Renewable Energy's Blind Spot

The Environmental Risks and Opportunities at Solar Sites

In its Clean Energy Commitment, APS laid out a path that includes tripling the renewable energy provided to customers in the next 10 years. Much of that goal will come from large solar sites in the Arizona desert. But what about the environmental, sustainability and governance (ESG) impact of those megawatts?

 

It may seem counterintuitive to ask about ESG for solar, since renewable energy is considered good for the environment. But utility scale solar sites, like other large developments, can have negative environmental effects depending on how they are sited and maintained.

 

Rapid renewable buildout without careful siting and maintenance can harm sensitive environments and community relationships.  ESG issues at solar sites may be a blind spot when company metrics are focused on total renewable or clean energy without a biodiversity component. 

 

Siting

 

The Arizona desert has areas of high biodiversity that should be avoided during development of renewable energy. Although all projects receive some environmental review, the level of review depends on the landowners, regulators and companies involved. This regulatory patchwork means that projects can be approved while still having significant issues.

 

For example, a large solar project in California was approved in prime desert tortoise habitat, and the company involved spent at least $56 million relocating the threatened species from its solar site. A different species of desert tortoise lives in AZ, but resource managers here are also concerned about impacts from development.

 

AZ Game and Fish (AZGFD), in their Guidelines For Solar Development in AZ, call for avoiding areas of high biodiversity, with a preference for already-degraded sites. By using land that has already been impacted by farming or mining, utility solar development can avoid many of the environmental risks associated with building on pristine landscapes.

 

Maintenance

 

Solar sites in the desert are usually maintained as bare ground, which involves regular application of herbicides to control any sprouting vegetation. Unfortunately, bare ground can concentrate and channel water, leading to runoff, erosion, and water pollution. And when it doesn’t rain, dust from the bare ground can lower air quality and soil the solar panels, reducing their efficiency.

 

The AZGFD Guidelines call for native plant revegetation of areas not necessary for facility maintenance. Revegetating parts of the sites with native plant species provides valuable habitat for pollinators and other native flora and fauna. AZGF notes that revegetation can also help control or prevent erosion, siltation and air pollution by stabilizing soil surfaces.

 

Challenge as Opportunity

 

The International Union for Conservation of Nature (IUCN) states that “solar developments can demonstrate good environmental stewardship through conservation and rehabilitation of local biodiversity.”

 

Across the US, solar sites are increasingly evaluated for overall sustainability, including impact to biodiversity. For example, 15 US states have already created environmental scorecards for solar energy sites. Sites with native vegetation that benefits pollinators and other species are rated higher.

 

Including best management practices (BMPs) in the siting and maintenance of solar sites, such as those in AZGFD Guidelines, can help ensure that solar sites don’t contribute to environmental degradation and are part of the environmental solution they are intended to be.

 

By proactively addressing these challenges, utilities can show commitment to ESG values while reducing potential conflicts and costs.

Further reading:

https://forestpolicypub.com/2022/08/08/now-comes-the-hard-part-of-the-ira-the-problems-of-siting-wind-and-solar-by-sammy-roth-of-la-times/

OTEC: Ocean Thermal Energy Conversion

OTEC has the potential to harness the power of the ocean, while pumping water from the depths to the surface has challenges and opportunities. It can fuel plankton growth and may help sequester carbon.

1982 National Energy Laboratory Report on OTEC

The xerox scan of the old scientific report is dark and stained, with primitive printing and poor font and layout.  But the columns and official investor report style belie the real science presented, without preamble or typical science summary.

The 1-mile long cold water pipe was deployed successfully in 1981, thanks to "Calm weather and much hard work."  The pipe extends from the surface to 2,000 feet deep. It can pump 500 GPM of deep cold 9-10 C) water. The warm water pipe pumps 2,000 GPM of surface seawater (24-28C).  When allowed to foul freely, it showed immediate increase in resistance to heat transfer, which biofouling countermeasures ameliorated.

The article presents a glowing portrait of research advancing at a fast pace, but is offset with somber photos of cloud-mottled skies and the inclusion of disturbing headings like "biofouling countermeasures". (Biofouling is when nimals get sucked in, and the system can become clogged by marine animals and plants.  This could also be used positively to grow algae) Funding is flowing in from multiple sources like the cold and warm water siphoned from the rich offshore resources...

The project is strategically located with nearby availability of cold, deep ocean water and a warm ocean surface layer that is not subject to strong seasonal cooling. The warm water intake only 15 feet offshore may explain the much more rapid initiation of biofouling than previous experiments.  A 300 foot extension has been designed and was to be installed in 1983.  They plan to add 2 new 500 GPM pumps to replace the original coldwater pump that only pumped from Feb to June at 340 GPM before failing.  They propose reconfiguring the OTEC-1 coldwater pipe to provide a capacity of 22,000 GPM, which would "satisfy their coldwater needs for the foreseeable future."







What ever became of all of this? The Makai Engineering website presents research from the 2010s that seems directly related to work done in the early 1980's, as if a 30 year gap is missing from the story, a lull in research perhaps while people's careers stagnated, limited by something mundane like the size or strength of piping availability or funding.  Maybe the ocean was still there but the money stopped coming from Washington.  Reagon took the solar panels off the white house, and the country went back to sleep for 30 years while a couple of billion people were born and the climate inched toward the 2 degree warming threshold. 

This dark paper seems to hold secrets of the past, arcane mad science experimentation. All that is not said, like the sea creatures sucked up.  So that today when ocean researchers wonder about the effects of cold water outfalls they have to design and bring their own small pipes and pumps.

2008 Reserach: Artifically Induced Upwelling
Used to understand how marine microbial ecosystems respond to large-scale perturbations. Diatoms will consume nitrogen, leaving some amount of phosphorus in the water, which will stimulate a second-stage bloom of nitrogen-fixing cyanobacteria. These blooms are often observed during summer months in open ocean waters when there are almost no nutrients at the surface and the winds generally are calm. What triggers the blooms and where are the nutrients coming from? We need to know.

Vast, seemingly barren regions comprise more than two-thirds of our oceans and nearly 40 percent of the entire Earth.  Need to replace about 10 percent of the surface waters with upwelled water to fuel a bloom.  Some scientists have looked at iron fertilization as a way to trigger biological growth in nutrient-poor areas of the ocean, but “everything responds to iron,” Letelier said. “You can’t control what grows.”

The researchers believe they can control plankton growth by determining which species respond to specific nutrients, and then adjusting the rate of nutrient feeding by the frequency and duration of water pumping.

Where the ocean is about 4,500 meters deep, the bottom layers of water have too much CO2 because of the decaying organisms that have sunk to the floor.  Their studies have shown, however, that water at a depth of 300 to 700 meters has the proper ratio of nitrogen and phosphorus to trigger a two-stage phytoplankton bloom.

Currently, they are able to pump about 50 cubic meters of water per hour (=4 GPM) using wave energy. "If we want to generate a bloom in an area of one-square kilometer, we would need to replace about 10 percent of the surface waters with upwelled water, which would take about a month at the rate we pumped.”

The scientists used undersea gliders in their Hawaii study to monitor the water from the pump so they have an idea how widely and quickly it disperses, and how much of an impact it can have on surface waters.





Resources
List of OTEC plants around the world: https://en.wikipedia.org/wiki/Ocean_thermal_energy_conversion

1982 report about OTEC work at NEL Hawaii: https://nelha.hawaii.gov/wp-content/uploads/2014/01/NELH_AnnRpt_1982.pdf

Upwelling Press Release: https://today.oregonstate.edu/archives/2008/sep/scientists-test-%E2%80%9Cartificial-upwelling%E2%80%9D-learn-more-about-complex-ocean-ecosystem-be

More NEL reports: https://nelha.hawaii.gov/resources/library/

Makai Engineering: https://www.makai.com/ocean-thermal-energy-conversion/

Desertification

Land-atmosphere feedbacks amplifying climate change in the Sahel. Click on image for a zoom.
From Dryland Systems in Ecosystems and Human Well-Being: Current State and Trends, part of the Millennium Assessment.


Service of Climate Regulation in Drylands. The central grey box --the components of biodiversity involved in service provision-- maintenance of soil moisture (bottom left) and modulation of rainfall (top). IN bold -- the major alternative/complementary function involved in the effect of live vegetation cover on rainfall: successive multiplication of signs along each trajectory generates an increase in rainfall (+) when service is ameliorated and a decrease in rainfall (-) when land is degraded. Land degradation (grey circle) degrade the service through affecting surface temperature; when surface temperatures increase along the albedo trajectory, it decreases along the evaporation trajectory; this trend is reversed when land is not degraded.

Much more information on desertification in Africa.

How Much Energy It Takes to Eat

Most energy use in the path from farm to fork happens in the kitchen. Just driving to the grocery store to pick up the groceries uses more energy than all the industrial agriculture, shipping warehouses, and long-hauls trucks used to get your groceries into the store. Also, depending on how much you buy at one time, you are likely burning more calories (in gasoline) than you just bought....think about that the next time you're calorie-counting!

Apparently, most of the (increasing) energy consumption in the kitchen comes from more people owning dishwashers and second refrigerator/freezers. Energy use has increased in the kitchen even while people spend less time in the kitchen.

Of course, the above perspective does not mean that reducing energy consumption in any sector is less important than any other sector.

Source.

Emergy is not the new Money

Emergy analysis aims to document and compare the amount of energy required to produce different products. In comparison to Embodied Energy analysis, which measures just human inputs of energy, Emergy analysis measures both natural and human energy inputs. The laudable goal is to put all calculations in the same currency so that everything can be compared. However, emergy is an impossible concept and, in the end, really just weird.

First, it is weird economics. In fact, it is Marxist economics because Emergy, like Marxism, seeks to go beyond the capitalist system that assigns value based on demand to an alternative system based on supply. But then Emergy turns around and assigns emergy to dollars, a blatant contradiction. Also, emergy is not able to account for opportunity costs. For example, there is still no way to value the salmon that would have lived had it not been for the dam that destroyed their spawning grounds.

Second, it is a weird way of valuing raw resources (inputs). Putting everything in terms of solar energy makes some sense, but not when a dubious logic is used to convert rain and wind into solar equivalents, let alone when metal ores are assigned an arbitrary emergy. The urge to put everything into a hegemonic coinage is as old as the simplifying instinct, and as faulty. Everything can't be reduced to solar energy. Sustainability needs a more adaptive system and a more adaptive framework to ask questions.

Third, it has weird system diagrams (see above). While they look cool at first, one quickly realizes their myriad failings by comparing emergy diagrams to contemporaneous dynamic stock-and-flow modeling software like Stella. Also, emergy puts the controlling forces in the same format as the flows of energy, confusing both.

Fourth, it is weird ecology. The idea of "resources required" for a certain product seems to assume that the resources are "used up" in making that product, but ecosystems don't work that way. The grass that the cow eats might otherwise have died and decomposed, or if a cow eats all the grass in the lot it may create better habitat for some bird species. Presence and absence, especially of niches, are not physical qualities of a habitat. An emergy-type analysis applied to fishing suggests that eating one tuna is equivalent to eating 1,000 sardines, but that is only true if you have to farm the sardines to feed a farmed tuna. In the wild, that tuna has already eaten 1,000 sardines, whether you now eat the tuna or not. In fact, your eating the tuna may spare the next 1,000 sardines from being eaten! While it may be desirable to spare the tuna for other reasons, emergy fails any.

Fifth, it is a weird idea of sustainability. Emergy explicitly doesn't want to "double count" sun and wind, yet a smart farmer could do just that by harvesting wind energy and solar energy. Emergy doesn't do a good job of figuring out what is sustainable versus what isn't: it provides a plethora of weird ratios for calculating "Environmental Yield Ratio" and other indices of sustainability, but these ratios are all based on predetermined categorization of whether a given input is sustainable or not, thus assuming the very thing they seek to prove.

To put everything in the same system to compare everything comes from a good motivation but the conclusions end up being trivial. In my humble opinion, it may be impossible to accurately compare fish and electricity and sedimentation in terms of the energy that went in to them. Weirdly, dollars are still best.

How efficient are plants? (part II)

Insolation at Earth's surface (the total solar irradiance, in units of W/m2):

On sunny days, about 1 kilowatt of solar radiation bathes every square meter of the earth's surface every hour. Because of the seasons and weather, the annual average for much of the united states is between 1/2 and 1/3 of this ideal "clear sky" condition.

Photosynthetically Active Radiation, or PAR, is only ~40% of that total, depending on which chlorophyll molecules are present in the plant. Because of physiological requirements, plants actually use an order of magnitude less, usually about 2% of total solar insolation. Of that, orders of magnitude less are available for conversion into biomass. Contrast that with commercial solar arrays that can capture about 20% of the energy in solar radiation!

Either way, the rest of that kW is either reflected or converted to heat...and heat makes the wind blow. A 20mph wind contains enough energy to generate 1 kilowatt per square meter for every hour it blows.

references: http://www.pages.drexel.edu/~brooksdr/DRB_web_page/papers/UsingTheSun/using.htm

"America is the Saudi Arabia of negawatts"

Amory Lovins goes on to say that "more productive use of energy is not, strictly speaking, a physical "source" of energy, but is only a way to displace physical sources. This distinction is rhetorical, since the displacement or substitution is real and makes supply fully fungible with efficiency."