Month: October 2013

Hydrogen and Fuel Cells: Important Parts of Our Energy Future?

Hydrogen is a simple atom/molecule and the most abundant element in the universe.

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As a physicist it is an an article of faith with me that mankind will eventually make large scale use of hydrogen as a fuel. As a realistic physicist I also acknowledge that such large scale use of hydrogen is a number of years away.

The device that will convert hydrogen into a major energy source is the fuel cell, which is an electrochemical device that combines hydrogen and oxygen to produce electricity, with water and heat as its by-product. First invented in the 19th century, today there is extensive research and a large and growing literature on fuel cells.

In its simplest form, a fuel cell consists of two electrodes – an anode and a cathode – with an electrolyte between them.

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When cells are stacked in series the output increases, resulting in fuel cells with power capacities ranging from several watts to several megawatts. A fuel cell system that includes a fuel reformer can obtain hydrogen from any hydrocarbon fuel such as natural gas, methanol, or gasoline. Since fuel cells rely on an electrochemical process and not combustion, emissions from fuel cells are significantly lower than emissions from even the cleanest fuel combustion processes. Fuel cells are also quiet, durable, and highly efficient. They are different from batteries in that they require a constant source of fuel and oxygen/air to sustain the chemical reaction; however, fuel cells can produce electricity continually for as long as these inputs are supplied.

My enthusiasm for hydrogen goes beyond my physics daydreaming: I often refer to it as the ultimate energy storage system. For example, what does a utility do with excess electricity generated by wind turbines at night when the wind is often strongest and consumer demand for electricity is lowest. The simple answer is to store it for delivery during the next day when demand and electricity prices are higher. Of course, storage is not energy- or cost-free, and still expensive today. My attraction to hydrogen is that excess electricity can be used to electrolyze a common substance (water) into hydrogen and oxygen and the hydrogen can be stored and used in fuel cells which transmit their generated electricity to consumers in many locations via power lines. No need to transport hydrogen via pipelines which are inherently expensive and often hard to site, and these pipelines have to be impervious to leakage by the tiny hydrogen molecule, unlike more standard fossil fuel pipelines. The kickers in this game are that water has to be available and the efficiency of electrolysis devices needs to be improved to reduce the cost of hydrogen production.

A fuel cell is a transformative technology that changes the way we generate and use electricity, a characteristic it shares with solar PV. It can be used in small and large sizes, in mobile and stationary applications, and has several technological foundations (proton exchange membrane, phosphoric acid, solid oxide). The hitch in fuel cells is cost reduction, a tough problem to address, and they’re competing as storage devices with lithium ion batteries which are steadily getting cheaper. Flywheels, when mass produced, may also offer some competition.

I’ve been following fuel cell development issues for almost forty years, since arriving in Washington, DC, and cost seems to be the major barrier to their large-scale use. Lots of effort is going into related research, including how to mass produce cheaply. The U.S. Department of Energy is supporting this effort both for mobile applications (i.e., cars) and larger stationary applications.

Considerable effort is also going into development of micro fuel cells that can be used to power cell phones, laptop computers and tablets – all of which can benefit from longer-lasting portable power supplies. These will probably be fueled by replaceable alcohol-water cartridges where the alcohol (ethanol/C2H5OH or methanol/CH3OH) supplies the needed hydrogen. For example, one mixture under investigation is 35% methanol in water. Such a micro fuel cell could provide ten hours of laptop time, although some computer tablets today achieve that goal. The reason for not going above 35% is that methanol interacts chemically with common anode and cathode materials and degrades the fuel cell. Nanotechnology may offer new material options, allowing this percentage to increase. An interesting aspect of alcohol use in micro fuel cells is that alcohol, being flammable, requires a waiver to be brought onto airplanes. Ethanol clearly has such a waiver as witnessed by drink service on most aircraft. Methanol only recently obtained such a waiver.

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Carbon Capture and Sequestration: Is It a Viable Technology?

As mentioned in my previous blog (‘What I Took Away From the Doha Clean Energy Forum’): “three speakers made a strong case for carbon capture and sequestration (CCS) as a means of addressing global warming and climate change, especially in heavily carbon emitting industries such as cement production. Lots of questions remain, and will be discussed in a future blog.” This is that future blog on a well trod but still controversial subject.

Wikipedia defines CCS as “..the process of capturing waste carbon dioxide (CO2) from large point sources, such as fossil fuel power plants, transporting it to a storage site, and depositing it where it will not enter the atmosphere, normally an underground geological formation.”

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Considerable literature exists on CCS, exhibiting a wide range of opinions on its viability as a technology to reduce carbon dioxide emissions. The principal argument for CCS is that the world today is fueled largely by coal, oil and natural gas and that this situation is not likely to change any time soon. In fact, as many developing nations industrialize and emerge from poverty, the demand for energy increases steadily and it is argued that only fossil fuels can meet that demand in coming decades. It is also argued that while solar and wind and other renewable energy technologies can eventually replace electricity from coal and natural gas power plants this will not occur quickly and people will need fossil energy during the long transition. In addition, some industries like steel and cement are not so easily ‘fixed’ and will continue to use fossil fuels in increasing amounts as global industrialization grows.

These points raised in support of CCS are countered by the following arguments:
– CCS is expensive, whether added to an existing power plant or industrial carbon dioxide source, or included in newly constructed facilities. The energy penalty for operating CCS is also high, requiring a fair amount of parasitic energy that reduces efficiency and revenues.
– When operating, CCS systems require large amounts of water.
– captured carbon dioxide must be liquified and stored for indefinite periods of time in such a way as to avoid leakage and large ‘burps’ that can be toxic. This requires identification and development of storage sites (depleted oil and gas wells, coal mines, underground aquifers), infrastructure to transport liquid CO2, adds additional costs and raises questions of liability if something goes wrong and stored CO2 is accidentally released.
– the time required for development, demonstration and large-scale deployment of CCS technology that can have a meaningful impact on global warming is too long compared to other options.

Proponents of CCS (see http://www.globalccsinstitute.com) argue that CCS costs can be brought down significantly with a sufficient number of demonstration projects and economies of scale associated with large-scale deployment. Nevertheless, at the recent Doha Clean Energy Forum even one of its supporters admitted that an impactful global CCS system will cost an estimated 3.6 trillion USD (and I did say trillion). My immediate reaction was that for $3.6 trillion I can deliver an awful lot of renewable energy that will replace coal, oil, and natural gas use in power generation and transportation. Nevertheless, there is the argument that the CO2 emissions from some industries will still be there in large and growing amounts even with large-scale deployment of renewables and CCS is the only way to limit these emissions.

These are strong arguments for some attention to CCS R&D and demonstration, but, in my view, not at the expense of rapid development and deployment of renewables. This creates a conundrum as CCS demonstrations are expensive, and the money for them would have to come from somewhere. Government funding is at best problematic in current budget situations. Other possibilities are the fossil fuel industries themselves, which have a vested interest in continued purchase of their commodities. Countries with large reserves of fossil fuels – e.g., the U.S., with large reserves of coal – will also see value in CCS allowing extended use of secure domestic energy reserves.

In a world committed to reducing carbon emissions CCS offers a helping hand but not a definitive one. It may offer a partial answer for the rest of this century, but governments are unlikely to provide the needed funds for large-scale deployment. Let’s see if the private fossil fuel sector is willing to step up to protect its vested interests.

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What I Took Away From the Doha Clean Energy Forum

Returned on Friday (11 October) from four days in Doha where I participated in the final annual Global Clean Energy Forum sponsored by the International Herald Tribune (IHT). In the future IHT will be known as the International New York Times.

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The Forum organizers put together an excellent set of international speakers on a broad range of clean energy issues, including fracking gas and it’s impact on investments in renewables, energy technology innovation, sustainable energy in Arab and developing countries, carbon capture and sequestration, and perspectives of the financial community on investments in renewable energy. The agenda can be found at http://www.inytcleanenergy.com/2013-agenda.asps.

Some of my take-aways are the following:

– shale gas from fracking is seen as a definite part of future energy supplies and will be considered ‘complimentary’ to other natural gas supplies such as those from the large reserves in Qatar.
– the availability of relatively low cost, large shale gas supplies will affect the pace of investments in renewable energy technologies.
– the fact that water and energy issues are ‘inextricably linked’ is gaining wider acceptance but is still not routinely mentioned in discussions of energy supplies.
– global investment in deployment of renewables is increasing, but the pace of investment will have its ups and downs, with national policies being a critical determining factor in these early days.
– transportation will be an important future market for fuel cell and other forms of green electricity.
– there is much opportunity and need for innovation in clean energy technologies, with a corresponding need for appropriate incentives.
– The United Nations is finally on board with the need for greater attention to energy issues in sustainable development (there were no energy goals in the 2000 Millennium Development Goals).
– The financial community sees solar energy as the best bet for future renewable energy investments. De-risking clean energy investments is a critical need in funding decisions.
– three speakers made a strong case for carbon capture and sequestration (CCS) as a means of addressing global warming and climate change, especially in heavily carbon emitting industries such as cement production. Lots of questions remain, and will be discussed in a future blog.

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Off to Doha – international Herald Tribune’s Global Clean Energy Forum

I will be leaving on Sunday, October 6th to spend most of a week in Doha, Qatar. This will largely be to participate in the International Herald Tribune’s annual Global Clean Energy Forum. My next blog(s) will be based on what I experience and learn at the Forum. (Note: as of October 15th the IHT will formally be relabeled New York Times International).

The following description is from the 2013 Forum web site (http://www.ihtconferences.com/gcef-2013.aspx):

“Sustainability in the new energy reality

The 2013 Global Clean Energy Forum will explore the new energy reality – that of abundant fossil fuels, cooling political sentiment towards renewables and risk-averse investors.

It will examine the new role of clean energy within the overall energy mix, and the complete journey towards a sustainable future which will include cleaner hydrocarbons and nuclear 2.0.” The full agenda and other Forum details can be found at the web site.

Solar PV

Specifically, I will be a speaker in the October 9th interview session labeled ‘The new energy mix’ (details below):

“On-stage keynote interview: The new energy mix
Shale gas, and increasingly shale oil, are changing the dynamics for the whole energy industry – especially in the US, but with global repercussions. What does this mean for renewables?

How will renewable energy prices be affected by the rise of shale?
What part will gas play in the transition to clean energy?
What next for onshore and offshore wind?
What is the place for Concentrated Solar Power in tomorrow’s energy mix?
How can the water energy nexus be balanced?
Dr Allan Hoffman, Visiting Professor of Renewable Energy and Desalination, GORD (Gulf Organization for Research and Development) and former Senior Analyst, Office of Energy Efficiency and Renewable Energy, US Department of Energy (DOE)
Santiago Seage, CEO, Abengoa Solar
Omran Al-Kuwari, CEO & Co-founder, GreenGulf Inc.”

Meetings such as this are becoming more common and needed as renewables enter the energy mainstream.

Solar Power Satellite Systems: A Viable Option?

In earlier blogs I’ve commented on Solar PV and Concentrating Solar Power. Here I will comment on Solar Satellite Power Systems (SSPS). As proposed, such systems would use electricity generated by a collection of solar PV panels in geosynchronous orbit (i.e., an orbit above a fixed point on earth) to power a microwave generator. The generated microwaves would be beamed through the atmosphere to a ground-mounted receiver (‘rectenna’) that would convert the microwaves to electricity that would be distributed to consumers via the terrestrial grid.

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This concept first received NASA attention and review in the 1970’s which raised a number of issues which still remain problematic. A small group of SSPS enthusiasts still promote the technology but broad support is lacking.

The obvious advantage of SSPS is its access to unimpeded radiation from the sun without the interference of clouds or atmospheric absorption and scattering. This is partially offset by the need for the microwaves to pass through the atmosphere to the rectenna but presumably a microwave frequency would be chosen with minimal atmospheric absorption. It should also be noted that every step of SSPS is technically feasible and well established – solar conversion to electricity, microwave generation, microwave transmission through air, microwave collection and conversion to electricity, and grid transmission.

Personally, I am not a supporter of federal investment in the technology for the following reasons:

– putting anything into orbit is expensive, very expensive, and until these costs are reduced significantly SSPS will not be cost competitive.
– economics dictate that large SSPS concentrations (100’s to 1,000’s of MWe’s) be placed in orbit. One suggestion I recall is to place a 10 GWe unit in geosynchronous orbit to supply the electrical needs of New York City. In my opinion this is crazy – putting all your eggs in one highly vulnerable basket.

These vulnerabilities include exposure to higher-than-usual radiation levels in space which will shorten expected equipment lifetimes, possibility of collisions with space debris and micrometeorites, ordinary technical failures (with a lot of electricity potentially at risk), and vulnerability to sabotage/attack in the event of international tensions.

– aircraft will need to avoid the beams passing through the atmosphere to avoid any possible impacts to humans from exposure to relatively high strength microwave signals. Birds will be another potentially impacted species.

– the large land areas required for rectennas which would ideally be located in close proximity to cities with large electricity demand.

So, is SSPS a viable option for future electricity supply? Not in the near- to mid-term in my opinion. Long-term may be a more optimistic story. Solar PV costs are now much lower than they were just a few years ago and going down, radiation resistance of solar cells and microwave generating equipment may be improved, the cost of insertion into geosynchronous orbit will hopefully come way down, and small SSPS units (100-300 MWe) may become practical to be considered. The other problems would remain, and terrestrial competition from other renewable electric technologies will increase.

In a time of limited federal budgets R&D investment in SSPS does not strike me as a prudent use of government funds. Nevertheless, I recognize that SSPS has its core of ardent supporters (several came to my office while I worked at DOE) and I hope some of them will comment on this blog with their own views.