Definition of Renewable Energy Standard

The renewable energy standard (RES), or renewable portfolio standard (RPS), in its most basic form, is a policy that requires the increased generation of energy from renewable sources.

The policy can take on different forms depending on the state and organization. The goal is to increase renewable power generation capacity in a given region or market under each approach.

RES requires electricity producers to supply a minimum share of renewable power to meet the demand. It can establish technology-specific targets or goals that need innovation and advancement in renewable energy generation.

The policy can also create a market for renewable energy certificates (RECs) created by renewable energy generators. Such a system creates a demand for RECs and financial incentives to produce them, which helps increase the number of renewable energy sources in a given regional or national grid.

How Is RES Implemented?

RES can be implemented by a state, regional organization, or national government.

To implement it, they should draft and pass a policy with a renewable energy generation goal.

There are many different strategies to comply with the RES, depending on the goals and guidelines of the policy.

For example, California targets to have 60% renewable energy by 2030.

The RECs generated from these sources can then be traded in REC markets.

The grid operator purchases the RECs according to the RES to meet its compliance requirements.

RES can be imposed by either a state or regional organization. Each state will have a different RES depending on what they feel is appropriate. However, RES can also be imposed by a national government.

RES Goals

The goals of the RES are:

To Provide Market Certainty

RES policies aim to create a level playing field for all electricity generators and do not incentivize investment in less efficient technologies.

To Increase Generation From Diverse Sources

RES policies typically establish targets for a progressively increasing percentage of electricity generation from renewable sources.

To Expand Clean Energy Generation

RES policies attempt to create a market for renewable energy generators and promote the development of technologies.

To Reduce Greenhouse Gas Emissions

The policies aim to expand generation from renewable sources, which reduces regional reliance on fossil fuels and, as a result, reduces greenhouse gas emissions.

RES Requirements

Electrical utilities and other retail electric providers are required to supply a specified minimum percentage (or absolute amount) of customer demand with eligible renewable electricity sources.

Electricity suppliers comply with this requirement through one of these mechanisms:

  • Possess a renewable energy facility while keeping its renewable electricity, including RECs
  • Obtain electricity and RECs from renewable facilities, also known as bundled renewable electricity
  • Only purchase RECs, also known as unbundled RECs

States With RES Requirements

RES currently exists in 29 states and the District of Columbia:

  1. Arizona: 15% by 2025
  2. California: 60% renewable energy generation by 2030
  3. Colorado: 30% renewable energy generation by 2020, 100% renewable energy generation by 2050.
  4. Connecticut: 44% by 2030
  5. Delaware: 25% by 2025
  6. Hawaii: 100% renewable energy generation by 2045
  7. Illinois: 25% RES by 2025-2026
  8. Iowa: 100% renewable energy generation by 2050
  9. Maine: 80% by 2030
  10. Maryland: 50% by 2030
  11. Massachusetts: 35% by 2030 +1%/yr thereafter
  12. Michigan: 35% RES by 2025
  13. Minnesota: 25.5% renewable energy generation target by 2025
  14. Missouri: 15% renewable energy generation target by 2021
  15. Montana: 15% by 2015
  16. Nevada: 50% renewable energy generation target by 2030
  17. New Hampshire: 25.2% by 2025
  18. New Jersey: 50% by 2030
  19. New Mexico: 80% renewable energy generation target by 2040
  20. New York: 70% by 2030
  21. North Carolina: 12.5% by 2021
  22. Ohio: 8.5% by 2026
  23. Oregon: 50% renewable energy generation target by 2040
  24. Pennsylvania: 18% by 2021
  25. Rhode Island: 38.5% by 2035
  26. Texas: 5,880 MW of new renewable energy capacity by 2015 and 10,000 MW by 2025
  27. Vermont: 75% by 2032
  28. Washington: 15% RES by 2020
  29. Wisconsin: 10% RES by 2015, 15% RES by 2016, 20% RES by 2017, and 25% RES by 2018
  30. District of Columbia: 100% by 2032


Benefits of RES

Generating electricity from renewable sources has many benefits. These benefits range from providing environmental and economic advantages to promoting sustainable energy development.

RES helps provide the following benefits:

Energy Diversity

Creates a more diversified energy mix, which reduces the risk of electricity shortages for consumers.

Power Quality

Generates electricity without emitting pollutants, minimizes hazardous wastes, and can reduce noise levels.

Secure Supply

It helps maintain stable supplies of power independent of traditional fuel sources.

Local Economic Benefits

RES brings local investment and new jobs. RECs also add value to the RECs market, which provides a potential economic benefit by raising the price of electricity for consumers.

Supports Sustainable Development

Promotes a move toward a more sustainable economy to help decrease the environmental footprint.

Challenges of RES

The challenges related to RES are diverse but can include:

High Capital Expenditures

Typically requires significant capital investment in the construction of new generation assets. This means that financial resources need to be committed upfront for several years before realizing the benefits.

Reliability Issues

This can result in lower capacity factors than traditional fossil fuel technologies due to geographical constraints or the intermittent nature of some renewable resources.

This brings up concerns over power quality and reliability when integrating large amounts of renewables into regional grids, leading to increased costs for consumers.

Generation Inefficiency

Can include generation technologies that are less efficient than traditional generation methods and may require additional modifications and components to support them.

For example, a higher percentage of wind power is generally accepted as the RES portfolio standard because the variability of wind does not affect grid reliability as much as solar.

However, variable output from wind generation will require additional components in the transmission and distribution systems to maintain power quality and reliability within acceptable limits.

Key Takeaways

RES promotes the development of renewable resources.

RES requires electric utilities and other retail electric providers to supply a specified amount of power from eligible renewable electricity sources. These standards are often implemented at the state level.

The generation of electricity from renewable sources has many benefits for society. RES helps provide the following benefits: energy diversity, power quality, secure supply, and local economic benefits.

The challenges related to RES are diverse but can include high capital expenditures, reliability issues, and generation inefficiency. RES requires significant capital investment in constructing new generation assets.

The benefits of RES are apparent when considering energy diversity, power quality, and local economic development. 

While there are cost challenges associated with implementing renewables in some states, the advantages generally outweigh these costs in most cases.


1. What is RES?

The renewable energy standard (RES) sets a goal for the amount of renewable electricity a state's retail electricity providers must supply to their customers, usually by a specific year. It also specifies what types of renewable energy technologies are eligible to meet these obligations.

2. Where does RES come from?

RES is created when a state legislature passes a bill requiring electric utilities and other energy suppliers to get a certain percentage of their power from renewable sources.

3. What is RES used for?

RES has been implemented in 37 states and the District of Columbia. Each state is used to promote renewable energy production and stimulate the development of new renewable technologies.

4. Does RES reduce pollution?

RES reduces harmful emissions from electricity production by requiring a minimum amount of energy from renewable sources.

5. How does RES affect the economy?

RES can help bolster state economies by creating new jobs, increasing energy security, and lowering operating costs for consumers.

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