Trees as AC, Alternative Batteries and a Net-Zero Success Story

Weekly news and views about housing-related climate and sustainability issues.

Trees Buy Us Time, But They Need TLC

Especially in urban areas, shade from trees reduces heat gain in pavement and buildings. But to withstand extreme heat for long periods, they may need our help.

Trees, from a human perspective, have some miraculous qualities. They can protect us from the elements, provide habitats for wildlife and raw materials for our homes. They’re also (fortunately for us) quite resilient. Some species can withstand dramatic seasonal temperature swings, from well below zero degrees to over 100 degree heat waves.

But they do have limits. According to the Washington Post, trees have several ways of accommodating extreme heat, for a limited time. For example, many deciduous trees can wilt, which is a way of reducing the amount of solar energy striking their leaves.  

“The second stratagem,” the article explains, “is to close the microscopic pores — stomates — found mostly on the undersides of the leaves. This shuts down transpiration and the gaseous exchanges needed for photosynthesis, in which the tree takes in carbon dioxide and releases water and oxygen.”

Note that when trees reach their upper temperature limit, they don’t simply die. They employ several natural protective tools to survive. It’s important to note, however, that photosynthesis stops in these extended stress period, and dependency on water increases. And water needs are about the same across the species. Can they survive a few weeks, or even months of a heat wave? With the right watering protocol, yes. But the longer the heat wave, the more stess and risk of the tree actually succumbing to the heat. Each tree is slightly different, but you’ll note that even the most heat resistant “top out” at about 100 degrees.

Tree Survival Parameters (1)

Water Wardens?

Another way trees handle heat is by constantly refueling their upper limbs and leaves with water pulled up from the ground. Naturally, if the ground gets too dry, they have a harder time moving liquid through the upper system. It’s key, therefore for anyone concerned about tree health in extreme heat to use some sort of soil monitoring and add sufficient water to protect roots.

One thing citizens can do is take charge of the trees in their neighborhoods. Cities may not have the resources to manage watering with much efficiency.

One way to do this is by combining wireless or Bluetooth compatible soil sensors with “smart” irrigation systems such as Rachio. Different soils require different levels of soil saturation to provide healthy ground for tree roots. You many find this discussion board about soil sensors helpful.

Are Truly Sustainable Solar Batteries Being Nudged Out by EV Fever?

Although many technologies are being pursued, some of the most promising ones, such as sand-based, salt-based and algae based have not even made the “A” list yet. They deserve better.

If you’re looking for emerging technologies, you’re likely to get a list like this:

Lithium-sulfur - Lighter lithium-sulfur chemistry could improve energy density

Solid state - Replaces liquid electrolytes with solid conductive materials

Sodium-ion - Uses more abundant sodium instead of lithium

Silicon anodes - Boosts lithium-ion capacity with silicon-based anodes

Aluminum-airHigh theoretical energy density from aluminum-air reaction

Graphite foam - 3D graphite foam structure improves lithium-ion performance

One thing you’ll notice about these technologies is that, with the possible exception of sodium-ion, they’re mining intensive, designed for high-power applications with rapid recharging. In point of fact, their designed for cars. What you get is a “pile on” effect of narrowly focused battery research tied to the push toward electric vehicles.

But home storage batteries don’t need the same kind of performance as electric vehicles. They don’t need to travel up and down hills with the “driver.” They don’t need to recharge in an hour. They do need to be reliable and affordable and safe and eco friendly, and you can argue that some of the most popular EV batteries are none of the above.

So let’s quickly review some of the most promising, low-impact battery solutions that hold promise for a carbon-free future. These are batteries that can don’t need mobility and compact size. They may be centrally located, or, If they can fit on a pallet in your basement, they may ultimately turn out to be the greenest, most efficient way to bring energy storage to the masses:

Salt-Based Batteries

I remember when Aquion began selling salt-based batteries for home use. It was an exciting innovation, albeit a bulky package. Alas, they couldn’t get the investor backing they needed to scale up. Their excellent salt-based storage batteries, were dependent on private capital, and they went bankrupt. They’ve since been purchased, but it’s not clear if the new owners will pursue the salt battery trajectory. If only the US government could have used a small portion of the wasteful billions it heaps on fossil fuel companies, we might be telling a different tale about Aquion. As a footnote, Aquion has a great little how-to article telling you exactly how to make your own salt-based battery!

Sand-Based (Thermal)Batteries

One way to store solar energy is to convert it into heat. A prototype thermal sand battery from Polar Night Energy in Finland is already in operation, capturing waste heat and redistributing it into a local district heating system.

Algae-Based Batteries

Researchers have already demonstrated that, weird as they may sound, algae based batteries can continue producing power for long periods, without the use of any exotic metals or hard-to-get materials.

algae power generation

They note, for instance, that the tiny batteries used in the “Internet of Things” have proliferated, and need regular replacement. Algae batteries could provide an eco-friendly and longer lasting alternative.

Mix and Match Storage

It’s also worth mentioning that, for large scale storage of energy, several clever systems are being explored, including the use of pressurized air, hydrolic transfer, flow batteries and other methods. These may be the true game changers for large-scale storage.

100 Years Later, An Affordable Net Zero Upgrade

An Oregon couple offers a real-world breakdown of the costs, and it’s less than you think.

As reported by CNBC, a couple in Portland, Oregon, just conducted a complete energy retrofit on their 116-year old 3-bedroom house. The amount of the total cost, $48,235, and they carried it out in phases. They started with an annual energy bill of $2,247, when they bought the $275k house in 2014, eventually switched to all electric and added solar power. They’re not producing more power than they use. They figure about a 16-year payback on all of the improvements in terms of energy savings.

According to the report,

“In total, the couple spent $61,325 retrofitting the house:

  • Insulation: $10,000
  • Air sealing: $150
  • Heat pump: $12,000
  • Heat pump water heater: $950
  • Energy Star appliances: $2,900
  • LED light bulbs: $25
  • Solar panels: $30,000
  • New electric system: $3,500
  • HEPA air filters: $1,800

That number was reduced to $48,325 after the couple received several tax credits, rebates and incentives from the state of Oregon and the federal government.” 


Unrelenting Heat: Are We the Frogs in the Pot?

Here are several stories that caught my eye this week addressing various aspects of the extreme knock-on effects of the Climate Emergency.

These are the 10 American states that are the most prepared for extreme weather (Published on 2023-07-28 by Scott Cohn): This article highlights the preparedness of various American states in facing extreme weather conditions, emphasizing the importance of resilience and planning.

Phoenix’s Month in Hell: 31 Days of Extreme Heat Tests the City (Published on 2023-07-31 by Jack Healy): This piece explores how Phoenix, Arizona, has been grappling with a relentless heatwave, testing the city's infrastructure and resilience.

As Heat Waves Intensify, Europe’s Cities Rely on Age-Old Ways to Stay Cool(Published on 2023-07-28 by Jenny Gross): This article discusses how European cities are utilizing traditional methods to stay cool during intensifying heatwaves, reflecting a sustainable approach to urban living.

Heat Is Costing the U.S. Economy Billions in Lost Productivity (Published on 2023-07-31 by Coral Davenport): This piece explores the economic impact of extreme heat on labor productivity in the U.S., emphasizing the need for sustainable and resilient work environments.