Council discusses upgrade to long-term load forecasting capabilities, reviews new market study & price forecasting

The Council is upgrading its load forecasting capabilities for the ninth power plan. Power system analysts will be able to produce annual, monthly, and hourly forecasts of load across 20+ years for the region as well as individual utilities' balancing authorities, shown on the map above. They'll also include data for 27 weather stations around the Northwest (noted with purple dots on the map).

The Northwest Power Act requires the Council's power plans to include a load forecast for the region of at least 20 years. That was not an easy task when the Council was created in 1980. It's only gotten more challenging since then as the Northwest power system has grown in complexity and size.

While producing the 2021 Power Plan, Council power system analysts kept bumping up against limitations to their old computer models' ability to do long-term load forecasting among other essential tasks in power planning. To address this issue, in 2023 staff contracted with Itron, a company offering energy forecasting software tools, to upgrade the Council's long-term load forecasting. Power system analysts have been using the improved capabilities since July.

During the Council's August meeting, Senior Energy Forecasting Analyst Steve Simmons, Senior Power Analyst Tomás Morrissey, and Itron Senior Forecast Consultant Michael Russo walked through what these changes will mean for upcoming power planning work to produce the ninth power plan. (Read presentation | watch video)

Additionally, Manager of Planning and Analysis John Ollis gave a presentation on results from the Power Division's new study of the wholesale power market price forecast. (Read presentation | watch video) Read below for more information about the results.

Long term load forecast improvements

Power system analysts will now be able to produce annual, monthly and hourly forecasts of load across 20+ years for the Northwest as well as for 13 individual utilities' balancing authorities. They'll also be able to include data from 27 weather stations in Oregon, Washington, Idaho, and Montana. Forecasts will represent residential, commercial, and industrial sectors, as well as four special sectors: electric vehicles, data centers, electrification, and rooftop solar. Collectively, this will allow analysts to capture load trends, as well as changing power system dynamics such as hydrogen production or electrification of loads from buildings, transportation, and industrial sectors.

Simmons discussed the evolving nature of power demand in the Northwest:

• Increasing adoption of electric cars, trucks, buses is fueling demand growth, with charging impacts on winter and summer peaks. Power system analysts will be able to better capture how these vehicles are charged, such as at home in the evening, in morning hours, after midnight, at work, or using public chargers, as well as time-of-use incentives offered by utilities.
• Data centers and chip fabrication plants are also forecasted to drive significantly more energy demand in the Northwest in the next five years.
• More homes and buildings in the Northwest are installing air conditioning to deal with increased temperatures in summer months, leading to more demand in that season.
• For the first time, he said the Northwest is seeing significant increases in adoption of rooftop solar, driven by decreasing costs of installing the systems. This is also helping to lower demand on the grid overall.
• Some homes and buildings are electrifying by switching from natural gas furnaces and water heaters to heat pumps and heat pump water heaters, adding to winter demands.
• The potential to construct hydrogen hubs in the Northwest could also add new large energy users onto the grid, because the hubs would create green hydrogen through a power-intensive production method called electrolysis.
• Climate change scenarios and their impacts to temperature and weather would also be a factor in future energy demand.

In the residential and commercial sectors, analysts will gauge the number of homes, building square footage, building efficiency, as well as the number of end-use appliances, among other data points, which builds off research by the Northwest Energy Efficiency Alliance and the Energy Information Administration. Russo said NEEA's research has captured a comprehensive picture of every end use that consumes electricity in buildings throughout the Northwest, which is built into the Itron forecasting model the Council is now using.

Morrissey said the Council will also have better ability to gauge future power demand caused by shifts in temperature in the Northwest. This drives the need for space heating in winter, and space cooling in summer - both significant factors in ongoing energy demand in those seasons, as well as in peak periods. Analysts will be able to forecast these temperature shifts across 27 weather stations in the four states. The Council's Climate and Weather Advisory Committee is currently working to select the temperature and climate data that will be used in this long-term forecasting.

Simmons reiterated the importance of the Council's advisory committees and the need to work collaboratively across the region with utilities, energy providers, technical experts, climate scientists, and many others to fine-tune the data and assumptions used to produce long-term load forecasting, which will be included in the ninth power plan.

"Any forecast is only as good as your inputs and your assumptions," he said.

Updated market price forecast study

The Power Division's new study on wholesale market prices revisited analysis done in the 2021 Power Plan. Due to significant clean and Renewable Portfolio Standards (RPS) policies and less dependence on new baseload generation to meet growing loads, the market price forecast studies from the 2021 plan scenarios consistently showed extremely large buildouts of new resources, especially solar generation outside the region.

Ollis briefed the Council on what market buildout has looked like in the Western Electricity Coordinating Council territory since then, discussed buildout results and wholesale market price and avoided emission rate forecasts from the new study, identified market risks to monitor, as well as improvements to methodology and computer modeling that staff will be working on with Council members and the System Analysis Advisory Committee for the upcoming ninth plan.

From 2020-24 in the WECC, 24.3 GW of solar and 8.6 GW of wind have been built; 2.8 GW of coal generation retirement has been offset by a 2.8 GW increase in natural gas generation; and 25.8 GW of energy storage has been added. The Power Division's 2024 study included updating to a new version of its AURORA modeling software; adding long duration storage resources; updating out-of-region loads; factoring in policies like the Inflation Reduction Act; updating fuel prices; and updating existing generation and transmission.

The study examined a baseline demand forecast as well as a high demand scenario, delaying emerging resources, delaying transmission builds as well as adding new transmission builds, and limited storage resources.

Buildout results

Results of the Council's new market study show significant resource builds in the WECC will be needed by 2030 & 2045, although the amount varies by scenario.

Similar to previous studies, monthly Mid-Columbia wholesale power prices will still depend heavily on hydro conditions. The new study examined 30 regional hydro/load/wind conditions for multiple scenarios. It found that, in general, prices and emissions trend down over time due to investment in lower emitting resources. Other findings include:

• On a daily basis, price and emissions variability increasingly follow the availability of wind and especially, solar generation.
• Midday, when solar generation is peaking, prices are consistently low. During the sunrise and sunset periods, prices and emissions are volatile reflecting increasing utilization of emitting, high variable cost resources (like gas plants).
• Some of the variability in prices should be mitigated further by improving storage unit operation.

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