Over the past 15 years, the US electric grid has undergone some massive shifts (mostly for the better). Renewable energy and natural gas are up, while coal and GHG emissions are down.

Here we can see how the US grid has evolved in recent years:

Source: Energy Information Administration. 2018 figures are YTD to October.

Let’s also put it in table form for ease of access:

So during this time-span, every energy source declined except for natural gas and non-hydro renewable energy. This is good news for the environment, as emissions intensity in our electric sector has dropped to new lows:

Source: Scott Institute for Energy Innovation, Carnegie Mellon University

This chart shows the emissions intensity of the US power sector. That means that 1 MWh of electricity results in over 35% less emissions in Q2 2018 (the most recent data point available) than it did in 2003.

Some of these gains have been offset from increased electricity production, but total US power sector emissions are still substantially lower than in 2003:

Source: Scott Institute for Energy Innovation, Carnegie Mellon University

Total electric-sector emissions still saw a 26% reduction during that time-frame. Due to this, the electricity sector may finally lose its mantle as the largest emitting sector in the US to the transportation sector.

Natural Gas And Coal

Since 2003, the most profound shift occurred between coal and natural gas. While natural gas has been on a steady rise, coal has seen a continual decline that isn’t likely to stop soon:

Source: Energy Information Administration

With both renewable energy and natural gas still expanding at rapid pace, the future looks increasingly grim for coal. By taking a look at coal capacity changes, we can peak into the future of coal in the electric grid:

Source: Energy Information Administration

Preliminary estimates are showing that 2018 continued the trend of large coal retirements — possibly even breaking the record. With coal additions coming to a complete halt, the decline looks to be terminal from here.

Renewable Energy

From renewable energy, we can break it down further to see what energy sources are producing the gains.

Source: Energy Information Administration

The rise of wind and solar energy is very evident. In 2003, hydroelectricity made up almost 78% of renewable energy production. By 2018, that share had dropped to 39.7%. 36% of renewable energy is now wind, and 13.6% is now solar. Wind energy is likely to overcome hydro in the near future.

According to the EIA, in 2017 wind generated 6.3% of electricity while solar generated 1.3%. Both of these figures are likely to be higher in 2018 once the full year of data is available. While natural gas has outpaced renewable growth to date, the EIA predicts that they will lead the charge from here on out. Meanwhile, coal’s share of generation is expected to continue to decline in the next few years.

Causes

The large shifts over the past 15 years have been a result of shifting economics.

Source: Energy Information Administration. Coal estimates ceased in 2015.

Natural gas, solar, and wind energy all experienced significant declines in cost in recent years.