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Introduction

1.1 Energy and Sustainable Development

This book is written by a chemical engineer and an electronic engineer who believe that continuing to burn fossil fuels for energy is not sustainable and that a transition to renewable energy is feasible. Let us start the discussion by reflecting on what sustainability of certain development is all about. “Sustainable development” is characterized as the “development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” Now it becomes clear why continuation of using fossil fuels for energy is not sustainable. First, the combustion of fossil fuels results in the release of carbon dioxide (CO2) and other pollutants (NOx, SOx, particulates, mercury, and other toxic metals) into the atmosphere. The increased atmospheric concentrations of these pollutants cause a series of environmental impacts, including global warming and respiratory health effects. Second, the rate at which we consume fossil fuels is much higher than the rate at which they are replenished so mankind cannot rely on this source of energy forever.

The main candidates for facing this dual challenge of carbon dioxide (CO2) emissions and fossil fuel depletion are coal with carbon capture and sequestration (CCS), nuclear, and renewable sources of energy. However, safe and economic concepts for carbon sequestration have not been proven; nuclear suffers from high cost, radioactive waste management, fuel availability, and nuclear weapon proliferation issues; and renewables have been limited by resource limits, high cost, and intermittency problems. Biomass could be a substitute for fossil fuels, but enough land or water to both meet the demand for power and to feed the world’s growing population is not available. Solar energy has huge potential—tens or hundreds of terawatts (TW) are practical, but it suffers from intermittency. Wind resources are less abundant and even more variable than solar, but in many regions they can complement the variability of solar resources.

The cost challenge for solar electricity is being resolved as recent drastic cost reductions in the production of photovoltaics (PV) paved the way for enabling solar technologies to become cost competitive with fossil fuel energy generation. Such cost competitiveness, called “cost grid parity,” has already been accomplished for parts of the southwest United States, Chile, Spain, Italy, and other countries. PV rooftop systems and utility power plants are relatively easy to build and deployment grows fast. Nevertheless solar is still a minor contributor in electricity mixtures worldwide as inertia in energy policy is stalling the transformation urgently needed. To this end, our book aims in conveying the great potential of PV and helping accelerate their deployment in a world longing for sustainable development.

1.2 The Sun, Earth, and Renewable Energy

We are entering a new solar age. For the last few hundred years, humans have been using up fossil fuels that took around 400 million years to form and store underground. We must now put huge effort—technological and political—into energy systems that use the sun’s energy more directly. It is one of the most inspiring challenges facing today’s engineers and scientists and a worthwhile career path for the next generation. PV, the subject of this book, is one of the exciting new technologies that is already helping us toward a solar future.

Most politicians and policymakers agree that a massive redirection of energy policy is essential if planet Earth is to survive the 21st century in reasonable shape. The 21st Conference of the Parties (COP21) that brought 190 countries together in Paris in December 2015 agreed that consistent efforts are needed worldwide to keep the global temperature increase to below 2°C, or preferably below 1.5°C.

This is not simply a matter of fuel reserves. It has become clear that, even if those reserves were unlimited, we could not continue to burn them with impunity. The resulting carbon dioxide emissions and increased global warming would lead to a major environmental crisis if we do not curtail the CO2 concentration in the atmosphere and do it soon, before we are locked into irreversible processes. So the danger is now seen as a double‐edged sword: on the one side, fossil fuel depletion and, on the other, the increasing inability of the natural world to absorb emissions caused by burning what fuel remains.

Back in the 1970s there was very little public discussion about energy sources. In the industrialized world we had become used to the idea that electricity is generated in large centralized power stations, often out of sight as well as mind, and distributed to factories, offices, and homes by a grid system with far‐reaching tentacles. Few people had any idea how the electricity they took for granted was produced, or that the burning of coal, oil, and gas was building up global environmental problems. Those who were aware tended to assume that the advent of nuclear power would prove a panacea; a few even claimed that nuclear electricity would be so cheap that it would not be worth metering! And university engineering courses paid scant attention to energy systems, giving their students what now seems a rather shortsighted set of priorities.

Figure 1.1 Toward the new solar age, this rooftop PV installation at the Mont‐Cenis Academy in Herne, Germany, is on the site of a former coal mine.

(Source: Reproduced with permission of IEA‐PVPS)

Yet even in those years, there were a few brave voices suggesting that all was not well. In his famous book Small is Beautiful,1 first published in 1973, E.F. Schumacher poured scorn on the idea that the problems of production in the industrialized world had been solved. Modern society, he claimed, does not experience itself as part of nature, but as an outside force seeking to dominate and conquer it. And it is the illusion of unlimited powers deriving from the undoubted successes of much of modern technology that is the root cause of our present difficulties. In particular, we are failing to distinguish between the capital and income components of the Earth’s resources. We use up capital, including oil and gas reserves, as if they were steady and sustainable income. But they are actually once‐and‐only capital. It is like selling the family silver and going on a binge.

Schumacher’s message, once ignored or derided by the majority, is increasingly seen as the essence of sustainable development. For the good of planet Earth and future generations, we have started to distinguish between capital and income and to invest heavily in renewable technologies—including solar, wind, and wave power—that produce electrical energy free of carbon emissions. The message has been powerfully reinforced by former US Vice President Al Gore, whose inspirational lecture tours and video presentation An Inconvenient Truth2 have been watched by many millions of people around the world. Most importantly, the vision was captured by industry leaders who made solar and wind systems affordable and continue to advance them.

Whereas the fossil fuels laid down by solar energy over hundreds of millions of years must surely be regarded as capital, the sun’s radiation beamed at us day by day, year by year, and century by century is effectively free income to be used or ignored as we wish. This income is expected to flow for billions of years. Nothing is “wasted” or exhausted if we don’t use it because it is there anyway. The challenge is to harness such renewable energy effectively, designing and creating efficient and hopefully inspiring machines to serve humankind without disabling the planet.

Figure 1.2 Three important renewable technologies: PV, wind, and wave.

We should perhaps consider the meaning of renewable energy a little more carefully. It implies energy that is sustainable in the sense of being available in the long term without significantly depleting the Earth’s capital resources, or causing environmental damage that cannot readily be repaired by nature itself. In his excellent book A Solar Manifesto,3 the late German politician Hermann Scheer considered planet Earth in its totality as an energy conversion system. He notes how, in its early stages, human society was itself the most efficient energy converter, using food to produce muscle power and later enhancing this with simple mechanical tools. Subsequent stages—releasing relatively large amounts of energy by burning wood and focusing energy where it is needed by building sailing ships for transport and windmills for water pumping—were still essentially renewable activities in the previously mentioned sense.

What really changed things was the 19th‐century development of the steam engine for factory production and steam navigation. Here, almost at a stroke, the heat energy locked in coal was converted into powerful and highly concentrated motion. The industrial society was born. And ever since we have continued burning coal, oil, and gas in ways that pay no attention to the natural rhythms of the Earth and its ability to absorb wastes and by‐products, or to keep providing energy capital. Our approach has become the opposite of renewable and it is high time to change priorities.

Since the reduction of carbon emissions is a principal advantage...