Of all the state-based RPS programs in place today, no two are the same. Each has been designed taking into account state-specific policy objectives (e.g. economic growth, diversity of energy supply, environmental concerns), local resource endowment, political considerations, and the capacity to expand renewable energy production. At the most basic level, this gives rise to differing RPS targets and years (e.g. Arizona's 15% by 2025 and Colorado's 30% by 2020). Other factors in program design include resource eligibility, in-state requirements, new build requirements, technology favoritism, lobbying by industry associations and non-profits, groups cost caps, program coverage (IOUs versus Cooperatives and Municipal utilities), cost recovery by utilities, penalties for non-compliance, rules regarding REC creation and trading, and additional non-binding goals. Since RPS programs create a mandate to purchase renewable energy, they create a lucrative captive market of buyers for renewable energy producers who are eligible in a particular state's RPS program to issue RECs. A state may choose to promote new investment in renewable energy generation capacity by not making eligible existing renewable energy such as hydroelectric plants or geothermal energy to qualify under an RPS program.