In this paper, we develop an agent-based model of a market game in order to evaluate the effectiveness of the U.K. government's 2008-2010 policy on promoting smart metering in the U.K. retail electricity market. We break down the policy into four possible policy options. With the model, we study the impact of the four policy options on the dynamics of smart metering diffusion and suggest policy implications. The context of the paper is a practical application of agent-based simulation to the retail electricity market in the United Kingdom. The contributions of the paper are both in the areas of policymaking for the promotion of innovation diffusion in the electricity market and in methodological use of agent-based simulation for studying the impact of policies on the dynamics of innovation diffusion.