12th International Symposium on District Heating and Cooling

The <strong>12th</strong> <strong>International</strong> <strong>Symposium</strong> on District Heating and Cooling,September 5 th to September 7 th , 2010, Tallinn, EstoniaThis type of heating supply scheme means thatconsumers are grouped and heating is performed fromheat source which is intended for the consumer group.About 70 % out of this thermal energy volume isproduced in the cogeneration cycle (only in Latvenergoowned CHP, and Rigas siltums) and around 30% ofcentrally supplied heat energy is produced in Riga CHPplants and boiler houses. Of course as main fuel inRiga natural gas is used approximately 98% of thermalenergy is produced from natural gas (CHP plants andboiler houses together) [3].As for heat supply outside of Riga, the dominantthermal energy is produced in boiler houses withrelatively high proportion of local fuel usage (as shownin Fig.1). Outside of Riga CHP heat production ratedoes not exceed 5%.2. EXISTING ENERGY SITUATION IN LATVIA:SHORT OVERVIEWDuring the recent past central (large) power plants inLatvia supplied roughly 65% of the total annual powerdemand - distributed energy resources (DERs) covered3–6%, but the rest were received as import suppliesfrom Estonia, Lithuania and Russia (mainly) [4].Regarding fuel sources Latvia has no real fossil-fuels ofits own and the consumption must be imported.However Latvia uses the domestic renewable-energyresources hydro-power and biomass.Table I. – primary energy-consumption in Latvia in theyear 2007 [1]PJ %Natural gas 56.92 27.8biogas 0.32 0.16Biodiesel 0.07 0.03Oil products 73.33 35.8Fuelwood 48.47 23.7Hydroenergy 9.84 4.8Import of Electricity 10.80 5.3of the gross energy-consumption from renewableenergysources in Latvia in the year 2007.The most important domestic renewable-energyresource in Latvia is biomass in the form of fuelwood:in fact approximately 45% of Latvia is covered withwoods and this substantial area makes wood asignificant potential as a resource for energy supplies.Even though the share of renewable is one of the mostlarge Europe the EU directive fixes the target of 40%share of renewable energy resources in the finalconsumption in 2020.This means that the increase is not feasible without theneed of refurbishment and/or construction of energeticinfrastructures.The fact that Latvia has domestic renewable-energyresources makes it interesting because the utilisation ofthe domestic fuels would be sustainable both from anenvironmental and an economic point of view.Latvia has comparatively well developed power, naturalgas supply and district heating systems, and as aconsequence the electricity is basically produced byhydro power plants and by cogeneration plants, whichare operated according to district heating demand, andpart of electricity is imported (fig. 2). Consequently themain objectives of the Latvian energy policy now are toensure sustainable accessibility to necessary energyresources and security of supply in order to favouritethe economic growth and improve quality of life, toensure environmental quality retention and meet theobjectives set in the Kyoto protocol of UN FCCC andLatvian Climate Change Program.Electricity amount, billion kWh87654321Electricity Supply in Latvia02000 2001 2002 2003 2004 2005Yearimported electicitywind generatorssmall HPSsmall CHPCHPHPPImport Coal and coke 4.36 2.1Wind 0.19 0.09Biodiesel 0.07 0.03Total 204.6The use of primary energy for the gross energyconsumptionin Latvia can be seen in Table 1. Theshare of renewable energy in the gross energyconsumptionis made up of fuelwood and hydro energy.That means that there is approximately a total of 30%178Fig. 2. Electricity supply in Latvia (Source: state JSCLatvenergo, Ministry of Economics, Central StatisticalBureau)2.1 Lack of energy sources for electricityThe main domestic electricity capacity consists of 1517MW of hydro and 520 MW [5] of thermal (CHP units inRiga) all of which is controlled by the state company,Latvenergo. The generating potential mainly consists ofthree hydro power plants (HPP) on the Daugava River,hence directly dependent on the river‘s water flow. Dueto small reservoirs, utilization rates are low and the