Integration of Renewable Resources and Other New Technologies

The 21st century is seeing the rapid expansion of power resource types in New England, from wind and solar power to demand resources to new energy storage options. Not only are these technologies supplying the region with electricity and participating in the wholesale electricity marketplace—they are changing the very nature of the power system.


Balancing new technologies with reliability is requiring changes in ISO system operations, planning, and market design

renewable resource integration

A Wide Array of New and Emerging Technologies

  • Demand resources (DR)—Increasing investment in energy-efficiency (EE) measures, an example of passive DR, is reducing regional energy use and slowing the growth of peak demand. Hundreds of megawatts of active demand response—resources which reduce their power consumption to relieve grid demand—also participate in the region.
  • Wind-powered resources—Over 1,000 megawatts (MW) of on- and offshore wind power have already come on line in New England, and much more is proposed to be built over the next several years.
  • Solar photovoltaic (PV) resources—About 2,500 MW of solar power was expected to be installed in the region through 2017, per the ISO’s forecast. The vast majority of this is in the form of small-scale systems, such as rooftop residential systems, that are not connected to the regional high-voltage transmission system.
  • New types of energy storage—In late 2015, grid-scale battery-storage projects requested interconnection to the regional power system for the first time, with 16 MW achieving commercial operation through 2017 and much more on the way. (Read “How Energy Storage Can Participate in New England’s Wholesale Electricity Markets.”) Advances in small-scale energy storage options, including electric vehicles, are expanding the ability of the region’s households and businesses to meet their own energy needs.
  • “Smart” technologies—From smart meters to smart refrigerators, all kinds of new technologies and devices are opening doors for consumers to have more control over their electricity use.

Clean-Energy Resources Are Playing a Small but Growing Role

The amount of renewable energy and energy efficiency in New England has been growing rapidly, though it will be many years before it may match the amount of natural gas capacity currently on the system and proposed for development.

Power Resource Types with Strongest Growth in New England


Renewables and other new technologies hold much promise for New England. For example:

  • With zero emissions, renewable resources can help achieve federal and state environmental goals.
  • Widespread residential solar-power and storage systems, electric vehicles, and smart meters will change not only how much electricity people draw from the grid, but when they draw it.
  • Smart grid technology and retail rate design changes will empower consumers to use electricity more efficiently and reduce their energy bills.
  • Distributed generation may be able to help lessen the impact of local power outages.


Despite their rapid growth, the region is still decades away from installing enough renewable resources and grid-scale energy storage to allow for complete independence from fossil fuels. The expansion of new technologies also brings challenges and costs. For example:

Intermittent output

Changing weather conditions can lead to rapid and sizeable swings in electricity output from wind- and solar-power resources, which is why they’re called variable or intermittent. More wind and solar power creates a need for fast-starting, flexible resources that can take up the slack when the wind stops or the clouds roll in. New natural gas generators will likely fill this role, further exacerbating New England’s fuel-security challenge.

Transmission investment needed

Interconnecting more onshore wind power in New England—or increasing access to hydropower from Canada—is going to require significant transmission upgrades. See Key Stats—Transmission.

Lack of visibility

Many solar arrays are installed “behind the meter” directly to retail customer sites or local distribution utilities. This means that ISO system operators can’t “see” their performance in real time. This makes forecasting and planning for the effects of PV very challenging, both on a long-term and day-to-day basis. See Solar Power in New England: Locations and Impact.

Less stable interconnection methods

The ISO’s forecasting efforts have revealed a potential problem: much of the region’s PV isn’t set up to “ride through” low-voltage conditions that can be caused when a transmission line or generator trips off line. Instead, they may automatically disconnect, exacerbating the problem. And if a large amount of PV were to shut down suddenly, demand on the regional grid would rise considerably, introducing instability. To learn more about how voltage, load ramping, and frequency help maintain power grid reliability and how they’re affected by the increasing penetration of variable generation, watch The Basics of Essential Reliability Services—a series of short videos presented by the North American Electric Reliability Corporation (NERC).

A risk to accurate market prices

The region’s capacity market—and the importance of accurate prices—are taking on greater significance as New England’s power fleet transforms itself. But certain state actions may inadvertently undermine the capacity market. Read more in Accommodating State Environmental Goals within the Competitive Marketplace.

Wind project proposals

Will Adding More Renewables Help During Winter?

Winter operations are becoming increasingly difficult due to natural-gas-fired generators’ fuel-security issue and the retirements of oil, coal, and nuclear power plants. Wind and solar resources can offset some natural gas use. However:

  • Their help is limited by still-low levels of regional installation.
  • Wind speeds are variable and can drop during extreme cold snaps, paradoxically creating a need for natural-gas-fired generators that can ramp up and down quickly to balance fluctuations in supply or demand and maintain continuity of electricity supply.
  • Solar energy isn’t dispatchable by the ISO and doesn’t help meet peak winter demand, which happens after the sun has set. (See an illustration of solar power’s winter impact.) Moreover, winter conditions, with snowfall and fewer daylight hours, also dampen solar output.

Accurately Forecasting the Load-Reducing Effects of Solar Power Is Increasingly Important

Because most solar power in New England is connected behind the meter, it serves to reduce the amount of electricity drawn from the regional grid. This load profile simulates the impact that growing amounts of solar power will have during winter—and shows how it can’t serve winter peak demand. The steepening ramp to peak load hour also illustrates how flexible, fast-responding power resources will become increasingly important for serving the region’s needs.

duck curve

ISO Innovation Is Paving the Way

To fulfill our responsibilities to New England in light of the evolving power system, we’ve made major innovations to how we operate the grid and plan for the future, to our IT systems, and to the marketplace we design and administer. For example:

  • ISO staff developed the first multistate, long-term forecast in the nation on the growth of energy-efficiency measures, as well as the first, multistate, long-term forecast for behind-the-meter solar installations.
  • To help manage the fluctuating output of wind and solar power resources, we’ve developed a highly accurate hourly wind forecast for the region and each individual wind farm, participated in several national studies to develop accurate solar forecasts, and prototyped a short-term forecast for solar power.
  • We’re leading the industry’s use of high-speed cloud computing to analyze vast quantities of smart grid data.

Learn more at Working toward a Smarter, Greener Grid.

Several market-based changes are also helping pave the way for future grid transformation:

  • In 2016, we incorporated wind resources and intermittent hydro resources into real-time dispatch for the first time, enabling them to set real-time prices. This project used a pioneering methodology the ISO developed to efficiently account for the variable “fuels” powering these resources.
  • We’ve opened the door for new energy-storage technologies, such as batteries and flywheels, to compete in the Regulation Market by introducing an “energy-neutral” dispatch signal to integrate these resources into grid operations.
  • Changes in 2018 will make it easier for storage devices and similar technologies that both consume and inject energy to participate as dispatchable resources in the energy market.
  • We’ve been a leader in integrating demand-response resources into the wholesale electricity marketplace and expect to complete full integration in 2018.
  • A new “clustering” methodology will go into effect in 2018 to support interconnection requests from multiple generators to be studied together. This will help move forward the requests in northern and western Maine, where thousands of megawatts of proposed new resources, mostly wind, are seeking to connect to the regional grid. It may also help generators save on interconnection costs.
  • Behind-the-meter (BTM) solar power will soon be integrated into operational load forecasts to help the ISO predict levels of demand with the higher degree of accuracy needed to operate the grid reliably and efficiently. Stakeholder discussions in 2018 will also include ways to improve modeling BTM solar power in calculations that will ultimately help determine the amount of generating capacity to procure through the Forward Capacity Market.

With the 2018 publication of its Operational Fuel-Security Analysis, the ISO has sought for the first time to measure the potential effects of fuel-related variables—including increased renewables—on the region’s ability to maintain a reliable supply of electricity in future winters. The report is intended to help support a regional discussion of fuel-security risks and potential mitigation efforts.

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