EarthTalk…Questions and Answers About Our Environment

Dear EarthTalk: We used to hear a lot about algae’s potential as a renewable source of biofuels. Is it still being cultivated and processed accordingly?               ~ P.K., Richmond, VA

A researcher holds up laminaria saccharina sugar kelp algae in Southeast Alaska. Credit: David Csepp, NOAA/NMFS/AKFSC/Auke Bay Lab.

In recent years, algae has emerged as a potential renewable and less pollutive energy resource. Some species have high levels of fat, carbohydrates and proteins that can produce up to 30 times more energy than other biofuels. And algae, unlike corn and soy-based biofuels, can thrive well in a variety of environments (including otherwise unusable waste or brackish water). Combined, the high-energy content and abundance of algae make it a promising alternative to current fuel sources.

Some companies, including the low-carbon energy research organization, Decerna, experimented with algae, hoping it could be produced at an industrial level. They cultivated it in artificial light, feeding it a mixture of glycerol, yeast and various chemicals. They then extracted the functional fats and converted them into biodiesel. The researchers calculated the energy required during each stage of the process and the carbon emissions produced from burning the resulting biodiesel. They concluded that the production process required more energy than the final product generates, and that total emissions produced during the production and combustion phases of the algae surpassed those of traditional petroleum diesel.

It was also learned that the extraction of the algae’s biomolecules may involve the use of harsh chemicals or solvent, and that the growth of algae may also require chemicals like fertilizers and pesticides, which can have adverse effects on aquatic ecosystems if they get into surrounding water bodies through runoff, or if they accumulate in the algae biomass. Mechanical procedures require fewer chemicals but are less effective at separating the diverse array of materials within the algae. Also, cultivation of algae on a large scale uses large amounts of electricity as it often relies on artificial lighting to ensure optimal and controlled growth conditions. Moreover, the space required to grow and process algae on a commercial scale can also be a significant environmental concern. Large-scale algae cultivation facilities often occupy substantial land areas or require dedicated infrastructure such as ponds, bioreactors or photobioreactors.

Despite the promise that algae holds, there is a clear need for technological advancements across the entire supply chain. Techniques for seaweed cultivation, harvesting and transportation must be made more efficient. Several laboratories, such as the National Renewable Energy Laboratory and the Las Alamos National Laboratory, have been cultivating and manipulating particular strains of algae to genetically maximize the production of fuel biomolecules and other bioproducts. Additionally, improvements in pre-treatment methods, co-digestion processes, and the development of eco-friendly extraction techniques are essential. Furthermore, advancements in fuel conversion technologies are necessary to ensure that the algae is economically viable and able to be implemented into the current infrastructure. With these changes, perhaps we will see the rise of algae-based biofuels in the future.

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Dear EarthTalk: What is so-called “embodied carbon” and what percent of our greenhouse gas emissions does it make up? And more important, how can we reduce it?      ~ Mike O., Durham, NC

Building with sustainably grown wood reduces embodied carbon significantly as compared to using concrete and steel. Credit:

As the process of reducing carbon dioxide (CO2) emissions continues to grow in importance, the building operations industry has been working hard on limiting theirs. The problem is that this industry typically targets operational carbon rather than embodied carbon. Operational carbon is the sum of the carbon produced over the lifetime of a building and includes things like lighting, heating, ventilation and general power usage throughout the building. On the other hand, embodied carbon is all of the emissions that are created during the process of constructing a building. Embodied carbon is associated with the harvesting, manufacturing, transportation, installation, maintenance and disposal of building materials.

Buildings in general tend to account for at least 39 percent of annual global carbon emissions. At least a quarter of these emissions are the result of embodied carbon. Cement alone is responsible for around eight percent of the world’s CO2 emissions. The production of iron and steel emits roughly the same number of emissions. These carbon-intensive materials are large contributors of embodied carbon.

There are some measures that have already been taken in efforts to reduce embodied carbon. The Inflation Reduction Act, which was passed by Congress in 2022, includes six sections that address the embodied carbon of construction materials. For example, section 60112 gave $250 million to the EPA to develop a program to help support enhanced standardization, measurement, reporting and verification of embodied carbon of construction materials and products. Overall, these sections of the Inflation Reduction Act gave money to various government organizations to help transition to lower carbon materials.

To reduce embodied carbon, the building industry will have to make operational changes. One key way to do that is to design buildings in a way that minimizes the number of materials needed. Companies can also replace carbon-intensive materials like concrete and steel with greener options like sustainably grown wood. Repurposing existing buildings instead of building new ones can also reduce embodied carbon.

Another way to limit embodied carbon is to use greener construction equipment. The traditional diesel-powered equipment so commonly used in construction accounts for roughly three percent of embodied carbon in new construction projects. There are some equipment manufacturers that are developing zero-emission construction equipment. Liebherr, the German-Swiss equipment manufacturer, has developed an electric crane that releases no emissions and still performs on par with the traditional diesel equipment.

Limiting operational carbon is important, but it’s also important to remember all of the carbon that comes from the processes prior to buildings being operational. The processes behind the scenes still emit CO2. Limiting embodied carbon needs to be prioritized on par with the emissions that come from typical building operations.

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Dear EarthTalk: What are the environmental/climate benefits (or drawbacks) of the Inflation Reduction Act?  ~ David Montague, via email

The Inflation Reduction Act (IRA), a bill passed by the Biden Administration in 2022 to bolster the U.S. economy, was especially notable for its unprecedented investments in clean energy and climate health. Setting $369 billion aside for climate investments, the IRA incentivizes citizens to implement and invest in renewable energy by increasing tax benefits to homes with installed solar panels and battery storage equipment, and by giving substantial funding to clean energy companies. The bill’s efforts were predicted to bring $3 trillion into renewable energy, open up 170,000 new jobs within the industry, and increase the sales of electric vehicles.

Homeowners can reap increasing tax benefits for installing solar panels thanks to the Inflation Reduction Act. Credit:

Climate analysts initially projected that America’s greenhouse gas emissions would be cut roughly 40 percent below 2005 levels by 2030 due to the IRA’s funding of clean energy, with an average of 46 to 79 gigawatts of carbon-free energy predicted to be added to America’s electrical grid annually. The IRA puts additional priority on making clean energy more affordable for disadvantaged communities and lower-income households by increasing tax benefits for specific areas and families to start establishing clean energy within their communities. Implementing clean energy in disadvantaged communities may assist in mitigating the harmful air pollution in those areas, and in reducing their carbon footprints.

Despite its environmental benefits, the IRA has still allowed the fossil fuel industry to thrive and even expand. The bill was only approved by the U.S. Senate after the Biden Administration agreed to sell a $200 million lease for oil and gas companies to develop a large plot of land in the Gulf of Mexico, as many senators are investing partners with those companies. In a recent USA Today article on the IRA, reporters Matthew Brown and Michael Phillis stated that “the bill prohibit[s] leasing of federal lands and waters for renewable energy unless the government has offered at least 2 million acres of public land and 60 million acres in federal waters for oil and gas leasing during the prior year.” Clean energy improvements notwithstanding, fossil fuels will continue to burn and communities will continue to suffer from environmental hazards if specific legislation to discourage oil and gas development is not passed.

As of now, fossil fuels are reaching record levels of development and usage in the U.S., while only 32 gigawatts of carbon-free energy, a trifling amount in the scheme of things, have been added to the grid per year due to project delays, supply issues and the resistance of local communities. Many supporters of the bill argue that it was right to secure energy security for the American economy and its citizens via fossil fuels, since the clean energy industry is still developing a greater capacity for energy output. However, it could just as easily be argued that discouraging the continued development of oil and gas could have accelerated the clean energy industry’s projects and growth. The IRA is undeniably an economic bill first, and an environmental bill second. But while environmentalists may have their issues with the final outcome, let’s remember that the IRA is still the single largest climate bill ever passed in U.S. history.

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