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Grid reliability and grid-edge resources

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A new study by MIT researchers looked at the potential for grid-edge resources to enhance the ability of the electric grid to respond to unforeseen power outages.  Grid-edge resources are devices found close to consumers rather than located near central power plants, substations, or transmission lines.  These include residential solar panels, storage batteries, electric vehicles, heat pumps, smart thermostats and smart water heaters.

These grid-edge devices can independently generate, store, or tune their consumption of power and increasingly, they are online internet-of-things devices.  The MIT study outlined a blueprint for how such devices could reinforce the power grid through a local electricity market.  Owners of grid-edge devices could subscribe to such a market and essentially loan out their device as part of a microgrid or local network as on-call energy resources.

Electric vehicles could provide power rather than consuming it when necessary.  Storage batteries could do the same.  Devices like smart dishwashers and thermostats would reduce their power demands when necessary.

In the event that the main power grid is compromised, an algorithm would determine which grid-edge devices were available and trustworthy and would either use them to pump power into the grid or reduce the power they are drawing from it in order to help mitigate the power failure. 

The MIT researchers illustrated this grid resilience strategy through a number of grid attack scenarios including failures from cyber-attacks and natural disasters.   Their analysis showed that various networks of grid-edge devices are capable of defeating various types of grid failures.

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Rooftop panels, EV chargers, and smart thermostats could chip in to boost power grid resilience

Photo, posted October 10, 2019, courtesy of Noya Fields via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Vertical-axis wind turbines

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Nearly all wind turbines in use today are horizonal axis wind turbines.  They are a familiar sight with their three giant rotor blades spinning about an axis high above the ground attached to a nacelle containing the gearbox and generator. 

A vertical-axis wind turbine has its rotor shaft transverse to the wind; that is, the shaft rises up from the ground and the gearbox and generator are located close to the ground.

This type of wind turbine does not need to be pointed into the wind, which eliminates the need for wind-sensing and orienting mechanisms.  It is also considerably quieter in operation than horizontal axis wind turbines.  Vertical-axis wind turbines have enjoyed minimal success to date because of a variety of problems including reliability issues and complications related to how they respond to changing wind conditions.

A next-generation vertical wind turbine is going on trial in Australia as part of a research collaboration between Flinders University in South Australia and the start-up company VAWT-X Energy.  The 6KW prototype will be installed at a field site in Australia’s Fleurieu Peninsula.

According to the developers, the new turbine design will be as efficient, or even more efficient, as existing horizontal turbines and will be able to thrive across diverse environments including being part of urban infrastructure where their relative quiet is a real advantage.   Such turbines would be more accessible for applications like off-grid power and sustainable energy solutions for small businesses and farms.  The developers claim the technology can also be scaled up for large-scale windfarms.

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Progress with new-look wind turbine

Photo courtesy of VAWT-X Energy.

Earth Wise is a production of WAMC Northeast Public Radio

Battery life in electric cars

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Most of us have lots of experience with the batteries in phones, computers, and other gadgets.  Batteries don’t last forever, and we sometimes have to replace them.  It’s a fact of life.   These days, it’s becoming more common to drive electric cars and the fundamental principle is the same.  However, the battery pack in an EV is the most expensive part of the car, so its reliability and lifespan is a greater concern.

EV batteries generally have generous warranties.  In the US, EV batteries are required by federal law to be covered for at least 8 years or 100,000 miles, whichever comes first.  So, the financial exposure from the battery pack is reasonably limited.  Even so, EV owners would like to know that their car’s battery pack is likely to last a long time.

Battery life is generally determined by laboratory tests involving repeated charge-discharge cycles over a relatively short period of time, as opposed to those cycles being spaced out over years.

A new study by Stanford University looked at battery performance under conditions much more like what would be experienced in the real world.  Cars experience frequent acceleration, braking that charges the batteries a bit, lots of stops, periods of rest, and so forth.  Nothing like just charging and discharging repeatedly.

The study found that today’s EV batteries may last up to 40% longer than expected.  Real-world stop-and-go driving benefits batteries more than standard test conditions.

The cost of EV batteries continues to get lower all the time and it is likely to be quite a long time before one is likely to need a new battery assuming one even keeps the car long enough.

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Existing EV batteries may last up to 40% longer than expected

Photo, posted August 27, 2021, courtesy of Ron Frazier via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Much more energy storage for New York

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As solar and wind power play an ever-growing role in the electricity grid, the need for energy storage also grows.  Even if sun and wind can provide more energy than is needed at a particular time, they can’t provide it at all times.  The ability to store excess energy waiting in reserve for when the sun and wind are not providing it is essential to avoid the need for burning fossil fuels to take up the slack.

The New York State Public Service Commission has announced that it has approved a new framework for the state to have in place a nation-leading six gigawatts of energy storage by 2030.  This represents at least 20% of the peak electricity load of New York State.

An extensive set of recommendations to expand New York’s energy storage programs describe cost-effective ways to unlock the rapid growth of renewable energy across the state as well as to bolster the reliability of the grid.  The buildout of storage deployment is estimated to reduce projected future statewide electric system costs by nearly $2 billion.  New York has previously established goals to generate 70% of its electricity from renewable sources by 2030 and 100% zero-emission electricity by 2040.

The new roadmap includes programs to procure an additional 4.7 gigawatts of new energy storage projects across large-scale, retail, and residential energy storage sectors across the state.  These future procurements, when combined with the 1.3 gigawatts already being procured or under contract, will allow the State to achieve the 6-gigawatt goal by 2030.

Energy storage plays a critical role in decarbonizing the grid, reducing electricity system costs, and improving the reliability of the electricity system.

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New York approves plan to add six gigawatts of energy storage by 2030

Photo courtesy of NineDot Energy.

Earth Wise is a production of WAMC Northeast Public Radio

Groundwater and climate change

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Groundwater is the vast reserve of water beneath Earth’s surface.  It’s an essential resource for humans, plants, animals, and other living organisms.  According to the United States Geological Survey, about 30% of all readily available freshwater in the world is groundwater.  In areas lacking sufficient surface water supply from rivers and reservoirs,  groundwater is critical for meeting the region’s drinking water and food production needs.

But climate change, as well as global population growth, is stressing groundwater resources.  As precipitation becomes less reliable due to climate change, surface water bodies can drop too low to provide the needed water.  As a result, people turn to groundwater. Depletion of groundwater is already a significant problem, and over-pumping will only increase further as climate change makes traditional sources of water less reliable.

According to a new study led by researchers from the University of Michigan, farmers in India have adapted to warming temperatures by intensifying the withdrawal of groundwater used for irrigation.  The study, which was published in the journal Science Advances, found that the rate of groundwater loss could triple by 2080 if this trend continues, further threatening India’s food and water security. 

India is the second-largest global producer of common cereal grains such as rice and wheat, and recently passed China as the world’s most populous nation. Without interventions to conserve groundwater, the research team finds that warming temperatures will likely amplify India’s groundwater depletion problem, further threatening the country’s food and water security.  

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Groundwater depletion rates in India could triple in coming decades as climate warms, study shows

Where is Earth’s Water?

Photo, posted August 2, 2013, courtesy of Rajarshi MITRA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Cleaning the grid can create messes

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The electric grid is increasingly embracing renewable energy sources like solar and wind power as well as the energy storage systems that support them.  These generation sources differ from traditional sources in that they produce direct current electricity rather than alternating current electricity.  Our power grid runs on alternating current.  Traditional generators produce alternating current that synchronizes with the grid.  Wind and solar power connect to the grid using electronic power converters called inverters that produce the required alternating current. 

All of this technical detail is something we don’t pay much attention to, except that the current state of inverter technology can lead to some problems that don’t exist with a fully synchronous power system. 

The electric grid frequently experiences disruptive events like trees falling on powerlines, squirrels shorting out substation equipment, and so on.  These things normally don’t cause widespread trouble, although there have been notable exceptions such as the massive Northeast blackout of 2003 triggered by an overloaded transmission line drooping onto foliage.

The issue with inverters is that they can shut down in the presence of certain disturbances to the grid.  This has happened on a number of occasions and has exposed vulnerabilities that need to be addressed by the industry.  Inverter-based resources currently constitute only a relatively small fraction of the grid, but that fraction is growing steadily and can have an increasingly widespread impact.  The grid was built predominantly for synchronous generation, and it must be adapted and improved to assure the reliability that is required and expected.  It is an issue that can’t be ignored.

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Renewables are cleaning the grid. They’re also messing it up

Photo, posted July 5, 2017, courtesy of Sue Thompson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Upgrading The U.S. Power Grid | Earth Wise

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The Department of Energy has launched the Building a Better Grid Initiative to accelerate the development of new power transmission lines.  The initiative aims to upgrade the nation’s grid, connect more Americans to clean electricity, and reliably move clean electricity to where it is needed most. The initiative is a part of the Bipartisan Infrastructure bill that was signed into law in November.

Under the initiative, DOE will identify critical national transmission needs and support the buildout of long-distance, high-voltage transmission facilities as well as support transmission planning, financing mechanisms, transmission-related research and development, and efforts on energy justice.

DOE will deploy more than $20 billion in federal financing that includes more than $10 billion in grants to states, Tribes, and utilities to enhance grid resilience and prevent power outages.  It will also coordinate with other agencies to streamline permitting for transmission infrastructure. 

Seventy percent of the US grid’s transmission lines and power transformers are over 25 years old.  There is also insufficient transmission capacity, especially for transmission that facilitates transfer of power across regions.  The current grid is vulnerable to harsh weather and needs improved reliability.

Providing more transmission capacity in areas where it doesn’t exist today is essential for the integration of more large-scale renewable generation sources into the grid.  The national goal of 100% clean electricity by 2035 is not just about decarbonizing the generation sources.  A substantial upgrade to the transmission infrastructure is necessary and the Building a Better Grid Initiative is a major step in the right direction.

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The big upgrade to the US power grid is kicking off

Photo, posted February 2, 2020, courtesy of Tony Webster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Drought And U.S. Hydropower | Earth Wise

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The ongoing severe drought in the western U.S. has led to low water levels in the rivers and reservoirs that feed hydroelectric power systems.  The Energy Information Administration is projecting a 13.9% decrease in hydroelectric generation this year compared to 2020.

Water levels in Lake Powell have fallen so low that it may not be possible to operate the power plant at Glen Canyon Dam starting as soon as 2022.  California officials took the Edward Hyatt hydroelectric plant offline in August because of low water levels on Lake Oroville.   Washington, the state with the most hydroelectric power generation, has seen an 11% drop in electricity generated to date this year as compared to last year.  That state is actually doing better than others in the West, such as California, where hydro generation is down 38%.

Hydropower accounts for over 7% of the electricity generated in the United States.  Five states – Washington, Idaho, Vermont, Oregon, and South Dakota – generate at least half of their electricity from hydroelectric dams.

The current decrease in hydropower is alarming, but it is not unprecedented.  The more significant question is whether the drop in generation this year is a sign that this power source is declining and becoming less reliable.   According to some scientists, the West is in a “megadrought” that could last for decades.

The greater concern is whether the bad years are likely to become more common because of climate change.  Climate projections agree that temperatures will continue to rise, but what will happen to precipitation levels in specific places is much less certain.  That is what will determine what the future holds for hydroelectric power.

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Inside Clean Energy: Drought is Causing U.S. Hydropower to Have a Rough Year. Is This a Sign of a Long-Term Shift?

Photo, posted May 7, 2014, courtesy of Tyler Bell via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

What’s The Best Way To Reduce Emissions? | Earth Wise

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A carbon tax is a fee imposed on the burning of carbon-based fuels, like coal, oil, and gas.  It’s one way to make the users of carbon fuels pay for the climate damage caused by releasing carbon dioxide into the atmosphere. 

According to a new study by researchers at Ohio State University, putting a price on producing carbon is the cheapest and most efficient policy change that legislators can make in order to reduce climate change-causing emissions. 

The case study, which was recently published in the journal Current Sustainable/Renewable Energy Reports, looked at the impact that a variety of policy changes would have on reducing carbon dioxide emissions from electricity generation in Texas. The researchers found that assigning a price to carbon, based on the cost of climate change, was most effective. 

The study did not look at how policy changes might affect the reliability of the Texas power system, an important consideration after the failure of the state’s power grid following winter storms in February. 

But the study did examine other policies and found that they were either more expensive or not as effective, including mandates that a certain amount of energy in a portfolio come from renewable sources.  Subsidizing renewable energy sources was also found to be less effective. 

According to researchers, market-based solutions have previously proven effective combating environmental issues.  For example, a cap-and-trade approach was used to reduce levels of sulfur dioxide, one of the chemicals that causes acid rain. 

For the sake of the climate, we should probably tax carbon. 

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Want to cut emissions that cause climate change? Tax carbon

What’s a carbon tax?

Photo, posted June 5, 2011, courtesy of John Englart via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

30 Million Solar Homes | Earth Wise

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A national coalition made up of more than 230 organizations has launched an initiative called the 30 Million Solar Homes campaign.  The goal is to add enough rooftop and community solar energy to power 30 million homes across the U.S. over the next five years.  That would be the equivalent of one in four American households.

The major focus of the 30 Million Solar Homes initiative is to rapidly and massively scale programs that help low-income families benefit from solar power.  The coalition lists 15 federal policy initiatives including making solar tax incentives more equitable, providing more reliable low-income energy assistance through solar energy, supplementing low-income weatherization assistance with solar energy, and specifically funding solar projects in marginalized communities.

The federal government spends billions of dollars every year to help families to pay their energy costs, but these efforts only serve less than a fifth of the eligible population.  Funding rooftop and community solar access for these households would provide long-term financial relief and reduce the need for annual energy bill assistance.

The more than 230 organizations in the coalition represent organizations focused on energy equity, climate, business, environment, faith, and public health.  The coalition estimates that executing the plan would create three million good-paying jobs, lower energy bills by at least $20 billion a year, and reduce total annual greenhouse gas emissions by 1.5%.

Over the coming months, the campaign will seek to educate lawmakers and the Biden-Harris Administration about the benefits of distributed solar energy.  The vision outlined by the coalition is an ambitious one to say the least.

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30 Million Solar Homes

Supporters of 30MSH

Photo, posted May 20, 2009, courtesy of Solar Trade Association via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

More Renewables Without Storage In Texas

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Texas has a Texas-sized appetite for electricity and relies most heavily on natural gas, coal and nuclear power to get it.  But in recent times, wind power has grown tremendously in the Lone Star State and it has already leapfrogged past nuclear power.  Coal could be the next domino to fall.

In the past few years, solar power has become competitive with wind in terms of price.  Texas is a large, coastal state in the sunny southwestern U.S. and has significant solar resources.  As a result, the amount of solar power in Texas is now growing rapidly.

In order for a combination of solar and wind power to address the bulk of electricity demand in Texas, there needs to be a way to provide reliability that these intermittent sources don’t necessarily provide.  Energy storage is a solution that ultimately is likely to be part of most electricity grids, but currently it is still expensive on a utility scale.

A new study from Rice University looked at the complementarity of solar and wind power in Texas.  Complementarity refers to balancing the output of solar and wind systems.  The peak performance of wind and solar occurs at very different times in different regions of the state.  The study suggests that the right mix of solar and wind systems in the right parts of Texas could provide a continuously reliable energy system.  On both a yearly and daily basis, wind and solar power resources in Texas complement each other in terms of peak performance.  It is a matter of locating the solar power and wind farms in the right places.

With the Texas solar industry really starting to boom, there is a real opportunity to integrate far more renewable energy into the Texas grid.

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More Renewables with Less Energy Storage: Texas Shows How

Photo, posted June 8, 2018, courtesy of Laura Lee Dooley via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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