Welcome to a 4-part series where our Operational Carbon Technical Lead and Licensed Engineer, Ilana Cember, dives into:

“(Almost) Everything You Wanted to Know About Electricity But Are Embarrassed to Ask” 

Understanding the basics of electricity generation, distribution, purchasing, greenhouse gas emissions, and the utility grids is key to understanding how we change any of those to keep our global commitment and meet the Paris Climate Accord.  We will go into the “why” for each of these topics as they are covered.

TOPICS WE WILL COVER 

• All things utilities 
• Electricity grids 
• Carbon emissions and decarbonization 
• End with some good news and wrap-up 

Part III: Carbon emissions and decarbonization

WHY? 

If the goal is to meet the Paris Climate Accords commitments, we must focus on carbon emissions. Different power generation fuels create different amounts of carbon emissions. Fossil fuels (coal, petroleum/oil, natural gas) are hydrocarbons – consisting of hydrogen and carbon molecules in different forms When burned to generate electricity, these fuels react with air to form carbon dioxide, a greenhouse gas, along with smog and particulates from incomplete combustion or contaminants. 

In addition, practically every step in the process of utilizing fossil fuels releases greenhouse gases into the atmosphere, accelerating global warming (xxvii) as shown in Figure 21. Leakage rates vary widely depending on the source and are estimated between 1% and 8% (xxviii). (“End use” encompasses residential natural gas equipment or power plants.) 

• Getting fossil fuels out of the ground with drilling, mining, or hydraulic fracturing (“fracking”). 
• Transporting fossil fuels to the processing plant. 
• Processing fossil fuels into a usable form (like gasoline or natural gas). 
• Transporting processed fossil fuels to the power plant. 
• Burning fossil fuels to create electricity. 
• Note that over 60% of the fossil fuel energy burned to create electricity is wasted as excess heat. (xxx)

Figure 21. Methane Leakage in Natural Gas Systems (xxx)

This is in addition to the incredible system losses through the process as shown below. Only 37% of the fossil fuel energy in the ground becomes useful energy. Solar, wind, and electrification all reduce energy losses from generation and end-use.(xxxi) 

Figure 22. Fossil Fuels are Extremely Inefficient (xxxi)

Alternatively, even accounting for embodied carbon emissions (the greenhouse gas emissions associated with manufacturing, transportation, etc), renewable energy like solar photovoltaic and wind energy are significantly less polluting and greenhouse gas intensive than fossil fuels, sometimes by orders of magnitude. (xxxiii)

Note that greenhouse gas is the general term for all the chemicals that contribute to global warming. For calculating global warming impacts, the greenhouse gas impact is converted into a carbon dioxide (CO2) equivalent (CO2e). Methane has a global warming potential of 25, meaning it has 25 times the impact on global warming as CO2. “Greenhouse gas” and “carbon” are often used interchangeably. 

Renewable Energy Procurement 

Referring to the EGRID map below in Figure 23, different regions exhibit varying carbon intensities, which measure the amount of greenhouse gas produced per unit of electricity generated, as shown in Figure 20 (back in Part II). Grids with higher carbon intensities rely more on fossil fuels, resulting in greater greenhouse gas emissions. Conversely, grids that utilize more renewable energy sources, such as solar photovoltaic, wind, and hydropower, produce fewer greenhouse gas emissions. 

Grid emissions essentially represent the average emissions from power plants within a region.  For instance, looking at NWPP (Northwest Power Pool) region, the pacific northwest gets most of its energy from hydropower, a carbon-free energy source, while the mountain region still relies on coal. When calculating a facility’s electricity carbon emissions (scope 2 location-based), the calculations take this into account. 

Figure 23. Carbon Intensity by EGRID Region (xxxiv)

This also complicates the impact from renewable energy certificates (RECs). Typically customers buy RECs on the open market, regardless of their location. As a result, the renewable energy generated may not be in the same region as the facility for which the RECs are purchased.

Conversely, the electricity a site uses might not be generated locally, as seen in the power distribution map. 

Figure 14. Power Distribution Map (xxxiii)

In summary, the electricity you buy on the open market, particularly RECs, is not the electricity you receive. Recent research indicates that market procurement of renewables does not increase the amount of renewable generation connected to the grid. (xxxii) Starting in 2021-2022, the cost of utility solar is about the same price as fossil fuel, meaning it now makes economic sense to install solar over fossil fuel regardless of carbon emissions (Figure 24). (xxxiii) Thus calculating scope 2 electricity emissions and applying the REC purchases does not necessarily show an accurate portrayal of a facility’s carbon footprint, and may be artificially lowering calculated emissions. 

Figure 24. Cleantech costs have fallen rapidly (xxxiv) 

Therefore, when working on decarbonization strategies, Brightworks Sustainability recommends thoughtful usage of renewable energy procurement using the below “good/better/best” model: 

• “Good” referring to the open market REC purchases discussed above.  
• “Better” is a dedicated power purchase agreement (PPA). This can mean a lot of things, but typically this refers to procuring energy from a specific (usually nearby) renewable energy site (solar field, wind farm, etc). Ideally this is a strategy where a customer is directly impacting adding renewable energy to the grid.  
• “Best” refers to onsite renewables with “behind the meter” referring to the configuration where the onsite renewable powers the electricity consumption at the facility before sending anything extra back into the electricity grid (“net metering” where available). 

In summary:

Decarbonization and Projections 

WHY? 

This is what it’s all about! 

The efficiency of heat pump systems significantly impacts carbon emissions reduction across different regions. Replacing a natural gas boiler with a heat pump system with a coefficient of performance (COP) of 3.0 can decrease emissions in most areas. This highlights the importance of considering system efficiency and regional grid emissions in the decarbonization process. 

Figure 25. Cleantech is three times more efficient (xxxv)

Using the 2021 EGRID emissions factors, an electrification project converting a natural gas boiler with 95% efficiency to a heat pump system with an average COP of at least 3.0 will reduce carbon emissions in nearly every EGRID region except HICC Oahu, MRO East, Puerto Rico Misc, and SERC Midwest (all shown in dark red). However, regions with higher grid intensity, such as HICC Oahu, MRO East, Puerto Rico Misc, and SERC Midwest, require a more efficient heat pump system with a COP of 3.8 or 4.0 to achieve similar reductions.  

Again, Figure 23; Carbon Intensity by EGRID Region

This is expected to improve as utilities take advantage of incentives in the Inflation Reduction Act (IRA) and Bipartisan Infrastructure Bill (BIL) as well as the existing economics to increase renewable energy and decarbonize the electric grid, as it is already doing. (See Figure 26 below.) Every year, climate solutions like wind, solar, and batteries are scaling faster than previously predicted, solidifying the exponential growth “S-curve” adoption rates. (xxiii)

Figure 26. Solar and batteries are taking over (xxxvi)

continued in Part IV →

Written by Operational Carbon Technical Lead Ilana Cember, PE, CEM

return to Part II →