Bright Ideas

Finding the big ideas that can improve air quality in Northern Thailand

Biomass Power: A Sustainable, Long-term Solution to a Critical Portion of the Northern Haze Problem

Every year, North Thailand is blanketed by a smothering pall of deadly smoke that kills 3,500 people, hospitalizes another 17,000, and costs Thailand billions of dollars. A significant portion of this smoke comes from burning corn and rice crop residues. If the burning of corn and rice waste alone can be stopped, it will have a major impact on climate change, public health, as well as environmental and poverty reduction efforts.

Eliminating half the smoke from these two sources will remove 34,600 metric tons of the most dangerous fine particulate pollution (PM2.5) from the air. Luckily, there is a known, tested, sustainable solution ready and waiting to eliminate this smoke: the biomass gasifier power plant. 1

What is a biomass gasifier power plant?

A biomass gasifier power plant is a simple piece of technology that can turn biomass such as chopped corn waste into electricity. This technology can be easily and quickly deployed in Thailand because it uses largely off-the-shelf components like a diesel engine modified to run on biogas (similar to the one on a truck that uses compressed natural gas) and a standard electricity generator. At its heart is a spherical tank called a gasifier. Biomass is fed into the tank which is extremely hot, but where there is insufficient oxygen for the biomass to burn. Instead, most turns to gas (is gasified) and rises to the top of the tank. There the gas is sucked out, cooled, cleaned and pumped into the engine that runs the generator.

Valuable electricity is generated while eliminating the smoke from burning corn waste. The engine’s only exhaust is CO2 and H2O (water) because the greenhouse gases and particulates are all consumed in the gasifier. Cooling is provided by water circulated from a rainwater fed pond; no water is removed from local resources and no wastewater is discharged.

What impact will the construction of one biomass gasifier power plant have?

Replacing the current practice of open burning corn waste with a biomass gasifier plant will have an immediate positive impact on local air quality. A single, one MW biomass gasifier power plant will clean burn – no particulates or greenhouse gases – 17,000 tons of crop residue annually. Annually, such a plant will eliminate 106 tons of PM2.5 otherwise emitted during field burning. It will sequester 13,500 tons of CO2 as inert carbon ash and offset the production of 18,295 tons of CO2 equivalents from the production of one MW of power with natural gas. It will further eliminate 99.5 tons of methane and 52.9 tons of NOx, greenhouse gases that are respectively 25 and 298 times more warming than CO2.

Will biomass power promote local economic development?

A single one MW power plant will bring 75 new jobs to a community and pay farmers $140,000 for fuel annually.2 Salaries and sales will provide grassroots stimulus to the local economy. If outsiders own the plant, community benefits end here, as dividends go to the external shareholders. If a community cooperative owns a share of the plant, however, dividends remain in the community. If spent locally, these funds, too, will provide economic stimulus; if used to capitalize development projects, they could have a real impact.

A biomass power plant opens the door to economic diversification and growth also by closing a supply chain gap. A gasifier creates the opportunity construct a community cold store in isolated areas. Here transportation costs discourage diversification into higher value fruits and vegetables or even pork raising, while the cost of electricity makes operating a cold store impossible.

The vast volume of corn and rice crop waste produced annually in Northern Thailand provides enough fuel for many small scale biomass plants to be deployed across rural communities. We estimate that by targeting a 50 percent reduction in the smoke generated from these two sources, the North can support over 100 such power plants.

What are the environmental benefits of biomass power?

Biomass gasifier power plants have both local and global environmental benefits. Locally, they improve public health by preventing the emission PM2.5 (see Table 1). They can help to slow global climate change because they sequester CO2, prevent emissions of greenhouse gases and black carbon and avert the burning of fossil fuels.

Table 1: Potential Benefits from Biomass Power Plants in North Thailand

100 Plants 150 Plants
Power Generated 100 MW 150 MW
Biomass consumed 1,700,000 tons 2,550,000 tons
PM2.5 smoke eliminated 10,642 tons 15,963 tons
CO2 averted (renewable energy) 1,829,500 tons 2,744,250 tons
Methane eliminated 9,945 tons 14,918 tons
NOx eliminated 5,287 tons 7,931 tons
Total CO2 equivalents eliminated 3,650,651 tons 5,480,638 tons
Jobs created 7,500 11,250
Money injected into communities (U.S. Dollars) $14,000,000 $21,000,000

Does biomass power have environmental risks?

This is a two-part question. First, are the potential risks of biomass power plants too high compared to the known environmental and health risks of continued burning and/or the availability of other, sustainable solutions to these risks? Second, if previous biomass power plant technology caused environmental, health, social or economic damage, are the downsides inherent in biomass technology or can they be avoided by this technology.

From a comparative perspective, biomass power trumps the alternative if the alternative is continued burning until another technology is found. The global, regional and local environmental and public health costs of burning 17,000 tons of crop waste (eCO2, black carbon, PM2.5, increased risks of COPD, heart attacks, infant mortality, respiratory disease, premature death and stroke) are well established. Scientists have documented no comparable environmental or health costs associated with biomass gasifier power plants.

The story of past biomass technologies is more complex. Biomass power came to Central Thailand three decades ago in the form of large (20-25 MW), steam turbine, rice husk fueled, foreign owned plants. These posed perceived threats to their host communities. Small, local businesses such as brick and tile makers use rice husk for energy; power plant competition seemed to put them out of business. Rice husk is high in silica; burned in a furnace it forms glass crystals that can cause silicosis if inhaled much as PM10 and PM2.5 smoke can. Large steam systems consume tons of water sucked from local resources and discharged into public waterways.

According to environmental protestors, the original Thai biomass power plants drove rice husk prices to astronomical heights, discharged silica particulate laced smoke, emptied local water supplies and polluted local waterways. In fact, the desirability of rice husk ash as a cement additive also drove the price rice husk so high that the power plants closed. Causality is uncertain, but even without the power plants, rice husk prices remain extremely high today. Owners contend that scrubbers installed on the smokestacks prevented the release of silica particles and note that there are no documented cases of silicosis. There is no credible evidence on either side regarding water use or water pollution.

Ambiguous facts notwithstanding, protestors won the day in the media. They succeeded in vilifying “biomass power” in general as a major threat to the environment, public health and local economies. In the case of the large, rice husk plants, there was no comparative to offset their claims, nor did the host communities care. The organizers never considered the supposed costs of these biomass plants relative to the known costs of producing 25 megawatts of power from coal. The communities considered the costs of electricity production to other communities immaterial compared to possible risks to them, no matter how small. Because of the scare and continued public protest, biomass power has been dead in Thailand for years.

Table 2: Comparison of the Supposed Risks Associated with the Original Biomass Power Plants and the Proposed Power Plants

Old New
Size 25 MW 1 MW
Will bankrupt local businesses Yes No
Will not encourage local business startups Yes No
Will release dangerous particulates Yes No
Will release toxic smoke Yes No
Will produce water shortages Yes No
Will discharge contaminated waste water Yes No
Will be foreign owned Yes No
Will generate no local income Yes No

What has been the cost of environmental protest against biomass power?

The environmental movement’s blanket condemnation of biomass power has cost Thailand dearly. While other renewable energy sources have advanced, solar most of all, they offer neither the environmental nor the economic development benefits of biomass power. Even ignoring the challenges of battery disposal, solar has immense appeal – it is cheap, easy to install, and flexible. However, it does not sequester CO2, prevent the emission of greenhouse gases and black carbon, or directly reduce the public health risk from particulates. The employment, opportunities and income generated in local communities from solar power are also far less than offered by community biomass.

Biomass gasifier power permits a direct measure of the cost of successful but misguided protest. Assuming (unrealistically) that none of these costs has secondary consequences, the annual cost of every megawatt of biomass gasifier power barred is:

  • 18,295 tons of CO2 equivalents generated to produce 1 MW from traditional fuels
  • 13,500 tons of CO2 not removed from the atmosphere and sequestered
  • 99.5 tons of methane released into the atmosphere
  • 52.9 tons of NOx released into the atmosphere
  • 106 tons of PM2.5 released into the air
  • $140,000 of income not earned by local farmers
  • Jobs for and salaries paid to 75 workers

Is biomass power a universal solution to the smoke crisis?

Of course not. As with all technologies, it makes sense to roll it out where most applicable – in high-intensity growing areas that generate large quantities of smoke, and where poor transportation bars alternative uses for biomass and possibilities for economic development.

Mae Chaem, Chiang Mai is a perfect example, although many others can be found in Chiang Rai, Nan, Tak and elsewhere. Mae Chaem produces 95,000 tons of corn waste annually, 47% of it in just two of seven sub-districts, Mae Na Chon and Mae Suek. 100% of this waste is burned because the tortuous road to Chiang Mai over Doi Inthanon makes transportation prohibitively expensive. As a result, Mae Chaem adds 595 tons of PM2.5 per year to the smoke that blankets the Chiang Mai city basin – equivalent to the smoke of 42,478,826,300 cigarettes.3

Conditions in Mae Chaem make it an ideal test case for biomass power. Its annual 95,000 tons of corn waste will support three, perhaps four 1 MW power plants. The concentration of cob and husk in just a few locations makes their collection easy; open, rolling fields permit tractor cutting, raking and baling of much of the stalk. The environmental consequences of burning – global, regional and local – are extreme, as are the local health consequences. The area currently grows strawberries that must be rushed to market in season for minimum profit. The strawberry and other high value fruit and vegetable businesses would benefit greatly from low cost cold stores.

How expensive are biomass power plants?

A single, 1 MW biomass gasifier power plant costs $2 million; the price falls to $1.6 million if build in multiples. Biomass power projects are private investments. In principle, they benefit from generous regulatory support from the Thai government; in practice, government support is unpredictable and qualified. The centerpiece of the Thai renewable energy support program is the Very Small Power Producer program (VSPP). Under the provisions of the VSPP, a qualifying producer is supposed to receive a “feed in” tariff in addition to the normal tariff paid for electricity, a 25 year guaranteed Power Purchase Agreement for 100% of power produced, an 8-year tax holiday and exemption from Customs duties. In fact, at present VSPP is being granted only to projects in the deep South and only to applicants that “bid back” the entire “feed in” tariff. Investment in biomass power has been at a standstill for years because of the uncertainty that surrounds the program.

The government has indicated that it would like to see – and would support – small-scale biomass power projects that originate at the community level. Most communities lack the financial and technical capacity to implement projects of this complexity; they will likely advance only as collaborations between local and outside partners. One such model, for example, might include NGO assistance to a community to form a power cooperative able to make the initial application to start a project. The cooperative might then contract with a renewable energy power company to design the project, complete the necessary paperwork, find equity partners and loans, manage bidding, construct and commission the plant, and hire a power plant operating company to run it for the cooperative. For this, the firm might receive a fee or an equity share.

Uncertainty about government policy and intentions will likely discourage private investment in biomass power except under special circumstances. Few investors will attempt future projects under the VSPP for the time being. The one real opportunity for biomass power under current conditions is where a community can offer a captive buyer for a plant’s power, and business partners interested in co-generation (a private sale to a captive customer avoids the complexities of attempting to sell to the Provincial Energy Authority). For a cooperative imaginative enough to propose a cold store, ice plant, fruit and vegetable canning, freezing or drying plant, and able to find a bulk buyer for the plant’s high carbon ash, there will be many potential investors. For those counting on government regulation to make investment in their communities appealing, the wait may be long.


There are many major sources of air pollution in Thailand and each will require its own solution. Open field burning of crop waste, however, is one huge source of air pollution for which there is a readily available, if currently stymied, solution: biomass gasifier power plants. If the government lowers the uncertainty and barriers to investment, community biomass power is likely to flourish because each plan it profitable and therefore sustainable. In contrast to most environmental programs built on the always-false assumption that the public will pay endlessly for a “good thing,” with biomass the “good thing” will always be delivered not because plant owners are altruists, but because they are making money. As long as cleaning up the air is profitable, we can anticipate clearer skies.

1. All references to emissions of PM2.5, methane, NOx, black carbon and so on, S.K. Akagi, et al., Emission factors for open and domestic biomass burning for use in atmospheric models,” Atmospheric Chemistry and Physics, 11, 2011: 4039-4072.

2. 17,000 tons of fuel at 250 THB/ton delivered.

3. Mae Chaem statistics, A.Mae Chaem Office. Cigarette calculation by author based on single cigarette smoke output of 14 micrograms.