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Trade-offs are Inevitable: Considerations for Our Energy System

By Evelyn Teel

It is easy to think of energy as simply a commodity that makes our lives easier – by fueling our cars, keeping our homes comfortable, and powering our many devices. However, what if we sought to understand the more fundamental role energy plays in our lives? How would this reframe the conversation around the conflicting demands on our energy systems?

These questions and more are at the heart of Kenneth P. Green’s book Abundant Energy: The Fuel of Human Flourishing. In this small but dense tome, he discusses a variety of topics and encourages the reader to think more deeply about his or her own values and priorities regarding energy systems and the policies that govern them.

First, a few caveats. The book is nearly a decade old (published in 2011), so some of its content and assertions are either out of date or have been proven incorrect in the intervening years. The author also largely sidesteps around climate change issues, which have become more prominent in the past decade. However, this does not diminish the value in understanding the overarching points in the book.

Green starts from the premise that external energy sources are so intrinsically linked with human lives that we have, in fact, evolved along with our use of them. The first power source our human ancestors were able to harness – fire – instigated evolutionary changes that shaped the future of our species. Much of what it means to be human, from our cognitive abilities to our physical structure, our digestive system to our hormonal system to our social structures, evolved in concert with our ability to harness fire and, later, more sophisticated forms of energy.

The book focuses on the topics noted below and encourages readers to think critically about what we take for granted in our energy system, how we can improve that system, and what trade-offs we are willing to make to facilitate those improvements.

Energy Affordability

Whereas we often think of our energy costs simply in terms of our utility bills or how much it costs to fill up our gas tank, the reality is that energy costs impact nearly everything we buy and use. There are, of course, direct costs, like electricity or natural gas service at our house or gasoline for the car. There are also indirect costs, which include the energy used to produce all of the goods and services we consume. There is an inverse relationship between income and the percentage of income spent on direct and indirect energy costs – disproportionately so. This means that any increase in energy prices is borne by those least able to absorb the additional costs. This relationship holds true not only within the United States, but also worldwide – poorer nations are more affected by increasing energy costs than are richer ones.

Energy Reliability

Most of the time, we take for granted that when we need electricity, natural gas, propane, gasoline, or other forms or sources of energy, we’ll be able to access them easily. When these systems fail, we are presented with a stark reminder of how essential they are to our lives.

In the case of the 2003 East Coast blackout, millions of Americans and Canadians were left without power for up to two days. Not just electricity was out – communication and transportation systems were inoperable. Other utilities, such as water, were affected. The event cost the economy billions of dollars. The 2003 blackout is an extreme example, but even much shorter blackouts can have negative effects and incur huge costs.

All of this underscores the importance of energy reliability. Consistent availability of power is what enables our society to function. When applying this thinking to fuel sources and how we can ensure energy availability, it is important to understand the capacity factor of various sources – i.e., the percentage of time a particular type of generation operates at full capacity. Some fuel sources can generate full power nearly full time (such as nuclear), while others operate more intermittently (such as solar). For more information about capacity factor, please check out two of our previous blog posts: https://avalonenergy.us/2014/06/capacity-factor/ and https://avalonenergy.us/2014/06/capacity-factor-part-2/.

Energy and the Environment

The majority of the world’s pollution comes from developing nations, and the best way to help curtail their emissions may be to help those countries expand their economies. Green argues that for every environmental resource – energy-related and otherwise – there is an optimal usage level that balances sustainability and economic growth. A society will generally overshoot that level at first, then correct and moderate its usage over time. The key factor in ensuring that a society can moderate its consumption of a given resource is whether it can afford to do so. With economic growth comes the ability to focus on priorities apart from basic survival, as well as the capacity to develop new, more efficient technologies.

Energy System Inertia and Momentum

All systems have momentum. Once a decision is made to proceed in one direction, each progressive step makes it harder and harder to backtrack. This is resonantly true in our energy system. Our electric generation capacity has been built based on certain criteria, and is intended to last for decades. The workforce has been trained within specific parameters. Our society has developed technology, architecture, manufacturing, and much more around the energy system that is currently available. This is not to say that the way we generate, distribute, and use energy must remain static. It does, however, require an understanding of the secondary effects of any changes, and an evaluation of the cumulative costs associated with those changes.

Green also touches on the topics of energy independence and security and the danger of unintended consequences. He highlights the various trade-offs we would need to be willing to make in order to ensure energy independence, such as ramping up fuel extraction in the US and accepting the environmental consequences of increased energy production at home.

Finally, every decision can (and likely will) have unintended consequences. In the realm of energy policy, these unintended consequences can be huge, affecting the lives of millions of people both domestically and abroad. Perhaps the best way to fully understand, evaluate, and resolve these unintended consequences is to test many, varied possible solutions to a given issue. Implementing broad, sweeping solutions without sufficient testing can bring consequences that may do more harm than the original solution was intended to solve.

Conclusion

The environment, climate change, and energy policy are hot topics these days, and it is important to have a general understanding of the different priorities and trade-offs in the energy realm. Which is more important: reducing carbon emissions; keeping energy costs low, particularly for the sake of our less affluent neighbors; ensuring power is available reliably; something else entirely; or a combination of all of these? Identifying (personal) priorities or guidelines for thinking about energy changes can help focus our thinking on individual topics. This book certainly does not cover every aspect of these issues and the many others we need to better understand (nor could any one book do so). However, it is a good starting point to understand several factors regarding energy policy.

The Avalon Advantage – Visit our website at www.avalonenergy.us, call us at 888-484-8096, or email us at info@avalonenergy.us

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Copyright 2020 by Avalon Energy® Services LLC

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Capacity Factor – Part 2

In our previous article we looked at Capacity Factor and how it differs between nuclear generation and solar PV (photovoltaic).   We concluded that in order to generate the same amount of electricity as 1/3 of the capacity of the US nuclear generation fleet (33,042 MW), 154,760 MW of solar PV capacity would be required.  This is a result of the substantially different Capacity Factors of nuclear (90.9%) and solar PV (19.4%) and is summarized in the table below.

A reader asked how much solar PV capacity would be needed in order for solar PV to generate as much electricity as the entire US nuclear generation fleet.  As noted in the previous article, the current US nuclear generation fleet consists of 100 operating units with a combined capacity of 99,125 MW which, during 2013, produced 789,016,510 MWh of electricity.

In order to calculate the amount of solar PV capacity needed, we can rearrange the Capacity Factor formula we used last time as follows:

Solving for the solar PV capacity needed to supply the same amount of electricity as the US nuclear generation fleet, we arrive at the following:

Capacity (MW) = 789,016,510 MWh / (19.4% x 8,760 hours/year)

Capacity (MW) = 464,280

In summary, 464,280 MW of solar PV capacity would be needed in order for solar PV to generate as much electricity as the entire US nuclear generation fleet.  This is 365,155 MW more than the existing 99,125 MW of installed nuclear capacity and is summarized in the table below:

As noted in our previous article, solar PV, like other sources of electricity generation (nuclear, wind, coal, natural gas, geothermal, biomass, etc.) comes with a set of tradeoffs.  Each source has its own strengths and weaknesses.  The focus here is simply on Capacity Factor.

The Avalon Advantage – Visit our website at www.avalonenergy.us, call us at 888-484-8096, or email us at jmcdonnell@avalonenergy.us.

Notes:

Data from the US Energy Information Administration

Evelyn Teel contributed to this article.

Please feel free to share this article.  If you do, please email or post the web link.  Unauthorized copying, retransmission, or republication is prohibited.

Copyright 2014 by Avalon Energy® Services LLC

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Capacity Factor

In a recent article in the Energy Law Journal, the authors state,

By as early as 2016, installed distributed solar PV capacity in the United States could reach thirty gigawatts (GW).  If that forecast is on track, distributed solar generation will have increased from less than one GW in 2010 to the equivalent of nearly one-third of the nuclear generating capacity in the United States in less than a decade.1

Is the comparison to “one-third of the nuclear generating capacity” meaningful?  Could the amount of solar PV (photovoltaic) generation output expected to be available as early as within two years be equivalent to one-third of today’s nuclear generation output?  The short answer to both questions is “no” and the reason is that nuclear and solar generating facilities have substantially different Capacity Factors.

What is Capacity Factor?

Capacity Factor is the ratio of the actual output of an electricity generating unit over a time period to the unit’s maximum possible output over the same time period.  This ratio expresses the extent to which a unit is, or is not, operating at full output.  A high Capacity Factor, say 80% or 90%, indicates that a generating unit is operating close to “full out,” whereas a low Capacity Factor, say 20% or 30%, indicates that a generating unit is operating well below its maximum capability.

More specifically, Capacity Factor is defined as follows:

For example, a 500 megawatt (MW) unit that generates 2,187,500 megawatt-hours (MWh) of energy during the course of a year has a Capacity Factor of 50%, calculated as follows:

Capacity Factor = 2,187,500 MWh / (500 MW x 8,760 hours/year)

Capacity Factor = 50%

Why don’t generating units operate at 100% Capacity Factor?

There are many reasons.  All operating equipment must be backed off periodically for maintenance.  Mechanical failures and accidents lead to unscheduled outages.  The individual economics of each unit lead to them being called upon more or less under grid operators’ economic dispatch models.  Wind and solar units are physically constrained by how frequently the wind blows and the sun shines.

US Nuclear Generating Fleet

The current US nuclear generation fleet consists of 100 operating units with combined capacity of 99,125 MW which, during 2013, produced 789,016,510 MWh of electricity.  The overall Capacity Factor of the nuclear generating fleet is therefore:

Capacity Factor = 789,016,510 MWh / (99,125 MW x 8,760 hours/year)

Capacity Factor = 90.9%

Analysis

The Energy Information Administration (EIA) reports that during 2013, the average Capacity Factor of solar PV in the US was 19.4%.

Over the same time period, 99,125 MW of nuclear capacity, with its 90.9% Capacity Factor, generated 789,016,510 MWh of electricity:

Going back to the opening quote, one-third of the nuclear generating capacity in the United States” is 33,042 MW, which was responsible for 263,005,503 MWh of electricity:

Given Solar PV’s much lower Capacity Factor, 33,042 MW of solar PV capacity would generate only 56,152,330 MWh of electricity, or 206,853,173 MWh (78%) less than the output of the same amount of nuclear capacity:

In order to generate an equivalent amount of electricity as 33,042 MW of nuclear capacity, substantially more solar PV capacity would be required:

In other words, in addition to the 33,042 MW of solar PV capacity projected to be online by as early as 2016, another 121,718 MW of solar PV would be required in order to generate the same amount of electricity as 1/3 the output of the nuclear generation fleet:

Is the amount of solar generation expected to come online in a decade equivalent to one-third of today’s nuclear generation capacity?  No, and the reason is that nuclear and solar generating facilities have substantially different Capacity Factors, 90.9% versus 19.4%, respectively.

This is a challenge solar PV faces.   The nuclear industry increased its capacity factor from 50% during the 1950s to what it is today through operational improvements.  The capacity factors of coal and natural gas units vary based on their individual economics and their dispatch merit.  Solar PV is bounded by the physical limits of when the sun shines.

The purpose of this article is to take a recent quote and use it as an opportunity to explain Capacity Factor.  Solar PV, like other sources of electricity generation (nuclear, wind, coal, natural gas, geothermal, biomass, etc.) comes with a set of tradeoffs.  Each source has its own strengths and weaknesses.  The article is meant simply to look at Capacity Factor.  Other tradeoffs will be the subject of future articles.

The Avalon Advantage – Visit our website at www.avalonenergy.us, call us at 888-484-8096, or email us at jmcdonnell@avalonenergy.us.

Notes: 

1Elisabeth Graffy and Steven Kihm, Does Disruptive Competition Mean a Death Spiral for Electric Utilities?, Energy Law Journal, Volume 35, No, 1, 2014.

Data from the US Energy Information Administration.

Evelyn Teel contributed to this article.

Please feel free to share this article.  If you do, please email or post the web link.  Unauthorized copying, retransmission, or republication is prohibited.

Copyright 2014 by Avalon Energy® Services LLC