Solar Water Heating Needs to Be Part of the Climate Solution

A big gap in California’s efforts to address climate change is in water heating. In the 1930s, California was a leader in domestic solar hot water systems; but as the availability of fossil fuels increased, together with support from state and federal policies, the solar thermal industry was overwhelmed. In 1973 OPEC’s oil embargo made energy independence a matter of national security worldwide. For some areas without fossil fuel resources, like Europe and Israel, the threat was existential.

The embargo led many countries to incentivize solar water heating. In 1978, President Carter created a 25 percent federal tax credit for such systems, and California created an additional 15 percent tax credit on top of the federal one. By 1990, a million solar thermal systems had been installed in America. Sales were $1 billion annually in 1982 but fell to $30 million by 2000. Why this collapse? Abundant and cheap fossil fuels returned, President Reagan ended the federal incentives, and the industry’s reputation of failure ended public confidence and enthusiasm.

Policy inconsistencies created a boom-bust cycle, but even more damaging and difficult to surmount were the many shoddy installations that led to leaks and extensive damage. Many of the cheaper systems froze during the unprecedented 1990 freeze in California, again causing expensive repairs. These failures brought training requirement for installers and state approval for only those systems with freeze protection. The industry has never rebounded, even though technical and installation issues have been fully solved. Hawaii is the exception among US states. Its 25-year program of incentives and post- installation inspections has made solar thermal ubiquitous in the islands.

Water heating accounts for 25 percent of residential energy use. Solar heaters can easily provide 70 percent of a household’s hot water. Since the 70s, consistent policies have led to 85 percent of Israel’s homes and apartments getting solar water systems, contrasted to 1 percent in the US. For the California consumer, “going solar” means just one thing: solar photovoltaics to generate electricity. Strong government support has yielded big reductions to the cost of PVs, and now in 2020, California has mandated solar PVs on new residences. We need similar policies to promote solar thermal. The lack of demand has kept prices high, $7,000 on average, compared to $700 for a solar thermal system in Israel.

China has been incentivizing solar water heating for the past 3 decades and now leads the world with 80 percent of all systems worldwide. It is required on most new construction, just as it is in Israel. In these countries, as in Europe and elsewhere, solar water heating is cost competitive with gas and electric water heating. China now has a robust solar thermal export industry. California and the US need to use policy and ingenuity to reclaim leadership in low carbon water heating. We have done well with photovoltaics, but other options need to be part of the climate solution as well.

Electrify, Electrify, Electrify

Each Time We Replace an Appliance Is an Opportunity to Reduce Warming Emissions 

Until recently, most of us have not had choices about the power we consume: the gas for our cars or the fuel used to produce our electricity. Most supply-side choices are made by giant corporations. Fortunately, the game is shifting, at least in California and a few other states, where community choice energy programs with more clean energy, often 100 percent, are increasingly available. Santa Barbara, City and County, now have community choice programs. This is changing the supply side of the equation.

On the demand side, however, we have always had more influence: We decide what we drive, how we heat our water, what heats our house, what cooks our food, and what dries our laundry. For the past 50 years, the climate focus related to the machines and appliances we routinely buy has been on efficiency — mandated vehicle fuel standards, tighter houses through more rigorous energy codes, and Energy Star appliance performance ratings. Efficiency policies are not going to get us to zero emissions, however, certainly not fast enough to address the urgency of the climate crisis. Electrifying everything can, however, go a long way toward solving the problem — and rapidly. How fast? As fast as appliances need replacing: cars roughly every 10-20 years, home furnaces about every 20 years, and kitchen and laundry appliances every 10-15 years. 

Thankfully, we now have good choices for these replacement purchases, and they are getting better every year. Electric cars currently have good range, are close to cost parity with combustion cars, and save money every mile we drive. Air-source heat pumps for heating, cooling, and hot water now perform four or more times better than traditional appliances. The modern induction cooking experience is better than cooking with gas and is twice as efficient.

Dispersed rooftop solar can be the cheapest energy source, but we make it cost more than it needs to by cumbersome, lengthy permitting and inspection requirements. Whereas the installed cost is around $1 per watt in Australia, it ends up near $3 per watt in the U.S. When the U.S. is fully electrified, 20-30 percent of electricity can be generated locally on rooftops, and the remainder will need to come from wind farms, utility-scale solar farms, geothermal wells, and hydroelectric facilities.

Thinking about addressing climate change can be overwhelming and depressing. Replacing fossil-fuel equipment with electric units will enable us to be and feel part of the solution, without sacrificing the conveniences of modern life. Moreover, the long-term economic benefits are not only in utility bill savings, but in creating jobs. Several studies link 25 million new jobs to mass electrification in the U.S. Many of these will be local.

Once we shift to clean energy, we’ll be able to enjoy all the comforts — warmth, air-conditioning, zippy cars, and hot water — but with lower costs and cleaner air. 

The Overlooked Heroes of Coral Reefs

Sea Cucumbers Maintain Coral Reef Biodiversity and Counter Ocean Acidification

Coral reefs cover only a small area of ocean floor, mostly along tropical coastlines. Their importance ecologically, however, is disproportionate to their prevalence. They protect coastlines from storms and erosion, serve as nurseries for fish, are critical to ocean biodiversity, generate half of the earth’s oxygen, and absorb nearly a third of manmade carbon dioxide emissions. Tragically, half of all reefs have died in the last 30 years. Scientists are saying that warming waters, increasing ocean acidity, pollution, and overfishing threaten the remaining reefs in the next 20 years. 

Coral reef restoration is expensive, according to NOAA (National Oceanic and Atmospheric Administration), costing about $1 million per acre. The main restorative approach is nurturing scraps of coral until they are large enough to replant on reefs. Through genetic research, scientists are hopeful of finding or developing more heat-tolerant species. Perhaps the most effective and least costly option is to encourage nature’s process by promoting healthy populations of sea cucumbers. These scavengers of the sea floor are garbage collectors and nutrient recyclers. It turns out that these slimy, faceless creatures play a critical role in maintaining coral reef health and biochemical balance.

Sea cucumbers’ digestive systems transform their diet of sand and bio detritus into nitrogen-rich, aerated sediment on which coral and algae rely. Not only do these vacuum cleaners of the ocean floor maintain healthy oxygen and nitrogen levels in the sediment, but their excrement also buffers reefs against acidification, a problem linked to ocean warming. Calcium carbonate, the building block of coral skeletons, is becoming increasingly scarce because of increasing acidity. The ammonia in sea cucumber waste increases the availability of calcium carbonate in the reef environment.

Scientists have struggled to assess how significant sea cucumber excrement is. Recently, an Australian research team, using drone surveys, satellite imagery, and direct observation, has gained a more accurate understanding of how beneficial it is. They estimate that there are three million sea cucumbers on the Heron Island Reef, the target zone of their study, and determined that each creature produces almost one and a half ounces of waste each 24 hours. Of course, this can vary widely between specific creatures, as they have been found to be from a few inches to six feet in length. An average of one and a half ounces aggregates to the weight of five Eiffel Towers of excrement each year on their research reef.

Because sea cucumbers are eaten as a dried delicacy in many Asian countries and considered to have medicinal properties in China, their populations are being heavily harvested and are declining at an alarming rate. Over 70 countries currently harvest these creatures. Drone surveillance techniques like those used by the Australian researchers could be employed to monitor sea cucumber numbers. Last year, the first sea cucumber conservation reserve was set up off an Indian island. Hopefully, this is just the first of many.

Hempcrete: A Carbon-Negative Insulation

Hempcrete Moderates Indoor Humidity and Temperature, While Being Fire, Mold, and Insect Resistant

The next frontier in green building is emerging as carbon-sequestering materials. Incorporating such materials into tight, energy-efficient building shells has the potential to fully offset the 40 percent of total greenhouse-gas emissions that structures contribute to global warming. One such material is hempcrete, an innovative insulation that is better for people and the planet.

Hempcrete, or hemp lime, as it is sometimes called, is made from the woody core of the cannabis plant combined with lime and water. Hemp is fast-growing (typically 3-4 months), likes a wide range of soil and climate conditions, and requires no pesticides. An acre of hemp can sequester an impressive 10 tons of carbon dioxide, more than an acre of trees can sequester in an entire year. When turned into hempcrete, the carbon remains locked in the inner woody layer. The lime binder also sucks up carbon. However, cultivating it does require a good amount of water.

The insulating value per inch of hemp is comparable to fiberglass insulation (R-2.5-3), yet it has none of the harmful synthetic ingredients that fiberglass and most other commercial insulations contain. Hempcrete acts like a toxic-free sponge that absorbs moisture from the surrounding air when it is humid and releases it again when it is dry. This ever-adjusting behavior creates a healthier relative indoor humidity and an improved sense of comfort. It has good sound-dampening properties that also contribute to good indoor environmental quality.

The use of hempcrete is growing rapidly in Europe. It has been used in Paris since 2012 and is now being government-funded in subsidized social housing projects. It is also getting traction in the U.S. but was hindered by a later start because of the legal ban on all hemp uses, only recently lifted.

Although made from the woody core of Cannabis sativa, hempcrete is highly fire-, mold-, and insect-resistant, due to the lime envelopment of the plant elements. Not surprisingly, all the other parts of the plant can be turned into other products. The only negative for hempcrete seems to be that it costs more than fiberglass insulation, about double, although that differential will diminish as it gains market share. The product comes in various forms: batts, blown-in, blankets, and rigid boards.

Hempcrete is part of a class of composite building materials that has received negative-carbon-material classification, and among these, it is the top negative-carbon performer. Many other building materials are now being made and analyzed for their carbon-storing properties. The optimum is to create carbon-storing buildings that also operate on renewable energy, making them zero-net-energy and zero-net-carbon structures.