With more solar and wind, North America’s grid is getting more reliable

By Will Driscoll

The North American electric grid’s annual checkup shows that it is becoming increasingly reliable, as solar and wind gain share, according to the North American Electric Reliability Corporation (NERC).

For solar, one grid reliability factor—frequency response—is of great interest because of concern, as stated in the report, that “a changing resource mix and increase in renewable resources” may have a “potential impact on frequency response performance.” 

Frequency response has steadily improved since 2013, as shown in the last two columns of this table (i.e., one or both measures are improving in each interconnection):

The report notes that inverters from solar and wind farms now provide frequency support, alongside the frequency support that has traditionally been provided by synchronous inertia from fossil-fired generators.  (See, for example, a report on solar and frequency support, prepared by California’s grid operator, First Solar, and the National Renewable Energy Laboratories.) 

The 2017 solar eclipse was another bright spot for solar, as “no issues developed” from the transitory loss of mid-day solar power, because utilities had planned for the occurrence—just as they plan for cloudy days.

Beyond frequency response, the report covered all 13 of NERC’s grid reliability metrics. NERC found that all metrics were either improving, unchanged, or stable, with the exception that the Texas Interconnection is expected to have tight reserve margins this summer.  Even there, the report noted that “ERCOT [the Texas grid operator] has a variety of operational tools to help manage tight reserves and maintain system reliability.”

The report provided updates on two incidents related to California wildfires and solar PV inverters.  After the first incident, related to a 2016 wildfire, NERC advised utilities to contact a specific inverter manufacturer to implement a reliability solution specific to that manufacturer’s inverters.  NERC also formed a task force that will produce a guideline for “inverter-based resource performance” to support grid reliability.  After the second incident, related to a 2017 California wildfire, NERC issued a follow-up to the first alert. 

Beginning in 2021, NERC expects to collect data on solar generating units that are 20 MW and larger, as part of its Generation Availability Data System that now covers fossil units and is phasing in wind units.  Utilities use the data for benchmarking the performance of their own generating units.

NERC was certified by the U.S. Federal Energy Regulatory Commission as the nation’s electric reliability organization in 2006, pursuant to the Energy Policy Act of 2005.  Alaska, Hawaii, and Puerto Rico are not included in NERC, although an Alaskan organization has an affiliate membership.

35 to 70 GW of solar, plus wind, could power all freight trucks in the U.S. or Europe

By Will Driscoll

Many truck manufacturers are developing electric freight trucks, whose projected lower costs for fuel and maintenance would, by one estimate, quickly outweigh their higher purchase price. With this cost advantage, electric trucks could ultimately dominate freight trucking. A charging infrastructure for an all-electric continent-wide fleet of freight trucks in the United States or in Europe could be powered by 35 to 70 gigawatts of solar farms, plus an equivalent amount of wind farms.

Tesla and Peterbilt are the first firms to develop electric heavy-freight trucks—the global term for tractor-trailers or Class 8 trucks. BYD already offers medium-sized electric trucks and a larger electric freight truck with a short range, while medium-sized electric trucks have been announced by Daimler, Cummins, Volvo, DAF, and a Navistar/Volkswagen joint venture.

The North American Council on Freight Efficiency predicts that electric trucks will have an “increasing role” in freight transportation. Also relevant—because freight trucks, like city buses, operate many hours per day—is a projection by Bloomberg New Energy Finance that electric city buses will capture 84 percent of global bus sales by 2030, due to low operating costs and declining battery costs.

In the policy arena, a report from the International Council on Clean Transportation, which supports national governments in reducing transport sector pollution, notes that “electric-drive heavy-duty vehicle technologies are essential to fully decarbonize the transport sector.”

These market and policy drivers point to a new market opening for solar power: solar farms, possibly near truck stops, to power electric freight trucks. A spreadsheet calculation shows that 35 to 70 gigawatts of solar power, plus an equivalent amount of wind power, would produce an amount of electricity each year equal to the needs of an all-electric fleet of heavy-freight trucks in the U.S. or in Europe. That’s because by coincidence, the fleets of heavy-freight trucks in the U.S. and Europe travel approximately the same distance each year. (A technical note below provides details of the calculation.)

Pursuing this market opening could help the solar industry maintain its approximate 30 percent global growth rate in recent years, even as the industry keeps expanding. Maintaining a 29% growth rate, deemed “challenging but feasible” in a research studypublished in Science magazine, would result in a global installed base of 10 terawatts of solar power by 2030.

As electric freight trucks become more widely available, solar industry participants could help ensure that charging stations for the trucks are solar-ready, and ultimately solar-powered. This could involve research and decisions regarding optimal placement of charging stations; ensuring that a sufficient number of charging stations is always available to meet growing demand; possibly optimizing charging during times of peak solar and wind production; and providing electricity storage as needed.

Powering electric heavy-freight trucks with solar and wind power would also cut CO2emissions by displacing diesel fuel. Globally, road transport accounts for 22% of energy consumption, of which 30% is long-haul road freight. Therefore, CO2reductions of about 7% (i.e., 30% of 22%) could be achieved by powering heavy-freight trucks with renewable energy, in each region that follows this path.

If most trucking firms ultimately conclude that electric heavy-freight trucks save money, they could aim to replace their diesel trucks with electric trucks as their diesel units reach the end of their useful life. The Bloomberg projection noted above projects that will happen for electric city bus sales by 2030. With global production of heavy-freight trucks estimated by Deloitte at 1.7 million in 2014, the pace of diesel truck replacements could be limited by global manufacturing capacity for electric heavy-freight trucks.

Technical note: The calculation starts with the annual distance traveled by the current U.S. and European fleets of heavy-freight trucks in 2015, as reported by the International Energy Agency; each is approximately 200 billion kilometers. For the energy needed to power a heavy-freight truck, the lower bound analysis uses an estimate of one kilowatt-hour per mile, developed by University of California/Berkeley materials science professor Gerbrand Ceder. The upper bound analysis uses a specification that Tesla reported subsequently for its heavy-freight truck of “less than 2 kWh per mile” (the upper bound uses 2 kWh per mile). Converting kilometers to miles, and kilowatt-hours to gigawatt-hours, and then multiplying shows that 124,000 to 248,000 gigawatt-hours per year would power such a fleet in either the U.S. or Europe. At a U.S. national average capacity factor for a solar farm pegged at 20 percent by the National Renewable Energy Laboratory, 70 to 140 gigawatts of solar would produce this amount of electricity each year (given 8760 hours per year). If solar and wind each provided half the energy needed, solar’s contribution would be 35 to 70 gigawatts.

Sensitivity analysis: Regarding solar’s capacity factor in the U.S., Lawrence Berkeley National Laboratory has reported the median capacity factor for utility-scale solar to be 26 percent. If this were to be the average capacity factor for future utility-scale solar installations, rather than the 20 percent value used above, the solar capacity needed would be reduced accordingly.

Global Battery Production Capacity Must Grow 21 Times To Electrify The Global Vehicle Fleet

By Will Driscoll

  • Market and policy forces may drive a global transition to electric vehicles.
  • Current and planned global battery manufacturing capacity is 313 gigawatt-hours per year.
  • An estimated battery manufacturing capacity of 6600 gigawatt-hours per year would be needed to electrify the global vehicle fleet.
  • That is about 21 times the current capacity.

Vehicle manufacturers are announcing plans for new and improved electric vehicle models on a seemingly daily basis. For passenger vehicles, the appeal is improved performance and lower operating costs; as prices fall, consumer demand will expand. For trucks and city buses, the appeal is lower life cycle costs and, especially for buses, cleaner air.

Nations may favor electric vehicles to reduce oil imports and protect the climate. Indeed, stabilizing the climate will require electrifying the global vehicle fleet and powering vehicles with solar and wind power.

Current and planned global battery manufacturing capacity is 313 gigawatt-hours (GWh) per year

The world’s major battery manufacturers include Panasonic, LG Chem, Samsung SDI, and Chinese newcomer CATL. These and other battery makers have an existing and planned manufacturing capacity of 313 GWh per year, according to Bloomberg.

About 6600 GWh of battery manufacturing capacity would be needed to electrify the global vehicle fleet

This analysis considers heavy commercial vehicle (HCV) trucks, medium commercial vehicle (MCV) trucks, city buses, passenger vehicles, and commercial vehicles made by auto manufacturers.

Because electric vehicles driven many hours per day achieve the greatest operating savings, fleets of trucks and buses are the strongest candidates for electrification, and thus are considered first.

Electric HCV trucks would require 900 GWh of battery manufacturing capacity

Deloitte projects that 1.8 million HCV trucks will be sold annually by 2026, while a Tesla Semi HCV with a range of 500 miles has been estimated to require a 500 kilowatt-hour (kWh) battery. Multiplying the two values yields an estimated 900 GWh of battery manufacturing capacity needed for HCV trucks. (Note that one million kWh equals one GWh.)

Electric MCV trucks would require 180 GWh of battery manufacturing capacity

Deloitte projects that 0.90 million MCV trucks will be sold annually by 2026, while Volvo plans an electric MCV with a 200 kWh battery. Multiplying the two values shows that about 180 GWh of battery manufacturing capacity would be needed for MCV trucks.

Electric city buses would require 50 GWh of battery manufacturing capacity

Bloomberg projects that 0.18 million city buses will be sold annually by 2025, while Proterra offers an average 275 kWh battery pack size for its city buses. Multiplying the two values shows that about 50 GWh of battery manufacturing capacity would be needed for city buses.

Passenger vehicles would require 3550 GWh of battery manufacturing capacity

An automaker’s association estimates that 71 million passenger vehicles were sold in 2017, while the standard Tesla Model 3 will have a 50 kWh battery pack. Multiplying the two values shows that an estimated 3550 GWh of battery manufacturing capacity would be needed for passenger vehicles.

Commercial vehicles made by auto manufacturers would require 1950 GWh of battery manufacturing capacity

An automaker’s association estimates that 26 million commercial vehicles were sold by automakers in 2017. This analysis assumes that on average they would have a battery capacity 50 percent larger than that for a passenger vehicle, or 75 kWh. Multiplying the two values shows that about 1950 GWh of battery manufacturing capacity would be needed for commercial vehicles.

Summing the capacity needed across the five vehicle types = 6600 GWh needed

Summing across all vehicle types shows that an estimated 6600 GWh of battery manufacturing capacity would be needed to electrify the global vehicle fleet.

Dividing 6600 by 313 (which is the current plus planned battery manufacturing capacity) shows that capacity must grow about 21 times to meet that target.

China’s Electric Buses Will Cut Global Oil Consumption By 0.5 Percent

By Will Driscoll

Shenzhen has replaced its diesel buses with 16,000 electric buses, and authorities there have determined that the electric buses will eliminate the use of 345,000 tons of diesel fuel per year.

China is promoting electric buses to improve urban air quality and cut greenhouse gas emissions.  Because electric buses are far more efficient than diesel buses, net CO2 emissions will decline significantly even with fossil-fired electricity generation.

Bloomberg has projected that China will have 1.2 million electric city buses by 2025.  To support the manufacture of electric buses, China has a large and growing battery manufacturing capacity.

In 2016 the world consumed 97 million barrels of oil per day, or 35 billion barrels of oil per year. Scaling up the savings of diesel fuel from Shenzhen’s 16,000 electric buses to China’s projected 1.2 million electric buses—and converting the units from tons to barrels—shows that China’s electric buses will eliminate the use of 194 million barrels of oil per year.

Simple division shows that China’s electric buses will reduce global oil consumption by 0.5 percent.

The impact of China’s electric buses on global oil consumption is a leading indicator of the changes to come, as the world transitions to 100 percent clean renewable energy.