Utility To Replace N-Gas Peaker Plants With Energy Storage

Duane M. Tilden, P.Eng                          November 10, 2018

The main caveat of Energy Efficiency is to do more with less. Energy Efficiency is low-lying fruit, easy to harvest. For utilities and the grid there are many advancements coming that will allow us to enable a more resilient and sustainable electrical transmission system connecting providers, consumers, and prosumers.

Electricity Prosumers & Renewable Energy

“Active energy consumers, often called ‘prosumers’ because they both consume and produce electricity, could dramatically change the electricity system. Various types of prosumers exist: residential prosumers who produce electricity at home – mainly through solar photovoltaic panels on their rooftops, citizen-led energy cooperatives or housing associations, commercial prosumers whose main business activity is not electricity production, and public institutions like schools or hospitals. The rise in the number of prosumers has been facilitated by the fall in the cost of renewable energy technologies, especially solar panels, which in some Member States produce electricity at a cost that is the same or lower than retail prices.” (1)

What is a Peaker Plant?

Peaking power plants, also known as peaker plants, and occasionally just “peakers”, are power plants that generally run only when there is a high demand, known as peak demand, for electricity.[1][2] Because they supply power only occasionally, the power supplied commands a much higher price per kilowatt hour than base load power. Peak load power plants are dispatched in combination with base load power plants, which supply a dependable and consistent amount of electricity, to meet the minimum demand.” (2)

As more renewable energy projects are added to provided base load power, in an absence of electricity when renewable sources of electricity are inactive a greater reliance is put on peaker plants to make up energy shortfall . However, as improvements in energy storage solutions gain traction through capacity and competitive costing it is now possible to replace fossil fuel powered peaker plants with energy storage.

Public Utilities Commission of the State of California (CPUC)

In a recent decision the State of California has proceeded with plans to develop and procure electrical storage solutions for the Public Utility as an alternative to aging natural gas peaker plants. A net reduction in carbon emissions by eliminating fossil fuel consumption.

Energy Storage California 2018

Table 1 – Summary of Pacific Gas and Electric’s (PG&E’s) energy storage power purchase
agreements (PPAs)

“Approval of PG&E’s landmark energy storage solicitation is the most significant example to date of batteries taking the place of fossil fuel generation on the power grid.

Energy storage has helped decrease the California’s reliance on gas for years, particularly since 2016, when regulators ordered accelerated battery procurements to counteract the closure of a natural gas storage facility outside Los Angeles.

The PG&E projects, however, are the first time a utility and its regulators have sought to directly replace multiple major power plants with battery storage.

The projects would take the place of three plants owned by generator Calpine — the 580 MW Metcalf plant and the Feather River and Yuba City generators, both 48 MW.

​Calpine and the California ISO last year asked the Federal Energy Regulatory Commission to approve reliability-must-run (RMR) contracts for the plants, arguing they are essential to maintain power reliability. The one-year contracts would see California ratepayers finance the continued operation of the generators, which are losing money in the ISO’s wholesale market.

FERC approved the request in April, but California regulators were already planning for when the plants retire. In January, they ordered PG&E to seek alternatives to the generators, writing that the lack of competition in RMR contracts could mean higher prices for customers. ” (4)

 

References:

  1. European Parliament Think Tank – Electricity Prosumers
  2. Peaking_power_plant
  3. Resolution E-4949. Pacific Gas and Electric request approval of four energy storage facilities with the following counterparties: mNOC, Dynegy, Hummingbird Energy Storage, LLC, and Tesla.
  4. Storage to replace California Peaker Plants
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Supercritical Carbon Dioxide – A Plan to Eliminate 25% of Existing Power Plants

Duane M. Tilden, P.Eng                           October 26, 2018

Is it possible that we can drastically reduce the existing fleet of power plants by 25% or more? Yes, this does seem to be a rather extravagant claim considering how many power providers or utilities such an increase in energy efficiency in output will impact.  Examining the United States as our example:

As of December 31, 2017, there were about 8,652 power plants in the United States that have operational generators with a combined nameplate electricity generation capacity of at least 1 megawatt (MW). A power plant may have one or more generators, and some generators may use more than one type of fuel. (1)

So, reducing the existing fleet by 25% would enable us to decommission approximately 2,163 of these plants.  This plan would require the examination of the total supply chain to optimize these reductions whilst maintaining the integrity of the existing distribution network. A significant project having enormous impact on the economy and meeting carbon reduction strategies on a global scale.

Supercritical Carbon Dioxide (SCCD) Turbines

In previous posts I have discussed the technology of SCCD turbines for power production and how this system can be used for a wide variety of power production and energy extraction methods. A recent article published by Euan Mearns with commentary delves even deeper into this technology to discuss the global impacts of increased power production efficiency on reducing carbon emissions.

GHG’s, carbon, NOx, pollution, waste heat, entropy effects, and consumption of resources are all commensurately reduced when we systematically increase power production energy efficiency at the plant level. An improvement of energy efficiency at the system level has a profound impact in output capacity or input reduction. For example, if we can increase the efficiency by 10% from 30% to 40% in conversion, the output of the plant is improved by 4/3 or 33% or inversely, the input requirement will reduce by 3/4 or 25%.

Power Plant Energy Efficiency

To measure the energy efficiency of a thermo-electric power plant we use the heat rate. Depending on the quality of the fuel and the systems installed we convert heat energy into electrical energy using steam generators or boilers. We convert water into steam to drive turbines which are coupled to generators which convert mechanical motion into electricity.

Examination of data provided will be simplified using statistical averages. In 2017 the average heat rates and conversion efficiencies for thermal-electric power plants in the US (2) are given as follows:

  • Coal: 10465 Btu/Kw – 32.6%
  • Petroleum: 10834 Btu/Kw – 31.5%
  • Natural Gas: 7812 Btu/Kw – 43.7%
  • Nuclear: 10459 Btu/Kw – 32.6%

Examination of the US EIA data for 2017 shows us that currently Natural gas is 11.1% more efficient than Coal in producing electricity while consuming 25.4% less fuel for the same energy output.

So we already have proof that at a plant level, energy efficiency gains in consumption are leveraged by smaller improvements in the thermodynamic cycle. For natural gas power plants the current state of the art is to use a combined cycle combustion process which is not employed in other thermo-electric power plants.

HOW A COMBINED-CYCLE POWER PLANT PRODUCES ELECTRICITY (3)

This is how a combined-cycle plant works to produce electricity and captures waste heat from the gas turbine to increase efficiency and electrical output.

  1. Gas turbine burns fuel.

    • The gas turbine compresses air and mixes it with fuel that is heated to a very high temperature. The hot air-fuel mixture moves through the gas turbine blades, making them spin.
    • The fast-spinning turbine drives a generator that converts a portion of the spinning energy into electricity.
  2. Heat recovery system captures exhaust.

    • A Heat Recovery Steam Generator (HRSG) captures exhaust heat from the gas turbine that would otherwise escape through the exhaust stack.
    • The HRSG creates steam from the gas turbine exhaust heat and delivers it to the steam turbine.
  3. Steam turbine delivers additional electricity.

    • The steam turbine sends its energy to the generator drive shaft, where it is converted into additional electricity.

Image result for combined cycle power plant

Figure 1. Schematic of Combined Cycle Gas/Steam Turbine Power Plant with Heat Recovery (4)

Comparing Combined Cycle Gas Turbines with SCCD Turbines

The study of thermodynamic cycles is generally a domain studied and designed by engineers and physicists who employ advanced math and physics skills. The turbine is based on the Brayton cycle, while steam turbines operate on the Rankine cycle. The Rankine cycle uses a working fluid such as water, which undergoes a phase change from water to steam. The Brayton cycle is based on a single phase working fluid, in this case combusted natural gas.

Both SCCD turbines and Gas Turbines operate on the Brayton cycle, however, they use different working fluids and requirements based on operating conditions. The gas fired turbine takes in air which is compressed by the inlet section of the turbine and natural gas is combined with the compressed air and ignited. The hot expanding gasses turn the turbine converting heat to mechanical energy. A jet engine operates on the Brayton cycle.

For a combined cycle gas turbine some of the waste heat is recovered by a heat exchange system in the flue stack, converted to steam to drive  a second turbine to produce more electricity and increase the overall energy efficiency of the system.

In the case of an SCCD the turbines working fluid is maintained in a closed loop, continually being heated through a heat exchanger from a source and run in piping through the turbine and a compressor. Secondary heat exchangers for recuperation and cooling may be employed. These are all emerging technologies undergoing serious R&D by the US DOE in partnership with industry and others.

Closed Loop SCO2 Recompression Brayton Cycle Flow Diagram

Figure 2. Closed Loop SCO2 Recompression Brayton Cycle Flow Diagram (NETL)

 

Technology Development for Supercritical Carbon Dioxide (SCO2) Based Power Cycles

The Advanced Turbines Program at NETL will conduct R&D for directly and indirectly heated supercritical carbon dioxide (CO2) based power cycles for fossil fuel applications. The focus will be on components for indirectly heated fossil fuel power cycles with turbine inlet temperature in the range of 1300 – 1400 ºF (700 – 760 ºC) and oxy-fuel combustion for directly heated supercritical CO2 based power cycles.

The supercritical carbon dioxide power cycle operates in a manner similar to other turbine cycles, but it uses CO2 as the working fluid in the turbomachinery. The cycle is operated above the critical point of CO2so that it does not change phases (from liquid to gas), but rather undergoes drastic density changes over small ranges of temperature and pressure. This allows a large amount of energy to be extracted at high temperature from equipment that is relatively small in size. SCO2 turbines will have a nominal gas path diameter an order of magnitude smaller than utility scale combustion turbines or steam turbines.

The cycle envisioned for the first fossil-based indirectly heated application is a non-condensing closed-loop Brayton cycle with heat addition and rejection on either side of the expander, like that in Figure 1. In this cycle, the CO2 is heated indirectly from a heat source through a heat exchanger, not unlike the way steam would be heated in a conventional boiler. Energy is extracted from the CO2 as it is expanded in the turbine. Remaining heat is extracted in one or more highly efficient heat recuperators to preheat the CO2 going back to the main heat source. These recuperators help increase the overall efficiency of the cycle by limiting heat rejection from the cycle. (4)

Commentary and Conclusion

We already are on the way to developing new systems that offer significant improvements to existing. Advancements in materials and technology, as well as other drivers including climate concerns and democratizing the energy supply. Every percentage of increase in performance reduces the consumption of fossil fuels, depletion of natural resources, generated waste products and potential impacts on climate.

SCCD systems offer a retrofit solution into existing power plants where these systems can be installed to replace existing steam turbines to reach energy efficiency levels of Combined Cycle Gas Turbines. This is a remarkable development in technology which can be enabled globally, in a very short time frame.

References:

  1. USEIA: How many power plants are there in the United States?
  2. USEIA: Average Operating Heat Rate for Selected Energy Sources
  3. GE: combined-cycle-power-plant-how-it-works
  4. https://www.netl.doe.gov/research/coal/energy-systems/turbines/supercritical-co2-turbomachinery

 

Hybrid Electric Bus uses Hydrogen as Fuel

“[…] According to Paulo Emilio, this is the most efficient hydrogen bus in the world. “A European company tested a hydrogen bus in ten cities, which consumed 25 kilos of hydrogen for each 100 kilometers; this month, the same company launched an improved version, with 14 kilos of hydrogen consumed for each 100 kilometers” where as “our bus consumes just 5 kilos of hydrogen”, he says. […]”

via Literally, a green bus

Shipping’s Growing Carbon Gap

Transport's Carbon & Energy Future

sinking_container_ship

On the face of it, Shipping is the most efficient of freight transport modes. Intermodal shipping containers kick-started rapid growth in trade globalisation 60 years ago, and container ships, tankers and bulk carriers have been getting bigger ever since. Carrying more freight with less fuel on a tonne-mile basis, shipping has the highest energy productivity of all transport modes.

Yet looks can be deceiving. While international shipping contributes 2.4% of global greenhouse gas emissions, business-as-usual could see this explode to a whopping 18% by 2050. As trade growth increases demand, today’s fleet burns the dirtiest transport fuels, and a new report shows the market doesn’t reward ship owners who invest in the latest fuel- and carbon-efficient technologies.

When you consider the scale of the sector’s emission reductions that need to start now to contribute to the COP 21 Paris Agreement target of 1.5°C to 2°C global warming, there’s clearly an…

View original post 604 more words

The “fuel” that’s helping America fight climate change isn’t natural gas

Power for the People VA

You’ve heard the good news on climate: after a century or more of continuous rise, U.S. CO2 emissions have finally begun to decline, due largely to changes in the energy sector. According to the Energy Information Agency (EIA), energy-related CO2 emissions in 2015 were 12% below their 2005 levels. The EIA says this is “because of the decreased use of coal and the increased use of natural gas for electricity generation.”

Is the EIA right in making natural gas the hero of the CO2 story? Hardly. Sure, coal-to-gas switching is real. But take a look at this graph showing the contributors to declining carbon emissions. Natural gas displacement of coal accounts for only about a third of the decrease in CO2 emissions.

Courtesy of the Sierra Club Beyond Coal Campaign, using data from the Energy Information Agency. Courtesy of the Sierra Club Beyond Coal Campaign, using data from the Energy Information Agency.

By far the biggest driver of the declining emissions is energy efficiency. Americans…

View original post 746 more words

Is Utility-Scale Solar Power the Economic Choice to Residential Solar Power?

Originally published on Solar Love. A new study has concluded that utility-scale solar PV systems across the US are “significantly” more cost effective than rooftop solar PV systems. Sp…

Sourced through Scoop.it from: cleantechnica.com

“[…] the study, conducted by economists at global consulting firm The Brattle Group, found that utility-scale solar PV systems were more cost effective at achieving the economic and policy benefits of PV solar than rooftop or residential-scale solar was.

The study, Comparative Generation Costs of Utility-Scale and Residential-Scale PV in Xcel Energy Colorado’s Service Area, published Monday, is the first of its kind to study a “solar on solar” comparison.

“Over the last decade, solar energy costs for both rooftop and bulk-power applications have come down dramatically,” said Dr. Peter Fox-Penner, Brattle principal and co-author of the study. “But utility-scale solar will remain substantially less expensive per kWh generated than rooftop PV. In addition, utility-scale PV allows everyone access to solar power. From the standpoint of cost, equity, and environmental benefits, large-scale solar is a crucial resource.”

The study yielded two key findings:

  1. The generation cost of energy from 300 MW of utility-scale PV solar is roughly 50% the cost per kWh of the output from an equivalent 300 MW of 5kW residential-scale systems when deployed on the Xcel Energy Colorado system, and utility-scale solar remains more cost effective in all scenarios considered in the study.
  2. In that same setting, 300 MW of PV solar deployed in a utility-scale configuration also avoids approximately 50% more carbon emissions than an equivalent amount of residential-scale PV solar. […]

The report itself was commissioned by American thin-film photovoltaic manufacturer and utility scale developer First Solar with support from Edison Electric Institute, while Xcel Energy Colorado provided data and technical support. Specifically, the report examined the comparative customer-paid costs of generating power from equal amounts of utility-scale and residential/rooftop-scale solar PV panels in the Xcel Energy Colorado system.

A reference case and five separate scenarios with varying degrees of investment tax credit, PV cost, inflation, and financing parameters were used to yield the report’s results.

The specifics of the study’s findings, which imagined a 2019 Xcel Energy Colorado system, are as follows:

  • utility-scale PV power costs ranged from $66/MWh to $117/MWh (6.6¢/kWh to 11.7¢/kWh) across the five scenarios
  • residential-scale PV power costs were well up, ranging from $123/MWh to $193/MWh (12.3¢/kWh to 19.3¢/kWh) for a typical residential-scale system owned by the customer
  • the costs for leased residential-scale systems were even larger and between $140/MWh and $237/MWh (14.0¢/kWh to 23.7¢/kWh)
  • the generation cost difference between the utility- and residential-scale systems owned by the customer ranged from 6.7¢/kWh to 9.2¢/kWh solar across the scenarios

The authors of the report put these figures into perspective, including the national average for retail all-in residential electric rates in 2014, which were 12.5¢/kWh.  […]”

See on Scoop.itGreen Energy Technologies & Development

Top Ten Most Viewed Articles of 2015

Water Vortex

Photo:  Top Viewed Article of the year on Water Vortex Hydro-Electric Power Plant Designs

This is going to be a fun post to write, as I get to review the statistics for 2015 and pick out the ten most viewed posts on my blog for the year.  I am looking forward to performing this review, as I get to find out what works and what does not.  The idea being to give me a chance to refine my techniques and improve my blog posts.

I am listing them in reverse order as we want to heighten the suspense, leading up to the most viewed article.  Each post will also have the posting date and number of views for comparison.  I know this technique is not perfect as some posts will have a longer opportunity to be seen than those written later in the year.  Such discrepancies will be left to discussed in a future article.

10.  Climate Change, Pole Shift & Solar Weather

Magnetic pole shift

This post discusses Earth’s wandering magnetic poles, the fluctuating field strengths and links to solar weather and climate change.  Some rather eccentric, yet plausible explanations based on historical data that pole shifts are possible and have happened, at unpredictable, largely spaced intervals of hundreds of thousands to millions of years, the average being 450,000 years.

Posted on March 3, 2015 and received 44 views.

9.  Leaked HSBC Files from Swiss Bank lead to Tax Evasion and Money Laundering charges

HSBC Scandal

Headline tells it all.  Large bank caught helping clients evade taxes and launder illegally obtained money through bank accounts.

Posted on February 9, 2015 and received 48 views.

8.  Michigan’s Consumers Energy to retire 9 coal plants by 2016

Michigan Coal Plant

Coal is unclean to burn and becoming costly to do operate due to emissions, resulting in coal fired plant closures, 9 by one Michigan utility.

Posted on February 10, 2015 and received 50 views.

7.  Life-Cycle Cost Analysis (LCCA) | Whole Building Design Guide

lcca_2

This article simply reprises, in part, the LCCA (Life-Cycle Cost Analyisis) procedure used for buildings as originally posted by WBDG.

Posted on February 15, 2015 and received 57 views.

6.  Energy Efficiency Development and Adoption in the United States for 2015

energy efficiency adoption

The article discusses the role of large scale energy efficiency programs as an investment and means to achieve certain goals when viewed as the “cheapest” fuel.  The graphic depicts a hierarchy of waste minimization correlating to cost and energy usage and effects with the environmental resources.

Posted on January 8, 2015 and received 59 views.

5.  Renewable Energy Provides Half of New US Generating Capacity in 2014

Renewable Energy

According to the latest “Energy Infrastructure Update” report from the Federal Energy Regulatory Commission’s (FERC) Office of Energy Projects, renewable energy sources (i.e., biomass, geothermal, hydroelectric, solar, wind) provided nearly half (49.81 percent – 7,663 MW) of new electrical generation brought into service during 2014 while natural gas accounted for 48.65 percent (7,485 MW).

Posted on February 4, 2015 and received 62 views.

4.  Cover-up: Fukushima Nuclear Meltdown a Time Bomb Which Cannot be Defused

260px-Fukushima_I_by_Digital_Globe

Tens of thousands of Fukushima residents remain in temporary housing more than four years after the horrific disaster of March 2011. Some areas on the outskirts of Fukushima have officially reopened to former residents, but many of those former residents are reluctant to return home because of widespread distrust of government claims that it is okay and safe.

Posted on July 22, 2015 and received 65 views.

3.  Apple to Invest $2 Billion in Solar Farm Powered Data Center Renovation in Arizona

Apple

The company plans to employ 150 full-time Apple staff at the Mesa, Arizona, facility… In addition to the investment for the data center,  Apple plans to build a solar farm capable of producing 70-megawatts of energy to power the facility.  […] Apple said it expects to start construction in 2016 after GT Advanced Technologies Inc., the company’s sapphire manufacturing partner, clears out of the 1.3 million square foot site.

Posted on February 11, 2015 and received 73 views.

2.  Determining the True Cost (LCOE) of Battery Energy Storage

Energy Storage

With regard to [battery] energy storage systems, many people erroneously think that the only cost they should consider is the initial – that is, the cost of generating electricity per kilowatt-hour. However, they are not aware of another very important factor.  This is the so-called LCOE,  levelized cost of energy (also known as cost of electricity by source), which helps calculate the price of the electricity generated by a specific source.

Posted on January 27, 2015 and received 109 views.

1. Water Vortex Hydro-Electric Power Plant Designs

Water Vortex

Austrian engineer Franz Zotlöterer has constructed a low-head power plant that makes use of the kinetic energy inherent in an artificially induced vortex. The water’s vortex energy is collected by a slow moving, large-surface water wheel, making the power station transparent to fish – there are no large pressure differences built up, as happens in normal turbines.

Posted on June 11, 2015 and received 109 views.

 

Armored Trucks get Natural Gas & Electric Plug-in Hybrid Conversion to Reduce Emissions by 99.9% & Big Fuel Economy

Efficient Drivetrains and American Repower are partnering to convert a fleet of six armored vans to run on compressed natural gas with a plug-in hybrid.

Sourced through Scoop.it from: www.autoblog.com

>”When hauling around massive amounts of money and valuables around Southern California, security is generally a much bigger concern than fuel economy. However, the need for vehicles to become more efficient is hitting every segment, even armored vans. That’s why Efficient Drivetrains Inc. and North American Repower are teaming up to convert six of these 26,000-pound behemoths run on natural gaswith a plug-in hybrid offering additional help. The first one should be hauling riches for Sectran Security around Los Angeles in 2016.

All three companies are already positioning the upcoming conversion as a win-win solution to current issues. The armored vehicles can still do their job of hauling money around the LA area but with a claimed 99.9 percent reduction in emissions from the current diesel engines. Generally, the vans make frequent stops while at work but must stay running for security reasons. This can potentially run afoul of California’s rule not to let diesels idle more than five minutes. With this upcoming version, drivers will be able to go electrically between stops and then will use the natural gas when cruising.

This work combines the strengths of both firms working on these vehicles. North American Repower already specializes in natural gas engine management and conversions, and Efficient Drivetrains is very familiar with the world of plug-ins. The funding for the project includes a $3-million grant from the California Energy Commission, plus the same amount in private funds.”<

[…]

>”Press Release:

North American Repower and Efficient Drivetrains, Inc. to Deliver First PHEV-RNG Armored Truck
Collaboration reduces emissions by 99.9 percent

OCEANSIDE, Calif. & MILPITAS, Calif.–(BUSINESS WIRE)–Two global leaders in developing and manufacturing advanced transportation vehicles have teamed up to manufacture a first-of-its-kind fleet of Class-5 armored vehicles that combine the benefits of Renewable Natural Gas (RNG) and zero emission Plug-In Hybrid Electric Vehicle (PHEV) technology.

“We’re excited to be partnering with EDI on this breakthrough innovation”

North American Repower—California’s leading natural gas engine management and conversion technology company— and Efficient Drivetrains, Inc.—a global leader in developing high-efficiency Plug-in Hybrid Electric Vehicle solution—will convert a fleet of six 26,000 pound, Class-5 medium-duty armored vehicles operated by Sectran Security into PHEV vehicles that run on electricity and renewable natural gas—known as “Zero Emission with Range Extension” vehicles. The collaboration supports the dramatic acceleration in California toward a zero emissions environment. Today, the Sectran Security trucks make frequent stops as part of their highly congested urban routes. At each stop, the engines are kept idling for security purposes, but now risk violating California’s strict diesel idling regulations, which prohibit idling the engine for more than five minutes. With the modernized trucks, Sectran can completely eliminate engine idling by operating in all-electric mode during stop-and-go operations on urban routes and in hybrid-mode during highway operations. When complete, the vehicles possess impressive performance statistics—the demonstration trucks will enable Sectran to reduce annual diesel consumption by 31,000+ gallons, significantly reduce annual fuel costs, and reduce emissions by 99.9 percent. […]”<

See on Scoop.itGreen Energy Technologies & Development