As global temperatures persist in rising to concerning new highs, national governments, multinational corporations, small businesses, and individuals are all urgently exploring ways to substantially reduce greenhouse gas emissions and mitigate climate change risks. One increasingly popular and impactful method that is gaining significant traction is the use of carbon credits to provide powerful financial incentives for businesses and consumers to cut emissions and support the rapid development of renewable energy sources.

This informative post is the 4th installment in our acclaimed new series based on our organization’s highly regarded 2023 Climate Change and Carbon Markets Annual Report.

The previous posts in this illuminating series so far have been:

Climate Change Basics: Causes, Impacts and Carbon Credit Solutions
Carbon Credits Are Essential For Climate Action
Carbon Credits For Fighting Climate Change


In this post, we will take a closer look at various energy sources and strategies, emphasizing the importance of diverse solutions like fuel switching, renewables, nuclear energy, and carbon capture to combat climate change and achieve a sustainable energy future..

The Wedge Theory – A Portfolio Approach to Emissions Reductions

Climate experts propose a “wedge theory” framework to conceptualize the portfolio of solutions needed to reduce greenhouse gas (GHG) emissions and stabilize the climate. This approach requires deploying diverse technologies and strategies, each providing a “wedge” of avoided emissions adding up to the total reductions needed. The original theory called for 7 wedges, but emissions have continued rising, so 9 are now required. Wedges include renewables, nuclear energy, fuel switching, energy efficiency, forests and soils, and carbon capture and storage.

Understanding Fuel Switching

Fuel switching entails replacing carbon-intensive fuels like coal and oil with less carbon-intensive ones like natural gas. For example, switching from coal to gas can decrease power plant emissions by 60% per kilowatt-hour.

Coal: 25 metric tons carbon per terajoule
Oil: 20 metric tons carbon per terajoule
Natural Gas: 14 metric tons carbon per terajoule

So switching to gas provides a “bridge” to zero-carbon energy systems. The shale gas boom enabled by hydraulic fracturing accelerated this trend in the United States. However, the environmental impacts of techniques like fracking cannot be disregarded.

Nuclear Energy: A Renewable Source?

Nuclear energy, often hailed as a clean energy source, is derived from the process of splitting uranium atoms through fission. This fission process heats water to produce steam, which in turn spins turbines, ultimately generating electricity. The entire procedure emits no greenhouse gases, making it an attractive option in the fight against climate change. However, the question of whether nuclear energy can be classified as “renewable” remains a topic of contention among experts and environmentalists. While it offers a more sustainable alternative to fossil fuels, concerns about radioactive waste, the finite nature of uranium resources, and potential safety risks make its categorization as a renewable energy source debatable.

Harnessing Inexhaustible Sources: The Role of Renewables

Renewable energy derived from inexhaustible natural sources like sunlight, wind, and water offers immense potential with little to no GHG emissions. Growing renewables is crucial for climate change mitigation.

Solar Energy: Ever Improving Technologies

Solar energy, a cornerstone of renewable power sources, harnesses the abundant energy radiated by the sun. This is achieved primarily through two technologies: photovoltaics (PV) and concentrated solar plants. Photovoltaic cells, commonly known as solar panels, are designed to directly convert sunlight into electricity. They achieve this transformation using specially crafted semiconductor materials that capture photons and initiate an electric current. One of the standout features of solar PV systems is their adaptability. They can be installed on a grand scale for utility purposes, powering entire communities or even cities. Alternatively, they can be set up in smaller, distributed configurations, such as on rooftops of individual homes, allowing homeowners to generate their own electricity and even feed excess power back into the grid. As technology continues to advance, the efficiency and applications of solar energy are bound to expand, making it an even more integral part of our energy landscape.


Geothermal Energy: Tapping into Earth’s Heat

Geothermal energy is a remarkable form of power that taps into the Earth’s innate thermal energy stored beneath its crust. This energy originates from the radioactive decay of materials deep within the planet and the original heat from Earth’s formation. In regions with pronounced subsurface temperatures, often marked by volcanic or tectonic activity, the potential for generating geothermal electricity is especially high. The typical process involves accessing hot water reservoirs located below the surface. This water, when pumped up through specialized wells, transforms into steam due to the pressure difference. This steam then propels turbine generators, converting the Earth’s heat into usable electricity. As a sustainable and environmentally friendly energy source, geothermal power offers a consistent and reliable alternative to more conventional power generation methods.

Hydro and Wind: Leveraging Flowing Resources

Hydropower converts the kinetic energy of flowing water into electricity using turbine generators. Dams with reservoirs
offer reliable large-scale hydro electricity, while run-of-river systems have lower impact.

Wind power harnesses the kinetic energy of wind, again turning turbines to produce power. Onshore and offshore wind farms are rapidly expanding as costs plummet.

But hydropower and wind face challenges in location constraints, transmission needs, and intermittency. Still, they are vital and growing pieces of the renewables puzzle.

Bioenergy: Leveraging Natural Carbon Sinks

Bioenergy stands out as a unique form of renewable energy because it taps into the chemical energy naturally stored within organic materials. This energy is derived from both living organisms, like plants and animals, and those that have recently died. A diverse range of sources, including forest biomass, residues from agricultural activities and livestock, as well as various waste streams, can be converted into renewable electricity, fuels for transportation, and heat for homes and industries.

However, it’s essential to approach bioenergy with a discerning eye. While it holds great potential, not every form of bioenergy is environmentally beneficial. For instance, clearing vast expanses of forests to cultivate energy crops can lead to significant carbon emissions and disrupt delicate ecosystems. This not only negates the carbon benefits but also poses threats to biodiversity. Looking at the positive aspects, bioenergy can be obtained from waste biomass or cultivated on lands that are not suitable for other agricultural purposes. This not only provides a sustainable solution, but also has a positive impact on the climate. Such practices ensure that greenhouse gas emissions are minimized, making bioenergy a viable and eco-conscious energy alternative.

Waste-to-Energy: Capturing Landfill Gas

Landfill gas (LFG) projects prevent methane emissions from landfills by capturing methane for flaring or energy use. Methane is a potent greenhouse gas, so converting it to CO2 via combustion provides immediate climate benefits. LFG projects also reduce local air pollution.
Captured LFG can be used onsite for electricity, heat, or even vehicle fuel. These projects provide environmental and socio-economic benefits to communities near landfills.

Sequestering Carbon: Storing Away Emissions

Carbon capture, utilization, and storage (CCUS) aims to balance continued fossil fuel use with equivalent carbon storage elsewhere. CCUS removes CO2 from large point sources like power plants or directly extracts CO2 from ambient air. The carbon is then stored via injection into geologic formations, old oil and gas reservoirs, or chemical conversion into stable solids.
While technologically feasible, CCUS still faces challenges with scaling up infrastructure, ensuring permanent storage, and lowering costs. More investment is needed to develop CCUS into a viable wedge.

The All-Out Effort Needed

Bending the global emissions curve downwards requires urgent economy-wide action across all sectors. Intelligently leveraging fuel switching, nuclear energy, renewables, bioenergy, and eventually carbon storage provides paths to a carbon-neutral future. But the clock is ticking. Successfully activating these climate wedges demands policies, partnerships, and funding on a massive scale. Our future depends on rising to this great challenge.

To learn more about the role fuel switching plays in fighting climate change contact us for the full report.


Photo by Jason Blackeye on Unsplash


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