Sustainable Energy – Without the Hot Air

The nations of the world are in a stage of transition regarding how they source energy for their economies and populations, a transition that is filled with noisy debate about economic cost, environmental impact and the respective roles that government and private sectors should play.  If one desires to strip away the cacophony and learn to think about how a nation might realistically supply energy to sustain itself, then Sustainable Energy – Without the Hot Air is a good book to read.  

Author David J.C. MacKay is a professor in the Department of Physics at the University of Cambridge and Chief Scientific Advisor to the UK Department of Energy and Climate Change.  He earned a BA in Natural Sciences from Trinity College, Cambridge and a PhD in Computation and Neural Systems from the California Institute of Technology.  His chapters are brief and direct, peppered with dry wit that amuses while emphasizing important points.  As he focuses on ways to compute estimates of energy consumption and generation, he is careful to use equations to illustrate, inform and educate rather than overwhelm with mathematics.  He includes technical chapters at the end of the book for those who are interested in the deeper investigation of the mathematics.

MacKay’s objective in Sustainable Energy is to apply numbers to demonstrate the scale of the challenge of providing energy from sustainable sources to a regional economy if one chooses not to deplete the finite resource of fossil fuels.  He discusses neither the impact of current energy consumption on the environment nor the economics of renewable energy sources.  Instead, he investigates the composition of the demand for energy at the level of the individual consumer and compares this to the supply that one can reasonably expect from sustainable sources of energy.  He uses the region of the United Kingdom as the domain and, while the UK is unique in its consumption and available resources of energy, he provides a useful framework for evaluating consumption and resource planning for any region of the world.  His conclusions are as surprising as they are practical.

The first section of the book constructs a “balance sheet” that provides an accounting of the energy needs per person on one side of the ledger and the potential sustainable supply of energy on the other side.  MacKay constructs the balance sheet using a sensible quantitative methodology that relies upon assumptions that are reasonable and verifiable. This section cuts away the hyperbole of the political arena and uses solid numbers to demonstrate the size of household demand for energy and the limits of sustainable energy to fulfill the demand.  One gets a sense for the immensity of the demand for energy today and the complexity of the possible solutions for satisfying this demand as it grows in the future.

The second section discusses MacKay’s thoughts on how to manage the demand side of the ledger and to optimize a supply side that draws on sustainable sources.  The section includes a chapter on vehicular transport that splashes cold reality on some popularly promoted alternatives to petrol-fueled vehicles.  It includes an interesting section on how to optimize the heating of homes and buildings with informative sections on heat pumps and Combined Heat and Power systems.  It also provides a constructive view on clean coal technology and the role it might play in a portfolio of energy sources.  The chapter on the import/export market in renewable energy is intriguing as well.

The chapter that I found most interesting was Chapter 27 entitled “Five Energy Plans for Britain” in which MacKay describes plans with the following objectives: (1) domestic sourcing of all renewable energy, (2) Not-In-My-Backyard that eliminates visually unattractive generation like windmills, (3) no nuclear, (4) no nuclear and coal, and (5) lowest cost alternatives.  The diversity of these plans demonstrates the difficulty in satisfying the array of preferences that currently confront policy makers and the complexity of the planning process.  

The author concludes that, in the context of the UK, the demand for energy exceeds what sustainable sources can supply.  He demonstrates that renewable sources of energy cannot be the sole answer to the energy challenge, and we know that the finite sources of fossil fuels are also clearly not the sole answer.  Therefore, the policy questions are (a) what combination of supply of fossil and renewable sources can sustain a growing economy? and (b) what combinations are possible based on the considerations of cost and impact on the environment?

Below are but a few of the interesting insights from the book:

• The consumption of coal and oil began to grow exponentially beginning with the Industrial Revolution in 1769 and this growth rate continues today. Generating energy from renewable sources is inevitable.
• Fossil fuel consumption and greenhouse gas emission is a function of wealth.  Globally, the average emission is 5 1/2 tons of CO2 per person.  North Americans emit approximately 24 tons of CO2 per person, Europeans emit an average of about 10 tons per person and Asians emit about 4 tons.
• Supplying energy in a way that reduces reliance on fossil fuels is a big problem.  Every little bit of reduction helps only a little. Replacement of fossil fuels as a source of energy is a large-scale problem that requires large-scale solutions.
• Automobile fuel consumes around 20% of the total energy that each person consumes.
• Standby power from fax machines, copiers, clocks, stereo equipment, etc. as they sit idle accounts for 8% of the power that people consume.
• The world has a very small stock of renewable energy generators.  If the UK were to cover only the windiest 10% of its geography with windmills, it would double the entire fleet of wind turbines currently standing on the planet.
• The energy yield from biological sources – the biomass category of renewable energy – is small. If maximized, it would only produce enough fuel to cover half of the auto fuel consumed in the UK, and that assumes that all agricultural land in the UK is used for this purpose and none for any other purpose, such as feeding animals and people.
• Hydro energy produces very little in the UK on a per person basis and has very little capacity to grow.  Because water can be stored, hydro is best used to cover periodic peaks in energy demand.
• Photovoltaic solar panels are 20% efficient in converting energy from sunlight and are already near their theoretical limit.  They may become cheaper to manufacture, which will improve their cost-effectiveness, but the solar industry is unlikely to identify a technological breakthrough.

Can the free market that only responds to spot prices create the best portfolio of energy sources to sustain economic growth and a high quality of life given the time, expense and use of commonly owned property required to develop generating capacity? This is the question that the author leaves with the reader.  The value of this book is that MacKay equips the reader with the framework for sensibly approaching this question.

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