DOE/National Renewable Energy Laboratory. “India can integrate 175 GW of renewable energy into its electricity grid.” ScienceDaily. ScienceDaily, 25 July 2017. www.sciencedaily.com/releases/2017/07/170725122019.htm.
The U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) has confirmed the technical and economic viability of integrating 175 gigawatts (GW) of renewable energy into India’s grid by 2022.
Working with the Ministry of Power and USAID — with co-sponsorship from the World Bank (ESMAP) and the 21st Century Power Partnership — NREL; Power System Operation Corporation, Ltd. (POSOCO); and Lawrence Berkeley National Laboratory (LBNL) produced the study Greening the Grid: Pathways to Integrate 175 Gigawatts of Renewable Energy into India’s Electric Grid. The team used advanced weather and power system modeling to answer many questions about how India’s electricity grid can manage the variability and uncertainty of India’s ambitious 2022 renewable energy target of 175 GW of installed capacity, including 100 GW of solar and 60 GW of wind, up from 9 GW of solar and 29 GW wind installed today.
“With renewable energy auction prices at record lows, an immense amount of renewable energy growth is anticipated to be added to India’s power system,” said Principal Investigator Jaquelin Cochran, a manager in NREL’s Strategic Energy Analysis Center. “We wanted to provide a systematic way to plan for that. The results of our study can inform policy and regulatory decisions that support system flexibility and renewable energy investment in India.”
The results demonstrate that power system balancing, where supply of electricity meets the demand, with 100 GW solar and 60 GW wind is achievable with minimal renewable energy curtailment. Curtailment is the amount of renewable energy generated that cannot be used due to grid limitations. India’s current coal-dominated power system has the flexibility to accommodate the variability associated with the renewable energy targets. Low-renewable-energy, coal-dominant states can play an important role by implementing operational changes that would facilitate renewable energy integration nationwide.
The study used a detailed production cost model to identify how the Indian power system is balanced every 15 minutes, the same time frame used by grid operators. The results reveal operational impacts, such as:
- The 160 GW of solar and wind capacity can serve 22 percent of India’s power demand, providing benefits of fuel savings and reduced emissions.
- The power system as planned for 2022 is able to manage the added variability of wind and solar without new, fast-ramping infrastructure (such as natural gas turbines).
- In a system with 100 GW of solar and 60 GW of wind, coal plants, on average, operate at only half their capacity, suggesting the potential role for a new tariff structure that moves away from focusing on energy delivery and instead compensates plants for performance that achieves flexibility goals.
The study also evaluated strategies to better integrate renewable energy and demonstrated the importance of policy and market planning. The results of the study indicate that:
- National and regional coordination of scheduling and dispatch eases renewable energy integration and results in cost savings by smoothing variability and broadening the supply of system flexibility.
- Flexibility of India’s coal fleet is critical to minimizing curtailment of renewable energy.
The results were based on a number of key assumptions the model made about India’s power distribution system in 2022, including perfect transmission planning existing within each state, but not necessarily on corridors between states; compliance of all coal plants with the Central Electricity Regulatory Commission regulation that coal plants be able to operate at 55% of rated capacity; and perfect load forecasting, so that results would not conflate wind and solar power forecast errors with load forecast errors.
“The challenge is harnessing the existing physical flexibility of the power system through appropriate market designs, operational rules, incentive mechanisms, and other regulatory and policy changes,” said Sushil Kumar Soonee, coauthor of the report and former CEO of Power System Operation Corporation Limited (POSOCO). “Robust planning will be critical to achieving the renewable energy goals set by the Indian government. In parallel with institutional changes, what happens at the state level will require follow-up and investigation. Additional studies will be needed to evaluate transmission and operations planning and generator flexibility as India advances toward its goal over the next five years.”
Input data, assumptions, and study results were validated extensively by experts from across the Indian power system — through a multi-institutional modeling team and a broad stakeholder review committee. Technical stakeholder review and guidance were provided by more than 150 technical experts from central agencies; state institutions, including grid operators, power system planners, renewable energy nodal agencies and distribution utilities; and the private sector, including renewable energy developers, thermal plant operators, utilities, research institutions, market operators, and other industry representatives.
This is the first volume of a two-part report. The first volume, the National Study, explores high-level trends and considerations from a national perspective. The second volume, to be released later this month, takes a more in-depth look at system operations in the Western and Southern regions. For an overview of the National Study’s key findings, policy impacts, and potential actions, read the executive summary. For additional details, visit the website and download the full study. From Materials provided by DOE/National Renewable Energy Laboratory.
Expanding and linking grids would enable broader energy trading, allowing export of cheap solar and perhaps import of cheap wind renewables elsewhere. It should shave peaks, improve regional transmission planning, reduce duplicative reserves, and substantially lower the cost of wholesale power, with great benefits for ratepayers, jobs, and state economies. The regionalization of grids — eventually linking them nationally and even internationally — is the cheapest way to integrate more renewable energy. It has to be done eventually and arguably there is an arc toward cleaner energy and wider grids.
In addition to maintaining energy markets where energy is traded, some ISOs — PJM (in the mid-Atlantic), ISO-NE (in New England), and MISO (in the Midwest) — also maintain capacity markets. In these, power plants are paid to remain available as reserves. (They bid in, just as they bid into energy markets.) In contrast, California does not have and does not want a capacity market; instead, to maintain reserves, it requires each balancing authority to maintain a minimum reserve of its own.
Understanding curtailment and what to do about it (extend the grid) (2017) Curtailment happens infrequently in day-ahead markets because supply and demand are balanced in advance. More often, it occurs in the real-time market when high production from subsidized wind and solar push down power prices, forcing traditional generators to choose between the costs of turning off or paying customers to take their power.
Update the Grid
America’s grid carries electricity from over 7,700 power plants across 707,000 miles of high-voltage lines, and through millions of miles of low-voltage lines and transformers to millions of customers. It’s an impressive machine, but like other early 20th century technologies, it’s due for a reboot. Hundreds of billions of kilowatt-hours of electricity are being lost en route to our homes and businesses every year but fortunately, solutions are available. The U.S. grid loses about 5 percent of all the electricity generated through transmission and distribution—enough to power all seven Central American countries four times. Separately, grid congestion, like traffic congestion, leads to waste and costs consumers approximately $6 billion annually in higher energy bills. At the same time, many transmission lines are underused, even at peak hours. (Chen, July 2018)
However, there are ways to improve grid efficiency. Advanced transmission technologies can help optimize how electricity moves through the system, much like real-time navigation apps are helping drivers negotiate congested roads. Newer technologies can also reduce electricity lost during transmission, saving consumers money, cutting pollution by reducing the amount of electricity that needs to be generated, and helping more emissions-free energy into our grid.
Improve grid components and efficiencies
One problem is that utilities are continuing to build transmission with old-technology wires that dissipate away too much energy (which is lost as heat radiated into the air). There are modern wires available today that use carbon fiber cores and pack conducting metal more closely together, making them lighter, stronger and more efficient. In Texas, these new conductors, installed over 240 miles of transmission, have cut electricity losses by 40 percent and nearly doubled the carrying capacity of the transmission lines. While the modern wires cost more, the energy savings more than paid for them—consumers saved an estimated $30 million in the first year alone from lower line losses, and cut the same amount of carbon pollution emitted from the tailpipes of 34,000 cars annually.
Add advanced monitoring. Synchronized measurements of voltage, current, and frequency at selected locations can help improve grid reliability, reduce costs, facilitate renewables integration, and help with grid planning and investment decisions.
Advanced monitoring technologies, like synchrophasor technologies, provide real-time information across the grid. In Kansas, where about 36 percent of the state’s electricity comes from wind, grid operators are using dynamic line ratings (or limits) enabled by monitoring the lines’ ambient conditions to add line capacity. Cooler lines can safely carry more electricity, warmer lines less, but lacking real-time information, transmission lines are assigned a fixed limit on the amount of electricity they can carry. Remote monitoring can help integrate more wind energy into the grid because line limits can be increased to reflect the cooling effect of wind. In doing so, less wind energy would have to be dialed down (or curtailed) due to inadequate transmission.
Direct flow of electricity to better use grid capacity with new tech: Line switching can reduce curtailment by up to 40%
Technologies that direct electricity away from overloaded wires and onto underused ones can reduce congestion on the lines to get more capacity out of existing infrastructure, thus reducing renewable energy generation curtailments. Transmission topology optimization uses software and existing high-voltage circuit breakers to re-route power flow around congested or overloaded transmission elements. This “line switching” can reduce renewable energy curtailment by up to 40 percent. Similarly, power flow control technology (devices that redirect power from overloaded to underused lines) can help incorporate more renewable energy into the existing grid at a fraction of the cost of building new grid capacity.
Align incentives with improving efficiency and encouraging innovation
There are a number of things federal and state regulators, grid operators, utilities, and legislatures can do to encourage modernizing our grid—and reducing costs and pollution.
The Federal Energy Regulatory Commission (FERC) regulates how transmission utilities make money, which usually means that utilities recover from their customers a percentage of how much they’ve spent on capital investments like transmission buildout. (This is COSR – cost-of-service regulation.) Thus, the more utilities spend on qualifying investments, the more money they make. The Energy Policy Act of 2005 required FERC to establish incentives for certain qualifying transmission projects to encourage the deployment of advanced transmission technologies. While FERC created such incentives in Order 679 and initially approved dozens of applications, these incentives were largely focused on grid expansion and less on optimizing the existing grid. Although FERC has since taken a much more restrictive approach after revisiting the incentive issue, it has not established a mechanism appropriately encouraging the technologies discussed here. FERC should consider more refinements to ensure that proven, cost-effective means of improving the efficiency of existing infrastructure are appropriately rewarded.
In 2015 alone, the Department of Energy (DOE) energy efficiency standards, covering over 60 categories of products, reduced the national energy bill by about $80 billion. But distribution transformers are currently the only type of transmission technology covered by DOE’s appliance and equipment standards. Expanding the scope of DOE standards (which cover appliances like air conditioners and furnaces) may be one way to improve efficiency, but standards likely would have to account for regional differences in climate and natural disaster challenges, which affect the type of transmission technology best suited for a particular region. Standards would also have to consider how improving the efficiency of one component of the interconnected grid would improve the overall efficiency the system.
A system-wide standard that looks beyond individual parts of the transmission system could provide the appropriate incentive and flexibility for a transmission-owning utility to seek out its least efficient components and find the most cost-effective solutions to meet the standard. To limit air pollution, for example, the U.S. Environmental Protection Agency) sets emissions standards for power plants and vehicles instead of requiring specific emission-control technologies. This flexibility can encourage innovation as well as technology adoption.
Changing the Regulatory System
The current regulatory process should do more to encourage utilities to adopt modern and efficient transmission technologies. One solution is for FERC, which oversees the interstate movement of electricity, and state public utility commissions to consider the benefits to consumers that more efficient technologies could offer in transmission rate proceedings and siting approvals. Regulators could require utilities seeking to build new infrastructure to demonstrate that they’ve at least considered cost-effective and more efficient technologies. Another is to change the system to directly reward utilities for achieving pre-defined outcomes, such as efficiency or affordability, rather than allowing them to recover whatever costs they incur. Known as performance-based regulation, this kind of system has already been implemented in the UK well as several states, including New York as part of its Reforming the Energy Vision initiative.
The technologies exist to make our existing grid stronger, cleaner, and more efficient. With a regulatory structure that allows utilities and grid operators to embrace these improvements, modern transmission technologies can help bring more clean energy to more people, reliably and cost-effectively, today.
In August 2018 Advanced Energy Economy (AEE) and Citizens for Responsible Energy Solutions Forum (CRES Forum) released a policy paper outlining recommendations in moving toward a more clean, secure, and affordable grid:
- Streamline Federal Permitting for Advanced Energy Projects
- Encourage Grid Planners to Consider Alternatives to Transmission Investment
- Allow Energy Storage and Energy Efficiency to Compete with Additional Generation
- Allow Large Customers to Choose their Electricity Sources
- Allow Utilities and Consumers to Benefit from Cloud Computing Software