Robotic Solar Armada by Helionauts
Synthetic fuel produced by solar harvesting ships can accelerate the transition to renewable energy by obviating an infrastructure overhaul.
At current rates, the global transition to renewable energy will take over four decades. Although renewables are close to cost-parity with fossil fuels, we cannot roll out $30 trillion worth of energy infrastructure overnight. This timeline is untenable because atmospheric CO2 concentration has surpassed safe levels, and the risk of triggering catastrophic climate feedback loops continues to escalate. It’s not enough to reach 100% carbon-neutrality. We must remove CO2 from the atmosphere.
Our solution is to use solar energy to extract CO2 and H2 from the oceans, where CO2 is 140 times more concentrated than it is in air, and convert it to syngas (a mix of CO and H2), a renewable synthetic fuel. Together with carbon capture and storage (CCS) technology, a synfuel economy can be carbon-negative. Synfuel is compatible with existing fossil fuel infrastructure, so it doesn’t require a long and costly infrastructure overhaul to bring renewable energy to market. It can even be used in aviation.
Synfuel production completely decouples the supply of renewable energy from the time and location of consumption. It solves the intermittence of solar power and allows solar collectors to be placed in remote locations (the ocean) where real-estate isn’t a concern and the sun is bright. A mobile collector can even travel to where the sun is brightest according to the season and weather. This capability allows the system to access over twice the insolation of a stationary solar collector.
We’ve designed these mobile, seafaring, solar-collecting, fuel-synthesizing platforms (dubbed "Helionauts") with an emphasis on rapid scalability. They leverage economies of utility-scale production without concomitant overhead, long lead times, and inconsistent funding cycles that plague typical utility installments. Helionauts exploit several other benefits of the marine environment (e.g. simplified cooling) to target cost parity with fossil fuels.
Category of the action
Reducing emissions from electric power sector.
What actions do you propose?
Build a team
The Helionaut Project will not succeed without a well-organized group of skilled and dedicated individuals to carry out the required work. It will require people with business acumen to help forge partnerships, secure investment, and execute the plan. It will require a legal team to help navigate regulations and intellectual property concerns. It will require an engineering team to develop the concept into a functional system. The composition of the teams is described in the “Who will perform these actions” section.
We will need to secure funding from both the private and public sector in several stages throughout the development and first few years of the Helionaut production.
Partner with universities
We may be able to accelerate the research, development, and prototyping phases by collaborating openly with universities.
Testing the synfuel technology
The first aim is testing fuel-synthesis technology, which can be broken down into four or five subsystems: pumping, H2 extraction, CO2 extraction, syngas production (a precursor to synfuel, comprising CO and H2), and, optionally, a hydrocarbon synthesis process. The full system, which can be constructed from common industrial equipment, is described below:
Seawater is pumped in through a filter to remove biomass. Some of the seawater is diverted to the CO2 extraction system while the rest is desalinated before heading to the electrolysis system, where H2 is generated.
The CO2 extraction system we intend to use was recently developed and patented by Xerox PARC. It uses electrodialysis (a process similar to electrolysis) to separate seawater into acidic and basic streams. The acidic stream is subjected to a vacuum, which induces desorption of CO2 gas from the solution. Finally the acidic and basic streams are recombined into CO2-depleted seawater.
The H2 and CO2 are combined in a water-gas shift reactor (WGSR), where they are converted to syngas (CO + H2) and water, which is redirected to the electrolysis unit. This reaction follows:
CO2 + 2H2 → CO + H2 + H2O
According to the Navy’s research into synfuel production from seawater, the above processes incur a 59% conversion rate from solar energy to chemical energy. At this point, there are many options: Syngas can be used as fuel in some systems without any processing, however it is also a feedstock in the production of many other chemicals:
We could store the syngas and sell it directly to customers, or we could process it further into another hydrocarbon (e.g. methanol).
Converting syngas into hydrocarbons is an exothermic process, so all further processing can be done with very little energy input. This makes it a very versatile product. Customers can buy our syngas and turn it into whatever hydrocarbon they need (gasoline, jet fuel, fertilizer, etc.) or they can burn it directly as a fuel. It also means that any further processing we do will release some of the energy stored in the synfuel as waste heat.
Storing syngas, however; involves all the same difficulties as storing hydrogen. It requires enormous pressure to store a reasonable amount in gas form, or very cold conditions (-252.9º C) to store it as a liquid. It’s also dangerous to store and transport syngas in either form.
It is possible to convert syngas to liquid methanol through a simple catalytic reaction:
CO + 2H2 → CH3OH
Methanol is much easier to store but less versatile as a feedstock. It would also require an additional onboard methane synthesis reaction chamber and separation system.
Our team needs to build and test the seawater pump, electrolysis stack, CO2 extractor, and WGSR. We will also need to study the available storage options and the market for syngas and its derivatives to determine the most feasible choice.
We believe China could be a good market for syngas or methanol because both are heavily used as industrial feedstocks and are typically derived from natural gas. China has few natural gas resources, so it must either turn to importing at a very high price or heavily investing in coal gasification. China plans to produce syngas for as little as $7-8/Mcf by 2020. The current price of methanol in China is ~$300/ton.
Design a seaworthy platform
Unfortunately, it isn’t feasible to purchase a free-floating platform “off-the-shelf.” Typical barges, container ships, and tankers cost too much per square meter of deck space to be economically viable for collecting solar power. Unlike the Helionaut, these ships are designed to carry heavy loads at a relatively high speed. It may be prudent to purchase one or more for prototyping purposes, but the engineering team will have to design a custom platform for the final product.
The platform needs to resist corrosion and biofouling. It must be durable enough to survive decades at sea with few pit stops. Any exposed optics for the solar collector need to resist deformation, UV degradation, and soiling for the collector to operate effectively. The design must also be hydrodynamically stable and efficient, and conform to maritime standards.
We believe we can build a floating platform at a reasonable cost by combining several functions (e.g. using the hull as a heat-sink) and by taking advantage of relaxed constraints. For instance, because the majority of the solar collector platform does not need to be used for product storage or personnel, it can be pressurized, similar to an aluminum can, allowing us to achieve a stronger hull with less material than conventional hulls.
Design the propulsion system
Propulsion allows the Helionaut to act both as an energy collection and an energy delivery platform. Our calculations show that mobility allows the Helionaut to access almost twice as much sunlight as a stationary platform.
We estimate the cost of the propulsion system at less than 1% of total system cost. This is because the migration pattern of the Helionaut only requires very low speeds (~4-6 knots). The power required for propulsion scales roughly with velocity^3, so a ship traveling at 20 knots uses ~125x more power than it does at 4 knots. This means we will likely be able to use off-the-shelf electric motors to power the ship.
Design the tracking system
The high cost of real estate on the floating platform drives the need for high collector efficiency. We will want to capture the most energy per square meter possible. The most efficient form of solar power is concentrating photovoltaics (CPV). Fortunately, some of the largest cost drivers for CPV (foundation, mounting, and cooling) can be mitigated in a sea-based design. Spherical floating collectors (depicted below) can effectively use the ocean as a gimbal mount and achieve a low wind cross-section. However, ocean waves add to the challenge of accurately tracking the sun.
When the tracking error in a CPV system exceeds a certain angle (called the “acceptance angle”) its efficiency steeply declines. Our system needs to keep tracking error below the acceptance angle (typically 1-2º) a high percentage of the time to justify the added complexity of CPV.
If we decide to use a CPV collector we will need to:
accurately measure the position of the sun in the sky
accurately orient the collector towards the sun
dampen the disturbance from waves and other sources
We can also increase the acceptance angle by:
using secondary optics
using high-precision manufacturing techniques for the optics
Accurately measuring the position of the sun relative to a given collector will likely involve several sensors (gyros, accelerometers, GPS, image sensors, etc.) and software to fuse and denoise the readings. Orientation can be achieved by simply shifting the center of gravity (COG) of the collector. A feedback controller connected to the weight shifting mechanism can allow the same system to be used to counter disturbances by making small, fast adjustments to the COG (much like noise canceling headphones). Flywheels can also be added, if necessary, to give the collector some angular momentum to dampen the impact of disturbances.
Automate the system
Automating Helionauts helps reduce the cost and logistical complexity of operation and maintenance (O&M). The most challenging aspect of this goal may be overcoming the legal, rather than technical, concerns surrounding autonomous ships. However, full autonomy isn’t crucial to the success of the Helionaut project. Autonomy can be implemented to varying degrees and in various functions, as it is on many commercial vessels today. Ideally, we would automate navigation, weather avoidance, collision avoidance, regular cleaning, and other maintenance tasks.
Ensure the safety of the system
We need to study the potential environmental impact of the Helionaut project to ensure we aren’t doing more harm than good. If we truly intend to ramp production up to scales that make Helionauts a meaningful player in the energy market, we have to be acutely aware of the potential damage an irresponsible design choice could cause the environment. We need to make sure Helionauts don’t release any toxic chemicals or disrupt any sensitive biomes. We also need to make sure that an accident will not result in environmental damage. Mapping and evading sensitive ecological areas is essential to minimizing environmental impact.
Develop security protocol
Investors will want some assurance against the threat of piracy and sabotage. We will need to consult with experts to assess the magnitude and probability of such threats and possible strategies for mitigation.
We will need to secure permitting from several nation-states and international organizations that control different parts of the oceans. We will also need to ensure that the Helionaut conforms to the various laws and regulations of each.
Launch pilot fleet
Once the engineers have finished prototyping, one or more small fleets will be deployed to prove the system’s viability before moving to full-scale production.
We will leverage existing fuel distribution infrastructure to bring our product to market. That means finding distributors who will buy our synfuel. The fleet’s yearly migration cycle between the northern and southern hemisphere means that we may need to find several ports in different countries that will take synfuel delivery throughout the year.
If the pilot fleet is successful, customers have shown interest, and we’ve raised enough capital, we can build a factory and ramp up production. Mass production will bring the cost of Helionauts down enough to ensure a healthy profit margin that will grow as Swanson’s law takes effect and fossil fuels become scarce.
Promote investment in Helionauts and CCS
In order for the Helionaut Project to yield a net reduction in atmospheric CO2, the synfuel produced must be burned in a system with CCS technology. Traditional renewable energy systems, on the other hand, are only ever carbon neutral. Therefore, when public officials are considering how to address their energy needs, we need to promote the option of upgrading and retrofitting any existing hydrocarbon plants and investing some of the savings in the production of more Helionauts.
Who will take these actions?
A working group will manage the various teams necessary for this project, the largest of which will be the R&D group.
The engineering team will be in charge of all the research, development, and prototyping work. It will include marine engineers who will ensure the design is seaworthy and hydrodynamically efficient. Electrical engineers will develop the power electronics and sensor and control hardware. Chemical engineers will work on the fuel synthesis system and corrosion and biofouling resistance. Software engineers will develop models of insolation, weather, optics, and other physical systems for analyzing different designs. They will also write software for automating the system. Production engineers will analyze how various design decisions impact the cost of production.
The legal team will serve several functions. They’ll protect intellectual property, help liaise between the Helionaut project and its partners, and ensure compliance with local, national, and international laws. We will need an international lawyer and a shipping/ocean ocean law permitting lawyer to help navigate the laws and regulations of operating our ships. We will also need an IP lawyer to help us protect our research and license key pieces of technology.
The outreach team will also have a variety of important tasks: they will seek funding and partnerships, and will work with lawmakers to stimulate implementation of the Helionaut model. Additionally, outreach will promote use of the Helionauts to energy industry trade groups.
Where will these actions be taken?
Development of a prototype will take place in California because it has several important benefits: access to ocean water for testing prototypes, mild weather allowing for year-round work, and several businesses and academic institutions that can provide input and partnership. California also has an excellent funding base, with investors familiar with the tech industry and start-ups, and the state provides incentives and resources for utilizing and developing green technologies.
We plan to conduct our pilot program in a small island developing state (SIDS). Because such locales are oceanic and require importation of fossil fuels. we believe that they would be best for developing the market and would be able to support the initial higher price point. Furthermore, SIDS have an incentive of avoiding ocean acidification and global warming, since they are likely to be hardest hit first as climate change radicalizes.
As discussed earlier, China is another good early market since they need natural gas for industry, but only have limited access at very high prices.
How much will emissions be reduced or sequestered vs. business as usual levels?
Synfuel offsets fossil fuels and opens up the opportunity to convert carbon sources (fossil fuel power plants, automobiles, etc.) into carbon sinks by equipping those sources with CCS technology. Current CCS technology can capture 80-90% of carbon from flue gas while adding as little as 21% to the energy costs. This highlights the importance of bringing synfuel to market quickly before potential carbon sinks are all but replaced by carbon-neutral renewable systems. -80% is far better than 0% emissions.
We estimate that a helionaut comprising 2000 pods (1-meter radius spherical solar collectors) would cost roughly $1.5 million and produce 1000 tons of methanol/year (worth ~$300,000 in Chinese markets). This represents 1500 tons of displaced carbon/year. 1200 tons of that 1500 would be permanently removed from the atmosphere if burned in an 80% efficient CCS equipped system. That comes out to a net total of 2700 tons/year CO2 reduction per helionaut and a payback period ~6 years.
What are other key benefits?
In addition to the carbon sequestration and renewable fuels generated by this project, we will create several permanent full-time jobs, as well as many more temporary positions during development, testing, and deployment.
Ocean acidification is a serious problem caused by the increase in CO2 concentrations in seawater, and it causes significant damage to sensitive ecosystems, such as coral reefs. Sequestering CO2 from ocean water will help alleviate this.
We hope to make a significant contribution to the understanding and development of synfuel production, carbon sequestration techniques, and autonomous sailing.
What are the proposal’s costs?
Although we aim to keep our team small, we also foresee the need for a diverse set of skills to tackle a complex engineering and implementation problem. We will need one electrical, marine, and chemical engineer. We’ll also need a programmer to develop software and production engineers for consulting on fabrication. At an approximate salary rate of $80,000 per person per year, we estimate a total budget of these personnel at $320,000 per year, with additional budgeting for outside consulting.
In addition, we’ll need several lawyers on retainer, versed in intellectual property, maritime law and permitting, and international law, respectively. We estimate that average expenses in this regard should come to approximately $50,000 per year, with larger expenses in the middle of development (anticipating and identifying legal hurdles) and at the end, when testing is underway.
We will need consultants and lobbyists versed in fuels and renewable resource markets who can provide invaluable advice on strategies of implementation; where testing, development, and harvesting might be most practical; and on markets open to our product. As well, they can, ideally, encourage lawmakers to stimulate employment and expansion of the syngas market, either by finding industries where it would be useful or by retrofitting existing infrastructure for syngas and carbon capture. We hope to keep costs for this service at below $75,000 per year on average.
We will need to rent out a workshop ($36,000/year) and some prototyping equipment, including:
A 3D-printer ($30,000)
Electrolysis stacks ($20,000)
Tools (Tools ($10,000)0,000)
Measuring/test equipment (Measuring/test equipment ($10,000)0,000)
This comes out to $70,000 capital costs and $501,000/year in operating costs.
We estimate that our team should be able to move from initiation to prototyping, development, and testing and be ready for market launch within 15 years.
First 6 months: Build a team and begin fundraising and networking
Years 1-3: Small scale prototyping.
Years 4-5: Large-scale prototyping.
Years 5-10: Launch pilot systems in SIDS and (possibly) China.
Years 11-12: Build a small factory.
Year 13: First production run.
Years 14-15: Ramp up to full-scale production.
Years 16+: Build more factories, work on CCS tech and promotion.
 timeline for transition to 100% renewables (p.20): http://srren.ipcc-wg3.de/report/IPCC_SRREN_SPM.pdf
 Solar set to reach grid parity: http://www.marketwatch.com/Story/story/print?guid=F4031B1C-52B9-11E1-A6A2-002128040CF6
 350 ppm considered upper bound on safe CO2 concentration: http://350.org/about/science/
 renewables are not enough: http://spectrum.ieee.org/energy/renewables/what-it-would-really-take-to-reverse-climate-change
 synfuel from seawater: http://bravenewclimate.com/2013/01/16/zero-emission-synfuel-from-seawater/
 Insolation data: https://email@example.com
 Chinese Syngas Market: http://blogs.platts.com/2013/01/03/china_2013/
 Chinese Methanol Market: http://www.platts.com/news-feature/2015/petrochemicals/asia-petrochemical-outlook/methanol