Cost for negawatt power can be calculated using cost-effectiveness analysis or CEA. For energy efficiency investments a CEA calculation produces the value of saved energy or "negawatts" in $/kWh. Such a valuation allows comparing the price of negawatts with price of energy such as electricity from the grid or the cheapest renewable alternative. Specifically, Tuominen et al. have suggested using the dynamic generation cost type of CEA for energy efficiency investments as it includes the best accounting for the time value among the various CEA methods available.