Overall there is no 100% clean source, there is something dirty in the chain everywhere. The main question for me is, is one thing an improvement over the other, is the improvement massive or modest? I think the improvement is massive and am hopeful for the future. This doesn't mean you can never improve, but I think this is already happening. For instance I saw an estimate from the Rocky Mountain Institute that they expect no further mining of lithium for batteries because it will be recycled. I obviously don't know if this is true, but even if lithium mining is environmentally unfriendly, if it's an improvement over what we have now, and if we can down the road get rid of that too, it's a positive development.