Above: Nagasaki Shin-Higashi waste-to-energy plant

Under a DBO (design, build, operate) contract, MHIEC will also take charge of providing operation & maintenance services for the new plant for a period of 20 years (while ownership remains with the municipality of Nagasaki).

The contract is valued at 27.59 billion yen (about $184 million), with startup scheduled for April 2026.

The rebuilt facility will employ state-of-the-art technology for municipal waste processing, says MHIEC. Besides the two stoker-type incinerators, each having a processing capacity of 105 tpd, the plant will have a reduced environmental footprint.

Heat produced during waste combustion will be used to supply hot water to the nearby Nagasaki Higashi Park community.

Bidding for the Shin-Higashi waste-to-energy plant reconstruction project employed a holistic evaluation method, taking into consideration not only the bid price but also factors such as bidders’ technology strengths and operating expertise.

Compact carbon capture

As well as having a strong track record in municipal waste-to-energy, Mitsubishi is also involved in developing innovative technologies for small-scale biomass-fuelled power plants.

A milestone achieved earlier this year was the entry into commercial operation of a world-first compact carbon capture system for a 7 MW biomass power plant, rendering the facility “carbon negative.”

The capture system was installed by Mitsubishi Heavy Industries Engineering (MHIENG) at the Seifu Shinto biomass power plant, located in a suburb of Hiroshima City.

It has the capacity to capture 0.3 metric tons per day (tpd) of CO2 and, according to Mitsubishi, is “based on a highly versatile standardised design”, requiring an installation space of just five meters in length and two meters wide, with modular construction enabling “rapid transportation to the site and easy installation.”

The CO2 captured from the plant’s flue gas will be used to support the growing of vegetables in on-site greenhouses.

The power plant is operated by Taihei Dengyo Kaisha Ltd and was originally supplied by Mitsubishi (entering service in October 2019).

As a next step, MHIENG was planning to perform demonstration tests of operational support services for the capture plant using a proprietary remote monitoring system.

MHIENG says it plans to expand its lineup of compact CO2 capture systems and to pursue reduced installation, operation and maintenance costs, as well as shorter delivery times.