accounted for 70 percent of total fuels and the remaining 30 percent was unused wood. After FIT was introduced 18 Bioenergy International No 80, 4-2015 and the second plant started operation the use of unused wood is increasing. Unused wood, including low-quality wood, logging waste and wood damaged by insects with legal certification are procured from national, public and private forests. Japanese cedars make up most planted forest tree species in the Hokushin area, situated in the northern-most part of Nagano Prefecture. Pulp was the only option for this low-quality wood, but demand has been decreasing. Being used as fuel in a biomass power plant is now an alternative for the unused wood. Miyazawa also purchases damaged Japanese red pines and so contributes to local forest improvement. Maintenance and management of the plant is carefully controlled. The plants’ combined rate of operation is about 95 percent with a power generating efficiency of 15- 20 percent. Invest in a pellet plant A small-scale biomass plant requires significantly higher initial investment and operational costs. Fuel costs represent 60 percent of total income. The two plants consume about 40 000 tonnes per annum of woodchips. Of this, 60-70 percent are self-supplied by Miyazawa. To reduce the fuel cost to 50 percent of the total income and ensure 100 percent self-supply, Mi- As of April 1 this year the new Feed-in Tariff (FIT) price for biomass plants under 2 MW using ”unused wood” as feedstock increases from JPY 32 to JPY 40 per kWh (about EUR 0.23 to EUR 0.29 per kWh). Mount Iizuna Thermal Power Station is located at the base of Mount Iizuna in Nagano, Nagano Prefecture, Japan. Founded in May 2003 it is operated by Nagano Forest Resources Use Cooperative Business Association. yazawa is constructing an onsite 5000-6000 tonne per annum pellet plant, using weeding, tree leaves and bark. 2500-3000 tonnes per annum of pellets will be made from weeding. Miyazawa will receive a JPY 13000-15000 (≈EUR 93-107) per tonne waste disposal fee for the weeding and a FIT price of JPY 13 (≈EUR 0.09) per kWh for the power produced from weeding pellets. Bark and cedar leaves will be mixed together to produce pellets, which attract a FIT price of JPY 40 (≈EUR 0.29) per kWh since it comes from unused wood. The moisture content is very high in weeding, so Miyazawa dries it with a 200°C exhaust gas. Text & photos: Xinyi Shen BI80/4911/AS (Left) Masanori Miyazawa, Miyazawa Wood Working Industry Co., Ltd; Ken Kojima and Masashi Sekiguchi, Pellet Club Japan.
Bioenergy no 4 july 2015
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