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This paper analyzes the impacts of imposing a Federal 20 percent non-hydropower renewable generation portfolio standard (RPS) on US energy markets by 2020. The US currently has no RPS requirement although some state RPS regulations have been adopted but not uniformly enforced (see http://www.eia.doe.gov/oiaf/analysispaper/rps/index.html for a recent summary on RPSs in the US). The renewable portfolio standard (RPS) requires that 20 percent of the power sold must come from qualifying renewable facilities. The analysis of the 20 percent RPS was developed by using the December 2001 version of the National Energy Modeling System (NEMS) of the Energy Information Administration (EIA) and the assumptions and results of the Annual Energy Outlook 2002 (AEO2002) reference case. 2 A policy that requires a 20 percent non-hydro-electric RPS by 2020 appears to be effective in promoting the adoption of renewable generation technologies while also reducing emissions of nitrogen oxides by 6 percent, mercury by 4 percent and carbon dioxide by about 16.5 percent relative to the reference case in 2020. Electricity prices are expected to rise about 3 percent while the cost to the electric power industry could rise between 35 and 60 billion dollars (in year 2000 dollars in net present value terms).

Renewable technologies in the US, Europe and Japan have been supported for over 20 years with R&D investments and, for some technologies like wind and solar, with tax credits or other subsidies. Support for such programs have almost always been motivated by combinations of interest in reducing energy import dependence, reducing damaging environmental emissions, and saving some of the depletable high-quality resources like natural gas for future generations (inter-generational equity). Underlying these obvious goals has been the hope that by providing moderate-term subsidies, these technologies would eventually become economic and not require further government support. To date, such subsidies in the US have largely failed to produce economic grid-connected renewable generation technologies except in niche markets, even though the technologies have often met or exceeded their program goals, because the competing technologies have also improved and fuel prices have remained relatively low. Concerns over the possibility that climate change may be caused by anthropogenic activities, particularly the combustion of fossil fuels, have raised interest in examining a series of policy options which may inhibit or reverse the growth of energy-related carbon emissions. A number of bills have been introduced by the US Congress that would simultaneously reduce emissions of nitrogen oxides (NOx), sulfur dioxide (SO2), mercury (Hg), and carbon dioxide (CO2) from power generators. Two of the more recent policy proposals studied include Senate Bill 1766 and House Bill H.R. 4. Other related analyses have been performed at the request of the House Committee on Government Reform ( Energy Information Administration, 2001a) and the Senate Committee on Environment and Public Works ( Energy Information Administration, 2001b). These may be viewed or downloaded from the Energy Information website: http://www.eia.doe.gov/. The policy considered in this paper is a 20 percent non-hydro electric renewable portfolio standard (RPS). A typical RPS requires that a share of the power sold must come from qualifying renewable facilities. Companies that generate power from qualifying renewable facilities are issued credits that they can hold for their own use or sell to others. To meet the RPS requirement, each individual electricity seller must hold credits—issued to qualifying renewable facilities or purchased from others—equal to the share required in each year. For example, a supplier of 10 TW h of retail electricity sales in a year with a 10-percent RPS requirement would have to hold 1 TW h of renewable credits. In a competitive market, the price of renewable credits would increase to the level needed to meet the RPS requirement. The RPS provides a subsidy to renewable generators (from nuclear, coal, natural gas, oil and hydro-electric generators) to make them competitive with other resource options while allowing the market to determine the most economical renewable options to develop.

5. Conclusions A 20 percent RPS for the US is expected to increase total consumer costs of electricity by about 3 percent. Although this does not appear to be significant on a national level, the regional distributional price effects can be quite significant. For example, producers in regions rich in coal- or gas-based generation are likely to experience much larger revenue reductions than those which are rich in renewable resources. The RPS is likely to significantly increase the costs to the power generation industry from about 35 to 60 billion dollars for the period ending in 2020. Whether the benefits of a 20 percent RPS outweigh the costs is a matter of considerable policy debate within the US. The answer clearly depends on how costs and benefits are perceived and if they can be measured at all. Hopefully, this paper has shed some light on an estimate of some of the costs and benefits while making it clear that the accounting is incomplete; the calculation of net costs and benefits to consumers, industry and the society as a whole is difficult if not intractable and has not been attempted in this paper.