by Guy Page

A Vermont environmental leader and 2020 candidate for governor is warning the Senate Natural Resources and Energy Committee that its plan to convert Vermont from fossil fuels to electricity will strain the state’s power grid.

James Ehlers is the children’s health advocate for Vermonters for a Clean Environment (VCE). He challenged former utility executive Christine Hallquist for the 2020 Democratic nomination for governor. In an open letter to committee chair Chris Bray (D-Addison) entitled, “Why are Vermonters asking about grid reliability, Senator Bray?,” Ehlers emphasized that the state’s energy experts have noted the following:

1. As reliance on electricity grows, the risk of blackouts increases.
2. Widespread retirement of backup coal and oil-powered generators have made New England increasingly dependent on natural gas power – and pipeline capacity limits the amount of natural gas available during a heating crisis.
3. The efficacy of wind and solar power “are hampered by extreme weather conditions.” Wind turbines can ice up, solar panels can be covered by snow.
4. New England’s existing nuclear fission and biomass power generators should be considered as alternate, low-carbon power sources while next-generation solutions such as hydrogen, etc. are being developed.

Ehlers emailed Chair Bray the following excerpts from the State of Vermont’s own Comprehensive Energy Plan:

P. 218-219 – As reliance on electricity for essential services grows, the risk and potential impact of loss of electricity increases, and remains a primary concern in the design and operation of the grid. ISO-NE has identified the winter season as having the highest likelihood for such an event. A “severe prolonged cold snap” lasting multiple days, paired inherently with high demand for electricity, could bring about inadequacy in available generation resources such that not all electric load can be served reliably. Procurement of a portfolio of resources, and the transition to a more renewable and clean future, must consider overall reliability of the grid. 

Increasingly, the New England electric system has become reliant on natural gas for power generation year-round. Available pipeline capacity limits the amount of natural gas that it is possible to procure from our neighboring regions and, during a cold snap, some natural gas plants would find their fuel supply restricted by the competing demand of residential heating. While it is possible for some generating stations to utilize liquid natural gas (LNG) in place of the gas piped in from neighboring regions, it may still be difficult for these plants to obtain fuel given supply chain challenges and competing demand from foreign markets. 

Over the past years, some generating plants in New England that were fueled by coal and oil have retired, largely to be replaced by natural gas plants. This has increased reliance on the remaining coal and  oil units during cold snaps. Concerning to ISO-NE, though, are the fuel reserves of these remaining units — there may be sufficient fuel to generate electricity for a day or more, but a prolonged cold weather event, especially paired with global oil supply chain limitations due to the pandemic, could prevent delivery or utilization of additional fuel shipments. 

The growth of renewable, intermittent resources in Vermont and elsewhere in the region has begun to decrease the demand for electricity from fossil fuel generators, and indications are that this essential process will continue. 

However, the efficacy and availability of these resources can be severely hampered by extreme weather conditions. It is expected that, in a winter weather event, wind turbines may be shut down due to blade icing or high wind, solar panels may be covered by snow or ice, and that small-scale hydro turbines could suffer from deficient water flow. Reduction of this risk will require the diversification of renewable resources with regard to technology type and geographical location across Vermont and, expressly, across New England. 

In preparation for a cold snap, it is possible to charge battery energy storage systems co-located with a generation resource or connected individually. However, at the present, most batteries are designed to output stored energy over the course of a few hours, rather than the duration of the few days that may be needed in a prolonged weather event. It is possible to stagger or ration the output of multiple batteries in concert, but to store an amount of energy fitting of the problem at hand would require the installation of many more batteries than may otherwise be economically feasible based on current market structures. 

Research and development is underway for other resource types, like green hydrogen production via electrolysis and storage for later use in a fuel cell; low-impact run-of-river hydro, utilizing technology similar to tidal generators; small, modular, next-generation nuclear fission, such as could use thorium fuel; and inertial or magnetic confinement nuclear fusion. These types of generation may be able to provide services that are expected to be in increasing demand. Hydrogen fuel cells could account for the instantaneous differences in load and generation by injecting power on a sub-second basis in a process called frequency regulation, acting as a kind of spinning reserve. Fusion plants could provide reliable, sustainable baseload power. 

However, it remains to be seen whether these kinds of resources will become accessible, affordable, safe, and sustainable. Until such time, and until thorough cost, safety, and environmental vetting procedures have taken place, it is premature to recommend these resources as solutions to the problems of energy supply and winter reliability in the region. Existing nuclear fission generators, like the Seabrook plant in New Hampshire, presently serve as a reliable source of carbon-free electricity and are especially important under such weather conditions as described here. 

Other types of resources for generating electricity that are already connected to Vermont’s grid, such as biomass and large-scale hydro, can operate efficiently even during periods of extreme cold. It is possible to store biomass fuel like wood chips at quantities that allow several consecutive days of operation, and large hydro facilities do not incur the same fuel transport concerns of other resource types. It is important to recognize that these resources provide unique reliability advantages.

P.253 As DERs deploy, the grid is already beginning to see areas of constraint on the transmission and distribution systems, as discussed in Chapter 4 on Grid Evolution. These constraints appear in a variety of ways, such as limits to hosting capacity for new solar on certain circuits of the distribution grid,281 which limit additional deployment of systems without costly upgrades to grid infrastructure, and create transmission constraints in areas where renewable generation far exceeds local load (e.g., the Sheffield Highgate Export Interface in northern Vermont 282). The latter of these scenarios has resulted in curtailments of existing renewable generation, to maintain system reliability, that are exacerbated as new generation is added. These curtailments have cost implications for the ratepayers paying for those resources.  

Other notable statements

• Consultants for the PSD’s Rate Design Initiative estimated that electrification technologies — including EV charging and heat pump use — could increase 2040 system costs by $500 million per year
• Eliminating fossil fuels from the regional fuel mix means there is a need to either find clean baseload alternatives, or rethink the amount of reliability risk that is acceptable to Vermont. 
• Forging ahead without due consideration of the red flags raised by grid planners and operators will lead to inefficient grid development that risks adding costs without necessarily reducing emissions