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Fuel From Coffee Grounds | Earth Wise

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The world drinks a lot of coffee.  Americans alone consume 400 million cups a day.  Each cup of coffee results in about half an ounce of coffee grounds.  Adding that up, this country produces over 6,000 tons of coffee grounds each day.  While coffee grounds are not particularly harmful, that is an awful lot of waste that mostly ends up in landfills or is incinerated.

Researchers at Aston University in the UK have developed a method of producing high-quality biodiesel fuel from coffee grounds.  Their study was published in the journal Renewable and Sustainable Energy Reviews.

The technique consists of growing a particular species of microalgae (Chlorella vulgaris) directly on spent coffee grounds.  The coffee grounds provide both the nutrients for the microalgae and a structure upon which it can grow.   Exposing the algae to light for 20 hours a day and dark for just four hours a day produced the best quality biodiesel.

Microalgae is well-known as a feedstock for biodiesel production.  Previously, it has been grown on materials like polyurethane foam or nylon which don’t provide any nutrients.   Using the coffee grounds as the substrate for growth means that no external nutrients are needed.

The resultant enhanced biodiesel produces minimal emissions and good engine performance and meets both US and European specifications.  This feedstock for producing biodiesel is ideal since it doesn’t require any competition with food crops and instead makes use of a widely available waste product.  The hope is that it may reduce the cutting down of palm trees to extract oil for biofuel.  In southeast Asia, this has been a major source of deforestation and increased greenhouse gas emissions.

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Aston University researchers ‘feed’ leftover coffee grounds to microalgae to produce low emission biodiesel

Photo, posted October 13, 2007, courtesy of David Joyce via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Hybrid Renewable Energy Plants | Earth Wise

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Hybrid renewable energy systems combine multiple renewable energy and/or energy storage technologies into a single plant.  The goal is to reduce costs and increase energy output relative to separate systems taking advantage of common infrastructure and the ability of one renewable energy source having appreciable output while a second one might not at a particular time.

Recently, the largest hybrid renewable power plant in the United States was completed in rural Oregon.  The Wheatridge Renewable Energy Facility combines a wind farm, a solar array, and battery storage.

Plants that include just solar power and energy storage are also called hybrid plants, but the Wheatridge Facility is special because it includes wind power.  The facility comprises a 200-megawatt wind farm, a 50-megawatt solar array, and a 30-megawatt battery system capable of providing power for four hours.  The combined system can provide for the electricity needs of about 100,000 homes.

There are about 140 projects in the United States that combine solar and storage.  There are 14 that combine solar and wind.  There are only four plants – with the completion of Wheatridge – that have wind, solar, and storage.  

Wind and solar energy are generally complementary technologies.  Wind is usually strongest at night while solar, of course, is a daytime source of energy.  Solar and wind plants don’t need to be close together to take advantage of this, but hybrid projects benefit from needing only one grid connection and one lease for land.

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A Clean Energy Trifecta: Wind, Solar and Storage in the Same Project

Photo, posted December 27, 2015, courtesy of Gerry Machen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Timber Cities | Earth Wise

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More than half of the world’s population lives in cities and by 2100, this percentage is predicted to be much higher.  This means that more homes will be built with steel and concrete, which both have very large carbon footprints.  According to a study by the Potsdam Institute in Germany, housing a growing population in homes made of wood instead could avoid more than 100 billion tons of carbon dioxide emissions over the remainder of the century.  This is about 10% of the remaining global carbon budget for staying below the 2-degree Celsius climate target.

The study presents the alternative of housing new urban populations in mid-rise buildings – no more than 4-12 stories high – that are substantially made of wood.  Wood is a renewable resource that carries the lowest carbon footprint of any comparable building material.  Trees take up CO2 from the atmosphere to grow.  Producing engineered wood releases far less CO2 than production of concrete and steel and the finished product continues to store carbon.

The study shows that sufficient wood for new mid-rise urban buildings can be produced without a major impact on food production.  The wood would come from timber plantations as well as natural forests.  The study also looked at biodiversity impacts and ways that ecosystems could be protected while still providing the necessary timber.

Overall, the Potsdam study demonstrates that urban homes made out of wood could play a vital role in climate change mitigation based on their long-term carbon storage potential coupled with the reduced utilization of the carbon-intensive concrete and steel industries.

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Living in timber cities could avoid emissions – without using farmland for wood production

Photo, posted May 24, 2005, courtesy of Stig Anderson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Computing With Honey | Earth Wise           

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Researchers are always working to develop faster and more powerful computers.  Some of them believe that the future of computing lies with neuromorphic computers, which are systems designed to mimic the neurons and synapses found in the human brain.

The human brain has more than 100 billion neurons with more than 1 quadrillion synapses or connections among them.  These numbers far exceed anything people have built.  There have been some neuromorphic computer chips made that have the equivalent of more than 100 million neurons per chip, but this is still far less than the number in the brain.  Despite all its complexity, the brain uses vastly less power than a powerful computer.  Some supercomputers use tens of millions of watts to operate; the brain uses around 10 to 20 watts.

Many researchers are searching for biodegradable and renewable ways to make neuromorphic computing components.  Researchers at Washington State University have demonstrated a way to make them using, of all things, honey.  The honey is used to form a memristor, which is a component similar to a transistor that can both process and store data in memory.  The device uses honey processed into a solid form and sandwiched between two metal electrodes.  The organic device is very stable and reliable over a long time.

So far, these devices are on a micro scale – about the size of a human hair.  The researchers want to develop them on a nanoscale, which is about 1/1000 the width of a human hair, and then bundle many millions or even billions together to make a neuromorphic computing system.  Such a honey-based system would be renewable and biodegradable – which, pardon the pun, would be really sweet.

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Honey holds potential for making brain-like computer chips

Photo, posted January 28, 2008, courtesy of Dino Giordano via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Avoiding Blackouts With Renewable Energy | Earth Wise

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There are some people who worry that an electric grid heavily dependent upon intermittent sources like solar and wind power may be more susceptible to blackouts.  According to a new study by Stanford University, these fears are misplaced.

The study, published in the journal Renewable Energy, found that an energy system running on wind, water, and solar, when combined with energy storage, avoids blackouts, and lowers energy requirements and consumer costs.  In addition, implementing such a system would create millions of jobs, improve people’s health, and reduce land requirements.

The study focused on the stability in all U.S. grid regions as well as individual states based on the requirement that all electricity is provided by clean and renewable sources. No fossil fuel use, bioenergy, blue hydrogen, or even nuclear power were included in the modeling.  Critics of such a shift in the energy system point to grid blackouts during extreme weather events in California in 2020 and Texas in 2021 as evidence that renewable sources can’t be trusted.  But in both cases, renewable energy was not found to be any more vulnerable than other sources.

The study looked at the costs of the transition – which would be substantial – but found that it would pay for itself fairly quickly based on energy cost savings alone.

A significant finding of the study was that long-duration batteries were neither necessary nor helpful for grid stability.  That stability could be obtained by linking together currently available short-duration batteries.  Interconnecting larger and larger geographic regions would make the power system smoother and more reliable.  Overall, intelligent management of the electric grid can result in a reliable and clean power system.

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Stanford researchers point the way to avoiding blackouts with clean, renewable energy

Photo, posted October 17, 2016, courtesy of B Sarangi via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Clean Energy In Rochester | Earth Wise

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New York’s largest community choice clean energy program has been activated in the City of Rochester.   The program, offered by Rochester Community Power, offers 57,000 residences and small businesses access to clean energy from hydropower and wind sources.  It requires customers to opt out rather than enroll in order to provide clean energy to the greatest number of people.

Rochester Community Power is the city’s local community choice aggregation (CCA) program that leverages the collective buying power of participating residents to purchase renewable electricity and negotiate better terms for energy supply contracts.

The program will supply customers with more than 300 million kWh of renewable energy each year, which will avoid the emission of about 250,000 tons of carbon dioxide.  Rochester plans to add a community solar program next year which will provide additional clean energy opportunities, including offering guaranteed savings to thousands of participants in its Home Energy Assistance Program.

The project will be managed by Joule Assets, which is a provider of energy reduction market analysis, tools, and financing. Joule Assets, as program administrator for the Rochester program, managed the competitive bidding process that secured a fixed rate for electricity for the next two years, shielding participating residences and businesses from volatile market prices.

Community choice aggregation programs are local, not-for-profit public agencies that are an alternative to investor-owned utilities.  They give municipalities the ability to make decisions about the procurement, sourcing, and rates for energy for its residents.

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New York activates its largest opt-out 100% renewable energy program

Photo, posted June 25, 2011, courtesy of Paulo Valdivieso via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Hydrogen-Powered Jetliners | Earth Wise

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Airbus, the giant European aerospace company, hopes to have hydrogen-powered commercial airliners in the sky by 2035.  Such planes would have no carbon dioxide emissions.

Greenhouse gas emissions from commercial aviation have been a rapidly increasing contribution to the global total.  Of course, the Covid-19 pandemic has drastically reduced air travel, so emissions are currently lower than they have been in a very long time.  But at some point, they will resume at previous levels and continue to increase.

Planes themselves produce over 2% of global CO2 emissions, and between the climate effects of contrails and the emissions associated with the rest of the air travel industry, commercial aviation drives about 5% of global warming.

Airbus is studying design concepts in which planes run off of hydrogen and oxygen fuel and have no carbon exhaust.   Making such planes practical and environmentally advantageous requires solving an array of complex technical challenges. 

One of the biggest challenges is that the hydrogen on the market today is considered to be “brown” rather than green, meaning that it is not a sustainably produced energy source.  Almost all hydrogen produced today comes from natural gas reforming, which results in carbon emissions.  A viable hydrogen-powered aviation technology assumes that producing hydrogen by splitting water molecules into oxygen and hydrogen using renewable energy becomes the standard source for it.

There have been test flights of small planes and drones powered by hydrogen, but Airbus expects that intensive research and development for the next five years will be required to evolve its current preliminary designs to a stage where they could be developed for future use in its product line.  It won’t happen overnight, but according to Airbus, hydrogen planes are coming.

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Airbus Hopes to Be Flying Hydrogen-Powered Jetliners With Zero Carbon Emissions by 2035

Photo, posted April 15, 2019, courtesy of Olivier Cabaret via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Renewable Natural Gas

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Small-scale biogas systems have collected methane from landfills, sewage plants, and farms for decades.  Here in the US, biogas is finally catching up with modern techniques with the advent of third-party operators introducing more sophisticated technology to capture methane and pump it directly into pipelines.

Renewable methane or natural gas represents a significant mostly unexploited source of energy.  Examples include the vast amounts methane generated by manure from some of the 2,300 hog farms in eastern North Carolina, biodigesters that can turn clusters of large California dairy farms into energy hubs, as well as diverting food waste from landfills and transforming it into vehicle and heating fuels.

According to a 2014 EPA study, the U.S. could support at least 13,000 biogas facilities, fed by manure, landfill gas, and biosolids from sewage treatment plants.  Those facilities could produce over 650 billion cubic feet of biogas per year – enough renewable energy to power 3 million homes.

A study by the World Resources Institute estimated that the 50 million tons of organic waste sent to landfills or incinerated every year in the U.S. has the energy content of 6 billion gallons of diesel fuel, amounting to 15% of all diesel consumed by heavy-duty trucks and buses.

Utilizing all that biogas could help lower greenhouse gas emissions from some of the most difficult sectors to decarbonize – transportation, industry, and heating buildings.  In addition, ramped up renewable gas could keep organic waste out of landfills and prevent manure runoff into rivers and water supplies.

Renewable natural gas could be the next big thing in green energy.

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Could Renewable Natural Gas Be the Next Big Thing in Green Energy?

Photo, posted June 19, 2013, courtesy of Alan Levine via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Car Parts From Agricultural Waste

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A new bio-composite material made from date palm fiber biomass could be used to produce sustainable, lightweight and low-cost parts for the automobile and marine industries.

A team of researchers from the UK has developed a date palm fiber polycaprolactone composite that is completely biodegradable, renewable,sustainable and recyclable, in contrast to synthetic composite materials reinforced by glass and carbon fibers. The team tested the mechanical properties of the material and found that it achieved better low-velocity impact resistance than traditional man-made composites.

The idea would be to use the material in non-structural auto parts such as car bumpers and door linings.   The result would be to reduce the weight of vehicles, contributing to less fuel consumption and lower emissions.  The new material can be produced using less energy than glass and carbon fibers and is biodegradable and therefore easier to recycle.

Date palm fibers are one of the most available natural fibers in many parts of the world.  The trees produce a large quantity of agricultural waste, which is mostly burned or land-filled,causing serious environmental problems.

Convincing industry to use a new class of materials such as natural-fiber reinforced composites is challenging.  First it is necessary to obtain consistent,reliable properties from the material. Then the industries need to work closely with the developers to test the materials and convince themselves of the viability of using them.  The team, led by researchers at the University of Portsmouth, has been working with industry to test the viability of parts made from a variety of other sustainable materials as well including flax, hemp, and jute.  Someday, our cars may have bumpers made from agricultural waste.

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Agricultural waste drives us closer to greener transport

Photo, posted October 27, 2017, courtesy of David Stanley via Flickr. 

Earth Wise is a production of WAMC Northeast Public Radio.

More Power From The Sun’s Heat

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When we think of solar power, we usually are talking about the panels that generate electricity using the photovoltaic effect.  These panels are on millions of rooftops around the world and in utility-scale solar farms.   There are also solar water heating systems that use the sun’s heat to provide hot water for homes and businesses.

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The Earliest Overshoot Day Ever

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Earth Overshoot Day marks the date when humankind’s demand for ecological resources and services in a given year exceeds what our planet can regenerate in that year.  The deficit for the remainder of the year means we are liquidating stocks of ecological resources and accumulating waste, primarily carbon dioxide in the atmosphere.

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Biomass: Renewable But Not Sustainable

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Biomass is often touted as a green energy source. Just recently, the US Environmental Protection Agency declared biomass energy to be carbon neutral – a policy already embraced by many European countries. However, burning forests for fuel has hard limitations and ecological consequences.

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New Energy Goals For New York

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Since 2015, New York has had in place an energy plan aimed at building a clean, resilient and cost-effective energy system for the state.  A key part of that plan is to reduce greenhouse gas emissions by 40% from 1990 levels by the year 2030.  Another major goal is to have 50% of the state’s electricity produced from renewable sources by the same year.

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Hydrogen Progress

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As low-cost solar and wind energy become increasingly pervasive, the prospects for hydrogen-based transportation systems are improving.  The reason is that cheap electricity makes it practical to produce hydrogen by breaking down water rather than getting it from reforming natural gas, which results in carbon dioxide emissions.  The real goal is for hydrogen to be a renewable and carbon-free fuel.

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Hydrogen On Demand

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Researchers at the Technion-Israel Institute of Technology have developed a new method for producing hydrogen from water using solar energy.  If successfully developed, their approach would make it possible to produce hydrogen in a centralized manner at the point of sale such as at a fueling station for hydrogen-powered cars.

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Tires From Trees

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Car tires are generally considered environmentally unfriendly because they are predominantly made from fossil fuels.  Natural rubber is generally not used anymore; most tires are made from isoprene, which is chemically very like rubber but is produced by thermally breaking apart molecules in petroleum in a process called cracking.  The isoprene is separated out and purified and then reacted to form the artificial rubber that is the major component in car tires.  The tires eventually end up discarded in giant piles that represent one of our biggest waste disposal problems.

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The Largest Battery Storage Substation

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At the end of last year, Southern California Edison turned on the largest lithium-ion battery storage facility in the world in Ontario, California.   It is a substation with 80 megawatt-hours of capacity, enough energy to power 2,500 households or charge 1,000 Tesla cars a day.

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2016 Carbon Progress Report

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Last year was a big year for progress in the U.S. power sector.  Renewable energy provided nearly 17% of the country’s electricity, up from 13.7% in 2015.  The first offshore wind farm in the U.S. opened off the coast of Rhode Island.  And most significantly, carbon emissions from the power sector continued to decline and reached the lowest levels in nearly 25 years.

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