I prezzi alle stelle del petrolio, l’instabilità politica in Nord Africa e Medioriente, gli effetti a lungo termine del disastro nucleare in Giappone, hanno sollecitato un nuovo confronto sulle politiche energetiche, a tutti i livelli, ma gran parte delle discussioni si concentra sulle vecchie e scadenti soluzioni: energia nucleare “sicura”, gas naturale, carbone pulito e biocarburanti, che non risolveranno i nostri problemi.
Possiamo soddisfare tutto il fabbisogno energetico mondiale con il vento, l’acqua e il sole. E possiamo farlo in maniera affidabile, sicura, sostenibile ed economicamente conveniente. Affidabile in quanto, sebbene una sola centrale eolica o solare-fotovoltaica non possa provvedere al fabbisogno energetico di una regione, una rete intercontinentale di centrali elettriche, linee di trasmissione ed accumulazione catturerebbe in modo naturale il vento, l’acqua e l’energia solare, che abbondano su questo pianeta, garantendone la distribuzione secondo le necessità in maniera sicura, pulita ed economicamente conveniente. Sicuro e sostenibile perché l’emissione di inquinanti atmosferici è pari a zero, hanno bassissimo impatto su qualità dell’acqua ed ecosistemi, non si associano a significativi rischi di catastrofi dovute ad errore umano o calamità naturali e si basano su risorse primarie inesauribili. Economicamente conveniente in quanto non più dispendioso di quanto non lo sia ora in termini di costi privati e costi sociali. Ad esempio, il costo di produzione di elettricità da energia eolica terrestre è già inferiore al costo di generazione da combustibili fossili convenzionali. Per realizzare questa visione, abbiamo bisogno di una completa trasformazione del settore energetico, dalla produzione alla trasmissione per l’utente finale. Dobbiamo mandare in pensione le centrali nucleari ed i combustibili fossili e sostituirli con vento, acqua, e centrali elettriche solari. È un impegno enorme, ma gli ostacoli ad una tale trasformazione del settore energetico sono principalmente sociali e politici, non tecnici ed economici. High gasoline prices, instability in North Africa and the Middle East, and the lingering effects of the nuclear power disaster in Japan have gotten everyone talking about energy policy again. Most of the discussion (see for example US President Obama’s plan) involves the same old inferior options: “safe” nuclear power, offshore oil, natural gas,“clean” coal, and biofuels. But these won’t solve our energy problems, and we don’t need any of them. We can supply all of the world’s energy needs with wind, water and sunshine. And we can do it reliably, safely, sustainably and affordably. Imagine not worrying about – or spending billions to recover from – reactor meltdowns, fallen oiligarchies, offshore drilling disasters, air and water pollution, or dangerous climate change. Instead, an intercontinental grid of power plants, transmission lines, and storage would capture the natural wind, water and solar energy that abounds on this planet and send it where needed — safely, cleanly and economically. But is a system based 100 percent on wind, water and solar power reliable? Yes. Although no single wind or solar-photovoltaic farm can reliably supply all the power demand in a given region, neither can any individual coal or nuclear plant. Our existing electricity system ensures reliable power by using large grids that connect many power sources, back-up systems, spinning reserves, peak-power plants, and other control and management techniques. A global wind, water and solar grid would be just as reliable, with different tactics, such as: linked, geographically dispersed energy sources; non-variable sources such as hydropower and geothermal; “smart” computer-based energy management that moves power where and when it is needed; oversized plants making excess power that can be used to produce hydrogen fuel for heating and transportation; and power storage in the batteries of our electric cars. The next question usually is: Is it safe and sustainable? Yes. Wind, water and solar power have essentially zero emissions of greenhouse gases and air pollutants over the whole “life cycle” of the system; have low impacts on wildlife, water quality and terrestrial ecosystems; do not have significant catastrophic risks associated with waste disposal, terrorism, war, human error or natural disasters; and are based on primary resources and materials that are indefinitely renewable or recyclable. Nuclear power, coal and biofuels are the opposite. Biofuels and so-called “clean coal” still cause air pollution, water pollution, habitat destruction, and climate change, and biofuels can cause higher food prices for the poor. Nuclear power already has had two catastrophic accidents, and even though the industry has improved the safety and performance of new reactors, and has proposed even newer (but largely untested) “inherently safe” reactor designs, there is no guarantee that the reactors will be designed, built and operated correctly, and catastrophic scenarios involving terrorist attacks are still conceivable. Furthermore, any nuclear-fuel cycle can contribute, even if very indirectly, to the proliferation of nuclear weapons. With a wind-water-solar system, the risk of any such catastrophe is zero. The final question is: What will it cost me? In fact, no more than you pay for electricity now, in terms of both “private costs” (which are what consumers pay, in dollars) and “social costs” (which are what society pays, directly and indirectly, in monetary and non-monetary terms). For example, the private cost of generating electricity from onshore wind power already is less than the private cost of conventional generation from fossil fuels, and is likely to go lower in the future. What’s more, by 2030, the social cost of generating electricity from any wind-water-solar power source, including solar photovoltaics, is likely to be less than the social cost of conventional fossil-fuel generation — even when the additional costs of an expanded transmission system and decentralized energy storage in vehicles are included. And the social cost of powering our cars and trucks with electricity (based either on batteries or hydrogen fuel cells) is likely to be equalto or less than the social cost of transportation based on gasoline, diesel and biofuels. Thus, a large-scale wind-water-solar energy system can reliably supply all of the world’s energy needs, with significant benefits to climate, air quality, water qualityand ecological systems, and with zero catastrophic risk — at reasonable cost. To realize this vision, we need a complete transformation of the energy sector, from production to transmission to end user. We must retire nuclear and fossil-fuel power plants and replace them with wind, water, and solar power plants. We must dramatically expand our power-transmission infrastructure to accommodate the new power systems. We need to greatly improve the efficiency with which we use energy, and more intelligently manage our demand for energy. We should replace the fossil-fuel engines in cars, trucks, tractors, ships, and trains with electric motors powered by direct electricity, batteries orhydrogen fuel cells, replace fossil-fuel heating and cooling systems with electric heat pumps, use resistance heating where feasible, use electrolytic hydrogen for high-temperature processes, and so on.
Although this is an enormous undertaking, it does not have to be done overnight, and there are plenty of examples in recent history of successful large-scale infrastructure, industrial and engineering projects. During World War II, the U.S. transformed its motor-vehicle production facilities to produce over 300,000 aircraft, and the rest of the world made 486,000 more. In 1956, the U.S. began work on the Interstate Highway System, which now extends for 47,000 miles and is considered one of the largest public-works projects in history. Starting in 1963, the iconic US Apollo Program, one of the greatest engineering and technological accomplishments ever, put a man on the moon in less than 10 years. The obstacles to a comparable transformation of the energy sector are primarily social and political, not technical or economic. If we continue to make decisions based on interest-group politics, and muddle through with nuclear power, “clean” coal, offshore oil production and biofuels, then our energy system will continue to threaten the health and well-being of everyone on the planet. But if we can muster the political will to make a concerted effort to develop a global wind, water and solar-power energy system, we can solve the world’s energy and environmental problemsby mid-century.
Research Scientist Institute of Transportation Studies University of California, Davis