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Renewable portfolio standards in the United States

Renewable portfolio standards in the United States is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Renewable portfolio standards in the United States rather than just read about it. In short: A Renewable Portfolio Standard (RPS) is a regulation that requires the increased production of energy from renewable energy sources, such as wind, solar, biomass, and geothermal, which have been adopted in 38 of 50 U.S. states and the District of Columbia. The United States federal RPS is called the Renewable Electricity Standard (RES).

Key takeaways

  • Renewable portfolio standards in the United States belongs to physics; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Renewable portfolio standards in the United States to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Renewable portfolio standards in the United States from memory before moving on to harder problems.

Reference excerpt

A Renewable Portfolio Standard (RPS) is a regulation that requires the increased production of energy from renewable energy sources, such as wind, solar, biomass, and geothermal, which have been adopted in 38 of 50 U.S. states and the District of Columbia. The United States federal RPS is called the Renewable Electricity Standard (RES). Several states have clean energy standards, which also allow for resources that do not produce emissions, such as large hydropower and nuclear power. The RPS mechanism generally places an obligation on electricity supply companies to produce a specified fraction of their electricity from renewable energy sources. Certified renewable energy generators earn certificates for every unit of electricity they produce and can sell these along with their electricity to supply companies. Supply companies then pass the certificates to some form of regulatory body to demonstrate their compliance with their regulatory obligations. Because it is a market mandate, the RPS relies almost entirely on the private market for its implementation. Unlike feed-in tariffs which guarantee purchase of all renewable energy regardless of cost, RPS programs tend to allow more price competition between different types of renewable energy, but can be limited in competition through eligibility and multipliers for RPS programs. Those supporting the adoption of RPS mechanisms claim that market implementation will result in competition, efficiency, and innovation that will deliver renewable energy at the lowest possible cost, allowing renewable energy to compete with cheaper fossil fuel energy sources.

Program diversity 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. Many states that have mandatory Renewable Portfolio Standards also have additional voluntary targets either for the total proportion of renewable energy or for a particular technology type. In many states, municipalities and cooperatives are exempt from the RPS target, have a lower target, or are required to develop their own targets. Furthermore, in some states such as Minnesota, individual utilities (e.g., Xcel Energy) are singled out for special treatment.

Renewable energy certificates (RECs) States with RPS programs have associated renewable energy certificate trading programs. RECs provide a mechanism by which to track the amount of renewable power being sold and to financially reward eligible power producers. For each unit of power that an eligible producer generates, a certificate or credit is issued. These can then be sold either in conjunction with the underlying power or separately to energy supply companies. A market exists for RECs because energy supply companies are required to redeem certificates equal to their obligation under the RPS program. State specific programs or various applications (e.g., WREGIS, M-RETS, NEPOOL GIS) are used to track REC issuance and ownership. These credits can in some programs be 'banked' (for use in future years) or borrowed (to meet current year commitments). There is a great deal of variety among the states in the handling and functioning of RECs and this will be a major issue in integrating state and federal programs.

Multipliers RPS multipliers adjust the amount of renewable energy credits (RECs) awarded (up or down) for each MWh of electricity produced based on its source. Since the definition of what is considered "renewable energy" varies, for example, nuclear power, and whether an RPS program should consider environmental damage of a renewable energy source (for example, hydroelectric dams, bird strikes of wind turbines, geothermal earthquakes, solar thermal water use) affects RPS program design and implementation. A state can use a multiplier as protectionism to local renewable energy generators from out of state renewable generators. Since RECs are regulated at a state level, their ability to be traded over state lines varies.

Solar renewable energy certificates (SRECs) Over 16 of the approximately 30 states with RPS programs have also established a set-aside for solar energy. This results in the creation and trading of RECs specific to solar known as solar renewable energy certificates (SRECs). With a separate market for SRECs, states are able to ensure that a portion of their renewable energy comes from solar. As a result, states with solar carve-outs, such as New Jersey, have had more success in promoting solar energy through the RPS than states, such as Texas, with a generic REC market or REC multiplier.

Tiers and set-asides Energy supply companies need to show that they have acquired a particular percentage of their power sales from the designated technology type. Multiple technology types are bundled together in tiers or classes with similar effect. Not all states have set-asides or tiers (some preferring to promote particular technologies through credit multipliers) and each state that groups technologies together in a tier does so differently.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Renewable portfolio standards in the United States

Start with the simplest possible case. Write down what Renewable portfolio standards in the United States claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Renewable portfolio standards in the United States before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Renewable portfolio standards in the United States ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Renewable portfolio standards in the United States

In research
Renewable portfolio standards in the United States appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Renewable portfolio standards in the United States in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Renewable portfolio standards in the United States is common in secondary-school and first-year university syllabi. It links to neighbouring topics Energy policy of the United States, Renewable electricity, Renewable energy law, so understanding it makes those chapters shorter.
In everyday life
Look for Renewable portfolio standards in the United States outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Renewable portfolio standards in the United States in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Renewable portfolio standards in the United States means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Renewable portfolio standards in the United States out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Renewable portfolio standards in the United States in simple terms?

A Renewable Portfolio Standard (RPS) is a regulation that requires the increased production of energy from renewable energy sources, such as wind, solar, biomass, and geothermal, which have been adopted in 38 of 50 U.S. states and the District of Columbia. The United States federal RPS is called th…

Why does Renewable portfolio standards in the United States matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Renewable portfolio standards in the United States?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Renewable portfolio standards in the United States.

Tags

  • Energy policy of the United States
  • Renewable electricity
  • Renewable energy law
  • Renewable energy policy

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