Sunday, October 4, 2020

EVs Could Make a Renewable Grid Work

In December 2018 the California Air Resources Board approved a regulation that sets a statewide goal for all public transit agencies to transition to 100 % zero-emission bus fleets by 2040. In June of 2020 the California Air Resources Board approved a regulation requiring more than half of all trucks sold in the state to be zero-emissions by 2035. Finally, in September of 2020 Governor Gavin Newsom issued an executive order requiring sales of all new passenger vehicles to be zero-emission by 2035 and additional measures to eliminate harmful emissions from the transportation sector.

Combined these are huge goals that will require the remaking of much of the infrastructure and the economy of California. Though there is a long time lag between banning the sale of new internal combustion passenger vehicles and having every car and bus and a large portion of the truck fleet transition to zero emissions, still there is tremendous amount of work that needs to be done. According to the U.S Energy Information Administration,  California has the fifth-largest share of U.S. crude oil reserves and is the seventh-largest producer of crude oil in the nation. California ranks third in the nation in petroleum refining capacity, after Texas and Louisiana, and the state accounts for one-tenth of the total U.S. refining capacity.  A network of crude oil pipelines connects California's oil production to the state's refining centers, which are located primarily in the Central Valley, the Los Angeles area, and the San Francisco Bay area. California also refines imported oil and gas.

The goal is to transition every vehicle in California to zero emissions would require more electricity, a re-imagined  and modernized grid, charging stations and probably hydrogen fuel cell charging stations.  Eliminate all the oil and gas related portions of the economy and infrastructure and transition to zero emissions vehicles. Will California maintain gas and diesel fueling stations for out of state vehicles? Also, be aware that existing electric vehicle batteries are not without environmental consequences and require rare earth metals only mined in China.  

As U.S. EPA Administrator Andrew Wheeler pointed out  in his letter of response to the Governor ;” The truth is that if the state were driving 100% electric vehicles today, the state would be dealing with even worse power shortages than the ones that have already caused a series of otherwise preventable environmental and public health consequences. For example, in August, after the East Bay Municipal Utility District wastewater treatment plant experienced a power outage for nearly two hours, a pump station failure caused 50,000 gallons of raw sewage to be spilled into California’s Oakland Estuary. Also, just this month, the inability to maintain a reliable energy system led the California Independent System Operator (CAISO) to seek an emergency exemption from federal air quality standards in an attempt to maintain power...”

California has struggled to keep the lights on even before the wildfires. As California has clearly demonstrated in their recent failures to maintain adequate power during the heat wave, solar and wind sources of electricity cannot be ramped up when needed. As a matter of fact, solar output in California actually begins falling off at peak demand time. Adequate energy storage is an essential part of planning for a grid that relies significantly on solar and wind. California would need tremendous amounts of storage to best use the wind and solar excess power when it is generated, and there would have to be planned and stored excess. The wind does not always blow and the sun does not always shine when it is needed . This is a fundamental shift from the way most of the system is managed today.

Currently, solar and wind supply about of a third of California’s power. Despite still having gas turbines that can supply power at peak demand, California was not able to meet the full demand even with conservation orders in effect. In part this was because California relies heavily on its neighbors- it is a net importer of electricity and the nearby states were also experiencing higher than usual demand.

More energy storage seems to be the answer. Ninety-eight percent of existing energy storage in California is pumped hydro. The state has seven existing pumped storage facilities with a total capacity of 3,967 MW, including projects at Lake Hodges, Castaic Lake, Helms, San Luis Reservoir, O’Neill Forebay, Big Creek, and Oroville. Nonetheless it was not enough to cover the recent shortfall in power or even close to what is necessary to manage a grid entirely dependent on renewable power.

Governor Newsome’s turn to emissions free vehicles where a significant number of personal vehicles might be electric vehicles (EV) brings up the  idea of a vehicle-to-grid power transfer and control system that has been knocking around engineering circles for a decade. In a  2017 study by Lawrence Berkeley National Laboratory predicted the current power problems saying: “we forecast the significant grid challenges that arise as more renewables are deployed (for power generation), specifically the increasing daytime over-generation, increasing evening peaks (in demand), and increasing up-ramp and down-ramp.”  However, the study finds “evening peaks, down-ramping, and up-ramping, all get slightly worse (with EV’s). EVs with uncontrolled charging will do little to mitigate the daytime over-generation problems and evening shortfalls in power generation.  So, Administrator Wheeler has a point.

The solution according to the researchers at Lawrence Berkeley National Laboratory is grid controlled charging of vehicles and utilizing the stored energy. “When comparing against uncontrolled charging, it is clear there is a substantial lost opportunity if vehicles are not integrated with the grid.” In other words, the California power storage needs can be met “ through the ZEV (zero emissions vehicle) Mandate provided that controlled charging is also widely deployed. The capital investment for stationary storage can instead be redirected to further accelerate the deployment of clean vehicles and vehicle-grid integration, and could even be used to pay EV owners when their vehicles are grid-connected with controlled charging. In this manner, not only are clean vehicles an enabler for a clean electricity grid at substantially lower capital investment, but the avoided costs of supporting renewables with stationary storage can be used to further accelerate the deployment of clean vehicles.

So, the solution to the reliable power challenge may be electric vehicles. The challenge is integrating electric vehicles into the grid in a way that is effective and accounts for human behavior in using their vehicles and remembering to plug them in. There would also need to be some method of assure that a vehicle would have and adequate charge when it was needed. Drawing down EV batteries during the evening and night to recharge during the day when solar excess peaks could leave little range for vehicles in the morning for longer trips or car service. Imagine if every EV power reserves were drawn down when the evacuation order was issued.   

No comments:

Post a Comment