Biomass to energy looks promising for The Netherlands
The Dutch Ministry of Economic Affairs initiated a study of bottlenecks in The Netherlands biomass to energy development
By Sigrid I. Bestebroer, KEMA Nederland B.V., and Gerard J.J. Smakman and Kees W. Kwant
The Netherlands Agency for Energy and Environment
Large-scale importing of wood as fuel for electricity generation is economically feasible and should receive careful consideration for the near future. This was the conclusion of a 1995 report published by KEMA on behalf of The Netherlands Agency for Energy and the Environment (NOVEM). The report was the result of a study initiated by the Dutch Ministry of Economic Affairs, which installed a committee to identify bottlenecks in biomass development for energy and to address possible solutions. The committee?s report analyzed the entire biomass-to-energy chain.
Stabilizing atmospheric greenhouse gas concentration at a level which averts harmful climate change is an important objective in the context of the Climate Treaty, launched during the 1992 LN Conference for the Environment and Development in Rio de Janeiro. The Treaty has now been ratified by many nations including The Netherlands. The European Union (EU) has translated this objective by jointly agreeing to stabilize the atmospheric greenhouse gas concentration at 1990 levels. However, the burden in the emissions reduction for different members of the EU may differ. The Dutch contribution to the European policy sets absolute CO2 emissions reduction at 3 percent in 2000 compared to 1990. This policy is based on two objectives: 1) the need for energy conservation and 2) the reduction of CO2 emissions. Within this framework the Dutch government aims to enlarge public support for renewable energy, including biomass.
Organic residues and energy crops are potential fuels for energy production. As a consequence of the energy policy, the Dutch government is strengthening the research and development of renewable options for the longer term. In addition, the energy distribution companies in The Netherlands recognize the need to consider renewable energy for the future and have put together an Environmental Action Plan. The plan sets a goal of producing 7 PJ of energy from biomass before the year 2000. This translates to about 100 PJ MW installed biomass capacity. Current initiatives in the Dutch electricity sector include a co-combustion demonstration project of 60,000 tons of waste wood per year in a 600 MW coal-fired power plant, and advanced plans to build a biomass gasification plant with a capacity of about 30 MWe.
Biomass is considered to be an attractive energy resource because it is nearly neutral in CO2 emissions and may play a significant role in a sustainable energy supply system. From an economic viewpoint, it can also be cheaper than other renewable energy technologies. Moreover, considerable technological progress has been made in the development of biomass gasification in combination with a combined heat and power plant. Finally, the specific circumstance of food crop overproduction in the EU is a positive stimulus for energy crops. The report distinguishes three categories of biomass for energy. These categories are organic residues, imported fuel wood and energy crops. Table 1 summarizes the estimated calorific value of each category.
Organic residues consist of industrial and forestry-related wood residues, agricultural residues and straw, grass from roadsides, residues from the food industry and others. The total amount of organic residues are estimated to account for 80 petajoules (PJ) of primary energy input (water content 15 percent). Although this amount is considerable, there is a difference between the potential supply of organic residues and the amount that will truly be available when needed.The report concludes that speculations on market price developments are too premature and leaves them out.
The second biomass category analyzed in the report is imported biomass. The Netherlands is a small but densely populated country with high industrial and agricultural activity. About 10 percent of Dutch land area is covered by nature reserves and forests, 70 percent is agricultural land, and 10 percent is industry and buildings with about 450 people per square kilometer. The amount of biomass that could be produced nationally, being either organic residues or energy crops, will ultimately be limited. Therefore, the import of wood and wood residues from other countries that have a potential surplus is considered a possible major resource for biomass.
These countries include the Baltic States, Scandinavian countries, Canada and Russia. The report refers to a study which estimates the calorific value of wood in forests that can be exploited sustainably in some European countries, the US and Canada to be about 13,700 PJ. The report mentions a preliminary price of (US)$21 to 28 per ton (dry weight), but also indicates that recent developments in this market have pushed up biomass prices. Developing countries might also be biomass-for-energy exporters.
The last category mentioned in the report is energy crops. The interest in energy crops was stimulated by the EU policy on setting aside land because of overproduction of certain food crops. Since The Netherlands is a densely populated country with high industrial and agricultural activity, there is also a large claim on land for infrastructural development and other physical planning activities. The competition between land uses with different added values will ultimately determine how much agricultural land is set aside for energy crop growth. The report gives both an optimistic and a conservative estimate for the available land area.
The optimistic estimate is based on a study which accounts for the expected developments within the agricultural sector and claims for land use as stated in several policy plans. The study concludes that the remaining area might be destined for energy crop growth. The conservative estimate is given by the Dutch Ministry of Agriculture, Nature Conservation and Fishery and is based on conditions set by the European regulation on setting aside agricultural land. This regulation compensates farmers for income loss as a result of setting aside their land. Because the regulation is subject to regular revision, the farmers desire more certainty if they are to consider growing energy crops. Even when maximum profit is taken from all the existing agricultural and forestry related subsidies, the price for energy crops grown in The Netherlands seems to be about twice as high as for imported wood fuel.
The report describes five different routes (summarized in Table 1) for the conversion of biomass to electricity and mentions either commercially available technologies or technologies that are still in development but which have a realistic market potential before the end of the century. Other technologies mentioned in the report are considered to be still in their infancy but are indicated as technologies with a long term potential (e.g., pyrolysis and hydro-thermal upgrading). The lowest scale for commercial operation of specific installations seems to be 5 MW, and is in principle determined by investment costs. From a technical viewpoint, there is no restriction on the upper scale limit of a biomass conversion installation that provides the biomass. However, other factors set a price limit on the upper dimension, such as the radius of the area around the installation. The report mentions an upper limit of 50 MW as realistic for organic residues and energy crops. When imported biomass is used and the installation is situated near the coast, there is in principle no dimensional restriction.
With regard to net electric efficiencies, gasification yields the highest efficiencies both as a stand-alone facility with a combined-cycle unit and as a combination with co-combustion. However, the expected specific investment costs are highest for gasification. The specific investment costs for co-combustion of biomass in a coal-fired power station are lowest. Note that for co-combustion, the biomass must be pulverized like coal, raising the specific electricity production costs and lowering net energy output.
The report concludes that based on state-of-the-art technologies, stand-alone combustion or co-combustion in coal-fired power plants would be chosen for biomass electricity production. Co-combustion in particular seems to be very attractive, especially from an economic viewpoint because it uses existing conventional facilities. In the long term, fluidized-bed gasification could be a promising technology. The report also concludes that although there are differences in development stage between combustion and gasification technologies, a good balance between the specific pros and cons of these technologies will only be possible when demonstration scale projects are compared.
Although using biomass for energy production is more or less neutral in its CO2 emissions, there are other emissions that are subject to air pollution regulations. In The Netherlands, combustion emissions are regulated in two decrees and in a guideline. The decree regarding emission requirements, environmental control-A (abbreviated in Dutch as Bees-A), sets emission standards for large-scale power production. The decree regarding emission requirements for waste incineration (abbreviated in Dutch as BLA) regulates emissions from municipal waste incinerators. The BLA not only gives standards for more components, but is also more stringent than the Bees-A. Finally, there are the National Emission Guidelines (abbreviated in Dutch as NER) for emissions not regulated by the aforementioned decrees.
In none of these regulations is biomass for energy specifically mentioned. Therefore, the Minister of Environmental Affairs issued a letter in which conditions were given for the application of the regulations, but only in the case of biomass defined as waste. The ministerial letter indicated that the Bees-A should apply when organic residues are co-combusted in a power plant in an amount more than 25,000 (metric) tons per annum, but with a maximum of 10 percent (weight basis) of annual coal use.
However, depending on the nature and composition of the organic residues, specific requirements may be formulated based on the BLA in addition to the emission standards given in the Bees-A. For all other biomass to energy conversions (also for nonwaste biomass) such as co-combustion of more than 10 percent, and for conversion in stand-alone facilities, the emissions are regulated by the NER. The specific standards that apply depend on the nature and composition of the biomass and may ultimately be based on the BLA. Table 2 lists the air emission standards.
An important aspect with regard to the use of biomass for energy is the definition of waste in relation to the application of biomass as fuel for power production. As soon as biomass is regarded as waste, some disadvantages arise that emanate from the Environmental Control Act (ECA). The disadvantages include a limited term of the environmental permit for facilities handling waste, the need to make an environmental impact statement for facilities that are considerably smaller than when nonwaste biomass is used, a duty to report to the competent authorities, procedural requirements with respect to transport of waste, and, last but not least, a negative stigma.
The definition of waste as given in the ECA does not provide enough clarity in the distinction between waste-biomass and nonwaste biomass. Furthermore, because the provinces are the competent authority in defining certain streams of biomass as being waste, differences in the conditions to use biomass for energy might occur among the provinces. Therefore, clarity in the application of the waste definition is highly desired to provide sufficient certainty for potential initiators of biomass projects.
The ultimate price for electricity reflects the costs for fuel, transportation and pretreatment of biomass, and capital costs for electricity production facilities. As mentioned earlier, it is difficult to give an accurate estimate of biomass market prices. The price will depend on market dynamics, but also on contract conditions set by the biomass supplier and purchaser. Because the biomass market is slowly progressing and there is currently very little experience with actual contracts, the current price estimates given in Table 3 should be regarded as indicative only. The wide price range for organic residues is caused by the different types of residues. Residues that originate from industrial processes, such as old construction wood, seem to be available for even negative prices. On the other hand, thinning residues from forests, which would otherwise be left in the forests, have a relatively high price because of activities specifically undertaken to make these residues available as fuel wood.
The prices mentioned for import should be regarded as even less indicative. Because this market for fuel wood imports is new and unexplored, accurate estimates are lacking. Moreover, prediction of price development is very speculative not only as a result of potential economic development in some countries, but also as a result of possible market dynamics. The price for the final category of biomass, energy crops, is determined by the application of currently existing subsidies for agricultural or forestry practices.
The distinction in biomass categories is also important with regard to the costs for logistics. The costs for transportation given in Table 3 are based on a feasibility study for a 30 MW gasification combined-cycle facility. Transportation of biomass from foreign countries is primarily determined by costs for loading and unloading, and harbor facilities. Sailing distance plays a minor part. Biomass pretreatment consists mainly of drying and size reduction. The report assumes that drying is included in the price for biomass. The costs for size reduction in Table 3 are based on the same feasibility study. When biomass is co-combusted in a coal-fired power plant, the costs for size reduction are assumed to double because the biomass has to be pulverized like coal.
The fixed costs for power generation facilities are based on specific investment costs and net electric efficiencies (Table 1). In the case of co-combustion, fixed costs for existing coal or natural gas facilities are added to the electricity production costs for specific biomass facilities. The fixed costs for electricity generation on biomass contribute considerably to the overall electricity production costs. Reduction of this part can be obtained by economy of scale or through replication of the used technologies. Figure 1 gives an impression of the range in electricity production costs for stand-alone facilities and for co-combustion for the three biomass categories. The horizontal lines in the figure represent the current grid sale price (lower line) and an allowance related to an energy taxation for which renewable energy is exempted (upper line). The report concludes that co-combustion of organic residues and the operation of small-scale, stand-alone facilities for electricity generation using organic residues are realistic options, and after 2000, large-scale import of fuel wood for electricity generation seems economically feasible.
How to proceed
Although the report indicates that large-scale biomass to energy is currently not economically feasible, the committee recognized this renewable energy option has the potential to play a significant role in a future sustainable energy supply system. Based on the analysis and the identified bottlenecks, the committee formulated actions regarded as solution headlines. The first group of actions aims to improve conditions set by the government. This can be improvements in either economic conditions or regulations. The committee also identified research and development needs which apply to the biomass supply and to technological improvements. Finally, in regard to market introduction, the committee identified the need for certain feasibility studies, pilot plants and demonstration projects.