Potential assessment of establishing a renewable energy plant in a rural agricultural area

Abstract

An evaluation of the green energy potential generated from biogas and solar power, using agricultural manure waste and a photovoltaic (PV) system, was conducted in a large geographical area of a rural county with low population density and low pollution. The studied area, Shoufeng Township in Hualien County, is located in eastern Taiwan, where a large amount of manure waste is generated from pig farms that are scattered throughout the county. The objective of the study is to assess the possibility of establishing an integrated manure waste treatment plant by using the generated biogas incorporated with the PV system to produce renewable energy and then feed it back to the incorporated farms. A filed investigation, geographic information system (GIS) application, empirical equations development, and RETScreen modeling were conducted in the study. The results indicate that Shoufeng Township has the highest priority in setting up an integrated treatment and renewable energy plant by using GIS mapping within a 10-km radius of the transportation range. Two scenarios were plotted in assessing the renewable energy plant and the estimated electricity generation, plus the greenhouse gas (GHG) reduction was evaluated. Under the current governmental green energy scheme and from a long-term perspective, the assessment shows great potential in establishing the plant, especially in reducing environmental pollution problems, waste treatment, and developing suitable renewable energy.

Implications

The livestock industry is a major point source that creates an enormous environmental pollution problem; generally, traditional treatment of manure waste can only reduce a portion of the problem without a better solution. Establishing an integrated treatment plant can lead to the development of renewable energy by using the treated waste; moreover, modeling results indicated that incorporated with the photovoltaic application, the system can achieve a win-win solution for the environment and energy utilization. Under the current governmental green energy scheme and from a long-term perspective, the assessment shows great potential and provides a better policy for the Environmental Protection Administration, Taiwan, in solving the pollution issue.

Introduction

Renewable energy is an essential choice for solving the energy shortage problem and in reducing greenhouse gas (GHG) emission. Many technologies, such as wind power, solar power, geo-thermo energy, and biomass energy have been applied all over the world; however, the suitability of renewable energy is not global but dependant on the in situ conditions. Selection and assessment of energy technologies worldwide and in Bangladesh have shown excellent examples of suitability and sustainability in the application of renewable energy, in which the researches have reported many potential technologies for the prospective areas (Angelis-Dimakis et al., 2011; Mondal and Denich, 2010; Sadrul Islam et al., 2006). Comparatively, Taiwan is an island with high population density and a major energy-importing country, in which the development of applicable renewable energy is crucial. Thus, in an agricultural area, the utilization of manure and farming waste into biomass energy is a suitable in situ development of alternative energy; moreover, a combined or integrated biomass utilization plant is much more appropriate than an individual one for the small farmer. Integrated manure and organic waste treatment has been well established in Denmark, Italy, Germany, and other European Union (EU) countries for the past decades; however, the authors have reported that government strategy, policy, long-term stimulation, or energy taxes were the key factors for their continuous development (Raven and Gregersen, 2007; Tricase and Lombardi, 2009).

In studying the economic feasibility and co-benefits from anaerobic digestion of on-farm biogas generation from swine farms in Nova Scotia, Canada, it was concluded that a combination of cost-sharing and energy policy can generate the most improvement in terms of financial feasibility. They also reported that on-farm biogas energy production has more potential in rural agricultural areas than tidal and wind power (Brown et al., 2007). Biogas can be generated from an anaerobic digester when treating live stock manure or agricultural waste, and an anaerobic system is a best available technology (BAT) that has been applied in generating green energy and reducing environmental problems in the farming areas (Alvarez and Lide'n, 2008; Ndegwa et al., 2008; Shih et al., 2008; Tricase and Lombardi, 2009). Biogas can be burned and converted into heat and electricity and fed back to those incorporated farms, though this energy production capacity may not cover all their electricity consumption, thus other sources of alternative energy may be required to make up the missing portion. Therefore, considering the local geographical condition, we also put the solar power application into the scheme to assess the integrated treatment and renewable energy plant.

The application of a region specific photovoltaic (PV) system was reported as having the advantages of being reliable, environmental friendly, and can be installed on a roof or the wall of a building, whereas the material of the PV module is the key factor in controlling the cell efficiency, which is around 11–20% (Bakos, 2009; Kikuchi et al., 2009). However, considering the in situ condition of the study area, which is a low industrial economic activity area, and the scattered distribution of individual farms with long hours of sunshine, we proposed the PV energy system as an alternative choice. In assessing a PV system, the RETScreen and other various models were applied, evaluated, and reported with regard to their distinctiveness for different objectives (Connolly et al., 2010; Mani et al., 2010; Musango and Brent, 2011; Rehman et al., 2007). The RETScreen has been widely used for clean energy analysis and is a decision-supported tool. The software was contributed in 1996 by the government, industry, and Natural Resources Canada (NRC) of Canada. Considering the database, user-friendliness, and applicable technology assessment, we used the RETScreen model (RETScreen International Clean Energy Decision Support Centre, 2011) to find out the possible solar energy output in the study. An integrated agriculture waste treatment and energy reuse system is a solution in combining individual and small farmers to solve those pollution and energy shortage problems, in which geographic information system (GIS) is an essential tool (Dagnall et al., 2010; Ma et al., 2005). Moreover, the development of suitable in situ empirical equations, and the application of GIS and energy utilization into a combined manure waste treatment and energy feedback system, has been seldom reported and this is the pioneer case study in Taiwan. Therefore, our final objective was to set up a practical methodology in establishing an integrated treatment and renewable energy plant. We collected the local database, conducted a field survey, developed empirical equations to calculate possible biogas and electricity generation by treating manure waste, modeling the in situ conditions for setting up the required PV system, and, finally, used a GIS mapping tool to locate proper plant sites.

Materials and Methods

The studied area

The studied area, Hualien County, as shown in Figure 1, is located in eastern Taiwan, which has the characteristics of low population density, less pollution, less industrial development, with long hours of sunshine, and a large amount of agricultural activities. Hualien County has a population of about 340,000, who make up only about 1.48% of people in Taiwan; the agricultural record shows that there are about 87,473 pigs in the county, which is about 1.34% of the total number of swine breeding in Taiwan (Council of Agricultural, Taiwan, 2009a). In the county, there were 124 registered livestock farms at the end of year 2009, and 82 of them were swine breeders with a scale of around 100 up to 2000 heads that were distributed all over the 12 rural townships within the county (Council of Agricultural, Taiwan, 2009a). In the rural areas, the manpower shortage, the aging problem of farmers, and a lack of knowledge and skill in treating waste all have caused long-term concern about how to deal with the pollution problems. Moreover, weather records show that Hualien County has an average of 1800 yearly sunshine hours, strong solar radiation intensity, and low particulate matter in the atmosphere. Therefore, combining the waste treatment, biogas energy, solar energy, and feedback system to the area is a practical and proper solution in the long term.

Figure 1. Geographical location (left: http://en.wikipedia.org/wiki/Hualien_County) and the GIS distribution of investigated farmers in the studied area (right).

GIS mapping and RETScreen modeling

To assess the possibility of establishing a renewable energy plant in this agricultural region, we used the GIS for mapping pig farms to locate the proper area to set up an integrated manure treatment site (Chang, 2006). Since the livestock farmers are scattered throughout the county, GIS application was essential to find a proper treatment site. The geographical location of this rural area strongly influences the sources of manure and transporting expense, and thus an economical potential site should be decided based on the technique. GIS mapping procedures were started by collecting the recorded livestock farmer distribution data in the area (Council of Agricultural, Taiwan, 2009b) and transforming those coordinates by using transform software (Academia Sinica Computer Center, 2003) to fit the County's coordinates and creating each farmer's shape file; following that, we used the buffer and union functions to establish the range and quantity of waste distribution for local farmers. To calculate the electricity generated by photovoltaic power, we used the RETScreen model (RETScreen International Clean Energy Decision Support Centre, 2011) to find out possible solar energy output in Hualien, Taiwan. Data from the studied area were inputted into the model: (1) basic local weather data in the National Aeronautics and Space Administration (NASA) database, including latitude, longitude, elevation, air temperature, relative moisture, pressure, wind speed, earth temperature, and solar radiation intensity; (2) the photovoltaic power project: PV model mono-Si BP 590F (BP Solar); (3) capacity factors and model units. The capacity factor is defined as the ratio of the actual output of a power plant over its output if it had been operating for an entire period of time. The reported capacity factors for wind farm, combined cycle gas plant, nuclear power, and base load coal plant were 20–40%, about 60%, 60–100%, and 70–90%, respectively (The British Wind Energy Association; Renewable Energy Research Laboratory; Laumer, 2011). However, due to the efficiency of the PV system, the reported capacity factor for photovoltaic solar power in Massachusetts and Arizona were 12–15% and 19%, respectively (Renewable Energy Research Laboratory; Laumer, 2011). Considering the terrain, the in situ characteristics and long hours of sunshine, we suggested that the PV system is more proper than other forms of alternative energy for the studied area. Moreover, the latitude of Hualien, Taiwan, is 24°N, and is closer to the equator than Arizona (latitude 32.4°N), thus, we designed the capacity factor as 19% in the model. Other than that, solar radiation intensity is also a major factor in modeling; thus, we compared the NASA database with our collected local data, which is listed in Table 1. These two sets of data showed minor differences and thus the data in the model can be used for predictions.

Table 1. Solar radiation intensity (in kW/m²/day) data in the RETScreen model and local record

Month	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
NASA ^a	2.87	2.99	3.65	3.95	4.23	4.71	5.33	4.88	4.2	3.72	3.21	2.87
AEC (2008) ^b	—	—	—	—	4.26	5.11	5.70	5.98	3.47	3.32	2.70	2.70
Notes: ^aData in the RETSCREEN model provided by NASA; ^bRecorded data from the set station in the Dong Hwa University by the Atomic Energy Council (AEC), Executive Yuan, Taiwan, Republic of China.

Empirical equations for biogas and electricity production

A survey of the pig farms in Hualien County was used to evaluate the capacity of biogas production from pig manure. The swine breeding technology in Taiwan had a well-matured technology, and the published data (Yuan, 2001) from the agricultural department is shown in Table 2, which lists the typical phases of the swine breeding period. In general, breeding is 174 day/period and the estimated total manure is 127.58 kg/head-period; these data were used to calculate the daily amount of manure by using eqs 1 to 2. Furthermore, a GIS mapping tool was applied to select two possible plans for establishing the renewable energy plant by using the in situ generated yearly amount of manure waste (W _c).

Table 2. Typical growth phase and manure weight during pigs' breeding period

	Piglet	Piglet	Piglet	Pig (grower phase)	Pig (finisher stage)	Calculation ^b
Live weight in each phase ^a (kg)	1–5	5–10	10–20	20–60	60–100
Growth day ^a	20 (a)	17 (b)	22 (c)	62 (d)	53 (e)	174 (day/period) (a + b + c + d + e)
Generated manure ^a (kg/day)	0.197 (a1)	0.259 (b1)	0.364 (c1)	0.711 (d1)	1.267 (e1)	127.58 (kg/head-period) (a × a1 + b × b1 + c × c1 + d × d1 + e × e1)
Average live weight	41.60 (kg/head)
	[(1 + 5) × a + (5 + 10) × b + (10 + 20) × c + (20 + 60) × d + (60 + 100) × e] ÷ (2 × 174)
Notes: ^aOverview of livestock and pasture—Pig Breeding, 2001 (Yuan, 2001); ^bCalculation results by using the reference data.

(1)

(2)

where

N _c = Calculated total swine head in the planning area (head)

W _b = Generated manure in a breeding period: 127.58 kg/head-period

C _c = Calculated total amount of generated manure in a breeding period (kg/period)

D _b = Total breeding days in a period: 174 days

W _c = Calculated yearly amount of manure (kg/year)

Following that, based on the calculated manure data in the study area, an objective set of operating parameters was needed to estimate the potential biogas production from these data. In several practical technical guidelines, researchers have reported that the anaerobic digestion (AD) was a critical unit in treating animal manure and they have concluded common key operating parameters, such as digester configuration, organic loading, hydraulic retention time, solid constitution, and various kinds of substrate in the feedstock (Barker, 2001; Brown et al., 2007; Costa Gomez et al., 2008; Ogejo et al., 2009; Steffen et al., 1998; Wellinger, 1999). Table 3 lists the reference parameters, which indicated their design data that were expressed in different units but show some common data ranges. However, the design of an AD still depends on many in situ conditions, such as feedstock and local breeding habits. We adopted the digester design criteria in Table 3 to estimate the possible biogas generation, the design parameters that produce manure (0.0051 m³/head), volatile solid production (0.295 kg VS/day-head), probable volatile solids destruction (50%), and biogas yield per unit of volatile solid (VS) destroyed (0.75 m³/kg VS) (Barker, 2001). However, we had to consider that the common breeding habits in our studied farms were using a lot of water to clean their pig enclosures and the estimated density for diluted manure wastewater was between 1020 and 1200 kg/m³. Generally, manure waste is an inhomogeneous mixture, and depends on the characteristic of feedstock and design parameters of the anaerobic digester; the total solid is about 2–12% (Costa Gomez et al., 2008; Ogejo et al., 2009; Steffen et al., 1998; Wellinger, 1999). Considering in situ breeding habits, we used the most diluted manure condition which had a density of 1020 kg/m³ to modify the produced manure into a daily amount and which is equal to 5.20 kg/day-head (i.e., 1020 kg/m³ × 0.0051 m³/head). In addition, a correction factor “f _c” (0.68) was applied, which was derived by using the calculated average live weight, 41.60 kg/head, in the in situ growth phase in Table 2 divided by 61.24 kg/head, which was the base live weight of the adopted design data in Table 3. Equations 3 and 4 were used to estimate the generated yearly amount of biogas (G _c) in the GIS mapped areas.

Table 3. Typical operating parameters for anaerobic digester in treating pig manure

Parameter	Swine ^a	Pig Slurry ^b	Swine (Grow to Finish)	Swine ^c
Produced manure ^d	9.3–29 (kg/day/454 kg)	1–14.9 (L/day; for fattening pig15–170 kg)	0.0047 (m^3/day-head)	0.0051 (m^3/head)
Total solid (TS %)	9.2–10	3–8	0.454 (kg/day-head)	6.7 (per head after dilution)
Volatile solid (VS)	1.7–5.4 (%) (moisture 90–90.8%)	70–80 (%; VS/TS)	0.374 (kg/day-head) (moisture 90%)	0.295 (kg VS/day-head)
Loading rate ^d	2.42–5.64 (kg VS/m^3/day)	Not reported	Not reported	2.00 (kg VS/m^3/day)
Biogas yield ^d	0.22 (m^3/day)	0.25–0.5 (m^3/kg VS)	0.75 (m^3/kg VS)	0.75 (m^3/kg VS)
Methane content (%)	65–70	70–80	Not reported	60
Retention time (days)	10–30	20–40	20	20
Reference	6	27	28	31
Notes: ^aBased on animal live weight per day per 454 kg; ^bOne livestock unit (LU) represents a live weight of 500 kg and equal to 6 fattening pigs; ^cBased on animal live weight (swine 61.24 kg/head); ^dUnit conversion was performed.

(3)

(4)

where

S _VC = Calculated yearly amount of volatile solid (kg/year)

S _V = Volatile solid production: 0.295 kg VS/day-head

W _c = Calculated yearly amount of manure (kg/year)

W = Diluted manure wastewater: 5.20 kg/day-head

G _c = Total generated yearly amount of biogas (m³/year)

f _c = Correction factor of animal live weight: 0.68

R = Probable volatile solids destruction: 50%

Y_i = Biogas yield per unit of volatile solid destroyed: 0.75 m³/kg VS

The next objective was to estimate the possible electricity generation by using the calculated amount of biogas in the planning area. Many of the studies reported that there was no significant difference of biogas yield or methane content between feedstock from swine and cattle manure (Steffen et al., 1998; Tricase and Lombardi, 2009; Wellinger, 1999). It was reported, especially in EU countries, that the utilization of biogas, using the combined heat and power (CHP) application, was the most commonly adopted method. Pretreating the biogas was the critical procedure to achieve the best energy efficiency; however, there were still many cases reported without treating the biogas and of course routine maintenance was necessary (Hegndal Farm Scale Biogas Plant, 2003; Cornell University, 2011; Entec biogas GmbH, 2009; Piccinni, 2004; The Nordic Folkecenter for Renewable Energy, 2011; The PigSite.com, 2011). Nevertheless, in an integrated plant, biogas treatment is necessary to increase the energy generation rate and reduce mechanical problems. In this assessment phase of the study, a proper relationship between biogas and electricity production was evaluated. Table 4 shows the list of reference field cases of biogas production, electricity generation, and difference sources between the feedstock and digester configuration. However, there was a trend toward biogas production and electricity generation. It was inducted by a regression analysis as in eq 5 and is shown as Figure 2; the result of linear regression is y = 1.75 × x, with an acceptable correlation coefficient (R ²), 0.81, which is applied to calculate the project electricity generation rate as follows:

Table 4. Biogas and electricity production rate of reviewed fields cases

Field Case	BiogasProduction ^a (10^3 m^3/year)	ElectricityGeneration ^a (MWhr/year)	Manure ofFeedstock	Type of Digester	BiogasTreatment	Reference (Country)
Spring Valley Dairy	62	219	Cows	Covered digester	No	^b (USA)
Martin Farms	122	150	600 sows	Anaerobic lagoon	Notreported	^c (USA)
S & B Pig Farm	142	204	3205 pigs and 330 cows	Insulated digester	Notreported	^d (Italy)
Morrisville State College	241	330	400 cows	Plug flow	No	^b (USA)
AA Dairy	354	251	500 cows	Plug flow	No	^b (USA)
Rokai Pig Farm	438	700	11,000 pigs	Not reported	Yes	^e (Denmark)
Noblehurst Farms	501	716	1600 cows	Plug flow	No	^b (USA)
Hegndal Farm	1000	2600	900 sows	Not reported	Yes	^f (Denmark)
Patterson Farms	1141	1625	950 cows	CSTR	Yes	^b (USA)
Gundorfer	1300	2800	Cow manure and solids	CSTR	Yes	^g (Germany, 2009)
Zwönitzer	1350	2920	Cow manure and solids	CSTR	Yes	^g (Germany, 2009)
Bolart	1800	4300	70,000 pigs	CSTR	Yes	^g (Germany, 2009)
Agrarproduktion Dedelow	2900	6350	5000 cows	CSTR	Yes	^g (Germany, 2009)
Bettona Centralized Plant	3504	4000	35 pig farms	CSTR	Notreported	^d (Italy)
Notes: ^aUnit conversion was performed. ^b Cornell University, 2011; ^c The PigSite.com, 2011; ^dPiccinni, 2004; ^e The Nordic Folkecenter for Renewable Energy, 2011; ^f Hegndal Farm Scale Biogas Plant, 2003; ^g Entec Biogas GmbH, 2009.

(5)

Figure 2. Regression result of biogas and electricity production rate for reviewed cases.

A study of Italian biogas production from animal manure was conducted and reported the conversion index of average generated biogas were 15.0 and 15.6 m³ per ton of cattle and swine sewage, respectively (Tricase and Lombardi, 2009). They also reported the relationship between biogas and electricity production, which was expressed as “electricity (kWhr/year) = biogas (m³/year) × 1.9 (kWhr/m³)” (Tricase and Lombardi, 2009). Comparing the trend of biogas production with the derived eq 5 from this study shows no significant difference. However, to be more objective, eq 5 was used to estimate the potential electricity generation in the GIS mapping area.

Results and Discussion

Based on the results of the field survey, statistical data of manure generation, and GIS application, Figure 1 shows that most of the pig farms were located in the township of Shoufeng followed by Yuli; and a further step of GIS mapping was used to find a proper integrated treatment plant. Due to in situ conditions, a proper transportation range from respective farms to an integrated treatment was set at 10 km; thus, Figure 3 shows the mapping results, which indicated that most of the circles were overlapping in the township of Shoufeng, which produced about one third of the manure waste in the whole county. The GIS database also showed that there were about 25,960 heads of pigs in the Shoufeng area (Council of Agricultural, Executive Yuan, Taiwan, Republic of China). Based on an economic perspective, setting up an integrated treatment plant in the Shoufeng area was the priority choice. Two circumstances were evaluated by using acquired data for the Shoufeng township, scenario A was to set up only one integrated plant and according to the collected data, which contain about one third of pig breeding in the whole county; instead of that, considering the flexibility and mutual support, scenario B had divided the total head into two separated integrated plants and Table 5 lists these potential plants and their projected electricity generation by using generated biogas in the area. To understand the in situ electricity consumption rate, three pig breeders with sizes of 1600, 1750, and 5056 heads were investigated and the results indicated that the average electricity usage during June 2008 to May 2009 was about 2.77 (in kWhr/head-month). This points out that, in Table 5, additional electricity generated from photovoltaic power was needed to be another choice of renewable energy in the area. Applying the empirical eqs 1 to 5, the calculated yearly electricity generation of biogas can be up to 176 MWhr/year for scenario A as listed in Table 5. Table 5 also showed that the generated electricity was 687 MWhr/year and potential reduced green house gas (CO₂) emissions were 135 tons/year by using solar panels in the central or isolated grid condition of the selected photovoltaic power (mono-Si-BP590F, BP solar; 90 watt/unit, 0.63 m²/unit, efficiency 14.29%) in the RETScreen model. This assessment of generated electricity indicated that biogas application had great potential and can be increased by incorporating more individual farms into the system by accepting a manure waste transportation range further than 10 km in the future plan. In the isolated grid condition, the area of solar panels can be distributed to each incorporated farmer and installed on the roof of the pig enclosure, which can also reduce the heat transfer during the hours of sunshine, reduce the direct application of electricity, and simplify the problems that might occur in the central grid system.

Table 5. Estimated electricity generation rate of plotted scenarios in the studied area

Estimated yearly electricity generation of biogas by using eqs 1 to 5
Scenario	Swine Number(N c; head)	Manure in a Breeding Period(C c; kg/period)	Yearly Amount of Manure(W c; kg/year)	Yearly Amount of Volatile Solid(S vc; kg/year)	Yearly Amount of Biogas(G c; m^3/year)	Projected Electricity Generation Rate(MWhr/year)
A	25,960	3,311,977	6,947,538	394,139	100,505	176
B-1	15,960	2,036,177	4,271,290	242,314	61,790	108
B-2	10,000	1,275,800	2,676,247	151,826	38,716	68
Photovoltaic power output by using the RETScreen model
Scenario	Swine Number(N c; head)	Estimated PowerConsumption ^a (MWhr/year)	NeededPhotovoltaicPower ^b (MWhr/year)	NeededPhotovoltaicUnits ^c	Solar Panel Area (0.63 m^2/unit) (m^2)	GHGReduction ^c (ton CO2/year)
A	25,960	863	687	4590	2892	135
B-1	15,960	531	422	2820	1777	82.9
B-2	10,000	332	265	1775	1118	52.2
Notes: ^aBased on results of field investigation, electricity consumption was 2.77 kWhr/head-month; ^bPower consumption subtracts the electricity generated by biogas; ^cOutput results by using the RETScreen model.

Figure 3. Estimated manure waste production and GIS mapping in Shoufeng Township.

The application of biogas is a proper solution from both the environmental and economic perspectives, since the establishment of an integrated plant can prevent possible point source pollution, reduce the waste treatment work for individual farmers, and achieve the goal of carbon reduction. Nevertheless, there are factors that need to be analyzed in the planning and implementation phases of the study. The basic quality of feedstock is related to the constituents of the animal manure, such as dry matter, volatile solid, and slurry in the feed stream and finally leads to the design parameters of the anaerobic digester; however, these parameters can be appropriately achieved in the engineering design phase. Economic feasibility and green energy policy may be the other major factors as reported and it was stated that farm scale biogas energy production was not economically feasible except for a size of over 600 pigs and the green energy scheme was better than other financial schemes (Brown et al., 2007). The scattered distribution of farmers and their breeding number of pigs in Hualien county suggests that setting up an integrated plant is the best economical choice and the Shoufeng area should have the highest priority. The user-friendly RETScreen model has a tremendous database and can be used worldwide in assessing various kinds of renewable technologies. If a potential study case has inputted the available detail information, the RETScreen modeling can provide good results for decision-making, such as costs and saving of energy production, financial feasibility, risk analysis, as well as emission reduction. From the green energy scheme perspective, the feed-in tariff (FIT) system was adopted by the Taiwan government and the official 20 years' basic wholesale electricity purchase rate of renewable energy in year 2011 are 2.6875 and 2.1281 NT$/kWhr for energy generated from waste and solar power, respectively (Bureau of Energy, Taiwan). Therefore, based on estimated electricity generation of scenario A in Table 5, the yearly wholesaled electricity from biogas and PV electricity can be up to 473,000 NT$ (about 15,767 US$) and 1,499,103 NT$ (about 49,971 US$), respectively. Consequently, the results of the assessment phase show great potential to develop green energy in the area, especially in the long-term perspective.

Conclusions

Hualien County was selected as a studied area to assess the possibility of establishing an integrated manure waste treatment plant and developing renewable energy by using biogas and PV power. Local manure waste distribution map were established from the results of the field survey incorporated with the GIS application. Shoufeng Township was the selected location in establishing an integrated plant by using GIS mapping within a 10-km radius of transportation range. Empirical equations were well developed to calculate the possible biogas production and the following electricity generation. A RETScreen model was useful to evaluate the in situ PV power and the potential electricity generation. Two scenarios were designed in developing the renewable energy and the estimated electricity generation as well as evaluating the GHG reduction. The results indicated that the area is suitable to establish an integrated manure waste treatment plant, and the acceptable financial analysis for developing a renewable energy system can meet the current governmental green energy scheme policy. Moreover, the project can reduce environmental pollution problems to approach the goal of resource efficiency.