EA Credit 1 - Using available waste oil for heating

The heating source and energy rate must be identical in the baseline and proposed. So your baseline would have used oil as the fuel source and the cost would also be zero. Also the heating energy use is typically only a fraction of the total energy use and the points are based on the total. As an aside, used motor oil is certainly not the cleanest burning fuel and would not be a strategy found in a green building project. The highest and best use for used motor oil is probably to ship it off and have it recycled back into motor oil.

I hope not but stranger things have happened. It is not in the old ID credit catalog.

We have a similar situation where a landfill heaqdquarters can use free landfill gas, instead of buying natural gas for heating. This has an additional benefit of getting rid of a powerful greenhouse gas (methane). But I take it the same restriction applies - the Baseline and Proposed models both must use the same fuel?

No, since landfill gas counts as a source of renewable energy. Use natural gas at the local price in your baseline.