The great paradigm shift of our time is the transition of our societies from carbon-emitting fossil fuels to clean and renewable energies such as wind, solar, hydro, marine and geothermal. For electricity generation, wind and solar are the two fastest growing sources. Our largest electric utilities in Arizona have each adopted aggressive emissions reduction targets, a step change from just a decade ago.
Why is that? I see four main reasons.
First, the evidence for man-made climate change is clear and climate disasters are now daily occurrences all over the world. We have to get rid of the carbon habit.
Second, people want clean energy. Most people want to leave the planet in a better place than where we found it.
Third, a series of tax credits have spurred the development of large-scale wind and solar power plants, providing utilities, developers and regulators with invaluable operating experience. We now know that renewable energy works.
And fourth, renewable energy is cheaper. Due to large investments in R&D since the 90s and until today, the cost of renewable energies has decreased considerably.
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My favorite resource for comparing the cost of generating electricity from renewable and fossil sources is Lazard’s Levelized Cost of Energy report. Lazard compares the unsubsidized cost of solar, wind and geothermal electricity generation to traditional sources like natural gas (combined cycle and peak), coal and nuclear. Their findings show that electricity from new wind and solar power plants is cheaper than electricity from any new fossil fuel or nuclear power plant, and in most cases, significantly. In fact, the cost of wind and solar is so cheap that it directly competes with electricity from already existing, paying fossil power plants.
Together, these four reasons plus local benefits from local development present a clear choice to evolve our energy systems now and for decades to come: use renewable energy.
Of course, not all regions have enough wind. In Arizona, we have approximately 100,000 square kilometers (= 38,610 square miles) with enough wind to generate economically competitive electricity (US Department of Energy’s WINDExchange website). Good examples of successful wind power plants in northern Arizona are the 99 MW Perrin Ranch Wind Farm and the 127 MW Dry Lake Wind Project. The 161 MW wind project and 60 to 80 MW solar energy project set up by Babbitt Ranches will soon join this list. The 477 MW wind power plant at Chevelon Butte near Winslow will soon begin construction and Babbitt Ranches plans to develop an additional 480 MW solar power plant by 2024. Together, these plants will generate enough electricity to power approximately 420,000 homes.
Energy development is not all rosy, even for renewable energies. Although the impacts of wind and solar are much smaller than those of coal, gas or nuclear, there are some potential impacts.
For wind, the main undesirable impacts are related to the field of vision (some do not like to look at wind turbines) and impacts on birds and bats. Personally, I’d rather see 700-foot wind turbines than see and smell a coal-fired power plant with 775-foot tall chimneys. Many more birds and bats die each year from collisions with buildings, cats and lead poisoning than from wind turbines. Unfortunately, the birds killed by wind turbines are often raptors. Therefore, wind power plants should be located away from migration corridors and critical raptor habitat. Bird detection systems using thermal imaging, Doppler radar and AI can identify incoming birds and stop turbine blades in their path. Compared to the effects of climate change, wind power is the clear winner.
So what happens to your electricity supply when the wind isn’t blowing or the sun isn’t shining? Fortunately, new developments in energy storage and grid management are addressing these challenges. Good examples are batteries, pumped hydro, molten salt heat storage, H2 generation, building dynamic loads and other techniques.
If you want to learn more about the answer to this question, I recommend the National Renewable Energy Laboratory’s Future of Renewable Electricity Study. Their study showed that we can make this transition. If we want to avoid the worst consequences of climate change, it is time to press the accelerator of renewable energies.
Tom Acker is a professor of mechanical engineering at Northern Arizona University and a board member of the North American Wind Energy Academy.