Introduction
The global construction of renewable power generation is proceeding at an astonishing rate at just over 1 gigawatt (GW) per day [1]. This rate is accelerating. For reference, the Vogtle nuclear power plants in Georgia are rated at just over 1 GW each. If current projections hold, by 2030, global construction of new renewable power generation will be on the order of 3 GW per day [1], or the equivalent of adding three nuclear power plants daily – see Figure 1. Still, this may not be fast enough.
source: Abbot
Figure1: 3 GW/day of Renewables Construction is Equivalent to Three Nuclear Power Plants
Why this is Important
Supplanting conventional fossil-fueled power generation – coal and natural gas – with renewables is seen by many, as an essential part of the strategy to battle climate change. Many, however, view climate change as either a non-issue or not caused by man. This article is not for them. Still others view widespread renewables integration as not feasible. This article attempts to explain, at a top-level, why renewables can be integrated at scale (and have already been) effectively, easily, and cost-effectively.
Is 3 GW A Day Fast Enough?
By the numbers, 1 GW a day of renewables construction is far from sufficient to make a dent in combatting climate change. With growing demand of global power generation, coupled with the inexorable retirement of coal power, this GW/day pace just keeps up with status quo. However, the accelerated rate of 3 GW/day for renewables construction by 2030 is a good start at a meaningful solution. The faster, and earlier, fossil fuel power generation can be retired, the better for minimizing the rise in global warming.
By the Numbers
The global cumulative installed capacity of hydro, wind, solar, and other renewables was approximately 3 terawatts (TW) at the end of 2023. This figure represents 25% of the total global power generation capacity of just over 8 TW [2]. The consensus COP28 required level of renewables for 2030 is 11 TW, which may be a stretch. Depending on the scenario, the projected total capacity of renewable power generation will be approximately 8 to 10 TW, or approximately 75% of the total projected global power generation of 11 to 14 TW. This puts the world on the path to 100% renewables integration for power generation by 2050 and is consistent with the many projections from EIA, IEA, BP, DNV, IRENA, Shell, and others, which predict an 80-100% production of electricity by renewables globally by 2050. Figure 2 shows this projected growth.
source: Abbot
Figure2: Global Renewables Penetration by 2030
GW versus GWh and Capacity Factors
Power plants get paid for delivering megawatt-hours (MWh), which is a measure of energy, but are also judged by how reliably they deliver MW (power). The nameplate rating of some renewables power plants, such as solar, shouldn’t be thought the equivalent of a central power plant with the same nameplate rating, because solar, for example, has a lower capacity factor. However, many renewable technologies have excellent capacity factors. For example, floating offshore windfarms have demonstrated a greater than 60% capacity factor [3,4], which undercuts the argument against intermittency and non-dispatchability, and require little, if any, energy storage. Hydro, too, has excellent capacity factors. Land-based windfarms, with their 35–50% capacity factors, make use of a low degree of energy storage for grid stability (firming) and can use regional transmission to overcome intermittency. Solar farms, with capacity factors in the 17 to 25% range, have raised their effective capacity factors in combination with energy storage to become reliable grid generation assets.
Energy storage doesn’t need to be immediately co-located with renewables to provide grid value. In Hawaii, a recently commissioned 185 MW, 565 MWh energy storage project is used by the utility to balance the grid, provide fast frequency response, synthetic inertia, and black start [5]. The energy storage system also cuts curtailment of utility-scale solar and wind power by nearly 70 percent. Of the 10.8 GW of energy storage installed in the US by early 2023, approximately 5.2 GW is in California and 3.3 GW is in Texas [6]. US energy storage capacity is expected to reach 30 GW by the end of 2024 [7], which demonstrates extremely rapid adoption.
What About Nuclear?
Notwithstanding plans for expansion by China for new nuclear power construction, nuclear power is in decline for many reasons, principally economic. Stringent regulatory requirements are the primary reason driving high costs, and little can be done to mitigate that. These requirements make it difficult for new construction of nuclear power to scale to make a meaningful difference, which would require daily global construction of three conventional nuclear power plants, or 20-30 small modular reactors (SMRs). That’s over 1,000 conventional sites per year, or 7,000-10,000 SMR sites per year, along with the attendant processing and delivery of fuel stocks. The demise of the UAMPs SMR program and the delay of Alaska’s microreactor [8-10] are setbacks. Fusion, given the most optimistic projections, will not come on line soon enough to mitigate climate change. The International Energy Agency (IEA) predicts a potential growth of nuclear from its current 417 GW to 650 GW by 2050, but nothing close to the terawatt level. Nuclear is an important interim contributor to the replacement of fossil fuels for power generation, but not for the long-term.
Why is the Rapid Integration of Renewables Happening?
Today, wind and solar are the lowest cost sources of power generation, even considering the inclusion of energy storage costs to support the firming of large-scale solar farms. Moreover, these costs continue to decline.
Combined cycle natural gas power generation is next lowest in cost, but suffers from the pricing and supply variability of natural gas. This has been especially true in Europe since early 2022. Unlike renewables, construction costs are not declining. Globally, the majority of grid additions over the past few years have been renewables and natural gas.
In the short term, natural gas power generation construction will continue, but will phase out in the long term, as power purchase agreements (PPAs) and other market forces demonstrate that natural gas power generation contracts, already struggling to be competitive in many of today’s markets, won’t be widely competitive with renewables in almost all future markets.
Superior economics, dispatch flexibility, fast construction schedules, improved grid security, demonstrated grid reliability/resilience characteristics, and investor confidence are all factors that make renewables compelling. They are the reasons for the disruptive growth in market adoption. Energy projections have consistently underestimated renewables growth. This consistent underestimation, if it continues, and in concert with the rapid rise of other mitigation strategies (e.g., electrification, energy efficiency), provides a modest degree of optimism that keeping to the 1.5C global warming limit may still be possible.
The Effect of Politics and Policy
The rate of renewables growth faces political headwinds and tailwinds. Headwinds are in the form of established power generation sources (fossil fuels and utilities), who mount well-funded political and grassroot campaigns to undercut renewables permitting [11-13]. Tailwinds are in the form of local, state, and federal government activities to streamline permitting and provide investment tax credits.
Headwind efforts have stalled many major and minor renewables projects. Tailwind efforts have enabled many major and minor projects to proceed. The battle between these two powerful, largely political, forces is ongoing.
However, if renewables and energy storage weren’t compelling for the reasons listed above, especially the low-cost economics, no amount of policy assistance would propel the demonstrated trends in market adoption.
Yes, But the Grid Can’t Operate on Renewables, Can It?
Grid operators are required to maintain a delicate balance between power supply and load demand. This balance is controlled by the algorithms achieving dynamic stability of grid performance at a frequency of 60 Hz in the US and 50 Hz in other parts of the world. Historically, power inertia has been regulated with the large mass of spinning machines which regulate the grid frequency governed to regulate the frequency by spinning primarily at a defined target of 3600 rpm.
A grid with primary contributions from renewables requires “synthetic inertia” to replace this spinning mass. Synthetic inertia can be provided by regulated, solid state power electronics solutions. However, this transition to the build out of synthetic inertial will take time and represents significant investment. The grid can operate effectively using synthetic inertia, and eventually without base load spinning mass [14].
Controllers, using real-time data from phasor measurement units (PMU) and micro-PMUs, which electric grid operators have used for many years, send commands to Distributed Energy Resources (DERs) to provide grid control via frequency regulation. Data from PMUs and micro-PMUs result in synthetic inertia capabilities that provides improved frequency regulation with faster response, accuracy, and the capability to control multiple grid resources [15, 16].
Historically, the Federal Energy Regulatory Commission (FERC) and grid operators have been required to depend on sub-optimal use of natural gas peaker plants to assist with frequency regulation. However, these systems are limited by an inherent response time on the order of 15 minutes. In comparison, inverters, of both large and small capacities, have the capability to be dynamically dispatched and can provide nearly instantaneous set-point adjustments with confirmation provided to balancing authorities within 4-second response times.
Not only is this useful in controlling large grid assets, but it is also useful with a multitude of small Distributed Energy Resources (DER), in aggregation, with energy storage. One type of DER, electric vehicles (EVs), coupled with either off-board or onboard chargers can provide a large source of energy storage capacity. Intelligent operation of energy storage can be automated to monitor and respond dynamically to fluctuations in grid frequency and provide up/down frequency regulation via simple control methods, some of which are included in chargers and other inverter-based devices [17]. For EVs, this is accomplished by enabling the EV charger to recognize a grid frequency that is low (say 59.995 Hz). In this case, the grid has too much load and the charger can be configured to temporarily decrease or stop charging the EV. If the grid frequency is high (say 60.005 Hz), then the grid needs more load, so the charger can be turned on or its power draw to be temporarily increased until the frequency returns to the nominal target of 60 Hz again. One EV charger won’t make a difference, but thousands operated in aggregate will.
The Role of Energy Storage
Energy storage, whether large battery sites (MW+) associated with solar and wind generation, or the large number of EVs with available batteries (> 1M EVs in California alone), provide a large reservoir of power generation when the grid requires it. The 2022 Southern California grid event, and the 2023 Texas winter cold storm preparations, serve as examples for energy storage coming to the rescue of distressed grids and being the difference between supplying adequate capacity or experiencing disastrous brownouts. The 2022 Southern California event, in particular, when just over 2 GW of energy storage (equivalent to two nuclear power plants) supplied power to the grid [18-22], was a dramatic demonstration of the value of energy storage. It was even more remarkable given the large increase of energy storage capacity connected to the grid over just the previous two years. As the capacity of energy storage increases, the stability and resiliency of grids will increase, along with the penetration of renewables power generation.
Technical Challenges to Renewables Growth
Renewables face long interconnection waiting times in many markets. Widespread renewables integration will also need new transmission and distribution infrastructure. These physical and regulatory issues can be costly and time consuming to work through.
The Role of Distributed Energy Resources (DERs) and Microgrids
The renewables as DERs, is a much different paradigm from that of centralized power plants – coal, natural gas, and nuclear. DERs provide tremendous advantages in flexibility, resiliency, and reliability to a variety of stakeholders such as industrial and commercial facilities, cities, power producers, and grid planners and operators. DERs enable microgrids, with the two acting in concert to provide a powerful risk mitigation tool against the potential outage of a central power plant [23]. One example of a simple microgrid integrates renewables, energy storage, and EV fast charging to provide a workable solution where the local grid might be weak. This solution would also have the capability of providing grid services.
Power Security
DERs, especially powered by renewables, are a powerful hedge against security risks compared with those of a central power plant, both physical and cyber. Central power plants are attractive targets, as are the fuels that feed them. A cyber-attack that disrupts a nuclear power plant would have a much greater impact versus that which disrupts a bank of land-based wind turbines. Likewise, it would take effort to physically attack a single wind turbine, and the relative impact, if successful, would be low.
Wrapping it Up
- The fundamentals of renewable’s exponential growth are driven by compelling economics. Land-based wind and solar (even with energy storage) is now more cost effective than natural gas generation, which is cheaper than coal and nuclear.
- The short-term outlook to 2030 looks favorable to a 60-80% global penetration of renewables for power generation, which will be a major factor in minimizing the impact of global warming.
- Over the further 20 years to 2050, 100% renewables penetration for power generation looks feasible, cost-effective, and better performing relative to the grid than legacy power generation [24, 25].
- Energy storage, whether co-located with renewables or not, has proven to be a true grid-saver in its two largest US markets, California and Texas. The projected growth of energy storage is even faster than renewables.
- Renewables with energy storage obviate the need for base load power.
References
[1] International Energy Agency, Renewables 2023: Analysis and Forecast to 2028, www.iea.org, January 2024.
[2] IRENA, NDCs and renewable energy targets in 2023: Tripling renewable power by 2030, ISBN: 978-92-9260-570-4, International Renewable Energy Agency, Abu Dhabi, www.irena.org, 2023.
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[4] Equinor, Equinor marks 5 years of operations at world’s first floating wind farm, https://www.equinor.com/news/hywind-5-years-world-first-floating-wind-farm, 29 December 2022.
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[7] Energy Information Administration, US battery storage capacity expected to nearly double in 2024, https://www.eia.gov/todayinenergy/detail.php?id=61202, 9 January 2024.
[8] Pearl, L., NuScale, UAMPS terminates mall modular reactor project in Idaho, Utility Dive, https://www.utilitydive.com/news/nuscale-uamps-terminate-small-modular-nuclear-reactor-smr-project-idaho/699281/, 9 November 2023.
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[17] Brooks, A., Vehicle Charging as a Source of Grid Frequency Regulation, EVS27, Barcelona, Spain, https://www.mdpi.com/2032-6653/6/4/875, November 2013.
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[19] Ferry, M., Op-Ed: California’s giant new batteries kept the lights on during the heat wave, LA Times, https://www.latimes.com/opinion/story/2022-09-13/california-electric-grid-batteries-heat-wave-september-2022, 13 September 2022.
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Author
Charles Botsford, PE is a professional chemical engineer in the State of California with 40 years’ experience in EV charging infrastructure, energy storage, and environmental management. He participated in California’s Vehicle Grid Integration (VGI) Working Group and participates in the Society of Automotive Engineers (SAE) J3072 AC Vehicle-to-Grid, J3271 Megawatt Charger System, and J3400 NACS standards committees. Mr. Botsford holds a bachelor’s degree in chemical engineering from the University of New Mexico, and a master’s degree in chemical engineering from the University of Arizona.
