Part one of this two-part series used a thought experiment to illustrate the sub-optimal outcomes that occur when the meteorological characteristics of renewable resources are not considered holistically. In the thought experiment, policy incentives encouraged maximizing annual energy output and no value was ascribed to variable resource quality. This is the situation today with renewable portfolio standards and tax credits based on energy production. As a result, meteorology is considered only on the periphery of electric system activities in two silos, resource assessment and siting at the project level during development, and operational output forecasting at project and balancing area levels during operations.
This second post will show that the application of meteorological and climatological knowledge to the entire spectrum of spatial and temporal scales is crucial to all aspects of the renewable energy transition, from policy setting, through planning, and into operations. Meteorology can no longer be confined to the two silos if we are to create resilient and efficient energy systems with high RE penetration.
Illustrative summary of the many ways that atmospheric sciences touches an electric utility with significant renewable generation. Figure may be freely distributed provided attribution remains intact.
In Part 1, we scratched the surface of the importance of weather driven resource attributes by showing in our thought experiment how ignoring these factors can lead to sub-optimal outcomes that can be traced all the way to initial policy positions. These attributes include the elements that follow and are summarized in the figure.
1) Variability, at all time scales, from the frequency, amplitude and ramp rate of short-term up and down ramps, to variability across seasons, and from year to year.
2) Uncertainty and the related item, forecastability at all time scales. This is more nuanced than one might first think. Some resources have well defined daily up and down ramp timing that is easy to predict, but the amplitude may be challenging. Others might be difficult to time, and still others might have wild swings across different years with little volatility on short timescales. The possibilities are infinite.
3) Correlations to other weather dependent generators within the system in space and time.
4) Correlation to load, as either individual plants or as a combined generation system (and thus, the covariance between wind, solar, hydro and temperature).
5) The likelihood and impact of extreme events like icing, extreme temperatures or damaging weather (e.g. wind, hail, lightning).
6) The possible impact of climate change on each of the foregoing attributes.
I refer to the combination of these factors as resource quality, a term that can refer to a single project or to a combination of different resources of one or more types. Amazingly, today, almost none of this is considered in most siting decisions because both utility practices and government policy typically incent the maximum possible annual yield and lowest possible cost per delivered unit of energy rather than the maximum value to the system. This leads developers to exploit sites with high annual yield, located near transmission, to maximize tax credits and minimize LCOE so that energy can be competitively offered in the RFP process.
The consequences of letting this situation stand as development rates accelerate are profound and the longer the status quo is retained and the more it is exacerbated by building transmission with the same principles in mind, the more expensive and challenging the transition to a high penetration system will become. Now is the time to fully consider the meteorology in the planning process and to ensure that policy incentives are aligned with the goal of high penetration in mind, rather than incrementally shoehorning renewables into the existing system designed for thermal generators and hoping the problems will wash out. They won’t. Further, forecasting, no matter how accurate, cannot mitigate the completely avoidable problems that will result; the forecast will just tell the operator how big the upcoming challenge is. Unless radical and unexpected breakthroughs occur, storage will also not save the day. The cost at the levels of deployment needed to balance a fundamentally lopsided system will likely always be prohibitive. Even if storage costs do dramatically drop, responsible planning now will still yield a cheaper system.
The good news is that a lot of knowledge and data needed to understand the renewable fuel resource quality is well established. The bad news is that a fundamental paradigm shift is needed to build and operate a high penetration renewable energy system efficiently. The key lies in building a portfolio of generation and transmission that will ultimately meet load in the most efficient and reliable way, and designing markets that properly compensate benefits to the overall system such as ability to serve load, flexibility, and capability to provide ancillary services at low cost. The fact that the transition to renewables will by necessity be gradual complicates matters. The period of moderate penetration (30 to 50%) may prove the most challenging from an integration perspective because of the mis-match in characteristics of slow moving, inflexible existing baseload, and variable, but fast moving and flexible renewables.
Weather is the fuel of the future. Meteorologists wishing to work in the energy business need to become conversant in current market and operating practices to be most effective and all power systems professionals need to have some basic atmospheric sciences proficiency. Together, we can evolve the system to integrate very high penetration renewables at low cost and high reliability. UVIG and The American Meteorology Society Renewable Energy Committee (AMS REC) have partnered to advance these goals. UVIG’s annual forecasting workshop is evolving into a forum that considers all aspects of how meteorology should be applied to improve RE integration. Meanwhile, the AMS REC is working on a definitive white paper describing all the ways that atmospheric science impacts the electric system today and in a high penetration RE future and is planning an Energy Summit to get actionable information into the hands of policy makers and corporate decision makers. Please consider joining our cross-discipline effort (email the author for more information) so that we may cross-pollinate as effectively as possible and create recommendations that are most relevant to the sector.
Justin Sharp
Owner and Principal, Sharply Focused LLC
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