5. RENEWABLE ENERGY

Figure 5.1 Share of renewable energy in TPES, electricity and TFC, 1978-2018

IEA (2019). All rights reserved.

Renewable energy is increasing in the US, especially in electricity generation, where the share of renewables doubled in the last decade.

*Includes direct use of renewable energy plus renewable shares of electricity and district heat in TFC. Latest TFC data are for 2017.

Notes: Excludes non-renewable waste. Data for 2018 are provisional. Source: IEA (2019), World Energy Balances 2019, www.iea.org/statistics/.

Supply and demand

Renewable energy in TPES

Renewable energy accounts for an increasing share of TPES in the United States (Figure 5.2). In the past decade, renewable energy supply grew by 50%, and its share in TPES increased from 5% in 2008 to 8% in 2018. Although wind and solar are growing rapidly, the major source of renewable energy in primary energy supply is still bioenergy and waste, followed by hydro.

Figure 5.2 Renewable energy in TPES, 2000-18

IEA (2019). All rights reserved.

Bioenergy dominates renewable energy in TPES, and has increased in the last decade, but the total share for renewables is still modest at close to 8%.

*Includes solid biofuels, renewable waste, liquid biofuels and biogases. Excludes non-renewable waste.

Notes: Mtoe = million tonnes of oil equivalent. TPES includes conversion losses when using biomass and waste fuels in heat and power generation, which is not the case for hydro, wind or solar. Data for 2018 are provisional. Source: IEA (2019), World Energy Balances 2019, www.iea.org/statistics/.

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In 2018, bioenergy and renewable waste accounted for 5% of TPES in the country. The largest share of bioenergy results from the usage of solid biofuels in electricity generation and in the industrial sector, mainly in the pulp and paper subsector (Figure 5.3). The other main use of bioenergy is biofuels in the transport sector. Biogasoline, or fuel ethanol, is the most commonly consumed biofuel, and the United States is a worldleading ethanol producer (Box 5.1). In 2017, ethanol accounted for 5.2% of total energy use in transport, which was by far the highest share among International Energy Agency (IEA) member countries. Biodiesel1 consumption has also increased rapidly in recent years.

Figure 5.3 Bioenergy and waste supply by source and sector, 2018

4% 3%

IEA (2019). All rights reserved.

Bioenergy accounts for over half of the total supply of renewable energy, and the United States is a world-leading producer and consumer of fuel ethanol for transport.

Source: IEA (2019), World Energy Balances 2019, www.iea.org/statistics/.

Box 5.1 Ethanol as transport biofuel in the United States

The United States is the world’s largest producer of biogasoline (ethanol), with around 60% of total global production in 2017. Some of this biofuel is exported but over 90% is used domestically. Corn is the primary feedstock for ethanol production in the United States, and six of the top corn-producing states account for over 70% of fuel ethanol production in the country (Iowa, Nebraska, Illinois, Minnesota, Indiana and South Dakota).

The supply of transport biofuels has increased rapidly since 2005, driven first by the Energy Policy Act of 2005. The act created the Renewable Fuel Standard (RFS) programme with blending requirements that have resulted in 10% ethanol blending (by volume) in most motor gasoline sold in the country. From 2007 to 2017, ethanol supply more than doubled, driven by expansion of the RFS under the Energy Independence and Security Act of 2007. However, growth has slowed down in recent years, as the sector runs up against the current 10% limit at which ethanol can be blended into conventional gasoline for use in non-flex-fuel vehicles.

Sources: EIA (2018a), Six States Account for more than 70% of U.S. Fuel Ethanol Production; EPA (2017), Overview for Renewable Fuel Standard.

1 Includes biodiesel of diesel quality produced from vegetable or animal oil, biodimethylether, Fischer-Tropsch produced from biomass, cold-pressed bio-oil, and all other liquid biofuels that are added to, blended with or used straight as transport diesel.

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5. RENEWABLE ENERGY

Hydro is the second-largest renewable energy source, contributing 1.1% of TPES, followed by small but growing shares of wind and solar. Despite the recent strong growth of renewable energy sources, renewables still account for only a small share of energy supply in the country. Compared with other IEA member countries, the United States has the sixth-lowest share of renewable energy in TPES (Figure 5.4).

Figure 5.4 Share of renewable energy in TPES in IEA member countries, 2018

50%

40%

30%

20%

10%

0%

IEA (2019). All rights reserved.

Despite recent growth in biofuels, wind and solar, the United States has the fifth lowest share of renewable energy sources in TPES among IEA member countries.

*Includes solid biofuels, renewable waste, liquid biofuels and biogases.

**Includes hydropower (excluding pumped storage), tidal, wave and ocean energy. Source: IEA (2019), World Energy Balances 2019, www.iea.org/statistics/.

Electricity from renewable energy

Total electricity generation from renewable energy sources has nearly doubled over the past decade, backed up by state and federal support (EIA, 2019a). The share of renewables in power generation increased from 9% in 2008 to 17% in 2018, mainly as a result of strong growth of solar photovoltaic (PV) and wind (Figure 5.5).

Wind power accounts for the largest increase in renewable electricity generation in the last decade, from 55 terawatt-hours (TWh) in 2008 to 278 TWh in 2018. Meanwhile, US electricity demand has remained relatively constant at around 4 300 TWh, and the share of wind in total electricity generation increased from just over 1% in 2008 to over 6% in 2018. Texas and Iowa were the states with the most wind power capacity at the end of 2018 (AWEA, 2019a).

Solar PV installations have seen an even faster growth rate than wind power in the last decade, although from a lower baseline. In 2018, solar power generated 92 TWh, over 80% more than the production only two years before. California remains the leading state for solar PV installations in the country (SEIA, 2019a).

The growth in wind and solar is expected to continue in the medium term. According to a recent IEA five-year forecast for 2018-23, wind power is set to increase by 122 TWh, an increase of nearly 50% compared with 2017. Similarly, solar power is projected to grow by 102 TWh, an increase by 143% from 2017 (IEA, 2018b). Federal tax incentives and state-level renewable portfolio standards (RPS) and technology-specific incentives,

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especially for distributed solar PV, along with continued technology advances and cost reductions will remain strong drivers of this growth. However, the forecast has been revised down slightly from last year due to recent tax reforms and trade policy changes.

Figure 5.5 Renewable electricity generation and projections, 1990-2023

IEA (2019). All rights reserved.

Renewable electricity has doubled in ten years, driven by large increases in wind and solar, and the forecast shows continued growth.

*Includes solid biofuels, renewable waste, liquid biofuels and biogases. Notes: Data for 2018 are provisional. 2019-23 are projections.

Sources: IEA (2019), World Energy Balances 2019, www.iea.org/statistics/; IEA (2018), Renewables 2018.

Hydropower is the largest source of renewable electricity in the United States and the fourth-largest power source after gas, coal and nuclear, accounting for 6.7% of electricity generation in 2018. Due to hydrological conditions, hydropower production can show large annual variations, but the overall trend is relatively stable. Hydropower generation was relatively high in 2017-18, which can be attributed to the reduction of drought conditions in the West and Southwest of the country, where a large proportion of hydropower capacity is located. Power generation from bioenergy and geothermal are more stable and have both increased by around 12-13% in the last decade.

In an IEA comparison, the share of renewable energy in electricity generation is quite low. In 2018, the US share of renewable energy in power generation was the eighthlowest among IEA member countries (Figure 5.6).

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