• Energy Research

AbstractIn Southeast Asia, peatland is widely distributed and has accumulated a massive amount of soil carbon, coexisting with peat swamp forest (PSF). The peatland, however, has been rapidly degraded by deforestation, fires, and drainage for the last two decades. Such disturbances change hydrological conditions, typically groundwater level (GWL), and accelerate oxidative peat decomposition. Evapotranspiration (ET) is a major determinant ofGWL, whereas information on theETofPSFis limited. Therefore, we measuredETusing the eddy covariance technique for 4–6 years between 2002 and 2009, including El Niño and La Niña events, at three sites in Central Kalimantan, Indonesia. The sites were different in disturbance degree: aPSFwith little drainage (UF), a heavily drainedPSF(DF), and a drained burnt ex‐PSF(DB);GWLwas significantly lowered atDF, especially in the dry season. TheETshowed a clear seasonal variation with a peak in the mid‐dry season and a large decrease in the late dry season, mainly following seasonal variation in net radiation (Rn). TheRndrastically decreased with dense smoke from peat fires in the late dry season. AnnualETforced to close energy balance for 4 years was 1636 ± 53, 1553 ± 117, and 1374 ± 75 mm yr−1(mean ± 1 standard deviation), respectively, atUF,DF, andDB. The undrainedPSF(UF) had high and rather stable annualET, independently of El Niño and La Niña events, in comparison with other tropical rainforests. The minimum monthly‐meanGWLexplained 80% of interannual variation inETfor the forest sites (UFandDF); the positive relationship betweenETandGWLindicates that drainage by a canal decreasedETatDFthrough loweringGWL. In addition,ETwas decreased by 16% atDBin comparison withUFchiefly because of vegetation loss through fires.

AbstractIn Southeast Asia, peatland is widely distributed and has accumulated a massive amount of soil carbon, coexisting with peat swamp forest (PSF). The peatland, however, has been rapidly degraded by deforestation, fires, and drainage for the last two decades. Such disturbances change hydrological conditions, typically groundwater level (GWL), and accelerate oxidative peat decomposition. Evapotranspiration (ET) is a major determinant ofGWL, whereas information on theETofPSFis limited. Therefore, we measuredETusing the eddy covariance technique for 4–6 years between 2002 and 2009, including El Niño and La Niña events, at three sites in Central Kalimantan, Indonesia. The sites were different in disturbance degree: aPSFwith little drainage (UF), a heavily drainedPSF(DF), and a drained burnt ex‐PSF(DB);GWLwas significantly lowered atDF, especially in the dry season. TheETshowed a clear seasonal variation with a peak in the mid‐dry season and a large decrease in the late dry season, mainly following seasonal variation in net radiation (Rn). TheRndrastically decreased with dense smoke from peat fires in the late dry season. AnnualETforced to close energy balance for 4 years was 1636 ± 53, 1553 ± 117, and 1374 ± 75 mm yr−1(mean ± 1 standard deviation), respectively, atUF,DF, andDB. The undrainedPSF(UF) had high and rather stable annualET, independently of El Niño and La Niña events, in comparison with other tropical rainforests. The minimum monthly‐meanGWLexplained 80% of interannual variation inETfor the forest sites (UFandDF); the positive relationship betweenETandGWLindicates that drainage by a canal decreasedETatDFthrough loweringGWL. In addition,ETwas decreased by 16% atDBin comparison withUFchiefly because of vegetation loss through fires.

Abstract The potential of biomass energy in Sabah, Malaysia was analyzed by data which was established from literature, statistic data and available documents for estimating the potential of biomass energy derived from oil palm, coconut shell, rice, livestock and forest. Nowadays, the issue of solid biomass residues including effluent from the palm oil milling process has become a big concern for the industry and the public in Sabah, because oil palm residues provide a huge potential of biomass energy in Sabah. This paper showed that biomass energy potential in Sabah was around 267,179,818 GJ/year in total, which was derived from oil palm EFB, shell, OPF (oil palm frond), OPT (oil palm trunk), coconut shell, rice, livestock and forest. Potential of biomass energy from oil palm, coconut shell, rice, livestock and forest was 263,635,079 GJ/year, 95,713 GJ/year, 710,028 GJ/year, 750,696 GJ/year and 1,988,301 GJ/year, respectively. Most biomass energy came from oil palm, which was around 98.7% of total potential. If this total energy potential is applied at a power plant with efficiency ratio of 25% and 8000 h per year of operation, this has potential of 2,288 MW, which is equivalent to around 3.8 times of total supply of electricity in 2010 in Sabah. This paper also suggests that relevant policy and innovative technology be developed based on the result to effectively utilize biomass.

Abstract The potential of biomass energy in Sabah, Malaysia was analyzed by data which was established from literature, statistic data and available documents for estimating the potential of biomass energy derived from oil palm, coconut shell, rice, livestock and forest. Nowadays, the issue of solid biomass residues including effluent from the palm oil milling process has become a big concern for the industry and the public in Sabah, because oil palm residues provide a huge potential of biomass energy in Sabah. This paper showed that biomass energy potential in Sabah was around 267,179,818 GJ/year in total, which was derived from oil palm EFB, shell, OPF (oil palm frond), OPT (oil palm trunk), coconut shell, rice, livestock and forest. Potential of biomass energy from oil palm, coconut shell, rice, livestock and forest was 263,635,079 GJ/year, 95,713 GJ/year, 710,028 GJ/year, 750,696 GJ/year and 1,988,301 GJ/year, respectively. Most biomass energy came from oil palm, which was around 98.7% of total potential. If this total energy potential is applied at a power plant with efficiency ratio of 25% and 8000 h per year of operation, this has potential of 2,288 MW, which is equivalent to around 3.8 times of total supply of electricity in 2010 in Sabah. This paper also suggests that relevant policy and innovative technology be developed based on the result to effectively utilize biomass.

Abstract not available.

Abstract not available.