1.1. Host country strategy: sustainable energy production and consumption
1.2. Renewable energy sources available at the site and corresponding facilities
1.3. The project main activities and objectives
1.4. The project's energy input-output flow
1.5. The farm
The project ESTABLISHMENT OF AN ENERGY INTEGRATED DEMONSTRATION BASE FOR CHINA'S COLD NORTHEASTERN REGION (CPR/88/ 053), which was started in 1989 by the United Nations Development Programme (UNDP), has been set up with the Food and Agricultural Organization (FAO) of the United Nations acting as the implementing agency, with the participation of the Shenyang Agricultural University of China. The project is designed to assist China in formulating programmes which would more effectively manage energy supply and demand in rural areas through the use of integrated systems of combination of renewable and conventional energies.
This book was written on the suggestion of FAO, and the authors responsible for the individual chapters arc members of the working team dealing with the subprojects of the project.
Selection of available technologies and practical applications for energy conservation as well as the use of alternative energy sources for rural areas in China is also a part of this book.
As the foundation of national economy, the energy industry is of importance to socioeconomic development and improvement of people's living standards. In an environment of rapid expanding economy, China's energy industry is confronted with dual pressures posed by economic development and environmental protection. This is reflected in the following ways:
(A) The level of management and technical support for the energy industry in China is not fully developed. The co-existence of serious energy shortage and waste has aggravated the large gap between energy supply and demand;(B) China has a coal-based energy structure, with coal consumption amounting to 75% of the total energy consumption. Clean energy only occupies a small proportion of the total energy consumption, so that large quantities of pollutants are released and serious atmospheric pollution results.
Therefore, changing the present energy production and consumption patterns and establishing a new energy structure that is less or not as harmful to the environment arc the major components for sustainable development. The policies and regulations formulated by the Chinese Government for environmental protection, resource management, and energy management, such as the Environmental Protection Law, the Mineral Resources Law, the Regulation of Land Reclamation, the Interim Regulations for Energy Saving, provide important bases for this goal.
There are four programme areas to be worked out for the future:
A. Comprehensive energy planning and management;
B. Improving energy efficiency and energy conservation;
C. Less polluting coal mining and cleaner coal technologies;
D. Developing new and renewable energy resources.
1.1.1 Objectives and Activities Related to Rural Energy Development
1) ObjectivesA. Establish a set of methodologies for the comprehensive energy environmental and economic planning which are in accordance with conditions in China and a socialist market economy, and diffuse such methodologies to all levels of energy management authorities. By the year 2000, formulating comprehensive energy, environmental and economic plans at both the national and subnational levels as well as corresponding implementation measures.B. Improve the energy supply structure, increase the proportion of clean energy and high quality energy in the overall energy scene. Strengthen the development and utilization of energy production, distribution and consumption technologies capable of reducing the overall energy demand. The key selection criteria are: continued improvement of people's welfare and reduction of environmental pollution particularly as related to global climate change.
C. Accelerate the construction of rural energy and electrification in order to put an end to the destruction of the ecological environment brought on by excessive consumption of biological substances in rural areas.
D. Reinforce the development and utilization of new and renewable sources of energy, improve the energy conversion rate, reduce costs, and increase the proportion of renewable energy in the overall energy structure.
E. By the year 2000, hydroelectric power plants will have an installed capacity of 80 GW, solar energy will be equivalent to two to three million tons of standard coal, wind power will have an installed capacity of 200 MW, geothermal will be over 800, 000 tons of standard coal, and biomass utilization will be primarily concerned with the production of biogas and clean liquid fuel.
2) Activities
A. Strengthen institutional construction for comprehensive energy, environment, and economic planning to promote capacity building in this respect and to coordinate the comprehensive development programs at the state and regional levels.B. Support the research, development, transfer, and utilization of various environmentally friendly energy systems, including new and renewable sources of energy.
C. Make the massive efforts required to strengthen the construction of rural electrification and comprehensive energy construction at the county level, establish demonstration sites for realizing sustainable and coordinated development of the rural economy and environment. Diffusing technologies for firewood saving stoves, biogas, firewood forests, small hydro, wind power, and solar energy, thereby alleviating the deterioration of the ecological environment brought on by excessive consumption of biomass.
D. Use and improve the existing statistical channels to collect and sort out data related to energy, environment, and economic sectors and establish energy, environment and economic information systems both at the national and local levels.
E. Give priority to the development of renewable energy sources within the national energy development strategy, adopt appropriate financial assistance to encourage measures and market economic means to increase the state financial input in the development of renewable energy sources and attract the participation of local governments and users:
(a) Expedite the development of water-based energy resources. Carry out full scope scientific assessment of environmental impact of hydroelectric power projects, and adopt effective measures to reduce adverse impact on ecological environment;(b) Reinforce the development and utilization of biological energy. Develop and exploit technologies for using biomass energy to produce alcohol or other clean liquid fuels, vigorously disseminate technologies for utilizing biomass to produce bio-gas for daily life and energy use. Reduce the ratio of biomass energy directly used for burning, prevent water and soil erosion, and protect environment.
(c) Strengthen the development of technologies both for direct or indirect use of solar energy. For the short term, the stress is on the development of solar photovoltaic devices so as to improve conversion rate and reduce cost, for long term, establish large scale solar power stations.
(d) In line with natural conditions, expand the utilization scope of wind power so as to provide electric power to remote areas. For the short term, emphasize the research on and development of large power generation units and reduction of cost. For long term, force attention on the development of large wind bases.
(e) Conduct nationwide exploration in assessment of geothermal sources, construct geothermal stations and guard against adverse effects on the environment during the process of geothermal development.
(f) Develop ocean energy sources, particularly in areas of energy shortage and tidal energy potential. Develop and build medium-scale and small tidal power stations to acquire comprehensive benefits in power generation, aquaculture, and land reclamation. Continue to develop technologies for utilizing wave, tidal, temperature and salt disparity power generation and establish demonstration stations.
F. International cooperation will include the use of foreign capital and technologies to carry out research on and build demonstration projects for the development and utilization of new and renewable energy resources.
All the above-mentioned are cited from CHINA'S AGENDA 21. Some of the main ideas of government strategy for energy development and consumption in rural areas are in accordance with the research work carried out by the project: ESTABLISHMENT OF AN ENERGY INTEGRATED DEMONSTRATION BASE FOR CHINA'S COLD NORTHEASTERN REGION.
1.1.2 Background of the project
The northeastern cold region of China consists of the provinces of Heilongjiang, Jilin, Liaoning and Inner Mongolia. The majority of the 199 million sq km covered by these provinces lies north and west of Korea. The temperature in January in this region ranges from -32 to -5 ° C, making home heating a particularly important issue in this region. Approximately 110 million people live in this cold region with roughly 82.5 percent residing in the neighbouring provinces of Heilongjiang, Jilin and Liaoning, which together occupy 42 percent of land area.
The northeastern region is heavily agriculture oriented. For example, from 70 to 90 percent of the land in these provinces is under cultivation, and well over half of the people in this region make their living from farming. The principle crops are corn, wheat, sorghum rice and soybeans. Some potatoes, sugarbeets, tobacco, cotton and beans are also produced. Liaoning is the most populous and industrialized of the provinces in this region. It has approximately 36 million people of which 60 percent reside in rural areas. In 1987, 2.7 million hectares of corn, grain, sorghum, rice and soybeans were cultivated in Liaoning province.
A common characteristic of all the provinces in this cold region is the serious lack of energy for agricultural production. Severe shortages have inflated the market price of diesel fuel and gasoline, exacerbating an already critical situation. Although electric utility lines are present throughout much of the region, electricity is often not available for the whole time during the peak working season of the year. Similarly, rural industries are adversely affected because the fuel shortage and consequent high prices reduce their capability for producing products for market. Family homes also suffer. Typically, crop production residues provide the bulk of energy for home heating. Negative medical side-effects due to smoke and adverse environmental impact of soil erosion and lack of organic matter in soil often result. Using Liaoning provincial data to illustrate the situation in northeastern China, it can be seen that extreme shortages exist. Per capita consumption of coal, fuel and electricity in the rural areas of Liaoning province are 81.4 and 4.4 kg, and 4.7 kwh per person, respectively. By contrast, biomass energy from wood, crop residues and grass are 81.8, 281.6 and 12.5 kg per capita per year, respectively. On an energy basis, rural families derive up to 95 percent of energy resources from biomass. Consequent loss of organic matter from soil, increased soil erosion and medical complications due to smoke in the living environment are serious negative side effects of the energy problem. It is estimated that the soil in northeastern China has experienced decreased organic matter content from an original 5 to 9 percent to the present two percent. From one third to one half of the principal crop residues are used for fuel in Liaoning province. In 1988, it is estimated that the Country's electrical energy shortage is approximately 30 billion kwh per year.
This project formulation included strategies to help facilitate training for farmers and rural organizations by providing a hands-on, practical demonstration unit for alternative energy production. Here, visitors will be shown the technical and economical advantages (and disadvantages) of food and energy-integrated production techniques.
From a technical viewpoint, the project strategy revolves around fuel ethanol production and animal husbandry with the goal of making crop and livestock production energy self-sufficient and profitable.
Sweet sorghum (Sorghum bicolor L. Moench) research at Shenyang Agricultural University has resulted in a promising variety with high grain yields and high sugar production. Enough sweet sorghum can already be produced to supply the farm with ethanol to operate tractors and vehicles for crop production. Bagasse would be used to produce fuel through pyrolysis for powering the ethanol plant. Pyrolysis will also be used to produce fuel from wood waste and other biomass materials. Waste from animals can be used in biogas plants to produce hot water and electricity for operating out-buildings and the home. Effluent from the biogas plant would fertilize the cropland.
The buildings would be designed to maximize energy conservation and utilization. Farming operations can be supplemented by greenhouses integrated with the ethanol plant and animal buildings.
(a) Ethanol from sweet sorghum
Liaoning province, is located in the southern part of northeastern China (118°53'-125°46'E and 38°43'-43°29'N). It enjoys the continental climate of the north temperate zone and is controlled by seasonal rains which provide four distinct seasons. Total sunshine is 2, 270 to 2, 990 hours annually and the sunshine rate is 51 to 67%. The total amount of solar radiation is about 100 to 200 kcal per square centimetre annually.
The average temperature is 4.6 to 10.3 °C and the annual precipitation ranges from 440 to 1, 130 mm. The frost- free period lasts from 124 to 215 days. According to 10 °C, the total annual temperature is about 2, 700 to 3, 700 °C. As the temperature is very high and the rain is concentrated in the summer in this province, it is very good for many kinds of crops to grow here. Liaoning has a rich variety of biological sources. According to statistics, there are more than 157 different crops families with 650 genera of more than 2, 200 varieties, among which are 1, 300 varieties that are of economic value. There are more than 200 new hybrids or fine artificially-developed varieties of corn, sorghum, rice and soybeans.
Grain sorghum is one of the four main crops raised in Laioning province. Sweet sorghum has been used as fresh fruit for children in autumn in China for many years. Since the 1970s, sweet sorghum juice from the stems has been used as raw material for liquor (50% alcohol), and bagasse used as raw material for fibreboard production in Honan province. Since 1983, breeding research work has been carried out in Shenyang Agricultural University with the sole purpose of breeding new hybrids of sweet sorghum for use as raw material in ethanol production.
The new hybrid named Shen Nong No. 2 in 1987 was proving to have excellent potential as a multipurpose crop for production both of food and fuel alcohol. Its advantages include high grain yield and high fermentable production per unit area of land. Shen Hong No. 2 is a long maturation period variety since it has a growing period of 140 days. It produces 45 tons per hectare of stems measuring three meters in height, and five tons per hectare of grains. It can be sowed at the beginning of May and harvested in September.
Shen Nong No.4 is another new hybrid of sweet sorghum recently provided by Shenyang Agricultural University. The Number 4 is a short maturation period variety (100 days of growing). It can be sown at the end of June and harvested before October. The yield of stems is about 22.5 tons per hectare with stems 2.6 meters in height, and the yield of grain is 7.5 tons per hectare. When compared with the Number 2, Number 4 is more resistant to wind which makes harvesting much easier and also produces higher yields of stems and grains.
Multiple cropping of sweet sorghum and potato enables much more biomass to be obtained from one unit of land. On the same plot, potato can be planted during the last ten days of March, and harvested during the middle ten days of June. The yield of potatoes is around 23 tons per hectare. Then sweet sorghum Shen Nong No.4 can be sowned between 15th and 20th June and harvested before October. With this alternative, the raw material for ethanol plant operation becomes available from the middle of June, since potato can also be used as the raw material for ethanol production.
Ethanol production was carried out with the facilities of a new process of single-concentration and continuous fermentation type and double-rectifying column system. The process consists of: mechanical pressing, sterilization through acidification, cooling, single-concentration and continuous fermentation, distillation of undecanted ethanol and rectification. The experimental reaction column has a volume of 30 litres. The juice produced had an ethanol concentration of 8.8-9.0 % (vol/vol).
A continuous fermentation process using fixed yeast poured into a reaction column was tested. Results showed that the systems with fixed yeast of calcium alginate had the following advantages: high ethanol production, low system cost and high structural strength. Equipment for producing fixed yeast can be designed and installed based on practical requirements. When this fermentation method was compared with the conventional type, the results showed a lower investment, a lower energy consumption and a shorter fermentation time.
(b) Biogas and cogeneration
The Chinese, during the past couple of decades, have developed appropriate technology and popularized the conversion of biomass (animal waste) materials to gaseous fuels. Over several million biogas methane generators are in use in rural areas. Biogas is mainly used for cooking. However, research is under way for its refinement for engine power utilization. Since the temperature is quite low in the northeastern region in China during winter, it is very difficult to operate the biogas generators continuously from October to May of the following year. Now, most of the biogas generators are built underground within greenhouses in the rural areas of the northeastern region. The sludge of biogas generators can be used directly as organic fertilizer for vegetables and other plants growing in greenhouses.
A cogenerator is needed to convert biogas to electricity and hot water. The electricity will be used for operating pumps, lights and electric motors on site. The hot water will be used for home heating and for warming the biogas generator during the winter season when typical units in northeastern China must be shut down for the lack of operating temperature. A TOTEM engine-generator cogeneration system was used as a prototype for this project. The engine can be fuelled by natural gas, LPG or biogas produced from both pyrolysis and the anaerobic digester. The biogas produced through the anaerobic digester of manure from a 100-head growing/finishing swine herd. A pyrolysis unit provides gas to the engine when the digester cannot work very well during winter. The electricity was used on the farm, and the hot water produced by collecting part of the engine exhaust, and water jacket rejection heat was stored in a storage tank. The TOTEM engine generator main features: electricity-15 kw, three-phase, heat-39 kw (33, 500 kcal). Since this is the only specific type of engine fuelled by biogas, the capacity is not matchable with the anaerobic digester and pyrolysis unit.
(c) Solar energyGreenhouses
Typical greenhouses in northeastern China are alpine-styled plastic-covered units with little or no control over heat loss or ventilation. Considerable gains in productivity could be made by introducing more advanced control systems and structural designs to this part of China. The solar greenhouses consist basically of opaque insulated north, cast and west walls, and north roof, with a polythene clad south roof to receive solar energy and light. This type of greenhouse is common in north east China. Professors of Shenyang Agricultural University have conducted trials on a modification to this basic design where a small fan circulates the greenhouse air through an underground heat storage. This concept was developed in the energy integrated system with two greenhouses constructed for comparison purposes. The design for the solar greenhouse was assessed and various improvements suggested by Dr. R G Ellis, CEng MIAgrE, Greenhouse Engineering Consultant, ADAS, Silsoe, UK.
The design parameters of the greenhouses are: length 24 m, width 6 m, height 2.7 m, North wall 0.5 m brick wall including insulation plus 1.2 m width of corn stalks for extra insulation. Parameter of south wall insulated by 1 m deep by 0.5 m wide trench filled with straw. South roof insulated with 50 mm thick straw matting at night. With an ambient temperature as low as -30° C in winter it is intended that the solar greenhouse provide frost protection during this period, without supplementary heating.
The potential heat losses and the likely solar gain for the greenhouse were calculated and therefore the efficiency. Certain key parameters were identified and their effect on efficiency evaluated.
Glasshouse
A design of glasshouse had been done by Dr. R G Ellis in 1990. The glasshouse is to be used for growing plant, and the heating system is capable of a temperature lift of 50 °C. For convenience, a glasshouse made in Italy has been purchased in 1992.
Solar house
The solar house is to provide accommodation for a resident looking after the project site. The insulation value of the proposed structure was assessed along with the likely passive solar heat gain. The requirement for additional active solar heating was then investigated by Dr. R G Ellis. A training building, also a solar house, was designed by the staff of Shenyang Agricultural University. In order to improve passive gain, a small glasshouse along the south wall and inserting vents in the wall to allow air circulation during the day will improve solar heat capture. A small stove of supplementary heating to allow for periods when solar energy is not enough, ie no sun or no electricity.
Pig House Building
The pig house was designed by Dr. R G Ellis in 1990. The pig house presently used is a greenhouse just as that for vegetables growing. Two biogas digesters are underground in order to keep the operating temperature during winter season.
Carbon dioxide is the major limiting factor in the productivity of plants. Theoretically, one kg of CO2 can produce the equivalent of 0.7 kg of glucose in the form of plant material through the photosynthetic process. A symbiotic relationship exists within a greenhouse which is a special form of plant-animal mixed producing system. A sow of 180 kg and her litter produce 4.2 kg of CO2 per day. The plant-animal mixed producing system with a biogas digester under the floor of animal house named Animal-Plant Complementary producing system (one greenhouse) was developed and experimented in 1986 to 1989 and has gained the popularity in rural areas in north east China.
For each kg of glucose converted to ethanol in the fermentation of sugar, 490 g of carbon dioxide are produced, since the fermentation of sugars derived from sweet sorghum involve enzymatic conversion of sucrose to glucose and fructose. Upon conversion of these sugars to ethanol, approximately 490 kg of CO2 will be released per matric ton of fermentable sugar in sweet sorghum. This can also be put to use in a properly constructed and operated greenhouse for plants.
(d) Pyrolysis
Pyrolysis is the combustion of organic material in minimum presence of oxygen. It is a simple process particularly well- suited to biomass material already accumulated and dried. Products of combustion include: gases such as hydrogen, methane, carbon monoxide and carbon dioxide; liquids including water, tar, light oils and other organics; and solid residues consisting of carbon and ash. The products, except water and ash, are useful as fuels. The process usually operate in the 500 to 1000 °C range. Its net energy yield from biomass such as wood and sweet sorghum residue is typically greater than that obtained from biogas generation. The pyrolysis process is quite energy efficient, but the relative amounts of gaseous, liquid and solid fuels produced through pyrolysis is greatly dependent on feedstock composition and process temperature. Typically the tars contain 45 to 800 MJ per metric ton of input biomass while the solid residues provide 14 to 21 GJ per metric ton. From 3.5 to 10.6 GJ of gaseous fuel (having energy contents of 11 to 19 MJ per cubic meter) can be produced per metric ton of cellulosic biomass but liquids usually provide less than 800 MJ per metric ton.
Inclusion of pyrolysis in this project not only provides a unique opportunity for energy integrated technology, it also enables China to develop expertise in a process that could provide a significant alternative to the conversional burning of crop residue and wood in rural areas. For purposes of this demonstration 5 hectares of sweet sorghum residue, if processed over a 6-week period, could require a unit capable of 3 metric ton per day. The unit could be made smaller by extending the pyrolysis season over a longer period of time and using the energy produced for purposes other than just fuelling the distillation boiler.
During the past couple of decades, Chinese have developed appropriate technology and popularized the conversion of biomass materials to useful fuels. China has placed, and still places, a strong emphasis on the development and utilization of the natural energy sources of solar, wind, water and geothermal. Current research and experiments which mainly concern components and individual processes, should therefore be considered as the first step towards acquiring basic information, for the successive synthesis to set forth technical-operative models for integrated energy systems to be used in different agricultural structures. These models should properly coordinate a number of integrated energy processes and crop patterns capable of: combing diverse on-site energy sources to reduce the farm's dependence on nonrenewable energy resources, limiting the traditional energy inputs while improving soil yield; maximizing the exploitation of available sources; making use of solar energy, both direct (by active and passive systems) and indirect (by full utilization of by-products).
This project, a demonstration base, besides its research and production activities, was also planned to be used for training of farmers and technical people. Through this, it will be possible to spread out the experience and knowledge generated in this project. The project was planned to develop following main activities:
- erection of greens, animal and human houses;- construction of one ethanol producing unit, one pyrolysis unit and biodigesters;- operation of all processing units and houses;
- sweet sorghum upgrading;
- utilization of ethanol fuelled vehicles;
- economic analysis;
- utilization of the produced fuels in the typical farm activities such as land owing and treating;
- training of staff, farmers and other people from China and abroad with interest on energy production and savings.
Aiming to help the Chinese government in increasing the energy availability in the Northeastern region, the project was conceived to establish and to operate a demonstration farm in the Shenyang Agricultural University. The project's immediate objectives are as follows:
Immediate objective 1
Determine the appropriate scale of the alternative energy technologies with due consideration for economic feasibility.
Immediate objective 2
To improve the technical and establish the economic feasibility of fuel ethanol production and use of by-products from sweet sorghum.
Immediate objective 3
Demonstrate how pyrolysis and biogas generation can improve the economic feasibility of fuel ethanol from sweet sorghum, and promote the use of energy produced by solar collectors to complement the economic feasibility in an integrated energy setting.
Immediate object 4
Introduce the use of livestock or poultry, greenhouse produced vegetables, and human living quarters in an energy integrated setting.
Immediate objective 5
To train local staff in integrated food and energy technologies and demonstrate technologies to rural sector.
An entirely new farm was constructed to achieve the main objectives mentioned above. It was located on the University property to maximize the opportunity to integrate the objectives into a farming operation. The farm was sized and operated to match that of a typical farm on which animals and grains could be raised and marketed.
Fig.1.1 The input-output flow in this-energy-integrated agricultural system
In China, agriculture fulfils various functions in various areas, depending on their development. Most of the farming level requires systems capable of ensuring at least food and energy self-sufficiency. This project farming system can be seen as a trial ground to set up models which could be applied to other areas in China. The input-output flow in this energy-integrated agricultural system is showing in Fig.1.1
1.5.1 General data
The farm is located in the east suburban area of the city Shenyang. The mean yearly temperature is 7.0-8.1 ° C. According to 10 °C the total annual temperature is about 3, 300-3, 443 °C over the last 24 years. The frost-free period lasts 147-164 days. The annual precipitation ranges from 574.8 to 684.8 mm over the last 24 years with the 474. 6 to 535.2 mm from May to September. The annual evapotranspiration ranges from 1, 408 to 1, 765 mm. The yearly total sunshine is about 2,570.9 - 2,748.3 hours with the 1,168.6 - 1,243.3 from May to September. The sunshine rate is 58-62% with the 55-58% from May to September. The winter time is 187 to 192 days. The minimum temperature is - 33.1 °C in January.
1.5.2 The layout of farm
Fig.1.2 Plan of the farm buildings.
1, 2 - Greenhouses with heat storage
3 - Greenhouse
4 - Glasshouse with heating system
5 - Solar house
6 - Cogenerator
7 - Biodigester
8 - Residence house
9 - Pig house (greenhouse)
10 - Pig house with underground biodigesters
11 - Sheep house
12 - Pyrolysis unit
13 - Boiler
14 - Ethanol production unit
15 - Training building
The farm lays on a single parcel on the campus of the University and covers 60 hectares of dry land. The scale of farm's components are as follows:
- The alcohol production unit was planned to produce 500 I/day, the whole year, using molasses, grains and sweet sorghum stems as raw materials. Extra grains and molasses are requiring to be purchased.- A pyrolysis unit with capacity to process 1.2 t/day of the lignocellulosic materials was selected for this farm.
- The biodigesters were designed to have a total capacity of 18.3 cubic meters of biogas produced per day, which is used to operate the cogenerator.
- Three greenhouses with the total area of 360 square meters. One glasshouse with the area of 60 square meters.
- The animal houses are to be used for pigs and sheep raising with the total area of 120 square meters.
- Two main buildings were designed. A smaller one with 55 square meters used as watching house. A bigger one with 267 square meters used for training and research.
References
1. China's Agenda 21 (draft)
The State Planning Commission
The State Science & Technology Commission
October 1993
2. The projects Document 1989
3. Integrated energy systems in agriculture three different case studies P.Balsari, L.Bodria, G.Castelli, A.Guidobono Cavalchini, E.Natalicchio, G.Pellizzi, G.Riva, F.Sangiorgi, October 1981
4. Energy integrated swine farm system in Nebraska
W.E. Splinter, D.D. Schulte
May 1987
