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Drought And U.S. Hydropower | Earth Wise

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The ongoing severe drought in the western U.S. has led to low water levels in the rivers and reservoirs that feed hydroelectric power systems.  The Energy Information Administration is projecting a 13.9% decrease in hydroelectric generation this year compared to 2020.

Water levels in Lake Powell have fallen so low that it may not be possible to operate the power plant at Glen Canyon Dam starting as soon as 2022.  California officials took the Edward Hyatt hydroelectric plant offline in August because of low water levels on Lake Oroville.   Washington, the state with the most hydroelectric power generation, has seen an 11% drop in electricity generated to date this year as compared to last year.  That state is actually doing better than others in the West, such as California, where hydro generation is down 38%.

Hydropower accounts for over 7% of the electricity generated in the United States.  Five states – Washington, Idaho, Vermont, Oregon, and South Dakota – generate at least half of their electricity from hydroelectric dams.

The current decrease in hydropower is alarming, but it is not unprecedented.  The more significant question is whether the drop in generation this year is a sign that this power source is declining and becoming less reliable.   According to some scientists, the West is in a “megadrought” that could last for decades.

The greater concern is whether the bad years are likely to become more common because of climate change.  Climate projections agree that temperatures will continue to rise, but what will happen to precipitation levels in specific places is much less certain.  That is what will determine what the future holds for hydroelectric power.

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Inside Clean Energy: Drought is Causing U.S. Hydropower to Have a Rough Year. Is This a Sign of a Long-Term Shift?

Photo, posted May 7, 2014, courtesy of Tyler Bell via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

More Extreme Wildfire Seasons | Earth Wise

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According to a new study led by researchers at Stanford University, autumn in California feels more like summer now as a result of climate change, and this hotter and drier weather increases the risk of longer and more dangerous wildfire seasons.

The research team, whose work was recently published in the journal Environmental Research Letters, found that the frequency of extreme fire weather conditions in the fall in California has doubled since the early 1980s.  Average temperatures during the season have increased by more than 2 degrees Fahrenheit, and rainfall has fallen by approximately 30%.  The most pronounced warming has occurred in the late summer and early fall.  That finding means that tinder-dry conditions coincide with the strong “Diablo” and “Santa Ana” winds that are typical in California at this time of year.     

In recent years, these conditions have fed large and fast-moving wildfires across California.  The state’s two largest wildfires, two most destructive wildfires, and the most deadly wildfire all occurred during 2017 and 2018, resulting in more than 150 deaths and $50 billion in damage.

Because summertime has typically been peak fire season, the recent spate of autumn fires is putting a strain on firefighting resources and funding.  The ongoing COVID-19 pandemic could further strain emergency resources.  Since fire-prone regions have historically shared  wildfire-fighting resources throughout the year, the consequences of California’s extended wildfire season could have a global impact.  (For example, California’s recent autumn wildfires have coincided with the beginning of wildfires in Australia). 

The researchers highlight some opportunities to manage the intensifying wildfire risk in California, including limiting the trajectory of global warming in keeping with the targets identified in the United Nations’ Paris agreement.

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Researchers forecast longer, more extreme wildfire seasons

Photo, posted September 12, 2019, courtesy of the California National Guard via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Agrivoltaics

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A new study by Oregon State University has found that the most productive places on Earth for solar power are farmlands.   In fact, if less than 1% of agricultural land was converted to solar panels, it would be sufficient to fulfill global electricity demand.

The concept of co-developing the same area of land for both solar photovoltaic power and conventional agriculture is known as agrivoltaics.

The synergy between agriculture and solar power is not surprising.   People have been growing crops around the planet for at least 8,000 years and, long ago, farmers found the best places to grow them which turn out to also the best places to harvest solar energy.  The needs for solar panels are pretty similar to those of food crops.  The efficiency of the panels decreases if they get too hot.  Barren land is hotter than cropland, so the productivity of solar panels is less in such places.

The Oregon State Study analyzed power production data collected by Tesla, which had installed five large grid-tied, ground-mounted solar electric arrays owned by Oregon State.  The researchers monitored air temperature, relative humidity, wind speed, wind direction, soil moisture, and incoming solar energy.  With the data, they developed a model for the best conditions for solar panel productivity and they coincide with excellent conditions for agriculture.  Solar panels are kind of like people with regard to the weather:  they are happier when it is cool and breezy and dry.

Previously-published research shows that solar panels actually increase crop yields on pasture or agricultural fields.

These new results have implications for the current practice of constructing large solar arrays in deserts.  Agricultural lands may be a much better option for both solar production and crop production.

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Installing solar panels on agricultural lands maximizes their efficiency, new study shows

Photo, posted April 20, 2011, courtesy of U.S. Department of Agriculture via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Falling U.S. Carbon Emissions

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Reducing carbon emissions is a goal embraced by nearly every country in the world, but actually accomplishing it isn’t easy. It is true that renewable energy sources are playing a growing role in energy systems, but counterbalancing that trend is growing energy demand, especially in developing countries.

Here in the US, energy-related CO2 emissions actually went up nearly 3% in 2018 compared with 2017.  But the US Energy Information Administration is now forecasting a 2% drop in emissions this year.

The main reason energy-related emissions are headed lower at this point is coal-fired power plant retirements.  More than 90% of the coal used in the US goes toward electric power and utilities are increasingly turning away from coal.

The rapid shift away from coal has mostly been due to the increasing use of natural gas.  Natural gas is not actually a clean and green fuel, but it is definitely less carbon-intensive than coal.  Overall, the total installed capacity of renewable sources – hydropower, wind, solar, geothermal, and biomass – has now actually surpassed the capacity of coal plants.  Given that renewables have in many places become the cheapest power option, there is little chance that coal has much of a future, despite efforts by the current administration.

The electric power sector is gradually moving away from all carbon-emitting sources – a trend that is being reinforced by legislation in many states.  The real CO2 emissions leader is petroleum, which accounts for nearly half of the total.  We have a long way to go to reduce emissions from the use of petroleum.  There are over 250 million cars and trucks on US roads and only a little over a million of them don’t burn fossil fuels.

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US energy-related CO2 emissions expected to fall this year, almost solely due to a drop in coal use

Photo, posted November 6, 2017, courtesy of Cindy Shebley via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

WAMC Northeast Public Radio

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