Solar Energy Has a Tail Wind

January 4, 2012 § 2 Comments

The price of solar panels dropped 70% in 24 months.  Good news for the consumer, not so good for manufacturers of panels.  Three of them went out of business last year including the infamous Solyndra.  You recollect this as the outfit that got $535 million in loan guarantees from the DOE.  They were excoriated for this by the Republicans in Congress.  Incidentally, a loan guarantee is not the same as a loan, as noted recently by the Brookings folks in an analysis of the merits of these measures.

The tail wind comes about from the realization that we may already be close to the generally accepted target of $1 per watt installed capital.  This is the number at which most observers felt grid parity could be met.

Grid parity is defined as rough equivalence to the delivered price of base load power, usually from coal.  But this measure is not completely relevant in cases where the solar power is used for peak shaving because the cost to the utility of delivering peak period power is a good deal higher than the average cost.  It is also not at all relevant when there is no grid, as in remote areas and villages in developing nations.

Initially the costs of panels came down largely due to the actions of Chinese manufacturers of silicon based panels.  Some believe that government subsidies allowed for this and that this was a play similar to that in rare earth metals.  In that case, China assured itself a virtual monopoly by causing mines all over the world to shut down due to inability to be profitable at the low prices set by the Chinese companies.  However, the excitement currently centers on alternative materials.  First Solar in Arizona is well on its way to the $1 target using Cadmium Telluride (CdTe) thin films as the material.  Eminent scientists are arguing that this approach is flawed because world supplies of these materials, primarily Tellurium (Te), are inadequate for large scale replacement of base load power.  This argument fails to take into account the fact that Te is a bi-product of copper extraction and has no other volume use.  Ores rich in Te almost certainly exist and could be targeted for exploration.  Until these avenues are explored, the warning bells are premature.  Cd being a heavy metal has also undergone scrutiny from an environmental risk perspective.  CdTe being a very stable compound is not subject to leaching and so this too ought not to be a concern except for the impassioned few.

The Te argument also underscores a general malady with alternative energy positions taken by people: the silver bullet problem.  There is absolutely nothing wrong with a market basket of alternatives pecking away at coal and gas.  Furthermore, the lesson in the CdTe story is that thin films are a viable avenue to low cost panels rivaling silicon on cost.  Other compounds will find a place and will either replace CdTe or simply co-exist with it.  There already are laboratory scale reports of success with Iron Pyrites and most recently with organic semiconductors.  In the case of the latter, efficiencies double that from CdTe is being claimed.

India is the latest country to make a big push in the solar arena, and this coincided with the dramatic price drops.  Subsidies are consequently much less costly than in other countries such as Germany.  At an auction at a state owned utility in Gujerat the winning bid was 8.77 rupees (16.2 cents) per kWh.  This is about double the coal based price and yet is 27% lower than the low bid a year ago.  As a reference, Germany, the biggest solar user in the world paid US 23 cents per kWh.  India has the opportunity to make a virtue of being late.  Besides, India averages 3000 hours of sunlight per annum; the sunniest city in Germany weighs in at 1600 hours.

Off-grid applications:  Parity with conventional alternatives is much easier to achieve in off-grid markets.  The principal application would be rural communities in developing countries.  Here the competing source is most likely kerosene or diesel based.  Kerosene is considered essential for lighting and cooking in many Indian rural communities.  As a consequence it is heavily subsidized.  But the subsidy is provided at the distributor level not directly to the consumer.  A recent estimate puts 38% of the kerosene as stolen (the government study making the estimate uses the euphemism “diverted”).  So the effective cost of the delivered fuel is very high and much more easily matched by solar.  Remote power is usually diesel based.  Not only is the fuel expensive, but the trucking costs are high.

Even in western nations, a rule of thumb breaking even with solar is running 1 km power line to the grid.  That is at today’s solar prices; those will continue to drop but not so the cost of running a line.

Storage Solutions:  Since the sun chooses to shine only during the day, storage is something of a necessity.  The greatest demand on the grid is in the late afternoon and early evening.  In the latter period, the photon intensity is low or absent.  The objective of peak shaving is best accomplished if some of the electricity produced earlier in the day is stored for evening use.  As discussed earlier, peak electricity is very costly because the natural gas generators operating in this period are idle for much of the time and so the fully loaded cost is high.  This is despite the fact that compared to coal and nuclear, natural gas cost is lightly loaded on the capital side, thus limiting the idle time cost.

One of the storage solutions being developed uses molten salt as the heat storage medium.  The so-called Solar Thermal method uses systems of mirrors to direct the rays to heat up a fluid rather than produce electrons.  This is analogous to childhood experiments using a lens to concentrate solar energy to set a piece of paper alight.  For direct conversion to electricity, this fluid is water and steam generated drives a turbine.  When storage is required, the heat is used to melt a mixture of salts, currently comprising nitrates of sodium and pottasium.  Lower melting salt mixtures are being researched in order to  minimize the risk of unintended freezing.  The heat in the salt is transferred to produce steam for a generator.

One purveyor of Solar Thermal systems claims that the storage and release will shave 4 cents per kWh off the cost.  If accurate, that is significant.  Much of the cost savings come from eliminating the peaking gas generator.

If the trend towards ever lower cost of solar panels in real terms continues, and if solar thermal systems become commercial, solar power could overtake wind as a near term renewable source to replace fossil fuels – at least in some places in the world.  Every little bit matters.


Energy Engineering in the Triangle

September 30, 2010 § Leave a comment

The national imperatives of energy security and sustainable energy development will drive the creation of new businesses centered around alternative energies. We expect these to fall into t wo areas: replacement of oil for transportation and less carbon intensive electricity production. In addition, research regarding intelligent electricity grid has become an interesting combination of these two areas.

Furthermore, the more efficient use of energy will also play a central role in sustainability. The engineering work force required to execute all of these would benefit from college training that recognizes these specific fields of study. An Energy Engineering (En E) curriculum could well be the solution. Here’s what such a discipline might entail.

The foremost disciplines in the general field of energy engineering are those of Nuclear Engineering and Petroleum Engineering (Pet E). We will use the latter for discussion because it is more widespread and serves a mature industry fairly well with a defined set of required training (Nuclear is similar). Thus it is able to sustain a specialist discipline.

This will not be the case for the En E program serving the alternative energy industry. The industries served could have elements of the following: solar electricity, wind electricity, biofuels with biochemical and thermochemical variants, smart grid and related enablers, energy efficient devices, batteries and other storage, clean coal, carbon sequestration, electric cars and related endeavors such as fuel cells, and hydro. This breadth alone hinders a unique En E four year program.

Even Pet E is subject to the whims of the industrial cycle. In a recent trade publication, an influential department chair recently put out a plea for hiring their graduates. One of the problems is that the hottest play in petroleum today is shale gas. They are hiring, but the volume required is in the hard core disciplines of Mechanical, Electrical and Chemical Engineering, not Pet E. In fact, far more of these comprise the petroleum work force in general. Alternative energy programs should use this knowledge as a guide.

A minor not a free standing major

The solution is to offer concentrations in En E, perhaps even minors. These would be enhancements to core engineering degrees. There would be an analog for the sciences, wherein a Chemistry degree could be supplemented with an Energy Science concentration.

Such concentrations would be expected to comprise four to five courses of nominally three units each. Courses would be selected from a menu, with the selections directing the student to particular industries. But the key to this approach is that a down cycle in that industry is not a catastrophe. The student can rely on the core engineering skill set for an entry level job.

Social Science is a key ingredient

An important element of this minor would be the treatment of the social science component. Engineering curricula typically requires few social science courses. But an En E concentration (minor) will enable students to learn more about the social science approach to sustainable energy.

In order to incorporate this concept into the minor, students would be required to choose courses from a set list that include the themes of energy and the environment. The intent would be to learn the principles of economics, psychology and the like, but linked to an energy setting. This could necessitate modified courses in those departments. Energy is a field of considerable interest to students today, as evidenced by surveys in the local institutions. So, such modifications would likely be welcome at a broad level.

The 3 U offering

When the offerings are compiled there will undoubtedly be gaps in faculty resources. NC State already has a concentration in power engineering, but even they will face gaps in other areas. The Triangle area offers the unique opportunity for a program that allows for collaboration between all three universities. We are referring to this as the 3 U solution.

Bi-lateral programs already exist, including the Robertson program (UNC and Duke) and the Biomedical Engineering curriculum (NC State and UNC). While faculty additions will be needed, the resource pooling will allow the program to get on track more quickly. RTI can also be expected to be a player, most likely in the biofuels space. The possibility exists for the participation of some of the RTP powerhouses playing in the energy space.

In short, the Triangle area is unique in that three important research universities participating in the energy space are in close proximity. Add to that the presence of RTI, an unquestioned leader in energy research, with a recent Department of Energy $169 million award directed to carbon sequestration. This powerful combination allows for a jump start to Energy Engineering. No other area in the world has this capability.

The Energy/Water Nexus

June 23, 2010 § Leave a comment

This piece is loosely based upon the RTEC Breakfast Forum on June 15, 2010

Sustainable energy can fall in two buckets.  One comprises all the means to lower the carbon footprint of current energy sources.  This would include clean coal, using natural gas in place of coal to produce electricity, combined cycle approaches to energy production, and the like.  The second bucket is that of renewable energy.  The outstanding examples of that are biofuels, wind energy and solar energy.

Each of the foregoing has very different water utilization.  One billion persons do not have access to drinking water.  Should efficiency of water utilization be a factor in our choice of alternatives, and not just carbon footprint?  Going further, should water usage be a litmus test in areas in which the citizenry suffer a high level of privation?  This was the subject of the RTEC Breakfast Forum on June 15, 2010.

We tend to use fresh water for everything when something less could do the job.  This is likely an artifact of water being relatively cheap.  If some of the major users were able to tolerate less than fresh water, water would be freed up for human consumption. An extremely topical area for this thought is shale gas drilling in the US.  Each well uses up to 5 million gallons per well as the main component of fracturing fluid.  Only about a third of the fluid used returns to the surface.  Currently it cannot be re-used because of contaminants, salt in particular.   Even if this were to be cleaned up for re-use, the other two thirds would need to be made up from fresh water sources.

Fortunately, industry is taking a hard look at the problem and is moving to modify formulations to be able to tolerate significant salinity.  So, not only would the flow-back water be re-usable, but other saline waters of convenience, such as sea water, come into play.  In an odd twist, it turns out that salinity is actually good for the operation (it stabilizes the clays).  Lemonade from lemons, as it were.

While not particularly applicable to the shale gas play in the eastern United States, a lot of “tight gas” exploitation occurs in the middle of the country, in areas that are severely drought prone.  Here, water for energy competes with that for agriculture.  The ability to tolerate salinity would be huge.  This is because saline aquifers are plentiful.  Supporting technology would be required in areas such as benign biocides.  Bacteria in these waters are often pernicious, some being sulfate reducing, and thus producing hydrogen sulfide in situ when used for fracturing fluid.  But these are all tractable if the major issue of some level of salinity is traversed and if innovations in cost effective water treatment are forthcoming.

The key to water treatment is to have a fit-for-purpose output.  Potable water is the most expensive.  An intermediate product could be adequate and meet the economic hurdles.  Today almost all desalination approaches have fresh water as the output.

Agriculture tolerant of brackish water is a new area without significant currency today.  The most obvious example is algae for bio fuel production.  Algae, of course, thrive on salt water (and consume carbon dioxide as another plus).  A class of plants known as halophytes make themselves saltier than the salt water, thus causing fresh water to flow into them by osmosis.  Most such would likely be for biomass for energy production, not food.

Water used in conventional energy production is also highly variable.  The paper by Mulder et al describes water efficiency of different energy production methods.  Any eye-opener is the significant difference between closed and open loop cycles.  An interesting nuance is also the difference between water withdrawal and water use.  For example, if a facility such as a nuclear plant, withdraws water from a river, and then returns hotter water, the subsequent evaporation downstream is not counted in some measures.  The withdrawal number remains low, even though the net usage was higher.

Using less water is not always productive.  Apparently in some areas drip irrigation leads to salt build up around the plant.  Also, drip irrigation returns no water to the aquifer.  But on balance that must still be more effective than spraying, where evaporative losses may not necessarily be returned as convective rainfall.

Drought tolerant biomass is highly touted these days.  Jatropha in India and elsewhere is seen as an important crop for biodiesel production.  However, an interesting twist on this is that these plants can tolerate drought, but they grow much faster with more water.  A farmer with water access will draw on it.  So, what is needed is clever business models and associated policy drivers to encourage water conservation in the face of a compelling economic driver to use more.  An interesting problem for a behavioral economist.

A case for decision science research in energy

March 16, 2010 § Leave a comment

A sustainable low carbon future is seen by most to center around breakthroughs in technology and the associated economics.  Most of the attention has been on carbon sequestration, biofuels, renewable sources of electricity and the like.  A number of states and countries have instituted policies to make some of these happen.  Many also see electrification of transportation as an avenue to zero emission vehicles and energy security of net oil importing nations.  All of these cause people to make choices, in many cases requiring changes in behavior.  Introducers of technology know that the barrier to wide scale adoption is particularly high when it involves substitution of something familiar.   The science of why people make the decisions they do, especially those involving green alternatives, merits further investigation, if for no other reason than that it may guide product and process development into areas with higher success rates of adoption.  It will undoubtedly be effective in informing on policy.  An example is in the area of solar energy.  If the primary driver for adoption is “seen as being green”, then hiding photo voltaic devices inside shingles would be counterproductive, as also the policy of many neighborhoods to disallow visible displays of solar panels on homes.

The International Energy Agency (IEA) has posited that for any reasonable 2050 targets for atmospheric carbon dioxide nearly 40% of the mitigation has to be from energy efficiency.  Their most recent forecast calls for 57% of carbon mitigation by 2030 as being from energy efficiency (and interestingly only 10% from carbon sequestration).  Undoubtedly this will in large measure be accomplished with engineering designs that provide the same utility for less energy. This has been the case with up to 90% reduction in standby power of household appliances through the simple expedient of low energy power supplies and modified circuitry.  Since standby power constitutes 10% or so of all electricity usage in IEA countries, this is a huge gain.  The Energy Star and similar efforts have produced further results, although some of these fall in a different bucket, that of the same utility at a somewhat greater price.  In the case of compact fluorescent bulbs, the initial price is higher but the life cycle cost is lower.  Now this begins to get into the realm of decision science because the consumer is required to understand and appreciate life cycle costing.  We are firmly in it for cases where the costs are substantially higher, as in the case of hybrid vehicles. Electric cars will get squarely into the behavioral arena from the standpoint of range anxiety, which is roughly defined as the fear of running out of charge.

Electrification of transportation is an RTEC priority because we see it as the fastest route to energy security through making electricity fungible with oil.  Furthermore, well to wheel efficiency of electric cars is about 45% better than that of conventional cars and the tail pipe emissions are zero, although the burden is shifted to the power producer, where it is more tractable.  Consequently, enabling the public’s acceptance of electric cars is an RTEC priority.

Addressing range anxiety and other behaviors falls at least in part in the area of decision science.  Some of it can be addressed with technology.   For example, Nissan’s introduction of the Leaf later this year will be accompanied by features such as remote monitoring of the state of charge of the battery and driver notification, including identification of the nearest charging station.  But in most instances, technical advances only take us so far.  When smart electricity meters are installed in homes, there is high variability in the manner in which the data are used by the homeowner.  Behavioral studies are needed to guide the programs to achieve the best results.  Non price interventions that rely on behavioral proclivities, such as conformance to societal norms, can likely be used to advantage.

In their matrix of program thrusts, DOE’s newly formed unit ARPAe has a matrix element that intersects social science efforts with transportation.  RTEC believes that this could be a fruitful area of pursuit for RTI/Duke/UNC collaboration.  One possible project would combine conventional survey based approaches with behavioral economics ones in addressing the electric car range problem.  At this time this is based on guesswork premised upon beliefs regarding consumer preferences when driving conventional cars.  Statements such as “the consumer expects a range of 300 miles” are rife.  A definitive study of driving distances in metropolitan areas that are initial target of electric vehicle entry could then be used to devise behavioral studies, the results of which could be expected to drive out interventions, both price based and not.  To aid this, the original study would be broken out by age, income and other relevant demographics. Finally, the interventions themselves could be tested on a population.

The foregoing notwithstanding, RTEC believes that the greatest gains for society in the realm of sustainable energy are going to come from simply using less.  Consequently, a major focus will be to encourage and assist members in devising social science based research with this goal in mind.

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