Solar energyThe current utilisation of solar power in the country is low. Total installed capacity between 1997 and 2002 reached 205 kW and increased to over 300 kW by the beginning of 2004. The New Energy and Industrial Technology Development Organisation used a 10-year annual average solar irradiation of 5.0 kWh/m2/day, based on readings of 4.7 kWh/m2/day average in the lowest area and 5.3 kWh/m2/day in the highest area. It is estimated that the theoretical maximum potential surface solar irradiation could reach as much as 21 GWh/day (13 times the power generated by the national power utility in 2002. Solar photovoltaic systems in Cambodia currently produce 200–250 kWh. Projects with NEDO Japan, SIDA, other international and national institutions including Prime Minister Project, solar photovoltaic with the capacity of around 1.5 MW has been installed in the country.Biomass energyNatural forests are the main source of fuel-wood in Cambodia. This resource has been severely degraded over the past 20 years due to widespread logging and conversion of forestland for various purposes. Biomass energy resources also include residues from plantation forests (rubber wood), agricultural crops (rice husk), livestock (cattle manure), municipal waste, and sewage.Cambodia has significant biomass energy resources, either as standing biomass, including plantation forests such as rubber and fast growing tropical trees like Glyricidia and Acacia species, or as agricultural residues like rice husk, rice straw, corn cobs, palm oil extraction waste, cashew nut shells etc. According to a study carried out by MIME with Japan’s Institute for Global Environmental Strategies (IGES) and the Cambodian Research Centre for Development (CRCD) in 2004, waste biomass (agricultural residues, domestic and animal waste) – excluding that biomass available from natural forests and waste timber from wood processing sector as well as rubber tree harvested at the end of their productive life─ has an estimated energy generation potential of nearly 19,000 GWhr per year. It can be used both for electrical energy generation, or converted into other fuels such as producer gas, biogas or a range of liquid fuels (the actual amount available for these options could be lower, since some of the waste is probably already being used for other purposes).Biomass-based energy generation in Cambodia has gain momentum during last 2-3 years principally applying biomass gasification technology both for captive consumption as well as electricity generation and supply companies. Though biomass-based gasification system is quiet flexible in terms of its capacity as per requirement, hours of operation and duel fuel generators to ensure uninterrupted supply, however, gasifier electricity generation efficiency is low, application is limited for smaller capacity. In addition, the fuel used at present in major successful gasifiers fabricated locally is wood which may not be sustainable as demand increases and only a few use Indian technologies which make use of rice husk. Based on the conventional steam route, there are currently two operating units using biomass as fuel in this capacity range in Cambodia and only power is generated making system efficiency very low. Also little is known about their operation, maintenance, trouble shooting and efficiency in long term.BiogasThe effectiveness of small scale biogas has been demonstrated in Cambodia by a number of different projects. The use of animal wastes to generate high quality gas for cooking has significant economic, health, social and environment benefits for poor rural households. Projects with Canada in Battambang (7 kW + 20 kW) and with DEDE Thailand in Kompong Cham (30 kW) are completed. There are also ongoing projects in Sambour District, Kompong Thom Province with the capacity of 30 kW by FONDEM France by 2009 and a number of biomass gasfiers done by local investors. HydropowerThe technical potential of hydropower resources in Cambodia in terms of installed capacity is estimated at 10,000 MW. Around 50% of these resources are located in the Mekong River Basin, 40% on tributaries of the Mekong River, and the remaining 10% in the south-western coastal areas. Current use of hydropower resources is, however, relatively limited, and the current contribution to electricity production is less than 20 MW. At present, only two projects are operating, with an installed capacity of 13 MW, while four projects are being developed. Previous studies have identified 42 potential hydropower projects, with a total installed capacity of 1,825 MW, being capable of generating around 9,000 GWh/year of electricity.Wind energyThe Wind Energy Resources Atlas Report in South-east Asia that covers Cambodia, Lao PDR, Thailand and Vietnam shows that the theoretical wind energy resource potential in the country amounts to 1,380 MW. The report indicates good sites for the future development of wind energy, but the potential values must be taken cautiously, since the simulations to determine them were based on global winds, and were not supported by ground measurements. The southern part of the great lake Tonle Sap, the mountainous districts in the southwest and the coastal regions, such as Sihanoukville, Kampot, Kep and Koh Kong have the annual average wind speed of 5 m/s or greater, the total area around 5%. Pilot projects, in part financed by the government of Belgium and the European Commission, are currently in place in the country.BiofuelsThe Jatropha Curcas and Cassava species appear to be a particularly suitable source of biofuel as it already grows commonly in Cambodia and has no other commercial value. One study suggests that the biofuel could be produced in Cambodia from Jatropha on a commercial basis for around US$0.53 per litre. This compares favourably with the current price of fossil fuel diesel at US$0.64 per litre. And the production cost of the biofuel is not likely to follow the rising trend of the international oil price. More than 10 companies are using Jatropha, planting around 1,000 ha, but there is no large scale production. One company from Korea has production capacity of ethanol 36,000 t/year from 100,000 tons of cassava.