e. The plant producing the time capsules generates about 6 tonnes of mixed combustible waste (from raw material coming in) per year. This goes to a waste-to-energy power station, which has an overall efficiency of 27%. If the heat of combustion of the waste is 8.0 MJ kg", calculate the amount of useful electrical energy generated each year by burning the waste. Explain your working and give your answer in units of MJ to 2 significant figures