Heating oil tank replacement: if your oil tank needs to be replaced, this is not a DIY project. The professionals at NRG will dispose of any existing oil and sludge in your old tank and dispose of it in the proper, environmentally friendly way. A new tank will be will be assembled. Legs, valves, filter and fittings will be assembled onsite. Your new tank will be primed and tested before approved by your local building inspectors office.