Healthy Solutions for the Low Carbon Economy: Technologies for Early Adoption
Conservation and Energy Efficiency
Conservation and energy efficiency are the obvious measures for early and widespread adoption. Conserving energy, water and materials by altering our behavior involves individuals and the groups to which we belong: families, neighborhoods, places of education, worship and work. This “behavioral wedge” can be pivotal for achieving savings and for sending signals into the marketplace. This shift is already underway and private and public sector incentives are needed to reinforce it.
Conservation and energy efficiency cut across all the wedges, and reducing overall energy demands can enable deployment of more small- and intermediate-scale power generators. Greater efficiency in industrial processes, buildings, transport and waste disposal will reduce demand and save money. These measures are the ubiquitous “low-hanging fruit” (McKinsey 2007b).
Industry accounts for one third of total CO2e emissions, with steel- and cement-production being the most energy-intensive and GHG-emitting sectors (Worrell et al. 2004; Bittner 2004). Material substitution (e.g., fly ash and steel blast furnace slag for concrete), and product replacement (e.g., reusable cloth for petroleum-based disposable plastic bags), decreases energy use and waste. Life cycle analyses of industrial processes, including upstream supply chains and downstream marketing and transport, can identify elements for improving efficiency, resource use, occupational health and safety, and consumer protection.
Green chemistry principles guide industrial chemists and molecular designers to create materials and products that maximize the use of biodegradable feedstocks and minimize waste (Anastas and Warner 1998). Green chemistry employs plant extracts as chemical platforms and avoids petrochemicals, many of which are persistent, hormone-disrupters and carcinogens.
The chemical sector consumes about 20% of the total fuel used by U.S. industry (Worrell et al. 2000) and fossil fuels are used for energy and for the products. Making ethylene, for example, is one of the most energy-intensive processes and is a platform chemical for plastics and medicines. Circumventing ethylene could, therefore, reduce energy use and shift dependence from petroleum for feedstocks.
Deriving plant platforms from highly productive algal ponds would obviate land displacement.
Apart from power generation, utility grids consist of transmission, distribution, storage and use. Over 50% of investments in U.S. utilities will go to upgrade these elements of our energy system. Intelligent technologies include movement sensors to turn on lights, and computer-controlled meters and sensors to identify and power critical functions within buildings (e.g., heating and refrigeration), and within cities (e.g., hospitals and nursing homes). Monitoring and feedbacks, made possible with digital transmission, are components of smart, self-healing grids that can cope better with stresses while stimulating innovation, jobs and enterprises.
A year-long Pacific Northwest Laboratory demonstration project on the Olympic Peninsula, Washington realized significant savings by using: 1. Electric meters to identify times with high prices and high use of coal; 2. Thermostats and computer software to curtail use during these periods; and 3. Remote devices to adjust the preferences. The U.S. Department of Energy estimates that digital monitoring and control technologies could save consumers $70-$120 billion over the next 20 years and obviate the need to build 30 large coal-fired plants.
|Estimated Savings from Green Buildings in the U.S. (In 1996 $US)|
|Respiratory disease||$6 to $14 billion|
|Allergies and asthma||$1 to $4 billion|
|Sick building syndrome||$10 to $30 billion|
|Worker performance||$20 to $160 billion|
|Total Energy Savings||$70 billion|
Schools with Natural Light
|20% faster on math tests|
|26% faster on reading tests|
Stores with Natural Light
|40% more sales|
|Kellert et al. 2008|
Hospitals with Better Lighting and Ventilation
|Improved patient outcomes and reduced hostpital stays|
Green buildings include natural daylighting, argon-containing, tinted windows that keep heat in during winter and deflect it in summer, renewable energy sources and green environs. Green buildings provide energy savings and employ products derived from green chemistry and sustainable forestry (e.g., fast-growing woods and grasses like bamboo). The Leadership in Energy and Environmental Design (LEED) certification of the U.S. Green Building Council (USGBC) includes efficiency in construction, recycling, operating energy and water efficiency, improved air quality, and profitability. Green buildings can be cost-neutral or cost-saving by reducing the size of equipment powering and managing the buildings.
In the U.S., retrofits are planned for almost 1,000 existing buildings (a half billion square feet), using LEED standards. Estimated payback periods range from 2 to 2.5 years.
Studies at the Lawrence Berkeley National Laboratory project that improvements in indoor air quality in green buildings offer tens of billions of dollars in savings.
A caveat: Some of the financial benefits listed (see box) may only be partially realized; further research is needed to assess the health and work performance benefits of green buildings.
Rooftop gardens, with a diversity of plants and bases to capture rain water, have many benefits. Green roofs: 1. Cool buildings; 2. Draw down CO2, toxic chemicals, smog and heavy metals; 3. Absorb noise and shield rooftops from damaging UVB rays; 4. Attract birds that control insect herbivores; 5. Provide useful water; 6. Decrease the urban heat island effect; 7. Create enterprises and jobs; and 8. Make life more pleasant. The cost- and energy-savings more than make up for the upfront costs.
Distributed generation -- on-site power or that produced near the point of use -- can provide both baseline and back-up power for peak use and surges. Distributed generation (DG) can be fed into grids and, with “net metering” and “feed-in tariffs,” provide income for local suppliers. DG can utilize solar, small wind turbines, natural gas and, in most areas of the globe, ground source energy. Fuel cells can generate and store power, and hybrids of energy production modes increase reliability.
Combined heat and power: Many industries require steam in their operations. Generating steam heat and power simultaneously can: a) displace power from the grid; b) be sold to other facilities; or c) be fed into the grid to avoid the need for additional generation. The elegance of this solution has motivated its use at smaller and smaller scales, and residential combined heat and power units are now becoming available. Casten (2007) estimates that recycling waste energy can reduce the fossil fuel burned to generate electricity by one quarter.
The sun provides more energy to the earth in one hour than all the energy consumed by humans in a single year (Zweibel et al. 2008). In
In living plants, incoming wave packets of light (photons)
excite electrons to jump up ladder rungs (quantum
levels), releasing energy as they fall back to intermediate
steps. Chlorophyll contains other components that
capture, transfer, convert and store the energy. In photovoltaic
(PV) systems, photons excite electrons to become energetic
electric charge carriers in external wires.
Nanotechnologies -- with components measuring
billionths of a meter -- increase the surface area of
components, and have the potential to dramatically
increase efficiency and reduce costs. (Their benefits
and risks are discussed below.
addition to the solar energy stored in fossil fuels and plants, solar energy can be harnessed via: 1. Direct daylighting and heating buildings; 2. Heating water; 3. Reflecting and concentrating sunlight with parabolic mirror arrays; and 4. Photovoltaic cells.
Almost 40 million Chinese homes derive hot water from rooftop solar-thermal heaters (Brown 2008).
Persistent drought in major agricultural regions, along with mounting demands on aquifers and surface water, threaten agriculture, hydropower and health in many areas (IPCC 2007b). Desalinated seawater in the Middle East (using oil for power) irrigates land and nourishes populations. Direct solar thermal evaporation and condensation -- and PV- and wind-driven electricity -- can provide communities and regions with freshwater (Morgan et al. 1998; Bourouni et al. 2001; Shannon et al. 2008).
The need for freshwater may become a driver for rapid deployment of clean energy.
In Mexico, water impoundment in lakes is being studied as a means to ameliorate sea level rise. Solar desalination of sea water to irrigate parched lands could play a contributing role.
Ground Source Heat Pumps
Ground source heat pumps supply buildings with heat and air conditioning by tapping into solar (heat) energy stored in the ground. (Geothermal energy refers to heat from hot springs, geysers, volcanic hot spots and hot rocks deep inside the earth.) Ground source heat pumps benefit from near-constant underground temperatures of ~55°F down to 150-200 feet, exploiting the differential between that and above-ground temperatures. The pumps operate to heat and cool, performing the latter by efficiently drawing heat out of buildings. (This naturally-derived air conditioning can help cope with heat waves.) Depending on site characteristics, ground source heat pumps can be shallow, closed or open loops, or deep standing column wells. They can be installed almost everywhere.
Due to drilling and construction costs, ground source heat pumps have payback periods of ~seven years; after that, minimal electricity (e.g., from wind or solar) is needed to drive fluids through the underground loops.
90% of Icelandic homes are heated and cooled with ground source energy (Brown 2008).
High Cap/Low Op Technologies
Technologies with high up-front capital expenditures and minimal operating costs (“High Cap/Low Op”) can be facilitated with creative financial instruments, whereby intermediate companies purchase them, amortize the costs and lease them to individuals and businesses.
Wind energy -- an alternative with competitive costs today -- can be used for distributed power generation and for central power for grids. There is great potential for wind power on land and in coastal waters (Kempton et al. 2007). Use of just 12% of the land suitable for wind power in the U.S. could generate about 1 TW (Lewis 2004). Off-shore winds have a higher potential; but distance from shore (i.e., grids) matters, and the costs are twice those for on-shore wind farms.
Globally, 1.5 million 2 MW turbines could produce 3 TW by 2020, one fifth of energy used worldwide today (Brown 2008).
Computer simulations at the Massachusetts Institute of Technology suggest that very large wind turbine farms could affect local weather conditions and general circulation patterns. Given this potential, the precautionary principle suggests distributing wind farms geographically.
Concern for Birds
Studies of modern turbines (with large, slow-moving blades) in the Netherlands demonstrate very low mortalities, with a higher risk of collision for local birds passing turbines (0.16%) than for migratory birds (0.01%) (Drewitt and Langston 2006). Most studies of bird collisions have found
|U.S. bird deaths from current wind turbines|| 10,000-40,000/yr |
|U.S. bird deaths from communication towers||5-50 million/yr|
|Estimated bird deaths with 2,500,000 turbines worldwide||2.5-10 million/yr|
|Estimated bird deaths from household cats (77 million, U.S.)||100s of millions|
|Worldwide bird deaths from avian flu ||200 million/yr|
Sources: American Bird Conservancy April 2006; M. Z. Jacobsen, pers. comm. 2007; San Jose Mercury News April 2006; World Health Organization 2002
similarly low collision rates; but flight patterns can be altered, especially for water birds (Krijgsveld and Dirksen 2006).
Comparisons of bird mortalities from cell phone tower guide wires and buildings, and due to climate change itself, indicate that the losses from wind turbines are orders of magnitude lower than from these other factors. The effect of wind turbines on birds is therefore projected to be small relative to the benefits of reducing fossil fuels; though siting with respect to avian flyways warrants on-going monitoring and research.
Fuel cells, consisting of two electrodes separated by a membrane, were first developed in 1839. They generate electricity by stripping electrons from hydrogen molecules, which then flow spontaneously through external circuits. Because fuel cells produce electricity electrochemically -- not by combustion -- they are silent, clean and easily scalable (stackable). Fuel cells emit only hot water that can be used directly or for space heating -- giving them twice the efficiency of fossil fuel generators. A 5-to-7 KW fuel cell prototype -- the size of a refrigerator freezer -- can power a 2,000 square foot home.
|Green Chemistry in Action|
Organically-derived materials can be used to manufacture
solar cells, light-emitting diodes (LEDs), transistors
and batteries. The diagram below depicts a small fuel
cell (that functions as a battery), with hydrogen derived
from sugar. Using photosynthetic-like processes and
wind power to split H2O and link the derived H2 with
fuel cells is a central challenge for providing and storing
energy derived from intermittent power sources
(Kanan and Nocera 2008).
Fuel cells, the most reliable of all generators, are being used in hospitals and international banking institutions.
But, separating hydrogen from water, methane, propane, ethanol or gasoline requires energy. Thus, using cleanly-derived electricity to split water (hydrolysis) is necessary for developing the non-fossil-fuel-based hydrogen economy.
|The Cambridge Energy Alliance|
The CEA is a five-year, $100 million energy efficiency project in Cambridge, MA. Its goals are to reduce peak
demand by 50 MW, decrease fossil fuel use 5% and achieve major reductions in GHGs. The program entails:
The CEA will help Cambridge, corporations and consumers stabilize energy costs, reduce pressure on the regional grid and create new jobs and economic development.
--Rob Pratt, Amy Panek, CEA 2008
Healthy Cities Programs
Cities concentrate air pollutants, and locally-trapped ozone (and probably CO2) enhance the urban heat island effect whereby inner cities heat up to 10oF above surrounding rural areas. Healthy cities with green buildings, rooftop gardens, walking paths, biking lanes, tree-lined streets, open space, congestion control and improved public transport can decrease vehicular miles traveled, promote exercise, save money and create jobs. “Smart growth” or mixed-use development combines commercial, service sector and residential housing to reduce commutes and promote community cohesion. Smart urban and peri-urban growth requires long-term, integrated planning.
Most discussions of GHG emissions reductions from the transport sector focus on changing fuel types and improving vehicular efficiency (CAFÉ or corporate averaged fuel efficiency) standards. But there are health-promoting and job-creating measures that decrease vehicle miles traveled (VMTs), and therefore demand for liquid fuels. They include:
- Changing modes of travel (e.g., from cars to bikes, buses and trains)
- Converting whole fleets of vehicles (e.g., from large to small plug-in hybrids)
- Inter-city light-rails to reduce highway traffic and short-haul air transport
- Smart growth to reduce transit and transport.
|Air Pollution and Climate Change: “Nasty Synergies”|
from Fossil Fuels
1. Increasing CO2 boosts ragweed pollen production and pollen grain allergenicity
2. Fine diesel particles help deliver pollen grains deep into the lungs
3. Heat waves accelerate the formation of photochemical smog, another respiratory irritant
4. Climate change is extending spring and fall allergy seasons
5. Floods foster fungi (mold) and fires transiently affect air quality
Epstein and Mills 2005
In the U.S., mass transit reduces road travel by approximately 100 billion VMTs yearly, or 3.4% of the 2007 VMTs. This could be greatly expanded.
Electric cars, developed in Belgium in 1899, dominated the market in the early 1900s. By 1920, however, cheap oil and the internal combustion engine displaced them. The Tesla Roadster is the primary electric vehicle available today, and plug-in hybrid and other electric vehicles will soon be available.
Shipping: CO2 emissions from shipping, with 70,000 vessels carrying over 90% of world trade, are more than twice those from aviation. Marine transport releases 600-800 million tons of CO2 per year, or ~5% of the global total. Neither shipping nor aviation is covered under the Kyoto Protocol.
To reduce GHG emissions from transport, plug-in hybrid electric cars, buses, trucks, trains and ships must plug into a clean grid.
Powering Grids with Clean Energy
With the advent of plug-in hybrid electric vehicles (PHEVs), powering utility grids cleanly becomes the overriding challenge. Deep underground ‘hot rock’ geothermal energy is a relatively untapped resource, and, as solar and wind are intermittent sources, there is a great need for improved means of storing energy.
New storage methodologies include: 1. Hot water and molten salt “power towers” for concentrated solar power (CSP) arrays; 2. Compressed air for wind and solar; and 3. New generation batteries (discussed in supporting materials, online). Impoundments can provide storage and back-up hydropower.
Meanwhile, as two-thirds of energy from power plants is lost as heat, capturing the heat, boiling water and running turbines -- combined heat and power or cogeneration (‘co-gen’) -- can dramatically increase efficiency at all scales of power generation.
Concentrated Solar Power
Large arrays of parabolic mirrors can concentrate solar energy 70-fold, heating liquids that boil water to run turbines and generate electricity. The arrays can also be focused on “power towers” that store energy as hot fluids (e.g., molten salt) up to 12 hours. Three large arrays generate as much electricity as a nuclear plant, and can be constructed in two years, while a decade or more is needed to build nuclear plants. CSP arrays cost roughly half that of PV systems, though twice that of coal-fired plants. CSP projects are under construction or planned in Algeria, Canada, China, Egypt, Israel, Mexico, Morocco, the U.S. Southwest, South Africa and Spain.
Employing hybrids of multiple means of power generation is applicable for stationary and mobile systems. Complementary means of generating power can support reliable, robust grids and facilitate integrated resource-planning. An “ecosystem-based” approach to design avoids “monocultures” of technologies, while diverse measures can avert unintended consequences of over-using any one technology.
And while it is unrealistic to think all our energy needs can be met soon without some use of fossil fuels, natural gas is the cleanest burning and can serve to power back-up generators and for regional and central power plants. With adequate investments and international funds, nations such as China and India can transition rapidly from coal to natural gas, just as did Europe and -- to some extent -- the U.S. in the 20th century.
A “Solar Grand Plan” has been proposed by Zweibel and colleagues (2008) to cover two-thirds of the U.S. utility demands by 2050 with photovoltaic, solar thermal arrays and direct current transmission lines.
CSP arrays and PV farms in the U.S. Southwest, wind farms in the Great Plains and geothermal in the West could generate most of the nation’s electricity by midcentury. CSP and PV in North African deserts, geothermal energy in Iceland and hydropower on the continent, connected by long-range transmission lines, could constitute a European “super grid.”
|The Solar Grand Plan|
|This plan aims to meet 69% of U.S. electricity needs by 2050 with solar energy, accounting for a 1% increase in|
energy needs per year and a modest increase in thin-film PV efficiency (not including nanotechnology). The plan
includes energy storage achieved with molten salt and compressed air. Its implementation would require rewiring
the nation with direct current (DC) transmission lines. Direct current is unidirectional electricity produced by solar
cells and batteries; alternating current (AC) varies cyclically in direction and magnitude.
In the U.S. Southwest, 250,000 square miles are suitable for solar development. This plan calls for 30,000
square miles for PV and 16,000 square miles for CSP. The land required to produce 1 GW of solar energy in
the U.S. Southwest is less than that needed for a coal-fired plant after taking into account land needed for coal
Implementation in Stages
|I. 2011-2020: Subsidies to begin building the infrastructure|
II. 2020-2050: Scale up to achieve the 69% goal
III. By 2100 renewable energy could generate 100% of grid power and over 90% of the nation’s energy
|$10 billion/yr or $400 billion spread over 40 years|
Zweibel, Mason and Fthenakis Scientific American, Jan 2008
The condition of the world’s forests constitute some 20% of the greenhouse problem. Logging, land-clearing, droughts, forest pests, mounting demands for meat and declines in fisheries, are placing enormous pressures on tropical, temperate and boreal forests. The quest for biofuels is the latest threat to these essential biological resources. Every second, one acre of forest is felled, equaling 32 million acres (or 50,000 square miles) annually (FAO 2007). Forests, wetlands, soils and coral reefs constitute the primary stores of carbon on the surface of the earth.
Forest pests are a growing threat associated with global warming. From Arizona to Alaska, pine bark beetles have exacted a heavy toll on North American forests, by overwintering, moving up in altitude and latitude, and increasing their annual generations.
Bark beetle infestations in British Columbia, Canada, have turned vast pine forests into carbon sources rather than carbon sinks (Kurz 2008).
Approximately 2,300 square miles in Colorado have vast stands of dead trees, setting the stage for destructive wildfires. Pine bark beetle infestations contributed to California’s lethal fires in 2006, 2007 and 2008.
An additional wedge of avoided CO2e emissions can be derived by properly managing and skillfully nurturing the world’s forests. Forest preservation, reforestation and afforestation (planting trees on previously un-forested land) contribute to climate adaptation, as forests absorb floodwaters and maintain regional hydrological cycles. Moreover, intact, diverse, healthy forests generate oxygen, draw down CO2, and are essential habitat offering nourishment and protection. Protective policies for U.S. forests include: 1. Extending timber rotations; 2. Banning steep mountain-slope logging; and 3. Prohibiting new roads and off-road recreational vehicles.
Financial instruments to reward avoided deforestation and tree planting include “Debt-for-nature swaps” that offer payments to local foresters in lieu of debt-repayment to international banks (Lovejoy 1984), and well-monitored and verified carbon credits and carbon offsets. The United Nations Development Programme and World Bank initiative, Reducing Emissions from Deforestation and Degradation (or REDD), will require adequate funding.
By paying land-holders to preserve and plant trees, Costa Rica increased its forest cover from 20% in the early 1990s to 50% in 2007 (Arias 2007).
But climate stabilization is needed to protect and preserve healthy terrestrial habitat.
Soils store 1,100 to 1,600 GtC (FAO 2007) and, while carbon is added to soils annually, an equal or greater amount is lost from erosion, forest clearing and overgrazing (D. Pimentel, pers. comm. 2008).
Soils can be carbon sources or sinks, depending on how they are managed and nurtured. Crop residues, roots and litter store carbon; conservation tillage leaves them to minimize soil disruption, absorb flood-waters, maintain soil fertility, and reduce run-off and erosion. Conservation tillage (or no-till agriculture) can improve crop yields, preserve micro-nutrients, sustain plant and animal biodiversity, and mitigate climate change by holding stored carbon.
Diverse fields of crops, interspersed with trees and shrubs, store more carbon than do large open fields and monocultures. High-diversity grasslands generate approximately two and a half times the energy yields as do monocultures, measured over a decade (Tilman et al. 2001). Poly-culture practices provide resilience to weather-related damage and crop pests (Zhu et al. 2000; Mitchell et al. 2002), and organic agriculture eliminates pesticides and minimizes fertilizers (both fossil fuel-derived), while locally-grown food decreases the “food miles” that generate greenhouse gas emissions. With targeted policies and incentives to enable investments in land conservation and low-carbon agricultural practices, these measures, along with no-till agriculture, can provide an additional wedge of avoided carbon emissions.
Less Intensive Livestock Rearing
Energy inputs and GHG emissions from animal agriculture stem from: 1. Animal-rearing; 2. Growing feed; 3. Fertilizers, pesticides and herbicide production; 4. Animal waste, including methane; 5. On-the-farm fuel use; 6. Processing and packaging; and 7. Off-the-farm transport of meat and dairy products. Together these steps account for almost 20% of GHG emissions worldwide. (Material adapted from Koneswaran and Nierenberg 2008, unless otherwise indicated.)
The bulk of the loss stems from land-clearing. Of the 2.7 GtCO2 emitted by livestock rearing, 2.4 GtCO2 (or 1 GtC) is released from deforestation to create grazing pasture and fields to grow grain for feed. Eight-to-ten pounds of grain (and thousands of liters of water) are needed to produce one pound of beef. For hogs and chickens, the ratios for grain-to-meat are two-to-three to one, respectively.
Concentrated animal feeding operations, or CAFOs, release CO2 and methane into the air and nitrates into ground water (Townsend et al. 2003). Nitrates have health (“blue baby syndrome”) and environmental consequences (eutrophication, “red tides” and “dead zones”). The air pollutants from CAFOs have been shown to increase asthma rates in children attending schools nearby (Mirabelli et al. 2006; Sigurdarson and Kline 2006), and intensive, industrialized farming requires high levels of antibiotics to prevent disease and promote growth, practices that encourage the emergence of antibiotic-resistant bacteria (Pew 2008).
Industrial livestock production has grown twice as fast as have mixed farms, and six times the rate of grazing systems. Globally, industrial systems account for an estimated two-thirds of poultry meat production, one-half of egg production, and two-fifths of pork production.
Healthy practices include: 1. Free-range and pasture-based production; 2. Local production; 3. Improved waste management; 4. Methane capture and use; and 5. Changes in consumption patterns. U.S. residents consume 200 lbs of meat (including fish) annually and Chinese counterparts now consume 110 lbs per person per year. Reducing red meat consumption is recommended to save energy, water and land, and reduce obesity, heart disease and some types of cancer.
Improved Municipal Solid Waste Management
Municipal sold waste (MSW) management is currently highly inefficient (as is municipal water management). In 2000, annual emissions from MSW were estimated to be 0.47 GtC/yr, and they are projected to double (0.99 GtC/yr) by 2054 (EPA 2002, 2005; Covanta and Trinity 2007). Increased use of recycling, energy recovery and energy generation (via landfill gas collection) have the potential to reduce GHG emissions more than 1 GtC/yr, thus comprising an additional stabilization wedge.
|Low Tech/High Opportunity Measures|
Innovative low tech solutions can be implemented in a variety of settings. They include:
Bicycle-driven systems augmenting solar- and wind-powered
Stairmaster- and bicycle-driven generators in health clubs and homes
Stairmaster-like kick- and hand-pumps for irrigation and small enterprises
Knee-mounted generators that turn “walks into watts”
(Donelan et al. 2008)
Powering vehicles with vegetablle oil
Solar-powered desalination and water decontamination
This is a chapter from Healthy Solutions for the Low Carbon Economy: Guidelines for Investors, Insurers and Policy Makers (e-book).
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