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Joules of Available Energy: The Currency that Matters

India experienced its worst ever power outage last July when a series of grid failures, over two consecutive days, eventually plunged an estimated 600 million people – half of the country’s population – into darkness.

While this causes us to question the reliability of energy infrastructures, a bigger issue is how we account for the energy used in everything we build and use – from the houses we live in to the products we buy, and the energy systems that create and power them. Everything around us has a lifetime of energy associated with its manufacturing, transportation, operation and reclamation. Particularly in the tech industry, where innovation and efficiency are expected, we must account for the lifetime energy associated with the things we build, and place a larger focus on how to get more from our products with less energy.

To get there, we need to introduce a key analytical component that’s currently missing when it comes to designing both physical and virtual products. We need to equip designers and engineers with additional tools that quantify a product or service based on the energy used over its lifetime. In light of social, economic and ecological trends, the unit of energy – the “Joule” – must become the currency for the designer, not dollars and cents.

But we are getting ahead of ourselves. Success requires the engineering community to connect with today’s high school students to encourage them to embrace the fundamentals in sciences. As an example, a student trained in fundamental concepts will have a firm understanding of thermodynamic principles that quantify available energy – the useful portion of energy – and be better prepared for the future resource-constrained world. Available energy, also called “exergy,” can be used as a metric, for example, to estimate how easily – and most efficiently – convert our existing natural resources (like coal or wind) into useful electricity. Likewise, it can also be used to determine available energy in waste products such as hot exhaust gases in factories or vehicles. Thankfully, these concepts can and are being taught in schools where a portion of students, such as those in advanced placement physics courses, are exposed to basics such as the second law of thermodynamics. It is also time the broader engineering society focused on these concepts once again. Indeed, in a world where Joules of available energy is the currency, old school is new school.

Accounting for the available energy required for extraction, manufacturing, waste mitigation, transportation, operation and end of life can provide strategic insights. For example, an analysis of a laptop computer may peg the cost at about nine gigajoules in lifetime available energy consumed – or roughly 200 liters of diesel destroyed. The analysis identifies “hot spots” – components such as the display that might require a lot of available energy across the lifecycle to manufacture and operate – and enables the designer to tweak the product to reduce its lifetime available energy needs. Such analysis, conducted for everything at design time, can conserve available energy on a massive scale. This key concept became the motivation for our researchers at HP Laboratories to devise lifetime available energy tools that can provide large impacts across HP’s expansive reach – from thousands of data centers to millions of printers and PCs.

One of my colleagues elegantly described the destruction of available energy as an hourglass with the grains of sand continually flowing from one half to the other. We cannot slow it down and, alas, we cannot refill it. Luckily for us, we have the potential – in both knowledge and programs – to slow the process by getting the most that we can out of every single grain of sand, or unit of available energy in our case. It is up to us to blaze a new trail for how to scale the available energy for the present generation while also leaving enough for future generations. And the time for action is now. The world cannot wait.

Chandrakant Patel is an HP Senior Fellow and the interim director of HP Labs, the industrial research lab that is the company’s central innovation-transfer organization. He is a pioneer in microprocessor and system thermo-mechanical architectures, end-to-end energy management in IT, and applications of sustainable IT ecosystem for a net positive environmental impact.

chandrakant Patel
HP Labs
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5 thoughts on “Joules of Available Energy: The Currency that Matters

  1. Ok, joules can be used to compare energy from various sources to each other. I guess we are talking mostly about giga joules now, but how long is a lifetime for a laptop? Is there an absolute number to replace that, too? LIfetimes are a lot like currency, they tend to vary.

  2. This article is absolutely on point, and this kind of analysis is not yet done in the mainstream media, in fact there is no discussion of total energy utilized at all during the life of a product.
    The author is way ahead of our time, maybe a natural disaster and/or a severe shortage of some valuable energy source will finally make the mainstream media start the discussion of how we consume energy unknowingly and what the long term impact of that is to the entire planet.
    We can only hope that energy consumption and its implications becomes a mainstream topic along with “going green”.

  3. This is definitely a start of a good discussion of how the world can speak the same language when we talk about energy. This approach would allow a better understanding of the concept we call energy and eventually provide us with quantitative ways of accounting for it. A rigorous accounting method is the best first step towards savings.

  4. Using joules of energy as a form of currency for designers is a very enlightened concept. It is a deceptively simple way to assure that resources are used efficiently because the exergy content of a design is also measure of the lifetime of wasted resources built into design decisions that at first may appear to be arbitrary without this concept.

    To make such a concept implementable would require an extensive understand of processes and engineering methodologies like six sigma or lean manufacturing and would need to add new databases and tools to support designers and process engineers.

    Also the mission to reduce entropy in processes would need to modify what we mean by quality. Many measures of quality use costs in dollars such as The Cost of Poor Quality. However, new metrics could be created such as “the cost of poor exergy decisions” or “the cost of wasted resources” which would measure the waste in joules of energy.

    Chandrakant Patel’s idea is a rational way for an engineer to quantify the marketing term “Green” or “Sustainable”. This is classic engineering thinking at its best.

    This is no surprise – coming from HP’s finest.

  5. I want to build upon Scott Burr’s comments on metrics and relate it to innovation metrics.

    Exergy can also be used to measure the value of an innovation. This is an outstanding way to measure one aspect of an innovation’s value. And the concept of its use over a lifetime allows for a lifetime value to be estimated.

    Another interesting application of using exergy as a measure is the challenge of preventative solutions. They are difficult to cost out in dollars when there is no baseline. This would not be a challenge using joules of energy since what is prevented could be quantified even if no cost history was available as long as the before and after condition of exergy could be estimated.

    The use of exergy will prove to be a more useful metric over time as limited resources force us to be practical in a more scientific way.

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