On Tuesday Jan 14th, between 10:00 and 10:30am PST, Solve for X is hosting a google+ hangout on air for StratoSolar.  It's a hosted event where I'm asked a series of questions by a moderator and the audience can also ask questions. I have never done anything like this so I'm not really sure how it will work, but people can watch and participate live and there ends up being a YouTube recording of the event.

The link https://plus.google.com/u/0/events/cv1m6fasvccse8uvlnlk9n0gf4g is to sign up to attend the hangout, post questions ahead of time, and watch it when it happens on the 14th

Another way to ask questions during the event would be to tweet me at @edkellyus

It's an interesting experiment. Please sign up if you can and let others that might be interested know as well.

Also, as I mentioned previously, the StratoSolar solve for x moonshot video has got high ratings on the solve for x site. If you login you can rate the video in various ways.  If you have not done this already, please do. https://www.solveforx.com/moonshots/stratosolar-edmund-kelly

Edmund Kelly

The non-fossil energy from current nuclear, wind and solar are failing and will continue to fail in reducing CO2 emissions. This is borne out by all credible projections by the EIA, IEA world bank and others. Optimists in all current non-fossil energy camps rationalize why these projections are wrong, but my assessment agrees with the objective observers.

Too much of alternative energy is wishful thinking. No current choice is economically viable so the common reasoning is to pick one and argue it will get better if we support it wholeheartedly, and by implication reject the other alternatives. This makes for a polarized debate that goes nowhere.

Currently the US spends about $12B/y on green energy. With current politics its hard to see this amount growing. This amount of subsidy will support wind, solar and bio at slow growth rates if they get cheaper. This is the acceptable amount of subsidy that balances the current political realities. Realistically the subsidy level is more likely to fall, with the wind PTC on a yearly cliff and the solar ITC expiring in 2016.

Energy is too big a part of the economy with too many powerful entrenched interests for government to afford the subsidies or fight the battles necessary for any meaningful impact based on currently available technologies.

Current economic and political realities make it clear that economically viable clean energy that does not need subsidy is the only way to grow clean energy.

My point is not that we should stop supporting current non fossil fuel alternatives. What we do need to do is to invest intelligently in new  non fossil technologies that might have the potential to succeed. While the debate centers on in fighting between the current alternatives, and a search for more taxes and subsidies to prop them up, a real debate on how to grow the pool of options cannot start. The air has been pulled from the room.

A new approach to fund power plant development (rather than basic research) is needed. A model I like is SPACEX. This is essentially a government funded system level startup that is succeeding. Rather than the cost plus model of government contractors, this was essentially funded with fixed priced contracts for tangible results. Unfortunately the DOE has not learned from NASA's experience, and even if it had, entrenched fossil fuel interests ensure that Congress will block any attempts at reform.

A stepped funding model that offered initially small funding for tangible results, with more funding as viability is demonstrated would allow a range of new ideas to be tested cheaply. There are currently a handful of fusion energy and advanced sustainable safe nuclear companies that could benefit from investments in the $10M/y to $100M/y range. There are some crazy wind and solar alternatives that might succeed. Were they to demonstrate they were on a path to viability, larger funding for the few that make it would be forthcoming.  A yearly budget of $10B could fund dozens of new system level energy companies. The key would be to avoid long term subsidies for boondoggles. The $10B/y is just a swag. Less could easily accomplish a lot, and it all does not have to come from the US.

By Edmund Kelly

I have written previous posts pointing out the benefits of StratoSolar for Japan and the UK, two very densely populated countries with few indigenous energy sources and a desire for clean energy. 

Though China is not as committed to clean energy the potential benefits of StratoSolar for China seem even more compelling, though for different reasons.

In general, solar and other renewables solve three problems:

1)      Fossil fuels are a finite resource.

2)      Burning fossil fuels damages the environment and is causing climate change.

3)      Energy security. Dependence on imported energy threatens national and economic security.

Interestingly, for the US, none of these problems are currently regarded as particularly serious, and the environmental argument 2)  is the only one propping up alternative energy.

China is the inverse of the US. For China 1) and 3) are already a problem today, and at China's rapid rate of economic growth the problem is only getting worse. China is now the world's biggest oil importer, but its oil consumption is set to a least triple by 2040, 75% of which will be imports.  This puts the Chinese economy at huge risk from oil price volatility and/or supply constraints. China has a lot of coal so coal is not in as precarious a situation, but China currently imports a lot of coal from Indonesia and Australia.

An unlimited local source of cheap energy solves these problems.  Not only does it remove the resource and security problem, it also potentially provides an economic  competitive advantage.  China has leveraged cheap coal energy into dominance of energy intensive industries like steel, aluminum and chemicals. If StratoSolar provides cheaper energy it can continue that strategy, with the added benefit of no pollution.  It also puts China in a leadership position in a technology of world significance. Following the PV cost reduction path and investing in fuel synthesis technology could cement and enhance this leadership position.

A quick short term benefit is StratoSolar deployment in China  would help some specific industries that China has overbuilt; aluminum and PV silicon. StratoSolar systems consume a lot of aluminum for the structure, and clearly use PV panels.  StratoSolar systems deployed on a large scale would rapidly become the world's  biggest aluminum and PV consumer.

Food for thought.
By Edmund Kelly

The StratoSolar concept is usually greeted with a high degree of skepticism.  The obvious way to answer this skepticism is to build it and demonstrate that the system works reliably and delivers low cost electricity.  This creates a catch 22 situation: It is necessary to raise money to demonstrate viability.  However, without a demonstration of viability it is impossible to raise money.  

Independent investors like venture capital or private equity are unable and unwilling to quantify the risks of something that appears so different.  Despite the view that venture capital invests in risky things, the reality is that they are mostly herd followers, and won't touch anything that has un-quantified risk.

The financing problem is further compounded by the fact that there are no general energy companies that have R&D budgets to fund energy as a general category. The energy field is isolated factions, each only concerned with their own business and wary of competition.  Oil and gas, coal, nuclear, wind, solar and  bio-fuel are separate islands.  They raise capital individually and spend it exclusively on their sector. Oil and gas have the most money to invest, but they see exploration as their R&D and other sectors as competitors.

In theory, government should see a big energy picture, but in practice democratic governments treat energy as multiple separate political constituencies and funds flow separately to each sector.  The only government funded sector that treats energy somewhat broadly is research, so peer reviewed science projects get some relatively small R&D funding.  This funding flows through pretty rigid highly regulated channels within academia and the national labs. The current US system provides no funding channel for possible new power system level entrants. 

Compounding this difficult funding landscape is the polarization of public opinion.  People are drawn into camps. Environmentalists see current wind, solar and bio-fuels as the solution and any new contender as a devious plot to undermine their support and delay or stop dealing with the climate problem.  Those who think wind and solar are impractical and favor nuclear only want nuclear.  Those who don't accept climate change or don't want the government involved favor burning fossil fuels.  This polarization of society is reflected in possible investors, most of whom fall into one of these polarized camps. This makes it hard for anything new to get consideration.

In pursuing investment we have gradually evolved an approach that uses engineering ingenuity to reduce the cost of the first step that proves viability. This is in the hope that a smaller investment enlarges the potential initial investor pool.  This is based on the expectation that seeing is believing and that crossing the divide to a minimal functioning system will give confidence to larger high risk investors attracted by potential for very large profit. 

Our other approach is to try and provide data and insight, mostly via the web site and blog, that can help reduce the general impression of science fiction by explaining the concept in more detail and with more context.  This unfortunately only works for those willing to make a significant effort, and is a pretty hard sell.

Overall raising money for this venture has proven to be  a far more complex problem than the actual technical design.
By Edmund Kelly

All approaches to eliminating CO2 emissions rely on a transition to a predominately electricity based energy system. We have EIA projections for energy demand in 2050, so it is possible to model different fossil fuel free energy systems that meet this energy demand. This is not an attempt to predict how the future will unfold, but by showing all the pieces and their relationships it helps in understanding the impact of various technologies on the overall system.

Today there is no significant electricity storage, and fuel synthesis from electricity is equally insignificant. The need to handle intermittent energy sources, and the need to provide liquid fuel for transportation mean that both technologies are necessary at significant scale by 2050 if fossil fuels are to be replaced. The relative cost of energy from each and the sector energy efficiency and demand for either fuel or electricity will determine the relative size of storage and synthesis. 

The range of possible outcomes is large and dependent on too many variables to predict. We only show centralized large scale storage but distributed storage at the destination, like batteries in transportation, residential or commercial sectors will also affect the balance of demand between fuel and electricity.

Fuel synthesis and electricity storage only exist today as small research prototype systems.  Alternative energy is too expensive, and synthesis and storage add considerable expense on top of the cost of energy they take in, so there is no economic incentive to invest in either.

The fundamental enabler for storage and synthesis is cheap electricity. Today we make electricity from fossil fuel. An electricity economy inverts this and makes synthetic fuel from electricity. If the synthetic fuel has to compete with fossil fuel, it needs to be cheaper. This means electricity has to be very cheap. Today's $4.00/gal gasoline is $0.10/kWh. The cost of electricity plus the cost of paying for the synthesis plant have to at least match this. If StratoSolar electricity costs $0.06/kWh initially, that leaves $0.04/kWh to pay for synthesis and conversion energy losses. That's about $0.80/Wp capital cost. That capital cost is a stretch for mature fuel synthesis but is not possible with today's technology. Investing in these technologies at the scale necessary for the decade or so needed  will only happen when it is clear that electricity is cheap and will get cheaper.

So the clean energy cost target is not competing with today's electricity, but being considerably cheaper. Wind and solar are about a factor of two too expensive to compete with electricity in favorable markets today.  That makes them four to six times too expensive to compete with fossil fuels using synthetic fuels.

Sankey diagrams are very useful for visualizing energy systems. They simultaneously show the elements of a system and their interconnectedness, along with a quantative representation of the magnitudes of the elements and the energy flows between them. 

Here are sankey diagrams for two possible StratoSolar driven energy scenarios that satisfy the projected energy demand in 2050. The first scenario assumes that the sectors consume fuel and energy like they do today. The second scenario assumes that sectors adjust to consume more of the considerably cheaper electricity, and their efficiency improve because of this. 
By Edmund Kelly

I have updated the web site main page to show graphs illustrating the extra solar energy available at 20km altitude. The visual comparison seems to be more compelling and revealing than simply quoting numbers.

NASA has provided a convenient SSE database covering daily ground level solar insolation for the entire planet based on satellite data gathered over 20 years.  Using this data and a model for solar insolation at 20km we show comparisons for significant urban locations at latitudes from 23 to 60 north.  StratoSolar insolation is just a little less than top of atmosphere insolation which is widely available data, (including in SSE) and a convenient check on the StratoSolar estimates.

A perusal of these charts shows how large and consistent the benefit of StratoSolar is. Desert level insolation is commonly used to optimistically represent solar, but the combination of a desert and a large urban area is rare, and the cost of long distance transmission offsets any benefit.  California does not appreciate how lucky it is in this respect.  North Africa, the Middle East and Australia are about it. An optimistic world average for ground PV utilization is 15%.

The chart accompanying the graphs condenses the visual solar insolation into numbers and also provides the equivalent utilizations which are useful for estimating actual power from a given PV nameplate power.
By Edmund Kelly

Click for larger image

Most approaches to improving PV focus on reducing the cost and increasing the efficiency. StratoSolar instead, is based on exploiting a more solar rich environment. A comparison with two other approaches that try to exploit more solar rich environments may better help in understanding StratoSolar. The two other approaches are to exploit the sunshine in deserts and sunshine in outer space. Both have been investigated extensively and are sufficiently plausible to have received significant funding. The most notable desert project is DESERTEC, which aims to exploit sunshine in North Africa and transmit the electricity to Europe. Space based solar power (SBSP) was researched heavily by the DOE in the seventies, and revisited by NASA in the late nineties.  A SBSP start-up company called Solaren obtained a PPA in 2012  from PG&E in California to deliver power in 2016.

In the DESERTEC case, the average PV utilization in North Africa is about 25% versus the average of less than 15% for the whole of Europe. The benefit is less than a factor of two overall. Offset against the benefit is the cost of High Voltage(HV) transmission over an average distance of 2000km. Given that this transmission is tied to the generation, its relatively easy to calculate the transmission cost. At today's PV costs HV transmission about matches the cost of generation. Transmission cost should reduce when HVDC transmission develops, but PV will also reduce in cost, so the ratio may not change much.  DESERTEC wants to exploit Concentrated Solar Power(CSP) but CSP prices are high and not falling, so that may not work out.

For Space based power, the advantage is constant almost 24/7/365 power. Measured using the ground based PV metrics, SBSP has a utilization of 130%, due to the higher intensity sunshine in space. Offset against this is the expected 50% loss in microwave conversion, transmission and receiving which could be regarded as reducing utilization to 65%.  PV efficiency would be higher at a colder operating temperature. PV panel lifetimes in space are short due to damage from cosmic rays. There would be advantages to a CSP solution in space, but the complexity is significantly higher than PV. The big problem with SBSP is the very high cost of launching the material into space, and then the assembly and maintenance costs in space. 

StratoSolar can be viewed as an intermediate point between desert power and space power.  Because of night-time interruption, its average utilization is around 40%, and can exceed 50% with one axis tracking. This is higher than the desert, but lower than space. Its transmission costs are low, 20km straight down versus 2000km from the desert or 35,786km via microwaves from GEO. Its equivalent of launch costs is gas bags full of Hydrogen which are very low cost. In the Stratosphere there is no weather or dust, very nearly like outer space, but there is still enough atmosphere to protect PV from cosmic rays, so without ground based weathering degradation or space based degradation, panels may have very long lives, exceeding thirty years. StratoSolar, unlike the desert, does not need water for washing or cooling, which adds to its major benefit over the desert in that it is situated near the demand for energy with few restrictions on where it can be situated.

So when viewed against deserts and space, both of which have received considerable attention, despite significant problems, perhaps StratoSolar can be seen as a possible contender from science fact, and not something from science fiction.
By Edmund Kelly

I have produced a short video that introduces StratoSolar as a possible solution to the looming CO2 climate crunch. Awareness of the problem is growing and some action is occurring, particularly in China. However, action on a scale necessary to solve the problem is not occurring, and as the video explains is very unlikely to occur with today’s technologies or politics. 
By Edmund Kelly

A simple question is why can’t ground PV do the same thing as the StratoSolar scenario? The simple answer is it is too expensive and  it won’t get cheap enough anytime soon. The sharp drop in PV prices over the last few years have stopped, and there is no rational basis for them to fall further for a long time.  A good thing about the recent price drops is it has raised awareness of PV and its potential for further improvement. A bad thing is it has created over optimistic and unrealistic assessments of PV’s chance to be a significant energy provider in the short term.  

In the end, energy is all about politics and economics. StratoSolar PV panels have an average utilization of 40%. Ground PV panels have an average utilization of about 13%. Based on a simple analysis, ground PV electricity costs three times as much, and importantly this is significantly more than electricity costs today. That means that it can only be sold with the help of subsidies.  As Germany has demonstrated, profitability drives investment.  By providing subsidies that guaranteed profitable investment, German private industry jumped at the opportunity and installations grew very rapidly. Japan and China are following Germany’s lead.

But things are actually worse than this.  Its always tempting measure solar with the best utilization from sunny places, but unfortunately with solar its all about geography.  There are very few places with good solar near population centers.  Southern California is a rare example.

Take Germany as a more representative example.  PV utilization in Germany is around 11% from the published data.  Germany could do a deal with a sunny location and build HV transmission lines to transport the power.  This has numerous problems. On purely money terms, as panels have reduced in cost, and transmission lines have not, its likely that the better PV utilization in the desert will not cover the HV transmission costs.  Don’t forget that the transmission lines will have the low PV utilization, which more than doubles the cost compared to conventional HV transmission lines. On top of this are the political constraints. HV transmission lines are not liked, and the countries where the panels and HV transmission lines are placed may not be the most politically stable.

Even in the US, politics and economics will favor New York, for example, building in New York rather than dealing with getting power from New Mexico via transmission lines through many states.  What this means is that ground PV discriminates, and northern climes get to pay twice as much, or more for electricity.  Economics will also dictate that southern climes will get most of the synthetic fuel business.

Because of the lower utilization, ground PV electricity will always cost 3X StratoSolar electricity.  This factor makes StratoSolar economic for electricity, and then fuels long before ground PV.  The learning curve is good but not that good. The learning curve will not continue for ever, and when it slows it will create a permanent cost barrier that ground PV will never overcome.

StratoSolar is far less variable with geography, so Germany or New York, for example could provide all their  energy needs, both electricity and fuel, locally.

So to summarize, ground PV is too far from viability today, and too variable with geography to ever be an easy political choice. StratoSolar is viable today, and does not discriminate against geography. The StratoSolar capital investment for both PV plants and synthetic fuel plants will average a sustainable $0.6T/year, in line with current world energy investment. $2T/year capital investment for ground PV is a lot harder to imagine.
By Edmund Kelly

The following describes a StratoSolar deployment.  The key point this illustrates is the simplicity. This is not an "all of the above strategy" with lots of moving parts and government interventions to subsidize or tax various market participants. The impact on land and existing infrastructure is indirect, and not an impediment to deployment. China in particular could adopt this strategy and replace coal without penalizing GDP growth. 

This shows that meeting the 450ppm CO2 goal in a realistic time frame with a realistic cost is feasible. Ground PV is still too expensive and will always be a factor of two to three behind in cost. The political costs and delays of land use and grid upgrades will further limit the scope and time frames of what is achievable. The key enabler is economic viability without subsidy.
 
StratoSolar deployment sequence:

Step 1) Deploy StratoSolar initially at $1.50/Wp, $0.06/kWh. This is profitable in most markets and volume growth is not constrained by amount or availability of subsidy.

Step 2) After about 25GWp of cumulative production, StratoSolar initial learning curve takes costs down to $1.00/Wp, $0.04/kWh.

Step 3) Start deploying electrolysers costing $0.50/W making hydrogen for $3.00/kg. This provides fuel for nighttime and winter electricity generation for $0.08/kWh and starts an electrolyser learning curve that will reduce the $/W electlolyser cost.

Step 4) Continue deploying StratoSolar to 1TWP cumulative capacity. Costs reduce to $0.50/Wp, $0.02/kWh. Electrolysers reduce to $0.20/W, Hydrogen reduces to $1.25/kg, nighttime electricity reduces to $0.04/kWh.

Step 5) Start liquid fuel synthesis using hydrogen and CO2. Synthetic gasoline costs $3.00/gallon. This starts a learning curve for fuel synthesis plants.

Step 6) By the 10TWp cumulative deployment point costs are down to $0.25/Wp, $0.01/kWh, $0.60/kg for Hydrogen, and synthetic gasoline costs $1.00/gallon.

This does not discuss time frames. These will depend on time to acceptance.  The cumulative TWp needed to replace all world energy demand projected for 2045 is around 80TWp.  The two time alligned graphs below illustrate a yearly StratoSolar goal of replacing 3% of world energy demand. Yearly StratoSolar production would need to ramp fairly quickly to 1.5TWp by 2020 and then increase slowly to about 2.5TWp by 2045 to meet increasing world energy demand. 3% is pretty aggressive, but not excessive and aligns with a 30 year plant life.

Yearly world  investment never exceeds $1T/y, as costs fall with cumulative installed capacity. For reference current world energy is about 8% of GDP, or about $6T/y. The 3%/year  replacement scenario shown in the graph replaces about 80% of world energy with StratoSolar by 2050 with the remaining energy coming from the current projections for nuclear, hydro and other renewables.

The CO2 emissions reduction chart below shows the CO2 reduction associated with this StratoSolar deployment scenario. We show a simple sequence with coal being replaced first, then oil, and finally gas. The reality would be along these lines but with less distinct transitions. Coal is the obvious first target as the biggest and dirtiest emitter and the easiest to replace with electricity.  Oil is next as its high cost make it the easiest to replace with cost competitive synthetic fuels.  Natural gas is last because it is the logical partner to solar, it’s the cleanest, and its low cost keeps it cost competitive for longer. The most striking aspect of the graph is the illustration of the scale of CO2 emissions saved.

Cumulative CO2 emissions between 2005 and 2043 are 1,800Gt with business as usual versus 820Gt with StratoSolar. By 2043 CO2 emissions could be zero, whereas business as usual is pumping out over 50Gt/year . 820Gt is well within the 450ppm CO2 goal of 1,700Gt.

 Sources: History: U.S. Energy Information Administration (EIA), International Energy Statistics database 
(as of March2011), website www.eia.gov/ies; and International Energy Agency, 
Balances of OECD and NonOECD Statistics (2010),website www.iea.org (subscription site). 
Projections: EIA, Annual Energy Outlook 2011, DOE/EIA0383(2011) (Washington, DC:May 2011); 
AEO2011 National Energy Modeling System, run REF2011.D020911A, website www.eia.gov/aeo, 
and World Energy.
By Edmund Kelly