Question

Let's say that the U.S. were willing to divert a one-time investment of 10 qBtu out of its 100 qBtu annual energy budget toward building a new energy infrastructure having a \(10: 1\) EROEI and a 40 year lifetime. How many qBtu will the new resource produce in its lifetime, and now much per year? How many years before the amount of energy put in is returned by the output?

Short answer

Answer: The new resource will produce a total of 100 qBtu in its 40-year lifetime, 2.5 qBtu per year, and it will take 4 years to return the energy invested.

Step-by-step solution

1. Calculate the total energy produced

Since the EROEI is 10:1, it means that for every 1 unit of energy invested, the system produces 10 units of energy. So, with an investment of 10 qBtu, the total energy produced will be: Total energy produced = Energy invested * EROEI Total energy produced = 10 qBtu * 10 Total energy produced = 100 qBtu

2. Calculate the energy produced per year

Given that the infrastructure has a lifetime of 40 years, we can find out the energy production per year by dividing the total energy produced by the lifespan of the infrastructure: Energy produced per year = Total energy produced / Lifetime Energy produced per year = 100 qBtu / 40 years Energy produced per year = 2.5 qBtu/year

3. Calculate the time it takes to return the energy invested

In order to find the time it takes for the amount of energy put in to be returned by the output, we can divide the initial energy investment by the energy produced per year: Time to return energy invested = Energy invested / Energy produced per year Time to return energy invested = 10 qBtu / 2.5 qBtu/year Time to return energy invested = 4 years Thus, the new resource will produce a total of 100 qBtu in its 40-year lifetime and 2.5 qBtu per year. The amount of energy put in will be returned by the output in 4 years.

Key concepts

EROEI Calculation

Understanding the Energy Return on Energy Invested (EROEI) is crucial for evaluating the efficiency of an energy infrastructure. It compares the amount of energy obtained from an energy source to the energy expended to harness that energy.

The calculation is straightforward: divide the total energy output by the total energy input. In the given example, for every 1 qBtu invested into the system, we get 10 qBtu out, which represents an EROEI of 10:1. This implies a net gain in energy, indicating an efficient energy infrastructure. To put it into a formula, the EROEI is calculated as: \[ \text{EROEI} = \frac{\text{Total Energy Output}}{\text{Energy Invested}} \] For the exercise scenario: \[ \text{EROEI} = \frac{100 \text{ qBtu (output)}}{10 \text{ qBtu (input)}} = 10:1 \]
Having a high EROEI is desirable as it means that less energy is consumed in producing energy, making the process more sustainable and economically viable in the long term.

Energy Infrastructure

Energy infrastructure encompasses all the facets of generating, transmitting, and distributing energy from its source to the end-user. This includes power plants, transmission lines, pipelines, and more. An energy infrastructure with a high EROEI is indicative of efficient energy use and minimal waste.

Investing in new infrastructure, like the one described in the exercise, is critical for a sustainable energy future. The 40-year lifespan mentioned is a significant duration for infrastructure, and the expected output of 100 qBtu over this period helps assess its usefulness and financial feasibility. Proper maintenance and technological advancement can further extend the utility and efficiency of such an infrastructure, maximizing the initial energy investment.

Sustainable Energy Investment

Sustainable energy investment refers to allocating financial resources to energy sources and systems that provide long-term environmental, social, and economic benefits. Such investments aim to reduce carbon footprints, mitigate climate change, and ensure energy security.

The one-time investment of 10 qBtu in the exercise exemplifies a strategic sustainable investment with a clear payback period. It highlights the importance of considering both the short-term impact and the long-term benefits. Once the energy invested is returned after 4 years, as calculated, the following 36 years of the infrastructure's life can be viewed as energy profit, thus showcasing the extended benefits of sustainable investments.

Energy Production Analysis

When conducting an energy production analysis, one assesses not only the total output but also the distribution over time and the sustainability of production. In the provided example, distributing the total energy production of 100 qBtu evenly over a 40-year lifespan results in an annual energy production of 2.5 qBtu.

This analysis is essential for understanding the flow of energy, maintenance needs, and planning for future capacity. It allows for a comprehensive view of the performance and reliability of energy investments. When the energy return is as high and as quick as in the example, it reaffirms the project's viability and potential to contribute positively to the energy supply.