Widespread public funding of nascent energy technologies, combined with recent increases in costs the most heavily supported, has introduced a policy dilemma: should policymakers sustain these programs in anticipation cost increases being temporary disturbances or should they eliminate them to avoid risking billions of dollars of public funds on technological dead ends? This paper uses experience curve to estimate possible policy outcomes and to introduce new ways of assessing near term cost dynamics. This working paper is published: Nemet, G.F. (2009). "Interim monitoring of cost dynamics for publicly supported energy technologies." Energy Policy 37(3): 825-835. Available through Science Direct.