Renewable Cogen Asia

Most of the sugar cogeneration systems developed in sugar mills in early days were purposely designed with lower efficiency in order to get rid of all the bagasse produced, as there was no scheme to sell excess electricity to the grid.  In the last 15 years, there has been tremendous technological development due to the possibility of selling excess electricity to the grid. In Southeast Asia, most of the sugar mills are very old. We have visited several sugar mills in Philippines, which are more than 50 years old.

The sugar mills in Southeast Asia use very low pressure cycle for cogeneration plants and most of the mills are inefficient.  In some of the sugar mills, up to 40 kWh electricity is consumed and up to 600 kg of steam is consumed for milling every tonne of sugar cane.  As low as 30 kWh of electricity is produced from the bagasse generated from milling of one tonne of sugar cane. Some of the sugar mills are even installed with used cogeneration equipment. Since the industry is in the early stages of transformation, the future investment potential in Southeast Asia is high. There is a huge potential in existing sugar mills to reduce the steam and electricity requirement for milling process.  In the new cogeneration plant, it is possible to produce electricity up to 110-125 kWh for every tonne of sugar cane milled.

Only in 2000, one sugar milling group in Thailand started developing the first modern sugar cogeneration plant with 67 bar steam cycle.  Two 41 MW identical cogeneration plants were installed in two of their sugar mills.  The plants started their operation in 2004. We got involved in the project right from the pre-feasibility stage itself and the performances of boiler and turbines were excellent. Following the success of the above plants, few more similar projects were implemented in Thailand. 

We also participated in some of the project development activities in Philippines. There was a phenomenal growth in sugar cogeneration in India for the past 15 years.  India started implementing 67 bar cycle fifteen years ago.

Based on the experience gained and lessons learnt from the operation of those plants, several 87 bar cogeneration systems were also installed 6 to 7 years ago.  Now, the industry is moving towards very high pressure systems of up to 110 bar.  Few such systems are already in operation and there are more than 25 projects under various stages of implementation.

Lot of developments are also taking place in the processing side.  Due to several innovative energy efficiency measures, technology options and improved house keepings, the steam consumption came down to as low as 350 to 360 kg of steam per tonne of cane milled.

Due to seasonality problems of bagasse availability, multi fuel boilers are used in new cogeneration plants. Wood waste, rice husk, sugar cane trash, cassava wastes etc. are also widely used along with bagasse. Boilers with LHV based efficiency more than 85% and over all plant efficiencies above 30% are common in these plants.

The cost of sugar cogeneration is quite low compared to rice husk power plants of the same size. Today several equipment suppliers are available in the market and due to which the equipment cost has been lowered. This turned out beneficial to the project developers.

Apart from the most common technologies such as travelling grate system, technologies such as vibrating grate systems are also used. CDM and favorable government policies are a big boon to sugar mills. We have worked with several sugar cogeneration projects around the globe of sizes upto 41 MW. Refer our recent publication section for additional information on sugar cogeneration.

If careful and innovative project development, implementation and operation  approaches, tactics, strategies are followed from the beginning stage itself then it’s possible to reduce the overall project cost to around 30 to 40% thereby leading to considerable increase in IRR. For services related to sugar cogeneration, contact us.