4 minute read
Biogas – A major source of Thailand’s renewable energy power supply
Hans-D. Westphal
One of the classic sources of renewable energy in Thailand is the production of biogas, due to the vast industry of food and agricultural products. These industries generate large amounts of waste water and other waste products that are suitable for producing biogas. Typical operators of such plants are the starch industry as well as breweries, palm oil and ethanol producers, and general food products and the beverage industries. The starch, palm and ethanol industries are the biggest players in this field; however, due to various factors, the capital expenses (CapEx) are usually kept at a quite low level with few exceptions. Outside the industrial sector the animal farms are also operating biogas systems, mostly applying quite simple technologies.
One of the factors is that this is a seasonal business and some plants operate only a few months per year. This leads to low efficiency and availability. Many plants have received special Power Purchase Agreements (PPAs) with motivating feed-in tariffs from the local grid, while others have been unable to obtain them due to shortage of feeders being available.
German technology has always been promoted but compared with the opportunities and high-efficiency technologies available, relatively little business has been recorded; instead, cheaper local, simple covered lagoon systems have been preferred. These systems work with relatively low efficiency and availability, but still seem to satisfy the owners who earn the larger part of their income from producing actual products such as starch, palm oil and ethanol.
The PPAs granted are on the basis of ‘non-firm’, meaning there is no need to actual sell the amount of megawatts for which the PPAs are granted. Those businesses with no PPA, or where the feedstock exceeds the amount of granted PPA, are utilizing the biogas in their own factories either for power generation or as boiler fuel, which is attractive enough since it replaces other fossil fuels or buying power from the grid.
Besides, gas engine generators can work as a Co-generation or Tri-generation (Co- or Tri-gen) solution that can produce chilled water by absorption chilling, or produce steam, hot oil etc. However, for most factories the efficiency of such systems is still low and leaves plenty of room for optimisations, which more and more plants are considering and implementing. Retech Energy Co., Ltd., together with its technology partners, is one of the most widely known names in this field and thus considers itself to be a local company that knows the needs of the market but still can offer the benefits of international technology. Complete biogas plants can be acquired. In fact, and quite a few such systems have been successfully running for many years, including gas treatment minimising the H2S in biogas, gas coolers and power generation.
Big hopes for biogas came with the Energy for All programme. However, in the past two years output has been heavily reduced from the initial 700 MW to only 75 MW. This programme is based on purposely planted energy crops and has given farming communities all over Thailand the opportunity to participate in such projects by planting Napier grass as a feed stock, harvesting as well as shareholding in such plants.
The sudden drop to pilot plant level of only 75 MW left many participants disappointed since many were supported by the local communities, and the final bidding on the feed in tariff FIT reduced the total number to approximately 25 plants with just 3 MW each. This is a great opportunity for German know-how, since Germany operates almost 10,000 biogas plants using energy crops, and most are running with high availability of more than 95% thru the year. The difference here is that an energy crop has to be factored in as a cost compared to waste water and other organic waste, which is available free to the plant owners and at the same time solves disposal costs and environmental issues, such as the reduction of CO2 emissions etc. The Energy for All programme is a major step in the right direction and increases the contribution to the share of renewables. However, no margins in plant failures are allowed, and the feedstock has a price and take-off commitments to the farming communities plus a limited storage timeframe after harvesting.
After the PPAs are issued, Retech Energy is a very active proposer of such systems based on German know-how, but with local and competitive costs. To operate such a system, special software programs have been developed to help running such plants with as little human interference as possible, guaranteeing a stable process. In addition, biological support and maintenance is offered to further contribute to steady gas and power production. However, there is very little space for trial-and-error since the margin between the operating expenses (OPEX) and revenue from power sales is rather small. In order to bridge the gap between daily supply of Napier grass, this programme also allows a feedstock mix of up to 25 per cent of other organic waste to ensure a continuous operation.
In addition to solar power and other echnologies, biogas will always be a main contributor to renewable energy power generation in Thailand due to its agri-based industries. There is plenty of room for additional systems, since much waste water still remains untreated, together with the optimization of existing plants.
Contact details: Hans-D. Westphal, Managing Director, Retech Energy Co., Ltd., Tel: +66 2 6788921-2, hans.westphal@retech-energy.com, www.retech-energy.com
