Greenhouse gas (GHG) emissions are causing global warming. Renewable Portfolio Standards (RPS) are created by US state governments to reduce global warming by reducing GHG emissions. The Kyoto Protocol measures GHG in metric tons (t_m) of carbon dioxide (CO₂), the major GHG.  In the Protocol, the other GHG emissions (i.e. CO, SO_X, N₂O, etc.) are standardized into t_m-CO₂ by their global warming potential (GWP).  Burning fossil fuels (coal, natural gas, oil) to generate electricity creates CO₂ emissions. Electricity generated with renewable energy has no CO₂ emissions. The reason for using a RPS is to require (request in Illinois) that electricity be generated with renewable energy is to avoid the carbon (CO₂) emissions from the generation of electricity with fossil fuels. Coal electricity has 996 gm-CO₂/kWh; a combined cycle gas turbine has 372 gm-CO₂/kWh; the US grid average is 612 gm-CO₂/kWh. A wind plant (and other renewable energy electricity) has 0 gm-CO₂/kWh. Nuclear electricity also has 0 gm-CO₂/kWh, but nuclear power has its own waste and possible emissions problems.

If global warming (and other air emission problems) are not an observed fact in Illinois; then there is no need for an Illinois RPS.

Interesting question.

This question requires an office consultation.

The basic economic principal behind a conventional (mandatory) RPS is to reverse Say's Law in the electric market. Say's Law is that supply creates its own demand. In an RPS market demand makes its own supply of renewable electricity, This is because retail electricity vendors that are not in compliance with their mandatory RPS requirement will be penalized.  The conventional RPS will cause demand to create its own supply because retail electric vendors will go to the wholesale electric market and ask for renewable electricity

Illinois already has the tool needed for a GHG emissions reduction program.  This tool is the Illinois Utility Environmental Disclosure Statement. To make the Utility Environmental Disclosure Statement into a tool for emissions reduction all that is required is that Illinois require each utility’s carbon emissions to be at or below a certain stated physical level (gm-CO₂/GWh).

I have publicly commented on using the Illinois Utility Environmental Disclosure Statement to implement an Illinois  Renewable Electric Portfolio Standard.

You can read my comments at the Illinois Commerce Commission webpage.

http://www.icc.illinois.gov/en/ecEnergy.aspx

My comments are listed in the section; Implementation Plan Comments.

Source: Illinois Commerce Commission

No, it is not conventional in the regulation of US electric utility sector to call a voluntary program that asks electric utilities (retail electric vendors) to use a certain per cent of renewable electricity a renewable portfolio standard.  

According to the article, Illinois Enacts Requirement for Renewable Energy, Renewable Energy Access, Juley 28, 2005, there are 19 states (including Illinois and DC) that now have RPS. I believe that Illinois has the only voluntary program. You can read the article and my response to the article at  http://www.renewableenergyaccess.com/rea/news/story?id=34813

If some states call a voluntary RPS, a RPS, there is statistical problem in knowing how many states have RPS and in observing the effect of a RPS on a state's GHG emissions. To count the number of RPS in the US, the statistician must first define RFP. To test whether there is reduction in GHG emissions from a state RPS the research analyst has to know if the RPS is voluntary or mandatory. I recommend that regulators restrict the term, RPS, and the algebraic symbol, RPS, to mandatory RPS and require the longer term, "voluntary RPS", and the algebraic symbol, RPS_v, for a voluntary RPS.

The terminology for % of retail demand covered by a RPS (or a voluntary RPS) should also be standardized.

No, not even a mandatory RPS will always result in a decline in the level of carbon emissions from Illinois' electric sector.

A RPS only requires that a certain X% of electricity be generated with renewable energy. All the remaining % of electricity (100%-X%) can be generated with coal. 

Assume that you want Illinois' new generation to have an average carbon emissions equal to or less than the current US average carbon emissions. (612 gm-CO₂/kWh). If 1,500 MW of coal generated electricity has been approved in Illinois, then 4,000 MW of wind generated electricity will have to be installed in Illinois to made the total new electric generation (1,500MW coal + 4,000MW wind) have its average carbon emissions equal to the current US  average. 

The per cent  of renewable electricity that Illinois' RPS suggests (not requires; this is a voluntary program) is a small per cent of Illinois' total retail demand. It is a per cent of Illinois' bundled retail demand for electricity; not a per cent of Illinois' total retail electric demand for electricity. In Illinois' competitive market, bundled retail electric demand means the residential demand; it does not include Illinois' industrial, commercial or government demand for electricity. I estimate that the residential demand is only 33% of Illinois' total demand for electricity.

Yes. Please make an appointment. 

I am an independent consulting energy economist.

Freud said that if the client really wanted help, the client would pay a private consulting economist.

Of course Dr. Freud worked before Global Warming and he was referring to psychotherapy patients, but I think that the insight is still appropriate.