Carbon Intensity (Still) Dropping For US Power Generation, But It’s Not Quite What You Think

When US President* Donald Trump pulled the US out of the Paris Agreement on climate change in 2017, carbon watchers were cautiously optimistic that the national economy would continue to decarbonize. Caution is still the operative word. A new report confirms that the power generation sector in the US is continuing to shed CO2 at a fairly rapid clip, but that’s just one piece of the carbon intensity puzzle.

A downward trend in carbon intensity for power generation in the US, as measured by carbon emissions from power plants. Image: Power Sector Carbon Index, Scott Institute for Energy Innovation

Carbon Intensity Dropping For Power Generation

The new report comes out of the Power Sector Carbon Index, a public data analysis program supported by Mitsubishi Hitachi Power Systems at the Scott Institute for Energy Innovation at the Carnegie Mellon University College of Engineering, in Pittsburgh.

The PSCI tracks carbon emissions from electricity generation in terms of pounds of carbon dioxide. The basic calculation is to divide direct emissions from all sources by the total net electricity generated in a given time period.

The researchers compared Q2 of this year to last year’s results, and found that CO2 emissions from power plants fell by 9%.

That’s the good news, though at least three caveats apply.

First, the report notes that total power generation in the US fell by 4% from Q2 in 2018 to this year. In other words, cleaner electricity did not replace dirtier electricity on a kilowatt-by-kilowatt basis. A sharp overall downturn in power generation was also a significant factor driving down carbon emissions.

The second issue is that natural gas is still a major force in reducing carbon emissions from power plants in the US. The supply chain, though, is a whole ‘nother can of worms. Natural gas has a methane emissions problem from the wellhead on through to transportation, storage, and distribution.

Finally, a one-quarter year-over-year comparison is not a trend. In particular, weather patterns can be a major factor influencing annual CO2 emissions in the US from one year to the next. Relatively mild weather in 2017 contributed to a 2% drop in emissions that year, for example.

Electrification Rising, Power Generation (Still) Falling

Nevertheless, the new report is encouraging. The twin drop in both carbon intensity and overall power generation occurred against the backdrop of two emerging trends that should push demand for electricity up, not down.

One trend is the building electrification movement. The electrification movement calls for eliminating natural gas and oil in residential buildings, and using only electricity for heating, cooling, and cooking along with lighting and other appliances. Commercial and industrial buildings are also targeted for electrification.

Some jurisdictions are beginning to ban gas hookups in new construction, though most of the activity in this area consists of gas-to-electric retrofits.

The other trend is the mainstreaming of the electric vehicle market.  EVs still account for a tiny fraction of total vehicles sales in the US and and they slid downward this year. However, that may represent a temporary blip. EV sales have been jumping over the past several years. According to Fortune Magazine, sales have grown by an average of 25% annually since 2013.

Keep Up The Good Work, Carbon Intensity Edition

The real question is whether or not the US economy can continue to cut carbon intensity in the power generation sector moving forward, as the building and transportation sectors push the demand for electricity up.

In terms of the PSCI and similar indexes, that is going to depend partly on how fast the trend toward small scale and distributed energy resources can accelerate, especially in the solar-plus-storage field.

The US  Department of Energy has been promoting a shift away from large centralized power plants and into a distributed energy resources model. The basic idea is to foster resilience and reliability in the nation’s power supply regardless of the energy source,

The practical result has been to support the use of solar panels for on-site and local power generation, including vast numbers of small scale rooftop solar installations.

Small scale distributed wind power has been slower to take hold, but the Energy Department is also looking to ramp up activity in that area as well.

Much of the activity in the distributed energy resources field does not show up in the PSCI, because the index only measures emissions from grid-connected sources with a nameplate capacity of 1 megawatt or more.

To the extent that smaller solar and wind projects help fill the growing demand for electricity from buildings and vehicles, indexes like PSCI will continue to record falling demand for electricity from conventional, large scale power plants.

By way of an assist, the electrification movement can lean on energy efficiency improvements to help offset the impact of gas-to-electric conversion in buildings.

Carbon Intensity: Where The Rubber Hits The Road

If you’re thinking hmmmm, well Mitsubishi Hitachi Power Systems supports the PSCI and it is all about selling gas turbines, so of course it is interested in amplifying the role of natural gas in reducing carbon intensity in the US power generation sector, then run right out and buy yourself a cigar.

That’s not the end of the story, though.

It looks like MHPS is among the energy sector manufacturing companies that are prepping for the day when the natural gas trend runs out of steam, so to speak. Earlier this year, the company launched a new renewable energy venture called Oriden.

According to the press materials, Oriden is a “renewable energy solutions developer” and a “new type of power generation organization” that will pursue “end-to-end solutions for renewable energy projects – including development and permitting, construction, financing / ownership, and asset management. “

That’s quite a bit to chew off in one hunk, but Oriden hit the ground running through a partnership with the leading New York company Solar Liberty under its umbrella.

Never heard of Solar Liberty? Join the club! Here’s the rundown from MHPS: