Thoughts of a Lapsed Physicist

Lighting: A Revolution In Progress

An energy revolution is underway before our very eyes – the replacement of traditional incandescent light bulbs with much more energy efficient and longer lasting light-emitting diodes (LEDs). It is a significant revolution because, according to NYSERDA, lighting accounts for 22% of electricity consumption in the U.S.. Other sources put this number at 19% on a global basis. It is estimated that LED use could cut the U.S. number in half by 2030.

At this point it may be fair to ask: What about CFLs (compact fluorescent lamps), which had been gaining market share for many years. A few words about lighting technology before we answer this question.

An incandescent light bulb, the most common type today in households and the least expensive to buy, produces visible light from a glowing filament wire (tungsten) heated to a high temperature (several thousand degrees) by an electric current passing through it. It was not invented by Thomas Edison, as is often stated (many earlier inventors had experimented with hot filament lamps), but he did invent the first commercially practical incandescent bulb. It was introduced into residential use more than 125 years ago. Its principal shortcoming is that more than 90% of the energy used by the traditional incandescent bulb escapes as heat and less than 10% goes into producing light. Filaments also burn out and are fragile, and a typical bulb lifetime is about 1,000 hours.

Halogen lamps, also in common use today, are incandescent lamps with a bit of halogen gas (iodine or bromine) added to the bulb. The chemical reaction between the halogen and the tungsten wire allows the filament to operate at a higher temperature and increases the bulb’s efficiency and lifetime.

A fluorescent lamp or fluorescent tube is a low pressure mercury-vapor gas-discharge lamp that uses UV-stimulated fluorescence of a phosphor to produce visible light. It is more energy efficient than an incandescent lamp but does require a ballast to regulate the current through the lamp, increasing its initial cost.

Compact fluorescent lamps (CFLs) fold a fluorescent lamp tube into the space of an incandescent bulb with a ballast in the base. They use 3-5 times less energy than incandescent bulbs of the same light output and have much longer lifetimes. They do contain a small amount of mercury, creating a disposal problem.

Light-emitting diodes (LEDs) are monochromatic, solid-state semiconductor point light sources. First appearing as practical electronic components in 1962, early LEDs emitted low-intensity red light, but modern versions are available at visible, ultraviolet, and infrared wavelengths with very high brightness. Today they are used in applications as diverse as aviation lighting, automotive lighting, advertising, general lighting and traffic signals. They are also used in the infrared remote control units of many commercial products including televisions, DVD players and other domestic appliances. Their high switching rates are useful in advanced communications technology.

LEDs have many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved physical robustness, smaller size, and faster switching. However, LEDs powerful enough for room lighting are still relatively expensive (but costs are coming down) and require more precise current and heat management than compact fluorescent lamp sources of comparable output. Their advantages over CFLs are greater efficacy (i.e., more light output in lumens per watt), longer lifetimes, smaller size, directionality of the light produced, and very importantly they contain no mercury which has to be disposed of. These factors will limit CFLs’ time in the ‘limelight’ (I know, bad pun).

(Note: LEDs are based on inorganic (non-carbon-based) materials. OLEDs are organic (carbon-based) solid-state light emitters which are made in sheets that provide a diffuse-area light source. They are still in an early stage of development and several years away from broad commercial application. Interesting potential applications include TVs, computer and cell phone screens, wall coverings that allow changes in color, and automobile skins that allow you to change the color of your car.)

It is useful to compare these different lighting technologies, as white light emitters, in terms of their current efficiencies (efficacies), lifetimes, and color temperatures (measured in degrees Kelvin, as an indicator of the warmth or coolness of the light emitted). Efficacies for monochromatic LEDs are higher but are not listed here.

Technology Efficacy Lifetime Color Temperature
(lumens/watt) (hours) (K)
…………………………………………………….
Incandescent 12-18 750-1,500 2,400-2,900
CFL 60-70 6,000-10,000 2,700-6,500
Fluorescent tube 80-100+ 20,000 2,700-6,500
Halogen 16-29 2,000-4,000 2,850-3,200
White light LED 20-50. Up to 100,000 2,700-6,500

A quick calculation will help to demonstrate the cost effectiveness of lighting sources that may be more costly to buy but save energy and money over extended lifetimes (and don’t forget that not replacing bulbs as often also saves money by reducing labor costs). I will use CFLs as my example.

Assume we buy a 15 watt CFL bulb that today costs $6 and replaces a 65 watt incandescent bulb that costs $1. We further assume that the CFL will last 6,000 hours, the incandescent 1,500 hours (clearly a worst case for CFLs and a best case for incandescents), and that electricity costs 10 cents per kilowatt-hour. Over 6,000 hours the CFL will consume (0.015 kW)x(6,000h)=90 kWh for a total cost (purchase + energy use) of $15. The incancandescent will have been replaced four times in 6,000 hours and consumed (0.065kW)x(6,000h)=390 kWh for a total cost of $43. You save lots of money ($43-$15=$28) despite the higher initial cost for the CFL, and this is per bulb. In addition to this reduced cost the reduced energy consumption will be reflected in fewer carbon emissions from power plants supplying the needed electricity.

Finally, a word about the claim that the U.S. Congress has outlawed use of the incandescent bulb. This is not true, although other countries have done so. What the U.S. Congress has done is pass the Energy Independence and Security Act of 2007, which set performance standards for all general service incandescent lamps producing 310-2,600 lumens of light. The efficiency standard will start with 100-watt bulbs and end with 40-watt bulbs. Light bulbs outside of this wattage range are not covered, along with several classes of specialty bulbs (e.g., stage lighting). Thus, if bulb manufacturers can develop an incandescent bulb that meets the specified performance standard it can be marketed and sold in the U.S. Some are even beginning to appear. This is the same approach that is taken with respect to reducing the electricity consumption of many other household appliances such as refrigerators and dish washers.

Mentoring: A Critical Need In Any Organization

This is a blog post I’ve been meaning to write for a long time. It is focused on organizational culture and addresses what I consider a critical need for organizational success – the need to mentor. My thoughts have been shaped by many years of serving in a large organization, the U.S. Government, but should apply to many other organizations as well. I will let you decide.

Staff development is often identified as an important, and even critical, organizational need. In my view and that of many others a successful staff development effort requires consistent top down encouragement and support. Lots of organizations talk about staff development as a worthy goal, and there is an extensive literature on the subject, but truly successful programs are limited in number because of lack of follow through and true organizational commitment to the goal. Without senior management buy-in and publicly expressed support for such an effort I see little value in an organization moving ahead with the needed planning – memo to the staff, and staff surveys to identify staff interests and potential mentors and mentees. Success is unlikely to happen, given everyone’s assigned responsibilities and management’s focus on ‘firefighting’, unless staff development is made a priority of the organization and rewarded as an activity.

Further thoughts:
– People really are an organization’s most important asset, and it is through people that we can have lasting impact on that organization. You make an enduring difference through the people you choose to develop.
– In addition to supporting continuing education, a critical ingredient of staff development is providing a mentor, someone whose knowledge and experience the mentee respects and someone whose wisdom and know-how can support the professional growth and development of the mentee.
– Corporate mentoring programs have long been recognized as an essential strategy for attracting, developing, and retaining top employees. They send a message to employees that they are valued and the organization wants them to be satisfied and happy.
– Mentoring helps new employees settle into an organization, understand what it means to be a professional in their working environment, facilitates the transfer of expertise to those who need to acquire specific skills, encourages the development of leadership abilities, and helps employees plan, develop and manage their careers.
– Mentoring is also a two-way street that can benefit both the mentee and the mentor.

All of this may sound trite – most of us have heard the words many times before – but the concept is right, and in my experience many organizations do a poor job of ‘preparing the next generation’ by translating the good words into meaningful and effective programs.

Unfortunately, this was my consistent view during my years at DOE and I hope that DOE’s current leadership will take the concept of mentoring and training successors more seriously than in the past. Some other federal departments and agencies did a better job at this during my time in government – e.g., as evidenced by their heavy participation in the open-to-all Excellence In Government Program. Such programs do take time away from other activities but are investments in the future, just as are federal R&D investments in emerging energy technologies.

Balancing Environmental Interests and Our Energy Future: Often A Difficult Call

I may be dipping my toe (foot?) in doo-doo by taking on this issue with my natural constituency – environmentalists – but here goes. Two articles in today’s (17 January 2014) Washington Post got my attention and stimulated this blog post.

The first piece, ‘Green groups assail Obama on climate’ (digital edition tile: ‘Environmental groups say Obama needs to address climate change more aggressively’), starts off as follows: “A group of the nation’s leading environmental organizations is breaking with the administration over its energy policy, arguing that the White House needs to apply a strict climate test to all its energy decisions or risk undermining one of the president’s second-term priorities.” It goes on to list a number of ways in which the Obama administration has taken steps to limit carbon dioxide emissions, but the environmentalists’ letter takes issue with the administration for “..embracing domestic production of natural gas, oil and coal under an “all of the above” energy strategy.”

The other Washington Post piece that got my attention was a brief reference to the draft of the soon-to-be-released IPCC (Intergovernmental Panel on Climate Change) report on global warming (‘U.N. cautions against delay on climate change’). It states: “Delaying action on global warming will only increase the costs and reduce the options for dealing with the worst effects of climate change…global warming will continue to increase unless countries cut emissions and shift quickly to clean energy.”

If one reviews my earlier posts in this blog it will be clear that I support a rapid transition to a clean energy future based on energy efficiency and renewable energy. Having devoted my professional career in government to that end, I believe that President Obama ‘gets it’ re global warming and the need for renewables. In fact, I chose not to retire from the U.S. Department of Energy in 2009, when I was more than old enough to do so, because we had finally elected a President who I believed did ‘get it’, after the frustrating years of Bush 43. I believe my trust was well founded based on President Obama’s subsequent behavior, in word and in action, and it bothers me that some of my environmental colleagues apparently see it differently. I may be getting old and you can say that I am getting more cranky and conservative in my dotage, but I don’t think so. I see myself as more aware of the realities of governing, especially after a long career in Washington, DC, and think Obama is doing a good job under very difficult circumstances (yes, I am referring to a dysfunctional Congress). I do see value in keeping the pressure up on a sometimes-too-political White House, but let’s at least acknowledge more often that the guy is doing a good job, and a much better one than Clinton and Gore did in the 1990’s when they faced similar political problems. Obama is finally getting us started on the path we should have been on twenty years ago.

To be more specific: I recognize and regret that the U.S. does not yet have an energy policy that creates the economic environment for a rapid transition to a clean energy future, as is true of a few other countries (e.g., the EU). It is critically needed, but the reality is that creating such a policy ultimately is the responsibility of our legislative branch. All the Executive Branch’s rhetoric can’t change that, although it has to keep pushing as much as it can and implementing as much as it can through executive orders.

One impact already is a significant reduction in power generation in the U.S. using coal, due to its replacement as a fuel by natural gas. This is due to the large amounts of shale gas released by fracking, a technology that I believe is unstoppable (see my blog entitled ‘Fracking: The Promise and the Problems’) and needs careful regulation. Many environmentalists oppose fracking because of the real risks it poses to water supplies, and I share those concerns, but the important upside is that using natural gas instead of coal for power generation puts much less carbon dioxide in the atmosphere. If renewables were ready soon to assume the power generation burden, and our transportation infrastructure was electrified and ready to use hydrogen in fuel cell vehicles (for which the hydrogen was generated from renewables-based electrolysis of water), then down with fracking for natural gas and oil. But that is not where we are today, and fracking and its economic returns will be with us for a while. Lots of work to prepare the way to our inevitable clean energy future still needs to be done. For similar reasons I do not oppose the Keystone Pipeline – I recognize its risks and wish we could avoid its extension, but stopping it is not going to stop Canada from exploiting its tar sands resources. I’d rather have that oil coming to the U.S. and reducing our continuing dependence on imports from other, less friendly countries. Imports are going down but will still be with us for a while until we introduce greater electrification of our transportation fleets.

Lots of other issues come into this discussion, for which I have no time in this blog if I am to keep it to a reasonable length. The bottom line in my head is that we (clean energy advocates, environmentalists) have to do a better job of educating the public about the long-term advantages of a clean energy society (including jobs) and elect representatives in both the House and Senate who ‘get it’ and feel the pressure from home to move us more rapidly in this direction. Ultimately, politicians understand the power of the ballot box if they understand nothing else. One of our tasks is to use that power effectively.

Water Disinfection: It Is Saving Lives

Every hour hundreds of people are dying unnecessarily of waterborne diseases, mostly children under the age of five. This is unforgivable.

To repeat some words from an attachment to an earlier blog (‘Water and Energy: A Critical Nexus’): “The implications of too little fresh water are significant. The World Health Organization estimates that, globally, more than 1 billion people lack access to clean water supplies and more than 2 billion lack access to basic sanitation. The amount of water deemed necessary to satisfy basic human needs is 1,000*cubic meters per capita annually. In 1995, 166 million people in 18 countries lived below that level. By 2050, experts project that the availability of potable water will fall below that level for 1.7 billion people in 39 countries. Water shortages plague almost every country in North Africa and the Middle East.
(*Note: this number is very uncertain and depends strongly on how ‘minimum requirement’ is defined. To illustrate the problem I quote from an article entitled ‘Minimum water requirement for social and economic development’ by Jonathan Chenowth of the University of Surrey: “There is no common understanding of the minimum per capita fresh water requirement for human health and economic social development. Existing estimates vary between 20 liters and 4,654 liters per capita per day, however, these estimates are methodologically problematic as they consider only human consumptive and hygiene needs, or they consider economic needs but not the needs of trade.” To clarify the situation somewhat most people who study the issue consider 10-20 liters per capita per day to be the right range for minimum drinking requirements.)

These shortages have significant health effects. Water-borne diseases account for roughly 80 percent of infections in the developing world. Nearly 4 billion cases of diarrhea occur each year, with diarrheal diseases killing millions of childrenn. Another 60 million children are stunted in their development as a result of recurrent diarrheal episodes. In addition, 200 million people in 74 countries are infected with the parasitic disease schistosomiasis, intestinal worms infect about 10 percent of the population in the developing world, and an estimated 6 million people are blind from trachoma, with an at-risk population of 500 million.”

These are not small numbers. One billion people is one seventh of the world’s population. Two billion people is almost three out of every ten of our global co-habitants. The enormity of the problem was recognized by the United Nations: at its 2000 Summit the UN adopted two Millennium Development Goals related to water and sanitation: to reduce by half, by 2015, the proportion of people without access to (a) safe drinking water, and (b) basic sanitation. Assuming a world population in 2015 of 7.2 billion, to meet these goals 1.6 billion more people will need to be supplied access to safe drinking water and an additional 2.2 billion access to basic sanitation. Even if the 2015 goals are reached, which is still questionable, 600 million people in 2015 will still lack access to clean water and 1.5 billion to adequate sanitation.

The problem in many cases is not the availability of water – the earth is a water-rich planet. Unfortunately most of that water, 97%, is saline and found in the oceans, and too much of the fresh water available for human consumption is contaminated by microbial pathogens (bacteria, viruses,..) and agricultural and industrial runoff. The question then becomes, other than desalinating brackish and seawater which requires energy, how do we convert contaminated water into potable water suitable for drinking, cooking, and hygiene. Many people and organizations have worked on this effort for many years (e.g., see http://www.unicef.org/wash), and progress has been made, but the world’s population is increasing, especially in developing countries with significant levels of poverty, and the numbers of people suffering from inadequate supplies of clean water are still problematic. In the following paragraphs I will describe briefly some of the techniques for water disinfection, with a special focus on disinfection using ultraviolet radiation.

Treating water at the household level has been shown to be one of the most effective means of preventing waterborne diseases. Even collecting clean water at its source is problematic because of the possibility of fecal contamination during collection, storage, and use in the home. Chlorination is the most widely practiced means of treating water at home and community levels. Boiling water to kill microorganisms is also widely used, but requires fuel to heat the water. Passing water through sand filters to remove suspended solids and microbes, and through ceramic filters coated with silver, are other common means of disinfection. Other techniques use exposure to sunlight (a slow process) and flocculation in which common substances like alum are added to water to facilitate sedimentation of harmful substances.

In 1993 Dr. Ashok Gadgil, Director of the Environmntal Energy Technologies Divisin of Lawrence Berkeley National Laboratory (LBNL) and Professor of Civil and Environmental Engineering at UC Berkeley, invented UVWaterworks as a means of disinfecting contaminated water using ultraviolet radiation. He was motivated by an outbreak of cholera in India, his native country, and focused on developing a technology that would be inexpensive and easily maintained without a skilled operator. It works by passing unpressurized water under an ultraviolet lamp which does not come in contact with the water and the radiation from which disrupts the DNA and RNA of bacteria and viruses, preventing their reproduction. The lamp can be powered by a single solar PV panel or another source of electricity. It has long been known that UV radiation in the wavelength range 240-280 nm has this hermicidal effect and recent research seems to pinpoint 260 nm as the most biologically active wavelength. UV lamps used in this application put most of their energy into this wavelength region.

A standard UVWaterworks unit can disinfect about one ton of water per hour at a cost of about five U.S. cents. An exclusive license for manufacture and sales has been granted by LBNL to International Health, Inc. (http://www.waterhealth.com), and units are now being used all over the world.

Dr. Gadgil’s work has already had a positive impact on millions of people in developing countries, will impact millions more in the years to come, and has led to several well-deserved awards for Dr. Gadgil. He has also done pioneering work in removal of arsenic from groundwater and in development of cookstoves for use in developing countries.

One further comment on use of UV radiation for disinfection: solid-state Light Emitting Diode (LED) technology has now been extended to the UV wavelength region and would be more energy efficient and potentially more reliable than broader spectrum UV lamps that have been used so far. If UV LEDs can be developed for emission at 260 nm and can be produced inexpensively, they should be attractive replacements for UV lamps in future UVWaterworks or similar disinfection units.

Biomass Energy: An Old and Future Technology

Biomass is defined by Wikipedia as “biological material derived from living, or recently living organisms.” It includes plant material and animal wastes. Combustion of biomass has been used throughout human history to provide heat, ever since the discovery of fire, and is the oldest form of renewable energy (it has an extensive literature). It is still widely used for heating purposes but other ways to obtain useful energy from biomass have now been developed, including gasification and conversion to liquid fuels. Each of these applications and biomass’ significant potential are discussed below.

A lot of biomass is produced each year in the world, about half in the oceans and half on land. It is biologically-produced matter based in carbon as well as hydrogen and oxygen. Estimated annual production is 100,000 billion kilograms of carbon. An important point to keep in mind is that the chemical arrangements of these organic materials can be changed, an important focus of biomass research.

On land biomass can be obtained from a variety of sources:

Wood, in the form of trees, tree stumps, branches, wood chips, and yard clippings remains the largest source of biomass energy today. In many developing countries it is still the only combustion fuel source for domestic use. Other common fuel sources include municipal solid wastes, animal wastes (e.g., ‘cow chips’ or bio-digested manure), and landfill gas (primarily methane and carbon dioxide).

In recent years pellet fuels, made from compressed biomass. have been used increasingly for heating in power plants, homes, and other applications. Wood pellets are the most common type, but grasses can also be pelletized. Pellets are extremely dense and can be produced with a low moisture content that allows them to be burned with a high combustion efficiency. Further, their uniform shape and small size facilitates automatic feeding. According to the International Energy Agency global wood pellet production more than doubled between 2006 and 2010 to over 14 million tons. In a 2012 report, the Biomass Energy Resource Center anticipated another doubling of wood pellet production in North America within five years.

An important application of biomass is its direct conversion into liquid fuels, or biofuels, that can replace petroleum-based fuels such as gasoline, diesel and jet fuel. These ‘alternative’ fuels fall into two categories, first generation biofuels such as ethanol that are derived from sugarcane and corn starch (and therefore compete with food crops) and second generation biofuels that use as feedstock non-food and low value agricultural and municipal wastes that are not edible. Production of first generation biofuels is well underway in Brazil and the U.S. but second generation production is still limited by high production costs. The problem is the difficulty in breaking down the lignocellulosic biomass that constitutes the bulk of plant matter. Governments and many private sector firms are attacking this problem and 2014 could be a breakthrough year as a number of second generation production plants come on line.

Ethanol, which is usually mixed with gasoline to produce E-10 (90% gasoline and 10% ethanol) can also be produced by gasification of biomass. Gasification processes use high temperatures in a low-oxygen environment to convert biomass into synthesis (or ‘syn”) gas, a mixture of hydrogen and carbon monoxide. This gas can then be chemically converted into ethanol (C2H5OH) or a wide variety of other C-H-O molecules and fuels.

An emerging and potentially major biomass field is the production of alternative fuels using algae (algaculture). Algae is Latin for ‘seaweed’ and are “..photosynthetic organisms that occur in most habitats. They vary from small, single-celled forms to complex, multicellular forms, such as the giant kelps that grow to 65 meters in length.” ‘Photosyntheic’ refers to algae’s ability to capture light energy to power the manufacture of sugars, carbohydrates composed of C-H-O that can then be converted to other C-H-O molecules. . Algae differ from plants in that they are primarily aquatic.

Interest in algae was triggered by the need for alternatives to petroleum fuels and the world food crisis. Algae produce lipids (a variety of organic compounds) that can be used for making biodiesel, bioethanol, biogasoline, biojetfuel, biomethanol, biobutanol, and other biofuels, using land that is not suitable for agriculture (e.g., land with saline soil). They can be produced using seawater, brackish water, and wastewater, and are biodegradeable. An important, and perhaps critical, aspect of algaculture is that it is claimed that algae farming can yield 10-100 (one claim says 300) times more fuel per unit area than other second-generation biofuel crops. It is estimated that growing enough algae to replace all U.S. petroleum fuels would require only 0.4% (15,000 square miles) of the U.S. land area, or a small fraction of land currently devoted to corn production. Algae crops also have a short harvesting cycle – 1 to 10 days – and so can be harvested repeatedly in a short time-frame.

The biggest barrier to greater use of algae-derived biofuels is the cost of scaling up to commercial production levels. Another concern, for open-pond algae facilities, is contamination by invasive algae and bacteria and vulnerability of monocultures to viral infection. Many schemes for reducing costs and potential contamination are being explored, given the large potential markets available. One obvious target is ground transportation. Another such market is the U.S. military which is already testing biofuels in aircraft and ships. A third large potential market is commercial air transportation. Finally, like all energy sources, biomass has environmental impacts and risks – e.g., water demand and deforestation if land is cleared for biomass production.

A brief word on biochar, a form of charcoal that is created by pyrolysis (low- or no-oxygen heating) of biomass. It is believed that pre-Columbian Amazonians used biochar to increase soil productivity. In addition, biochar has attracted growing attention because of its ability to sequester carbon for centuries (and thus reduce global warming) and its ability to attract and retain water because of its porous structure and high surface area. its production also does not compete with food production.

In my view, and that of many others, biomass will be a major part of our renewable energy future. It is available world-wide, grows in great and diverse quantity, can be used for direct heating and electricity production via heating of water, can be converted to liquid fuels and other C-H-O commodities, and, if used carefully, has significant potential to reduce greenhouse gas emissions. . The Union of Concerned Scientists has estimated that biomass can provide up to 248 GWe of power generation capacity if fully utilized in the U.S. Current U.S. generating capacity is just over 1,000 GWe. Costs, the major barrier, will come down and our children and grandchildren (and probably many of us) will be traveling in biofuel-powered cars, trucks, trains, airplanes, and ships before too long in the 21st century. It is an exciting option and real possibility that is just over the horizon.

Thoughts of a Lapsed Physicist

Perspectives on energy and water technologies and policy