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100% Renewables Does Not Necessarily Mean Carbon-Free

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Hundreds of companies around the world have committed to use 100% renewable energy in order to fight climate change.  But a new study from Stanford University points out that 100% renewable energy does not necessarily mean 100% carbon-free energy.

The problem is that the carbon content of electricity can vary a lot over the course of a day in many locations.  Using yearly averages can overstate the carbon reductions associated with a particular power source, in some cases by significant amounts.

Suppose a California company purchases or generates enough solar power to match 100% or more of their electricity use over the course of the year.  In reality, it may generate far more electricity than it uses during the afternoon and sell the excess.  Then, at nighttime, it purchases power from the grid, which would be far more carbon-intensive if it involves the burning of fossil fuels.

But in Britain, for example, the situation is very different.  With a high reliance on wind power, grid carbon intensity is actually lower at night.  So very different consumption patterns over the course of a day would be less carbon-intensive.

If sufficient energy storage capacity can be implemented into the grid as well as suitable long-range transmission, these time-based fluctuations in the electricity supply could be ironed out.  Until such time, electricity consumers need to evaluate the environmental benefits of their renewable strategies on an hourly basis rather than using averages.  And the best strategies are entirely dependent upon the characteristics of the specific grid they interact with.  The need for this kind of analysis will only grow as renewable generation expands.  Transparent, precise and meaningful carbon accounting is necessary.

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100% renewables doesn’t equal zero-carbon energy, and the difference is growing

Photo, posted January 29, 2013, courtesy of U.S. Fish and Wildlife Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Energy Vault

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A potentially transformative utility-scale energy storage technology has won a 2019 “World Changing Idea” award from Fast Company magazine.  Known as the Energy Vault, the technology seeks to be the successor to the granddaddy of grid energy storage:  pumped hydro.

Shifting water between higher and lower reservoirs is still basis of the vast majority of global grid storage capacity.  But it is limited both by its unique location needs and by environmental regulations.

A start-up company also called Energy Vault and based in both Switzerland and Southern California has come up with an extremely creative grid storage concept.  The technology consists of a six-armed crane that stacks huge concrete blocks using a currently available source of cheap and abundant grid electricity, and then drops them down to generate electricity when needed.

The system is said to operate at about 90% efficiency and can deliver long-duration storage at half the prevailing price on the market today.

A full-scale Energy Vault plant, called an Evie, would look like a 35-story crane with six arms, surrounded by thousands of manmade concrete blocks, weighing nearly 40 tons each.  When charging, the plant will stack the blocks around itself higher and higher in a Babel-like tower.  To discharge, the cranes drop the blocks down, generating power from the speedy descent.  This configuration can deliver 4 megawatts of power and store about 35 megawatt-hours of energy.

There isn’t even a factory needed.  The company would deliver a crane from a manufacturer.  The crane will then assemble the blocks onsite using recycled concrete.  Operation is then fully automated.  The system is expected to run for 30 or 40 years.

So far there is only a one-seventh scale demo unit in Switzerland.  But this is a very intriguing idea.

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Energy Vault Wins World Changing Idea Award 2019 from Fast Company for Transformative Utility-Scale Energy Storage Technology

Photo courtesy of Energy Vault.

Earth Wise is a production of WAMC Northeast Public Radio.

Utility-Scale Solar On The Rise

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According to research from Goldman Sachs, utility-scale solar power capacity is expected to grow by double digits globally over the next two years.  The growth will be driven by expanding use of the technology in the United States, Europe, the Middle East, and China.

Solar power is the world’s fastest growing source of electricity generation and is slowly taking market share from fossil fuels like coal and natural gas.  The transition is being driven by a combination of continuously lower prices for solar power and the impact of policies aimed at reducing emissions.

Utility-scale solar is defined as installations designed solely to feed electricity into the grid, in contrast to smaller-scale residential or commercial building units.  There are now solar farms larger than half a gigawatt in generating capacity.  According to the Goldman report, global utility-scale solar installations will reach 108 gigawatts in 2019, up 12% over the previous year, and will then grow another 10% to 119 gigawatts in 2020.

When residential and other smaller installations are included, most analysts expect global solar power capacity to soon hit 600 gigawatts.  To put this in perspective, the global capacity only reached 100 gigawatts in 2012 and was actually less than 10 gigawatts in 2007.

Even more dramatic than the growth of solar installations is the reduction in solar cost, and the two are obviously closely related.  Solar panel costs have dropped from around $70 per watt of electricity generated in 1980 to 36 cents per watt currently in the United States.  When favorable policies both from governments and related to corporate sustainability targets are added to the mix, the booming growth in solar power is easy to understand.

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Large-scale solar power set for double-digit growth: Goldman Sachs

Photo, posted March 7, 2019, courtesy of Hedgerow Inc via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Lots Of Renewable Energy In Germany

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As the contributions to the electrical grid from renewable sources continue to rise, people have expressed concerns about what might happen as sources like wind and solar energy become dominant.  Not many years ago, there was a common concern that if wind and solar contributed more than about a quarter of the energy mix, the grid might become unstable or unreliable.  Theoretical models looked at this situation but there hadn’t been much real-world data to look at.

One place where there is now real-world data on a large scale is Germany.  Germany has been aggressively deploying both wind and solar energy for years as part of a national initiative called the Energiewende or energy transition.  Germany recently increased its renewable energy goal from 55% to 65% by the year 2030.   The increased share of renewables takes into account the decommissioning of aging nuclear and coal power plants.

A demonstration of the feasibility of such a goal occurred in the first week of March when renewable sources actually supplied nearly 65% of Germany’s electricity.  Wind power alone provided nearly half of the country’s power.  As a result, fossil fuel plants ran at a minimum output and nuclear facilities were shut down at night.

Germany has a very large domestic coal industry and indeed lignite coal generated an average of 24% of the country’s power last year.   However, recently that share was down to just 12%.  During that first week of March, solar power contributed more than 5% of Germany’s electricity, biomass 7.6%, and hydropower 3.5%.

While the week with 65% renewable set a record, the ongoing trend is very positive as well.  In 2018, renewable energy generated an average of more than 40% of Germany’s electricity.

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Renewables Generated a Record 65 Percent of Germany’s Electricity Last Week

Photo, posted April 28, 2012, courtesy of 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.

Support For A Green New Deal

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Shortly after the November election, activists held a sit-in at Nancy Pelosi’s office calling for a Green New Deal – a plan to transform the U.S. energy economy in order to mitigate the effects of climate change as well as address various issues of economic justice.   While a number of Congress people have pledged to back the creation of a select committee to develop such a plan, it remains a political football and it remains to be seen whether anything will come of the idea.

There appears to be much less reticence on the part of voters, at least according to a survey conducted by the Yale Program on Climate Change Communication at the end of November.  The survey gave a brief explanation of the Green New Deal and asked respondents “How much do you support or oppose this idea?”

The result was that 81% of registered voters either “strongly” or “somewhat” supported it.  Support was stronger among Democrats at 92%, but a majority of Republicans were also in favor.  Some 57% of self-identified conservative Republicans even thought it was a good idea.

The Green New Deal would accelerate the transition from fossil fuels to clean, renewable energy.  The goal would be to generate 100% of the nation’s electricity from renewable sources within the next 10 years; upgrade the nation’s energy grid, buildings, and transportation infrastructure; increase energy efficiency; invest in green technology research and development; and provide training for jobs in the new green economy.

Even though most Americans have strong support for the ideas of the Green New Deal, it is quite uncertain whether such an initiative could become a reality, given that very influential special interest groups – notably the fossil fuel industry – will be fighting it tooth and nail.

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81% of Voters Support a Green New Deal, Survey Finds

Photo, posted March 19, 2012, courtesy of Kate Ausburn via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Water-Based Battery

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The transition from fossil fuel-based power plants to clean, renewable energy sources is accelerating as both wind and solar power get cheaper and increasingly become cost-competitive with traditional power sources.   The biggest stumbling block both energy sources face is that they cannot always supply power on demand but require the sun to shine and the wind to blow.

[Read more…] about A Water-Based Battery

Big Success From A Big Battery

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In the fall of 2017, Tesla took on the challenge of installing a 100-megawatt battery storage system in South Australia in under 100 days, promising that the system would be free if it was not built in time.  The project was actually completed in 54 days.

The system is located at the Hornsdale Wind Farm, which consists of 99 wind turbines with a generation capacity of 315 MW.  The Hornsdale Power Reserve installation is the world’s largest lithium-ion battery system and, after a year of operation,has proven to be a smashing success. Estimates are that the project has reduced costs associated with stabilizing the energy grid by about $29 million. The cost of the system was about $87 million, so it is paying for itself quite rapidly. The wind farm and battery systems are owned and operated by a French renewable energy company.

The battery storage system provides a variety of different services to the electric grid.  The primary motivation for it was to achieve system security and reduce the risk of blackouts and load shedding.   Having the battery system in place protects the regional interconnection from tripping,which reduces the risk of separation of South Australia from the National Electricity market.  The system also provides so-called ancillary services such as frequency control and other forms of electricity supply regulation.

The most significant contribution of the Hornsdale Power Reserve is that it has raised the profile of energy storage technology and demonstrated its unique capabilities.  Based on the success of the system, there are now about 2,500 MWh of new storage projects announced by the public and private sectors in Australia.

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Tesla’s Battery Has Already Saved South Australia a Huge Amount of Money

Photo courtesy of Hornsdale Power Reserve. 

Earth Wise is a production of WAMC Northeast Public Radio.

Powering Africa With The Sun

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There are roughly 600 million people in sub-Saharan Africa who currently live without electric power.  Putting in the infrastructure to supply power to these people in their various countries has been a major economic and logistical challenge.

[Read more…] about Powering Africa With The Sun

The 100-Day Giant Battery

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The Australian state of South Australia suffered crippling electricity outages in September 2016, which coincided with gale-force winds and flooding rains.  The outages were triggered by storm damage to major transmission lines followed by wind farms disconnecting from the power grid.

[Read more…] about The 100-Day Giant Battery

A Microgrid in New York’s Capital

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New York State has been encouraging its communities to install microgrids for quite a while.  Now the state has committed to build a 16-megawatt microgrid to power the Empire State Plaza in downtown Albany.  The microgrid will use combined heat and power to supply 90% of the electricity as well as heating and cooling for the 10 buildings where 11,000 state employees work.

[Read more…] about A Microgrid in New York’s Capital

Offshore Wind Progress

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Last December, the first commercial offshore wind farm in the United States started operation off the coast of Rhode Island.   The Fisherman’s Energy Atlantic City Windfarm off the coast of New Jersey is under construction.  With the lengthy logjam finally broken, there is increasing activity in the emerging U.S. offshore wind sector.

[Read more…] about Offshore Wind Progress

Utility-Scale Solar Power

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Solar panels on the roofs of houses have become a familiar sight in recent years, but utility-scale solar – installations of 10 megawatts and greater – are really booming these days.   Throughout the United States, more than 10.5 gigawatts of utility-scale solar were added to the electric grid in 2016 – enough to power more than 2 million homes – and at least 8 gigawatts more are scheduled to come online this year.

[Read more…] about Utility-Scale Solar Power

Solar Power From An Old Mine

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For more than a century, a wide stretch of land north of Kimberley, British Columbia, was used for intensive industrial hard-rock mining.   The site of Teck’s Sullivan Mine hosted a steel mill, a fertilizer plant and tailings ponds and was rendered treeless.

[Read more…] about Solar Power From An Old Mine

A New Low-Cost Battery

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Batteries have never been more important.  Not only do we all depend on cell phones, tablets and laptop computers that run on batteries, but two enormous industries are in major transitions that rely upon battery technology: personal transportation and the utility industry.   The electricity grid is increasingly turning to solar and wind power for generation and both will require effective energy storage if they are to truly become the predominant sources of electricity.

[Read more…] about A New Low-Cost Battery

Cheap Wind And Solar Power

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Multiple studies are now reporting that wind and solar power are the cheapest way to make electricity in a growing number of places around the world.   A thorough analysis of the levelized cost of energy – which considers every cost component from capital expenditures to operating and maintenance costs over a lifetime – shows that solar and wind power are winning the day.

[Read more…] about Cheap Wind And Solar Power

Too Much Of A Good Thing

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Germany has continued to be the most aggressive adopter of renewable energy among large industrial nations.  The country has the goal of shifting to 100% renewables by 2050.  Its continuing embracing of solar and wind generation resources over the past decade has resulted in renewables supplying a third of the country’s power on average.

[Read more…] about Too Much Of A Good Thing

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