What is the efficiency of the coal based power systems? 5-6% 7-8% 8-10% 10-12%

From the power plant, it took 100 kJ of coal to produce the 15 kJ of useful energy in your home.  What is the total efficiency?

14. How much of the energy in burning coal reaches the consumer as electricity?

In the use of coal to produce energy, which of the following does NOT decrease the energy efficiency of theprocess?a. extracting the coal from the groundb. waste heatc. cogenerationd. energy required to build the power plante. the removal of the waste products

Consider a simplified representation of the production of power from coal fired power stations:• Bituminous coal (most common for power in Queensland) is burned in a furnace where most of theenergy liberated by the combustion reaction is transferred to a power cycle.• Heat transferred to a power cycle is converted to shaft work via a power cycle.• Shaft work is converted to electrical work for the grid via a generator and transformer.• Electrical work is transported through the grid to a home.Based on this simple representation, we are going to determine the carbon footprint of 1 MWh ofelectricity delivered to a household. To do this, we will assume:Step EfficiencyHeat from combustion to shaft work 38% (based on HHV)Conversion of shaft work to electrical work in the grid 95%Delivery of electrical work from the power plant to a household 90%a) Draw a simple block diagram of the energy flows and transformations for power generation. Start withthe heat from the coal combustion and finish with the household. You only need shaft work, electricalwork, and heat as the energy transfers in your diagram.Quantify each energy transfer on your diagram to deliver 1 MWh to a household and put this on yourdiagram.b) What are typical ranges for the calorific value (HHV) for bituminous coal (in MJ/kg) and the carbonintensity of bituminous coal in terms of:• kg CO2e per kg of coal, and• kg CO2e per MWh (HHV)Please use high quality references for this information and reference clearly at the end of the question(not at the end of all the questions). Identify a “typical” number for kgCO2e per MWh (HHV) to usein the next question.c) What is the carbon intensity (in kgCO2e/MWh) for electricity delivered to a household? Use mid-point estimates from above, and assuming that the embedded emissions for coal (i.e. pit to gate) are20 kg CO2e per MWh (HHV) and other smaller embedded, direct and indirect emissions are about10 kg CO2e per MWh (HHV).

The usefulness of given sample of coal is determined by: