Why aren’t US carbon emissions falling?

Reducing U.S. carbon emissions has been a Federal and many States’ priority for many years.  Numerous Federal and State Governments’ Clean Energy policies and regulations have been implemented over the past decade to reduce the consumption of and the need for higher carbon fossil fuels.  Many of these Clean Energy policies have very successfully expanded the production and consumption of alternative, lower carbon energy sources including Renewable Power.  Some Government policies have also mandated and facilitated developing of higher energy efficiency technologies.  As a result of past-current Clean Energy policies, and the recent expansion of domestic lower carbon natural gas, the U.S. has successfully capped its total maximum carbon emissions at 6,000 million metric tons per year (MMT/yr.) almost 10 years ago.  Total U.S. carbon emissions have since decreased by almost 770 MMT/yr. during 2005-12.  This improvement is equal to nearly half of President Obama’s recently announced carbon reduction target for 2025.   Unfortunately, as the U.S. economy has recovered more fully from the 2007-09 Economic Recession, total annual U.S. carbon emissions have begun increasing significantly since 2012.  Why have past successful Energy policies not sustained reducing total U.S. carbon emissions in recent years?

Recent U.S. Clean Power Policies and Performance – Many Federal and State Government Energy policies have been implemented over the years to reduce U.S. reliance on fossil fuels.  The Government policies developed following the 1970’s Energy Crises were originally designed to reduce the need for crude and petroleum oil by mandating increased vehicle energy efficiency technologies and displacing petroleum motor fuels with alternative energy sources.  More recently major Energy policies evolved into replacing higher carbon fossil fuels with lower-zero carbon energy sources.  The combination of past Energy policies designed to displace petroleum and more recent lower carbon Clean Energy policies caused total U.S. carbon emissions to peak in 2007.  Carbon emissions have been successfully reduced by displacing higher carbon fossil fuels with alternative energy sources such as Renewables.  Some of the most successful Renewables have been developed in the Power Sector.  These include (non-hydropower) Wind, Solar and Biomass/Geothermal generation.  Refer to Table 1.

Table 1 – U.S. Renewable Power Generation 2007-14

Data Source – EIA Table 7.2a Electricity Net Generation: Total (All Sectors).  ‘Bio/Geo’ includes Wood+Waste Biomass and Geothermal power generation.  ‘Solar’ includes PV and Solar Thermal.

Biomass and Geothermal Power generation sources historically have been the largest (non-hydropower) U.S. Renewable Power sources.  The combination of Government Energy policies, including the Production Tax Credit (PTC) program and states’ Renewable (Energy) Portfolio Standard (RPS) programs have very successfully facilitated the expansion of Renewable Power sources.  In 2009 Wind Power became the largest (non-hydro) Renewable Electric Power source in the U.S.  The combination of all (non-hydro) Renewable Power generation has successfully reduced total U.S. carbon emissions by over 150 MMT/yr. since 2007.

Recent U.S. Total Carbon Emission Trends – Many Energy policies facilitated the production-consumption of lower carbon energy and further energy efficiency improvement technologies in order to reduce State’s and total U.S. carbon emissions.  The Federal and State Energy policies successfully capped maximum total U.S. carbon emissions in 2007 and significant reductions in most the following years.  The combination of Government Clean Energy and Efficiency policies and the 2007-09 economic recession led to reducing total U.S. carbon emissions 2007-12 by almost 13%.  Unfortunately, existing Federal and State Energy policies and regulations have not sustained continuous reductions in total U.S. carbon emissions since 2012.  Refer to Figure 1.

Figure 1 – Total U.S. Carbon Emissions 2004-2014

Data Source – EIA Table 12.1 Carbon Dioxide Emissions From Energy Consumption by Source

The most recent EIA data shows that total U.S. carbon emissions peaked at 6,000 MMT/yr., and then rapidly declined to 5,385 MMT/yr. during the 2007-09 Economic Recession.  Following the end of the recession total carbon emissions briefly increased by 195 MMT/yr. 2009-10 as the economy began growing significantly again, followed by a reduction to a 20-year total U.S. carbon emission low level of 5,230 MMT/yr. in 2012.  Unfortunately, total U.S. carbon emissions have increased to just over 5,400 MMT/yr. 2012-14.  So what changed in recent years?

The Most Successful Carbon Reduction Policies and Market Factors 2007-2012 – An analysis of major Government Energy Policies and Market performance influences was updated to illustration the relative impacts of different regulations and market related factors.  Refer to Figure 2.

Figure 2 – Major Policy and Market Impacts on Reduced Total U.S. Carbon Emissions

Data Source – Past TEC article: “Which Government Policies and Other Factors have Reduced U.S. Carbon Emissions?” Note: this figure was updated using more recent (2014) EIA MER data.

The ‘four primary’ contributing factors to 2007-12 carbon reductions were: 1) coal-to-natural gas ‘fuels switching’, 2) increase Light Duty Vehicle fuel efficiency from increasing ‘CAFE standards’  and reduced ‘vehicle miles travelled’ (VMT), 3) a combination of increased energy efficiencies (buildings, appliances, lights, etc.) and reduced energy consumption as a result of the 2007-09 Economic Recession, and 4) expanded ‘Wind Power’ capacity from the PTC program.  Other reductions were due to the increasing biofuels as required by the Renewable Fuels Standard (RFS2)  and increased non-wind power production.  The impacts of increased biofuels, hydro/biomass/geothermal and solar power, however, were relatively small compared to the ‘four primary’ carbon reduction factors.

Carbon Emission Increases Since 2012 – Despite the past success of many Government Clean Energy Policies and the economic advantages of lower cost-carbon and growing domestic natural gas production, total U.S. carbon emissions have increased by over 170 MMT/yr. 2012-14.  The reasons for this increase in total U.S. carbon emissions is due to a combination of growth in the economy, and many other factors that have possibly made past Government Energy Policies less effective in reducing carbon emissions.

A new analysis was made of the primary influential factors that have led to increased total U.S. carbon emissions 2012-14.  Refer to Figure 3.

Figure 3 – Major Policy and Market Impacts on Increased Total U.S. Carbon Emissions

Data Source – Past TEC article: “Which Government Policies and Other Factors have Reduced U.S. Carbon Emissions?”; updated based on recent 2012-14 EIA MER data.

Since 2012 the U.S. has experienced major changes to its production and consumption of different types of energy supplies.  The following list highlights the major factors that have affected U.S. energy consumption and associated carbon emissions 2012-14:

1. Wind and solar power continued to successfully reduce U.S. carbon emissions.  Since 2012 (Table 1) these zero carbon Renewable Power sources have increased their impact on reduced U.S. carbon emissions by an additional (49) MMT/yr. over the past two years.
2. The impact of biofuels required by the RFS2 unfortunately continues to decline.  This is due to combination of the ‘ethanol blend wall’  and the continued R&D inability to successfully develop commercial scale ‘advanced biofuels’ production technologies.
3. Biomass and Geothermal power increased by a healthy 6,700 GWh and 1,100 GWh respectively 2012-14.  Unfortunately Hydropower decreased by 17,500 GWh.  This led to a 2 MMT/yr. increase in Power Sector carbon emissions.  The drop in Hydropower appears to be due to recent droughts and environmental operating constraints.
4. The increase of new vehicle CAFE standards was insufficient to offset a large increase in average annual VMT, which led to increased total Transportation Sector petroleum consumption of 419,000 barrel per day.  This increase was due primarily to increased usage of Heavy Duty Vehicles, including Railroad transport, increased Light Duty Vehicle’s usage, and increased Commercial Aircraft transport.
5. Despite the increase of cheaper, lower carbon natural gas domestic production  during 2012-14, the consumption of coal actually increased and natural gas decreased within the Power Sector.  This recent, and somewhat unprecedented natural gas-to-coal ‘fuels switching’ operation, appears to be due to minimizing generation expenses and the need for properly managing and balancing of major Power Grids’ supply-demand; supplying optimal baseload and backup/peaking power supplies as needed for maintaining overall Grid reliabilities.   Providing the required Power Grid baseload generation capacity has apparently involved increased utilization of existing Coal Power plants and switching natural gas increasingly to Backup-Peaking power operations.
6. During 2012-2014 total U.S. energy consumption increased by 3.8 Quadrillion Btu/yr. (4%).  Renewables and Nuclear increased by 0.8 and 0.3 Quadrillion Btu/yr. respectively.  The balance of increased U.S. energy consumed was supplied by fossil fuels (20% coal, 52% natural gas and 28% petroleum).  The increased coal was primarily consumed by the Power Sector.  Increased natural gas was primarily consumed by the Residential, Industrial and Commercial Sectors, and increased petroleum was primarily consumed by the Residential, Transportation and Commercial Sectors.  Increased natural gas and petroleum (excluding the Transportation Sector motor fuels) were primarily consumed for heating fuels.  Yes, the more severe winter conditions 2012-14 made it necessary to increase the consumption of heating fuels; leading to the largest source of increased total U.S. carbon emissions 2012-14.

Needed Changes to Government Clean Energy Policies to Sustain Future Total U.S. Carbon Emission Reductions – Some People might argue that the recent 2012-14 increase in total U.S. carbon emissions was only a temporary event, similar to what happened in 2009-10.  In this case no changes would be needed to current and pending Government Energy policies and we should expect further reductions similar to those experienced during 2007-12 in future years.  However, with the growing Economy and Population, and possibly the extended record low costs of crude and petroleum oil in the U.S. and World markets, we are possibly experiencing a major change in energy consumption patterns and consumption behaviors that need to be addressed by significant future Clean Energy policy changes.

This article is published in collaboration with The Energy Collective. Publication does not imply endorsement of views by the World Economic Forum.

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Author: John Miller is a Consultant and Energy Professional.

Image: An American flag flies in the foreground. REUTERS.