The oceans are replete with organisms eager to fasten themselves to solid surfaces and grow there.
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Wave and tidal systems may also impede the flow of marine vessel traffic or cause undesired changes to the vistas of neighboring homes. From these examples for baseload electric power, it can be seen that water has a significant and growing relevance to energy production. Certain governmental agencies and nongovernmental organizations are becoming more interested in how energy, water, and food are interconnected because solutions or technologies in one area often affect other areas.
As another example, multiple coastal power plants in California have been shut down because concerns over harm to marine life from the heat of its released, used cooling water. As yet another example, nuclear power plants in the U. Northwest shut down briefly during a hot summer because the source of cooling water was too warm enough to operate the plant safely Associated Press, Many more examples exist, and instances are likely to grow in number and severity over time.
The oldest and most traditional source of renewable power used by humans is biomass.
Since the invention of fire, woody plants and dried ruminant manure have been used for space heating and for cooking food. Combustion burning is inefficient and generates smoke containing particulate matter, which can lead to respiratory distress especially for women and infants living indoors. The amount of dirt added is not sufficient to snuff the fire, but rather reduces the amount of oxygen in the air that can reach the burning embers. The ensuing incomplete combustion produces a smoke that contains flammable gases, such as methane, hydrogen, and carbon monoxide.
By capturing these gases and pumping them through pipelines, the gas can be flared at a stove for cooking or a lamppost for street lighting. Producer gas can be used as a fuel for ICEs, or its hydrogen component can be separated and used to operate a fuel cell, both of which can generate electricity. Modern agriculture has evolved crop yields that have risen steadily for decades. In North America the amount of above-ground plant material at harvest time is considerable.
Starting in the U. This document, along with other studies by the DOE and the U. Department of Agriculture, outline approaches for converting wood, grain, grasses, food waste, and animal manure from chemical energy into electrical energy, heat, and fuels. Although renewable, a fundamental challenge is the diffuse nature of biomass. Although storable solid, liquid, or gaseous fuels can be produced from biomass e. A nonfood cellulosic ethanol plant producing million gallons per year requires a majority of producers on long-term purchase contracts within a radius of 50 to 75 miles. The feedstock has a relatively low energy content per unit mass relative to fossil fuels like coal and oil.
The stalks, husks, cobs, and leaves are collectively called stover, which is a relatively dense source of lignocellulosic biomass. One promising source of biomass that potentially overcomes the bane of areal density is microalgae. Microalgae are too small to observe with the naked eye and appear as a green tint in water. Certain strains of microalgae produce a very high proportion of their body mass as lipids fats , which can be extracted and converted into storable fuels.
A key challenge in cultivating microalgae is the need to prevent feral algae from contaminating the high-lipid species, which tend to be less robust and can be quickly dominated by the wild strains. Microalgae also require nutrients to grow, and this represents a significant expense in using them to make biofuels.
Mechanically extracting lipids from cell-sized algal bodies is more difficult than pressing soybean oil from beans because the tiny algal bodies tend to pass directly through the filters or sieves, thereby requiring smaller holes and attendant higher pressures and energy. Considerable research in this area is ongoing, and industry watchers expect results to become more favorable around Baseload power from biomass can benefit from pyrolysis, an advanced conversion technology that mimics the geological processes that formed coal, oil, and natural gas but with greatly accelerated rates.
A close cousin to gasification, pyrolysis, applies heat to biomass in the absence of oxygen. Less clean producer gas can be used in an external combustion engine, the most well known of which uses the Stirling cycle, first conceived by a Scottish priest in the early s Organ, Refining of hydrocarbons is a large-scale industrial process and is tailored to the exact composition of the type of petroleum used which varies widely , and so is not widely employed on so-called pyro-oil.
The carbon-rich solids can be co-fired with coal in conventional power plants, as can pelletized wood or crop residues. However, biomass-derived solid fuels tend to have a high pH and can cause corrosion problems inside coal-fired power plants. Gasification and pyrolysis plants of 2 to 5 MW can execute power purchase agreements PPA and sell power directly to the wholesale grid for prearranged pricing.
However, the bane of areal density and the challenges associated with centralized processing of biomass into fuels and energy suggest that baseload power may be more effectively created from distributed generation DG. Smaller conversion systems can also communicate with the electric grid in a manner similar to residential solar or wind systems. These smaller sources of renewable energy can of course serve loads on-site, but they can also provide power to the larger electric grid via power electronics circuits and controls known as switchgear.
Switchgear controllers that can feed the grid can also be used to divert excess power to local energy storage systems such as batteries or ultracapacitors. The concept of combining smaller-scale renewable power generation with optional local energy storage and grid-interfacing switchgear is called a microgrid, or, in some parlance, a nanogrid.
A key task for the switchgear is to harmonize the on-site power generation with the electric grid for voltage, for frequency, and for phase. These three characteristics of alternating current ac power must be matched closely to avoid disruptive ripples of power either out to the grid and its other customers or into the microgrid.
India's Shift to a Sustainable Energy Future
Details of this interconnection logic are dictated by the local electric utilities and typically guided by state or federal regulations. With a large number of DG biomass gasifiers or pyrolyzers running gensets within microgrids, power can flow into the distribution and transmission lines.
In this way, biomass has the potential to provide the characteristics of baseload power so appreciated by all consumers of electric power. While earlier hints exist, this concept was first developed in some detail by Peter Glaser in the late s and patented shortly thereafter Glaser, The idea of orbiting solar farms solves the intermittency experienced by ground-based PV. By providing around-the-clock baseload power from space, the need for energy storage is dramatically reduced.
Peter J. Schubert
Such power plants produce no pollution or effluent during operation, although some wastes are generated during construction as is true for terrestrial PV and wind. Space solar power SSP can be made available to every large population center on earth. Because every nation can have access to power from orbit, there is no concern over globally finite or spatially restricted resources. The technology to make SSP possible has existed since the s but has not been realized largely due to economic challenges and lack of political will U. Senate, Lofting hardware into space is expensive and requires considerable expenditure of energy to reach escape velocity.
Many architectures for SSP have been proposed over the years Potter et al. Most rely on ultra-light solar cells to reduce the high launch cost per unit mass. Beaming power from orbit to ground is a larger-scale version of the modern communication satellite and would use similar frequencies of radiowaves see Fig. Figure 4: Configuration for solar power satellites comprised of a cylindrical shell of photovoltaic cells with a central electrical bus delivering power to a disc-shaped phased array antenna which transmits radio-wave power to receiving antennae on earth.
This satellite has no moving parts and rotates once each day. Lasers can be used. Lasers are energetically inefficient but are easily aimed and have a small receiving footprint.
However, lasers can be easily weaponized—making them unsuitable for nonmilitary applications. An attractive candidate for baseload electric power is transmission in the same ISM industrial-scientific-medical band as that used by cellular telephones. Beams at this frequency about 2. To justify the size of an ISM rectenna, the orbiting solar farm must also be large e. Clarke, satellites placed here move at the same angular rate as the earth turns, making the satellite appear to hang fixed in the sky to an observer on the ground.
This is where many communications satellites are already parked.
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Once operational, a GEO solar farm provides constant power at all times year round, with two minor exceptions. All architectures for SSP have the advantage of zero pollution during power production, plus it is silent and invisible. SSP is a monumental undertaking, one that requires considerable funding prior to the sale of significant amounts power to return the initial investment.
Sustainable energy for developing countries
Such a time horizon is likely outside the range of private enterprise and perhaps larger than any one nation could support alone. It may be that global cooperation is needed for this ultimate answer to powering human endeavors. These financial considerations are so significant for SSP that they help to illuminate the key role that economics plays in the adoption and expansion of renewable energy in general.
The global economy in is dependent on fossil fuels. Coal, oil, and natural gas power production are relatively inexpensive at present because of three economic factors:. Maturity: More than a century of steady technological progress has provided tools and practices for efficient and low-cost operation, together with high reliability. Economies-of-Scale: Broadly based revenues spread nonrecurring and fixed costs across more customers so that each one bears a proportionately lower fraction of such costs.
Externalities: Also called noncosted consequences, these are impacts for which no monetary value has been assigned and therefore do not factor into economic decision-making. To a certain extent, government regulation for safety and for effluent control do have a measurable economic value and are therefore not strictly considered an externality. Established energy interests also benefit from having helped drive infrastructure such as tanker ships, railroad lines, and transmission cables.
In some jurisdictions, energy companies have been granted monopolies, regulated by the government, precluding direct competition.