Combustible waste into energy policy is an effective method to respond to climate change and depletion of fossil fuels. Combustible waste into energy is the process of generating energy in the form of electricity and/or heat from the combustible waste such as vinyl, paper and plastic. This study tries to estimate the external benefit of enhancing the ratio of combustible waste into energy to primary energy from 1.89% to 5% using contingent valuation(CV) method. To this end, we report the results from a CV survey to elicit the willingness to pay (WTP) for combustible waste into energy. A CV survey of 500 households was conducted in the Seoul by using person-to-person interviews. Thus, the procedures of applying and the findings from the one-and-one-half bounded dichotomous choice spike model used to deal with the zero WTP responses are provided in the paper. The results show that the average WTP is estimated to be 2,724 won per household per month and statistically significant at the 5% level. Expanding the value to the Seoul gives us an aggregate value of 13.7 billion won per year.