Characterisation of some nigerian coals for power generation

Thesis Overview

<p> INTRODUCTION<br>1.1 Background of the Study<br>Access to energy, especially electricity, is a driving force for economic and social<br>development (Samboet al., 2009). Energy is a key factor in industrial development and in<br>providing vital services that improve the quality of life. Traditionally, energy has been<br>regarded as the engine of economic progress. Limited access to energy is a serious<br>constraint to development in the developing world, where the per capita use of energy is less<br>than one sixth that of the industrialised world(IAEA, 2005).It is widelyaccepted that there is<br>a strong correlation between socio-economic development and theavailability of energy.<br>The electricity demand in Nigeria far outstrips the current epileptic supply. Nigeria is faced<br>with acute electricity supply problems, which is hindering its development notwithstanding<br>the availability of vast natural resources in the country (Sambo et al., 2009). There are<br>currently 23 grid-connected generating plants in operation in the Nigerian Electricity Supply<br>Industry (NESI) with a total installed capacity of 10,396.0 MW and available capacity of<br>6,056 MW. Most generation is thermal based, with an installed capacity of 8,457.6 MW<br>(81% of the total) and an available capacity of 4,996 MW (48% of the total). Hydropower<br>from three major plants accounts for 1,938.4 MW of total installed capacity and an available<br>capacity of 1,060 MW (KPMG Nigeria, 2013). Total power generation as at 11 December,<br>2014 stands at 3,385.9 MWe as displayed on the website of the Federal Ministry of Power<br>(<a target="_blank" rel="nofollow" href="http://www.power.gov.ng)">http://www.power.gov.ng)</a>.<br>2<br>The Nigerian government, in a bid to fix this problem, has developed a roadmap for power<br>sector reform in Nigeria. Some parts of the roadmap read as follows (The Presidency,<br>Federal Republic of Nigeria, 2010):<br>“In view of the high capital costs and long lead times required to develop<br>commercial power generation through solar, wind, nuclear and biomass, the<br>Federal Government will focus its development efforts on hydro, coal and<br>natural gas …the Federal Government is committing to focus on electricity<br>generation in three areas, namely: Hydro, Coal and Natural Gas, of which the<br>latter represents the largestresource for fuel-to-power… Nigeria will largely<br>rely on hydro, coal and natural gas for generation of much of its power over<br>the next decade”.<br>From the foregoing, it is apparent that coal will play a significant role in the effort to achieve<br>the much-needed improvement in electricity generation in Nigeria.<br>Coal is a solid, brittle, combustible, carbonaceous rock formed by the decomposition and<br>alteration of vegetation by compaction, temperature and pressure. It varies in colour from<br>brown to black and is usually stratified (Speight, 2005). Coal accounts for 41% of the<br>world‟s energy source for electricity generation. This is distantly followed by gas (21%),<br>hydro (16%), nuclear (13%), oil (5%) and other renewables (3%). Coal is the key fuel for<br>generating electricity on almost all continents, with almost all developed and developing<br>countries relying on coal for the stable and secure supply of electricity (World Coal<br>Association, 2012).The 2011 Electricity information published by the International<br>3<br>EnergyAgency (IEA) showing the percentage contribution of coal for electricity generationin<br>some countries is listed in Table 1.1.<br>Table 1.1: Coal in Electricity Generation<br>Country Coal usage for<br>electricity (%)<br>Country Coal usage for<br>electricity (%)<br>Botswana 100 Zimbabwe 46<br>Mongolia 96 USA 45<br>South Africa 93 Germany 42<br>Poland 88 United Kingdom 29<br>PR China 78 Turkey 28<br>Australia 77 Japan 23<br>Kazakhstan 75 Netherlands 21<br>India 68 Vietnam 18<br>Czech Rep. 56 Russia 16<br>Morocco 50 Canada 15<br>Denmark 49 France 5<br>Source: World Coal Association, 2012<br>Coal also provides an affordable and reliable source of electricity generation. A Comparison<br>of electricity generation costs across international studies (US$/MWh) is shown in Table 1.2.<br>This proves that coal still remains the cheapest source of electricity in the world today.<br>Table 1.2: Comparison of Electricity Generation Costs across International Studies (US$/MWh)<br>Source<br>Researching Organisation<br>IEA/NEA<br>(2005)<br>CBO<br>(2008)<br>EC<br>(2008)<br>EPRI<br>(2008)<br>House of Lords<br>(2008)<br>MIT<br>2009<br>Coal 28 – 75 56 52 – 71 64 82 62<br>Gas 44 – 69 58 65 – 78 80 78 65<br>Nuclear 33 – 74 73 65 – 110 73 90 84<br>Biomass 54 – 109 n/a 104 – 253 80 180 n/a<br>Hydro 69 – 262 n/a 45 – 240 n/a n/a n/a<br>Wind 50 – 156 n/a 97 – 181 91 146 – 162 n/a<br>Solar PV 226 – 2031 n/a 674 – 1140 n/a n/a n/a<br>Source: World Coal Association, 2012<br>IEA/NEA: International Energy Agency/Nuclear Energy Agency, CBO: Congressional Budget Office, EC: European Commission, EPRI:<br>Electric Power Research Institute, MIT: Massachusetts Institute of Technology<br>The proportion of electricity generated from coal is currently on the increase. Under the<br>International Energy Agency‟s reference scenario, annual electricity generation from coal<br>4<br>could more than double between 2004 and 2030. Even the alternative scenario of lower<br>growth shows almost a 58% increase in annual coal-generated electrical units over the same<br>period. Table 1.3 shows data from the reference scenario.<br>Table 1.3: World Electricity Generation from Major Fuels, IEA Reference Scenario<br>Fuel<br>Year 2004 2015 2030<br>Total<br>Generation<br>TWh % share TWh % share TWh % share<br>17, 408 100 24, 816 100 33, 750 100<br>Coal 6, 917 39.7 10, 609 42.8 14, 703 43.6<br>Oil 1, 161 6.7 1, 195 4.8 940 2.8<br>Gas 3, 412 19.6 5, 236 21.1 7, 790 23.1<br>Nuclear 2, 740 15.7 3, 108 12.5 3, 304 9.8<br>Hydro 2, 809 16.1 3, 682 14.8 4, 749 14.1<br>Renewables<br>(excluding hydro)<br>369 2.1 986 4.0 2, 264 6.7<br>Source: International Energy Agency, 2007<br>Developing economies have a particularly strong dependency on coal for power production,<br>and the rate of growth in coal‟s contribution to electricity supply in these countries will be<br>greatest, as Table 1.4 shows.<br>Table 1.4: Developing Countries Electricity Generation from Major Fuels,IEA Reference Scenario<br>Source<br>Year 2004 2015 2030<br>Total<br>Generation<br>TWh % share TWh % share TWh % share<br>5, 754 100 10, 749 100 17, 001 100<br>Coal 2753 47.8 5659 52.6 8979 52.8<br>Oil 580 10.1 670 6.2 616 3.6<br>Gas 983 17.1 1955 18.2 3389 19.9<br>Nuclear 142 2.5 322 3.0 523 3.1<br>Hydro 1239 21.5 1928 17.9 2827 16.6<br>Renewables<br>(excluding hydro)<br>56 1.0 215 2.0 668 3.9<br>Source: International Energy Agency, 2007<br>5<br>Available data show that coal of sub-bituminous grade occurs in about 22 coal fieldsspread<br>in over 13 States of the Nigerian Federation. Table 1.5 shows the existing/potential coal<br>mines in Nigeria (Kibiya, 2012).<br>Table 1.5: Existing/Potential Coal Mines/Sites in Nigeria<br>S/N Mines Location State Type of Coal *Estimated<br>reserves<br>*Proven<br>Reserves<br>Mining method<br>1 Okpara Mine Enugu Sub- Bituminous 100 24 Underground<br>2 Onyeama Enugu Sub- Bituminous 150 40 Underground<br>3 Ihioma Imo Lignite 40 N.A Open-cast<br>4 Ogboyoba Kogi Sub- Bituminous 427 107 Opencast/Underground<br>5 Ogawashi Azagba/<br>Obomkpa<br>Delta Lignite 250 63 Opencast/Underground<br>6 Ezimo Enugu Sub- Bituminous 156 56 Opencast/Underground<br>7 Inyi Enugu Sub- Bituminous 50 20 Opencast/Underground<br>8 Lafia/Obi Nasarawa Bituminous<br>(Cokable)<br>156 21.42 Opencast/Underground<br>9 Oba/Nnewi Anambra Lignite 30 N.A Underground<br>10 Afikpo/Okigwe Ebonyi/Imo Sub- Bituminous 50 N.A Underground<br>11 Amansiodo Enugu Bituminous<br>(Cokable)<br>1000 N.A Underground<br>12 Okaba (Odagbo) Kogi Sub- Bituminous 250 3 Opencast/Underground<br>13 Owukpa Benue Sub- Bituminous 75 75 Open<br>14 Ogugu/Awgu Enugu Sub-Bituminous N.A N.A Underground<br>15 Afuji Edo Sub- Bituminous N.A N.A Underground<br>16 Ute Ondo Sub- Bituminous N.A N.A Underground<br>17 Doho Gombe Sub- Bituminous N.A N.A Underground<br>18 Kurumu Gombe Sub- Bituminous N.A N.A Underground<br>19 Lamja Adamawa Sub- Bituminous N.A N.A Underground<br>20 Garin maigungu Bauchi Sub- Bituminous N.A N.A Underground<br>21 Gindi Akwati Plateau Sub- Bituminous N.A N.A Underground<br>22 Jamata Koji Kwara Sub- Bituminous N.A N.A Underground<br>The proven reserves so far in the country are 639 million tonnes while the inferred reserves<br>are about 2.75 billiontonnes, consisting approximately of 49% sub-bituminous, 39%<br>bituminous and 12%lignitic coals. Up to the early 1960s, coal productionwas significant and<br>dominated the commercial energy supply. It was also thepredominant source of energy for<br>rail transportation and electricity generation (The Presidency, Federal Republic of Nigeria,<br>2003). Coal presently does not contribute to Nigeria‟s electricity generation. Of the new<br>Source: Kibiya, 2012 * Expressed in Million Tonnes<br>6<br>generation stations under construction, only the Oji River Power Plant with a planned<br>capacity of 20MW, is coal-fired (Sambo et al., 2009).<br>With the development of cleaner coal utilisation technologies such as Carbon Capture and<br>Storage (CCS), coal has shedthe toga of being called a “dirty fuel”. The International Energy<br>Agencydescribes CCS as “one of themost promising options for mitigatingemissions in the<br>longer term” while theIntergovernmental Panel on ClimateChange (IPCC) concluded that<br>CCSwas among the technologies with thelargest economic potential to reduceemissions from<br>electricity generation (World Coal Institute, 2008).<br>Nigeria has made a commitment to pursue vigorously a comprehensive programme<br>ofresuscitation of the coal industry and promote effective utilisation of coal for<br>complementing the nation’s energyneeds (The Presidency, Federal Republic of Nigeria,<br>2003). The Federal Government of Nigeria has awarded contracts for the provision of<br>consultancy services for feasibility studies, detailed engineering design and drafting of<br>contract documents for the development and construction of coal-fired power plants to be<br>located in Enugu, Benue, Kogi and Gombe States (Ogbu, 2011). In addition, the Federal<br>Government of Nigeria, in 2013, signed a Memorandum of Understanding with HTG/Pacific<br>Energy Company Limited, with substantial technical partnership with Chinese experts, for a<br>$3.7 billion coal-to-power projectscripted to provide an initial 1,200 MW power plant to be<br>built at Enugu, using coal from the Ezimo mine (Adetayo, 2013).<br>7<br>With vast supplies of coal and against the backdrop of severe shortages in much needed<br>supply of electricity, it is inevitable that Nigeria must move from rhetoric to concrete action<br>in the development and addition of coal-fired electricity to the nation‟s electricitysupply mix.<br>1.2 Statement of the Problem<br>With a conservative peak load forecast of 8,900MW and an average generation of less than<br>4,000MW, the resultant massive load shedding has made Nigeria an unattractive<br>environment for existing and prospective manufacturers. Manufacturers operating in Nigeria<br>spend a weekly average of N1.8 billion on diesel to run their electric power generating sets<br>(Iba, 2011). In addition, it is claimedby the Manufacturers Association of Nigeria (MAN)<br>that an estimated 60 million Nigerians now own power generating sets for their electricity,<br>while the same number of people spend a staggering N1.56 trillion ($13.35m) to fuel them<br>annually. This is besides private power generation by industrial consumers, which is almost<br>at the same level (Energy Commission of Nigeria, 2009). These reports paint a vivid picture<br>of the problem bedeviling the country.<br>1.3 The Present Research<br>This research coveredthe characterisationof coal from five deposits in Nigeria which include<br>Odagbo (Kogi State), Owukpa (Benue State), Ezimo (Enugu State), Amansiodo (Enugu<br>State) and Inyi (Enugu State). Estimated reserves of these deposits are 250, 75, 156, 1000<br>and 50 milliontonnes, respectively (Kibiya, 2012). Analysis carried out include<br>8<br>determination of Proximate Analysis, Calorific Value, Ultimate Analysis, Ash Composition,<br>Ash Fusion Temperature (in oxidising and reducing atmospheres),petrographic analysis and<br>thermogravimetric analysis.<br>1.4 Aim and Objectives<br>The aim of this research is to characterise coalsfrom five deposits in Nigeria which include<br>Odagbo (Kogi State), Owukpa (Benue State), Ezimo (Enugu State), Amansiodo (Enugu<br>State) and Inyi (Enugu State), thereby enriching the repository of existing data on properties<br>of Nigerian coals and make a strong case for the utilisation of these coals in power<br>generation.<br>The specific objectives of the research are:<br>(i) To carry out proximate, ultimate and ash composition analyses of the coal<br>samples.<br>(ii) The determination of calorific value of the coal samples.<br>(iii)To determine ash fusion temperature (in oxidising and reducing atmospheres) of<br>the coal samples.<br>(iv) To carry out petrographic and thermogravimetric analyses of the coal samples.<br>(v) To compare results of the above analyses with reference values of coal properties<br>for power generation in order to determine the suitability of the coal samples for<br>power generation.<br>1.5 Significanceofthe Research<br>9<br>The quality of the coal used affects most of the costs associated with coal-fired power plants.<br>Proper evaluation of the combustion performance of the coal to ensure optimum utilisation<br>and minimum costs is therefore essential.<br>This research will help determine the suitability of some Nigerian coals for use in coal-fired<br>power plants, not only in Nigeria, but as an export commodity to other coal-consuming<br>countries around the world. This will assist the potential investor in Nigeria‟s power sector to<br>make a decision on areas of the coal‟s performance that may be suspect,requiring further<br>investigation by a larger-scale form of testing (pilot-scale simulation or full-scale testing)<br>and also serve as a justification for investment in such a larger-scale testing.<br>The significance of this research is further underscored by the present dependence of Nigeria<br>on natural gas- and hydro-powered electricity.The unreliability of natural gas supply due to<br>frequent disagreement over appropriate pricing and pipeline vandalism and the susceptibility<br>of hydro-electric power to weather has made the inclusion of coal-fired electricity into<br>Nigeria‟s electricitygeneration mix imperative. The argument for nuclearpower has been<br>punctured by recent safety concerns arising from the Fukushima nuclear disasteras raised in<br>the website of Green Peace International (<a target="_blank" rel="nofollow" href="http://www.greenpeace.org)">http://www.greenpeace.org)</a>.<br>With world industrial giants such as the United States of America, Peoples Republic of<br>China, Germany, Australia, India and South Africa among countries heavily dependent on<br>coal for electricity generation, Nigeria cannot exclude itself from benefitting from this<br>resource which it has been richly endowed with. <br></p>