New York — Average annual daily temperatures in New York have been increasing about 0.7 degree Fahrenheit per decade, with summer arriving earlier and lasting longer, which is creating challenges in forecasting power demand, according to a presentation given to the New York grid operator.

The average temperature in New York has been increasing since the early 1990s and the number of cooling degree days in the shoulder months are increasing faster than in the peak months, global energy and water management company Itron said in a presentation given to the New York Independent System Operator's Load Forecasting Task Force.

The exception is Long Island, the company noted, where temperatures on the hottest days are increasing faster than on the average day.

Itron is preparing a weather-trend analysis based on daily and hourly temperature data back to 1950. An increasing temperature trend has been observed beginning in 1992 that exhibits "strong statistical support with [the] trend highly significant," the company said.

A degree day compares the mean (the average of the high and low) outdoor temperatures recorded for a location to a standard temperature, usually 65 degrees in the US, according to the US Energy Information Administration.

The observed average daily temperature trend in Albany shows average annual temperatures have risen 1.1 degrees per decade. Overall, hot days are getting warmer, increasing 0.8 degree per decade in Albany and the average daily temperature has increased 0.6 degree per decade in New York City.

At the state level, average daily temperature increases 0.71 degree/decade and the results show a 0.8% increase in cooling degree days with a faster increase in May than July.

The analysis shows peak demand shifts out two hours by 2022, Itron said.

HEATING, COOLING REQUIREMENTS

The modeling indicates New York cooling requirements will increase 26.3% by 2050 compared with normal weather conditions. Cooling requirements increase by 4,161 GWh in 2050 in the trend case to 20,009 GWh, compared with 15,848 GWh under normal conditions.

But heating requirements decreased a similar amount, which mostly balances out the impact of greater cooling requirements, the company said. Trended cooling requirements in 2050 are 16.9% lower than under normal weather conditions.

The increase in cooling load is offset by the decrease in heating load, the company said, and noted that heating and cooling are a relatively small part of the state's total energy requirements. Heating and cooling account for 13% of system end-use distribution, industrial accounts for 12% and "base" makes up 75%, Itron said.

Total power system peak demand is 1,326 MW to 2,653 MW higher under trended conditions than normal by 2040 and 1,927 MW to 3,259 MW higher by 2050.

Incidences of loads exceeding 32,000 MW increase from 22 hours to 80 hours by 2040, the company said. The NYISO's record peak demand of 33,956 MW was reached in July 2013, according to the grid operator.

The next steps in the analysis include developing scenarios for state public policy goals like increasing solar power capacity, electric vehicles, battery storage and electrification, which will have mixed results on the total demand forecast.

For example, addition of behind-the-meter solar resources will reduce peak demand and annual energy usage on the bulk power system, according to the NYISO, while EVs are expected to increase annual energy use on the grid by 4.2 million MWh by 2030.

The NYISO estimates essentially flat power demand growth over the next 20 years, driven by energy-efficiency gains and a considerable increase in behind-the-meter solar installations partially offset by the growth of electric vehicle consumption, according to forecasts released in April.

The NYISO's baseline summer peak demand growth forecast dipped 0.13% from 2018 to 2028, but then ticks up 0.19% from 2028 to 2038, which results in a cumulative 0.03% increase over the next 20 years, according to the grid operator's 2018 Load & Capacity Data Report, known as the "Gold Book."

-- Jared Anderson, jared.anderson@spglobal.com

-- Edited by Valarie Jackson, newsdesk@spglobal.com