New York — ISO New England Tuesday discussed its 2019 solar power capacity forecast with stakeholders, which showed a regional cumulative installed capacity increase to 6,744 MW in 2028 from 2,884 MW at the end of 2018, a 134% jump.
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The grid operator's Final 2019 PV Forecast that was presented to the Distributed Generation Forecast Working Group and posted on ISO-NE's website, estimates the region will add 463.1 MW of total nameplate installed solar power capacity in 2019.
Massachusetts is expected to provide 63%, or 292 MW, of the 2019 increase, with Connecticut providing the second-largest incremental increase of 68.4 MW.
The data will be used to inform ISO-NE's Report of Capacity, Energy, Loads, and Transmission, which provides 10-year projections that are used in power system planning and reliability studies, according to the grid operator. The CELT report will be released May 1.
In addition to installed capacity, ISO-NE forecasts the volumes of solar energy each state will produce. The solar PV energy forecast was developed at the state level using state monthly nameplate forecasts and state average monthly capacity factors developed from five years of PV performance data (2014-18).
The solar energy capacity factors for each state range from 13.8% in Vermont to 14.8% in Rhode Island, according to ISO-NE.
The grid operator's regional annual solar energy forecast estimates 4,047 GWh will be produced in 2019, a figure that increases to 8,511 GWh in 2028.
Properly accounting for behind-the-meter solar power output is important because these resources are connected to the distribution system and do not directly participate in the wholesale power markets. BTM solar resources impact the wholesale market by reducing load.
BTM solar PV systems are forecast to reduce estimated summer peak load by 707.6 MW in 2019 and 1,050.6 MW in 2028, according to the grid operator.
Interestingly, the region's two largest solar power states, Massachusetts and Connecticut, have very different local solar markets. Connecticut's solar power resources are estimated to be almost entirely BTM in 2028 with 1,120.3 MW of installed BTM capacity and just 135.6 MW of utility-scale solar capacity.
But ISO-NE estimates that Massachusetts' 2,133.2 MW of utility-scale solar installed by 2028 will be greater than its 2,010 MW of BTM installed solar capacity.
ISO-NE's behind-the-meter solar PV energy and estimated summer peak load reduction forecasts include the effects of a 0.5%/year panel degradation rate to account for the expected declining conversion efficiency of solar panels over time, the grid operator said.
Long-term solar panel degradation is often caused by the degradation of silicon or solder joints and problems with the encapsulant that causes delamination, increased opacity or water ingress, ISO-NE said. According to the grid operator's capacity-weighted composite solar system age calculations, Massachusetts and Connecticut have the oldest systems and Rhode Island has the youngest.
-- Jared Anderson, firstname.lastname@example.org
-- Edited by Valarie Jackson, email@example.com