Dienstag, 4. April 2017

How much land area does a 100% solar powered world need?

Land demand for solar power

Solar energy for Germany, Europe and the world

There is a picture in the solar scene (picture 1) that probably almost everyone knows, it shows how large the surface area is when the world is switched to solar energy. It was, as far as I know, published by Mrs. Nadine May for the first time in her diploma thesis at DLR [1]:

Figure 1: Space requirements for solar power plants, according to Nadine May [1]
This image is widely used and should be checked for correctness. First of all, Algeria is the country that contains the squares for the world and Europe, and Libya, the country which possibly receives the German solar power plants, are no more colonies.

The squares have an edge length of: world 254 km, Europe 110 km and Germany only 45 km.

How big is the energy consumption in the world?

The energy consumption of the world is constantly growing (see figure 2), so it is difficult to specify the energy requirement without a reference year. Currently the demand is over 30,000 TWh (30,000,000,000,000,000 kWh) using the further processed data from the International Energy Agency (IEA). I have considered transforming factors for certain energy forms (transportation, heating) into electricity.

Figure 2: Global energy demand for electricity, transport and all other forms of demand

This energy should be converted with solar cells (PV) into electricity. There are several factors to consider, the efficiency, the irradiation in the course of a year and the necessary storage of the energy for the night.

Solar cells made of silicon achieve an efficiency of around 20% and are currently the most economical method to generate large amounts of solar energy.

The irradiation is very different in different regions of the earth, in particular one must always distinguish between direct and global irradiation. For photovoltaics (PV) only the global irradiation plays a role. Therefore, only these radiation is considered.

Figure 3: Global radiation perpendicular to the ground (source: WEC [2])
The map shows that many areas have an annual irradiation capacity of 2000 kWh per year, in particular the Sahara, but also on other continents good locations can be found; only exception is Europe.

Necessary Land Area

The necessary areas of the solar cells can now be easily calculated. For the world, we need 30,000,000,000,000,000 kWh per year, since one square meter has an incidence of 2000 kWh which would theoretically be 15,000,000,000 m² or 15,000 km².
Now the efficiency comes into play, since only 20% is converted into electricity, we need the fivefold area, that is 75,000 km². However, one has to be able to build the cells and needs paths and additional areas for inverters and storage, which should double the space requirement. This is 150,000 km².
The transport and storage of energy, which is absolutely necessary, since at night the sun doesn't shine, will consume another 25% of the energy, so we are at 200,000 km².

This corresponds to a square of 448 km of edge length, roughly twice as large as in the drawing.

Fair World

Currently, only a few people consume a lot of energy and lots of people have little energy. I am convinced that in the long term all people want at least to reach the standard of living as in Germany. For this, an energy quantity of 15,000 kWh per year and per person would be necessary. There are some countries that already have a much higher energy requirement, but we hope that energy efficiency will also save some energy.

With a world population of 8 billion people, this will yield an annual energy demand of 120,000 TWh or 120,000,000,000,000,000 kWh, or four times the current demand. This would increase the area with solar cells to a square with an edge length of 1000 km (Fig. 4).

Figure 4: Supply the world completely with solar energy in the future
Furthermore, the area of ​​one million square kilometers is still small compared to the Sahara, but a serious part of the solid surface of the earth. The world has about 15 million square kilometers of sunny deserts, which means about 1/15 of this area must be used in the future for solar cells to deliver enough energy.

Storage requirements

If it is assumed that the energy must be stored for at least one day, this requires a storage capacity of 330 TWh (330,000 GWh)
Compared: Germany has pumped storage with a capacity of 0.04 TWh.
If large Gravity Storage systems with 80 GWh capacity (500 m diameter) solves the problem, a considerable number of 4000 pieces would have to be built.

Using batteries from Elon Musks Gigafactory, the gigafactory produces at a planned capacity 50 GWh per year; over 6000 years of production or 400 Gigafactories for 15 years are required. This is to provide the capacity for the first time and we have to continue production because batteries must be replaced after 15 years.

Gigantic conversion

If the global conversion to solar energy succeeds, huge buildings in the form of gigantic solar fields will be necessary. Surely the roof surfaces are never enough. Furthermore, investments are in the order of magnitude of the global gross social product of one year ($ 80,000 billion). This sounds a lot, but it will help mankind to be sustainable. Especially when one considers that afterwards energy is produced clean, without CO2 and at a low cost.

I think: we can do it!


[1] Eco-balance of a Solar ElectricityTransmission from North Africa to Europe, Diploma Thesis of Nadine May, Braunschweig, May 2005

[2] World Energy Resources Solar 2016, World Energy Council 2017

A 186 page paper going into details is from Jakobson et.al., 100% Clean and Renewable Wind, Water, and Sunlight (WWS) AllSector Energy Roadmaps for 139 Countries of the World

Montag, 24. Oktober 2016

Global Demand for Energy Storage

Energy Storage Demand in a Sustainable World

The global transition to renewable energy production is in progress. Last year, 2015, more renewable power capacity, like solar and wind power, was installed as conventional capacity like coal and nuclear. Beside this nice development, there is a weak spot, the installed solar and wind capacity produce only when the sun is shining or the wind is blowing. For a full change to an emission free world, we need energy storage.

How big is the storage demand on a global scale, this is hard to guess, because it depends on a lot of assumptions. I will try to make a good guess within this post.

The Global "Energiewende" 

I will not describe the "Energiewende" (change of the energy system) in Germany, I will focus on the global change. This makes sense, because we have to change the energy system on the global scale to stopp the carbon problem and limit the exhaustion of the scare fossile fuels. 

The strong growth of PV installations, about 70 GW are expected for 2016, continues the long term trend of constant fast growing installations over the last decades. 

This trend will change the energy system as we know it today within two decades, to understand this lets look into the near history.

Growth of the energy consumption and the installed renewable energy production.
Consider the logarithmic axis of the installed power. Data source BP 
The first thing is, the electric power demand has a constant annual global growth of 3%. The installation of wind and solar power combined grows every year with 22%. The result will be, that somewhere around 2025, more fluctuating renewable energy is installed as conventional power plants. 

But be careful, the produced energy of wind and sun will still not match the demand, because they only produce energy when sunlight or wind is available. Resulting in the green line, which represents the mean renewable power generation. This line hits around 2030 the demand.

The result is, the next century will be dominated by the installation of storage to match the flucuating production at any time with the global demand.

Influence to the Storage Demand

The main impact for the storage demand has the electric grid infrastructure. The reason is, that the grid is the most efficient way to transport the electric power from the source to the customer. Is the sun shining in the southern part of a country, it is efficient to bring the energy to the cloudy northern part. And similar, if the northern part has a lot of wind during the night it makes sense to bring the energy with the same grid to the customers in the southern part.

This results in a competition between grid and storage.

To find the economic optimum between power grid size and storage is complex
Theoretical, it would be possible, to span a global grid around the globe and connect this grid with all solar power plants. This would result in a perfect 24 hour solar power supply without any energy storage at all because the sun shines always at some places on our earth.

The main problem seem the high price of such a grid and the energy loss in the power line. The other extreme case is a power storage at home with a seasonal capacity (only necessary in the northern region) of 1000 kWh for every person in the house. Then we can go off grid, sufficient PV on the rooftop assumed. The price for the batteries may reach a million dollars, not affordable.

If we dive into detailed computer simulations as done by J. Tambke und L. Bremen [1] we learn, that a country like Germany needs a storage capacity of seven days after a complete conversion to wind and solar has happend and there is a perfect power grid, often called a copper plate. 

Expanding the area of the perfect grid connection to an area like Europe only two days of storage is necessary. If we are optimistic and assume a perfect grid of this semi continental scale we need only a storage capacity of two days.

Further Chances to Optimize

Beside the grid, another chance to minimise the storage demand is the so called smart grid. Whenever possible, a energy consuming element in the grid goes offline if the power price is high or goes online if the price is low.

We dont know the exact possible amount of energy demand that can be shifted to other times but a optimistic guess might be, that 50% of the demand can be shifted in a way that the storage demand is halved.

Asuming this, we need only one day of storage if a smart grid and a comtinent size grid is available.

Adding up the Numbers

The energy consumption in the world in the year 2030 will be around 4,000 GW. To store this energy over one day, we need a 24h storage system with a capacity of 96,000 GWh. Keep in mind, the Gigafactory of Elon Musk may produce 100 GWh per year. If all the storage is used for the global Energiewende, the production for this demand needs about 1000 years.

But be careful, other solutions may be available.  The energy stored in the lakes of Norway contain an astonishing amount of 80,000 GWh, although there is no pump, the stored volume can only be used once in a year and has to be refilled by natural perception.
Pumped hydro technology may be a good solution, especially the Gravity Storage system, a typical site can store about 8 GWh. We still need 10,000 Sites, but tis seems to be more within practical reach, than a bure battery solution.  


Montag, 17. Oktober 2016

World Energy Council Meeting 2016

World Energy Congress 2016 in Istanbul

From 9th-13th October 2016, the World Congress on Energy was held in Istanbul. It was the 23rd Congress since 1923.

The topics of the congress were distributed over the entire energy area, including the oil and gas production and renewable energies. There were many important statesmen like Russian President Vladimir Putin and the Turkish President Recep Erdogan, including many other government members from different countries, including the visit of Israeli Energy Minister Yuval Steinitz, the first official meeting after six years frozen relations between Turkey and Israel.
Side by side, Putin and Erdogan at the conference in Istanbul

Vladimir Putin talk was about the importance of energy and the price of oil, a remark about a co-operation with OPEC during the speech has moved the oil price to rise by 2 $! He was the only statesmen, who included the words "exponential growth of solar energy".

The issue of energy just brings together not only scientists and engineers, but also politicians and diplomats. The global linking of energy distribution, especialy natural gas, plays an important role and Turkey was presented as a hub between Asia, Middle East and Europe and the Mediterranean.

The world's energy

All participants have concluded, that the energy transition towards renewable energy, particularly solar and wind, is on the way. However, the completeness and how fast that arives is controversial. While I am convinced that before the end of the next decade the significant change of the energy system has been completed, Marie-José Nadeau, Chair, World Energy Council believes that in 2060 the share of renewable might reach only 50% of total energy production [1] ,
Marie-José Nadeau, Chair, World Energy Council

This is understandable from the perspective of the energy industry. They trade with oil, coal and natural gas. Should the change take place quickly, the oil and the coal is not any longer requested by the market. The industry worries about stranded resources. This means the oil in the ground, on which the wealth of large companies and nations is based, may become worthless.

Key issues in the energy transition in the coming decades

The importance of the Paris Convention for the CO2 reduction was repeatedly stressed. Generally, however, many see only a shift from coal to natural gas, as is well known, natural gas produces half as much CO2 when it is converted into electricity than coal! This is due to a fact that a methane molecule consists of one carbon and four hydrogen atoms, but also to the better efficiency of gas power plants.
Key finding: the phenomenal rise of solar and wind energy will continue!

Power Turntable Turkey

At the conference in Turkey, the geo- (energy-) strategic role of  Turkey was stressed by Erdogan.

Important oil and gas pipelines connect large resources of Asia with European customers, more gas and oil pipelines are planned.
Strategic position of Turkey

Finally, the construction of a new gas pipeline connecting Russian and other Asian gas fields to Europe by crossing Turkey, were one reason why Putin, but also the President of Azerbaijan, Ilham Aliyev, showed up in Istanbul.

The Importance of Hydro-Power

It's a certain irony, the most important renewable energy in the global mix, providing at least 71% of all renewable energy is hydro-power, or 6.8% of global electric energy production, is a often forgotten big player.

The importance of hydro-power may lie in a combination of solar, wind and hydro-power. At the conference solar power as named a water saver, in the form that during the day the turbines are shut down at the dam resulting in increasing water level, during the night, with redoubled turbines, water can be used for power generation. Thus normal dams are important energy storage elements for the energy transition. ot to forget pumped hydro storage or even the new technique of Gravity Storage .
A nice photoshop picture used as advertising billboard in Istanbul

There are, at least in Africa and in South America, still many untapped hydropower "reserves". However, anyone was well aware that each dam has also an enormous impact on nature and very often engages in the habitats of people! Especially in India, the water of the rivers is sacred and thus hardly the construction of dams possible as mentioned by Richard M. Taylorlearned Chief Executive, International Hydropower Association.

Africa to get electricity

While the inhabitants of the Americas and Asia are almost completely supplied with power, in Africa there are still 600 million people without electricity. This means no light, no easy way to charge a mobile phone, no fridge and no welder.

The last day of the conference was therefore devoted to Africa. In Africa, here essentially black sub-Saharan Africa was meant, you have to think about the huge areas and the still sparsely populated countries. This makes the construction of a conventional electric grid network uneconomical and therefore solar energy stand-alone systems and microgrids are very important.
The forum "Talent and Capacity Building" moderated by Samir Ibrahim from Kenya, right Sanjit 'Bunker' Roy from India, next to Andreas Spiess, Solar Kiosk , from Germany.

The practical implementation requires some knowledge of electricity and solar energy. Bunker Roy helps the people with his Barefoot College to teach this to everyone. While he teaches women worldwide (Grandmothers) to practical issues of the use of solar energy, an impressive project!

Andreas Spiess tries with his, as he stressed, commercial solution of the solarkiosk promoting the dissemination of locally adapted use of solar energy in Africa.

The Exibition

There was a international exhibition were companies and countries presented interesting ideas and investment opportunities.
Booth of Heindl Energy GmbH

The Heindl Energy GmbH has presented the "Gravity Storage" technology on its exhibition stand. Unfortunately, very few companies from Europe were represented at the fair. The booth was right next Aramco, the largest oil company in the world from Saudi Arabia. As far as I have observed, our stand had awakened almost more interest.

A 600 MW power plant on the water for emergency cases

There were of course many other interesting exhibition stands, I found the idea of ​​"power ship" interesting, which is a ship with a complete power plant (up to 600MW), inclusive substation, which anchors in a port and supports the local power generation, after a natural disaster or for other reasons.


Montag, 30. Mai 2016

Serious Problem: Battery and Automotive Industry

Lithium Ion drives the Future

The basic innovation LiIon battery, driven by the company Sony, has surprising, but that is common in innovation, enabled the development of electric cars. 

Previously there were only ugly batteries, some were extremely heavy, lead-acid battery, extremely toxic, nickel cadmium, or other drawbacks why they were not suitable for an energy storage device in a car. This has seduced the automotive industry to believe everything would stay the same and no special attention was given to the development of batteries. 

With the successful development of the Tesla S, an all electric car, everything has changed fundamentally, so I will report here about the importance of battery technology in the automotive industry.

The value Chain in the Car Industry (today)

Four things make the value of a car:
  1. the glider, a vehicle without power train and energy storage
  2. the engine with storage (tank or battery)
  3. the image of the brand (mostly through advertising)
  4. the amount of energy consumed by the car in his life
The glider is now a product of the OEM, headlights, bumper, seats or wheels and tires, almost everything visible to the driver is not produced in the car factory. Only the steel welding of the body remains in most car factories, with high automation done by robots.

The engine remains us to the 19th century. An internal combustion engine with a mean efficiency of about 20 percent, emitting significant amounts of particulate matter and other unhealthy substances, accelerates the car more or less rapidly to cruising speed and keeps on this pace. Thousands of engineers try to optimize this technology with legally or illegal means.

The image of cars of different brands developed by massive advertising budgets [1]. Through product placement in movies and elaborate sales centers, a high value of the car is suggested, although all the cars stuck in traffic driving at the same speed. For many people, the car is next to the house, the most expensive product that is purchased for own appreciation.

The fuel that a car burns in the course of its operational phase of approximately 200,000 miles, may sum up to $ 30,000 (depending on local tax) and is often more expensive as the whole car. In addition, no one knows at the time of car purchase how the gas price will develop. The money end up in the pockets of the oil companies and oil states, not in the automotive industry!

Summarized, the major car makers only have the ability to manufacture engines, the rest of the value chain is lost.

The electric car value chain

Electric cars have a significantly different distribution to the above points 1 to 4

The glider remains essentially the same, interestingly, the weight saving is less important than with previous cars, because by recuperation (recovery of braking energy). The energy to accelerate and the energy to go uphill is not used for heating the brake disk, as in conventional cars.

The use of non-rusting aluminum is useful because the life of an electric motor is considerably higher than that of an internal combustion engine. And who wants a rusty electric car that still has a good engine and a working battery.

The value of the electric motor is far below of an internal combustion engine, which consists of 6000 moving precision parts. Electric motors are simple, some copper wire winding and an aluminum cylinder which rotates. Rare earths are not necessary, which can only be found in hybrid cars like the Toyota Prius (46kg!).

There is no fuel in the electric car. But we need a battery and electric power to drive the car.The batteries are by far the most expensive part in an electric car and remarkably similar in price compared to the fuel costs of a conventional car.

Amazingly, this was not noticed neither by the big oil companies nor the major car companies. Exception: Tesla builds a Gigafactory, a battery factory which can supply batteries for about 500,000 electric cars a year, thus making the company independent from other suppliers.

Only the German company Volkswagen has announced that it is considering $ to invest in the construction of a battery company (GAS2) Unfortunately, I have heard such announcements in the area of e-mobility by automotive companies several times. Actual, so far nothing was created.

The "fuel" power would actually be a clear claim for the utilities or oil companies. Here there is complete silence.

The problem of everyday usefulness

If you want to use an electric car just like your previous car, it must be reliable cover about 60 miles a day, but it has also to master the holiday trip or extended business trips.

For daily demand the socket in the garage is sufficient for overnight charging. resulting in a very limited contact to a gas station. Except perhaps refill the windshield wiper fluid and visit the car wash.

On longer trips every car must refuel new energy. At the gas station this is done within five minutes. To charge an electric car during the trip should not substantial extend the duration of the trip. So it is imperative that there is a network of fast-charging stations. 

At this point I'm amazed to read that the policy in Germany will subsidize 10,000 charging stations (per charging station $ 70.000 tax money). However they do not demand the fast charging ability.

Only charging stations, where you can charge more than 200 miles range in 30 minutes (supercharger) lead to everyday practicality of electric cars.
No other company than Tesla operates or plans to operate a supercharger network. A network that could be owned by automaker or other organization. I think oil companies, motorway service areas or  power companies, should be interested to roll out a fast charging network,
Ending up in a monopoly situation, anyone who is interested in a everyday useful car can now only buy a car from Tesla, all other manufacturers have virtually no usable electric car on offer.

The fairytale "battery problem"

The common theme in the discussion about electric cars is the battery problem. It involves at least three subjects
  1. battery price
  2. lifespan
  3. raw materials
Prices of batteries are in free fall. On the picture you can see a slide that has been shown on the Menasol 2016 Energy Conference in Dubai. Compared to the drop in solar cell price, the price of LiIon batteries appear to move even more quickly down.
Development of battery prices, when the market doubles the volume, the price drops by 26%

If the price of batteries is at $ 250 per kWh and a car needs for the daily use about 80 kWh, the battery will cost $ 20,000. Counting the cost of electricity results in less than the fuel costs of a conventional car.

The service life for batteries depends on the charging cycles, and some other factors, such as temperature decreases. Thousand charging cycles required can be delivered by virtually all the batteries, even a lead battery. But this means 200,000 miles (1,000 times 200 miles per charge) is easy reachable by a battery and beyond the life span of the vehicles. Moreover, it seems to be that although there is a slight decrease in capacity, a second life of the battery is possible. For example to use the battery in a PV system for overnight storage.

The raw material lithium (60ppm [2]) is much more common than lead (18 ppm in the earth's crust [3]) to be found. Thus there is no problem of raw materials, even if it could lead to bottlenecks due to slow expansion of mining activity. Unlike oil, lithium is not consumed in the car but can be 100% reused. Lithium is also non-toxic, who spices his soup with sea salt, is eating lithium salt, which in large quantities is part of the sea(salt).

Old industry fails in innovation

Although the facts about electric cars are easy to understand, you wonder why the auto industry is doing almost nothing. The problem is more than a century grown structures. Virtually all automakers are over 100 years old, except for Volkswagen, a company which was established on 28 May 1937 by Hitler.
In these companies, there is extremely much knowledge about internal combustion engines. ignition and oxygen supply, exhaust and catalyst are investigated by expensive and complex means. The technological elite in the automotive industry understands the combustion engine, studied and graduated on that topic.

Battery technology, lithium ion and electrolytes they have heard about in the media. It is not their core competency. How to go about developing the technology? The natural reaction is waiting and building seven-speed transmission and hybrid engines or even worse hydrogen engines.

At the same time a startup, Tesla Motors, succeeded to be about five years ahead the pack. Installed thousands of supercharger stations and without expensive advertising build a brand image that fits to a clean environment with renewable energy.

It would not be new in the history of innovation that industry do not survive the change in technology. No sailing Shipyard has built steamboats, short before bankruptcy they tried with seven master sail and "hybrid" (Sail plus steam engine).
No mail order retailer could defeat amazon or ebay.
No telephone company, Siemens, Motorola nor Nokia, plays an important role in the smartphone league.

We will have to accept that some companies VW / BMW / Daimler are in ten years only a brand name but no longer large employers. 
Peter Schumpeter described this with the words
 "Creative destruction"
And he probably has once again right.

(I tried hard to translate this from my first German blog article "Lithium Ionen treiben die Zukunft an", should you find any flaws, tell me)

Further comments:

[1] Volkswagen spent more than $ 110 million in Germany for advertising in the months Jannuary till  April 2016, source: Nielsen / Statista.
[2] ppm stands for "parts per million", which means you take a ton of average rock, then 60 grams of lithium and 18 grams of lead are contained therein.
[3] The mass fraction concealed, that a kg of lead can only store about a factor of 50 less energy than a kg of lithium. Viewed from this condition, you need less lithium for all cars (if they are electric) than lead is used today for starter batteries in petrol and diesel cars. 

Sonntag, 8. November 2015

Intercontinental Energy Grid

The Vision of China State Grid

The energy production in the future will be based on wind an solar power. Even in a carbon rich power production country, like China there is no doubt about this long term development.
At the Dii conference 2015 in Dubai, I learned in the presentation given by Han Jun, Senior Vice President, State Grid Company of China, that a global energy grid can solve the problem of intermittent power production.
State Grid China, vision of a global electricity balance

  Is a global grid possible

The idea, to have a global grid is simple, but the physical hurdles are hard to overcome. The best solution would be, we take a high temperature superconductor and span the globe with this type of grid. The only remaining problem is, we don't have the technology, and although "high temperature superconducters" (Working at -130°C not high in everyday experience) have been discovered 1986 by Georg Bednorz and K. Alex Müller at the IBM laboratory. Till today it was not possible to construct a power line on the base of this very brittle material.

Knowing this, the only path in reality is the use of high voltage direct current connections. And it has been shown by Chinese engineering, that the power connection between the three gorges dam and the 2,600 km distant city of Shanghai works to transport 7.2 GW of electricity.

Knowing this, we can try to calculate the necessary equipment to transport the power of wind and solar energy around the globe by conventional technology. 

How much power?

The first question concerns the amount of power that has to be delivered to far apart regions and continents. Today, a conventional power fleet of 5300 GW produces electricity where the consumers live. In a renewable future, this will still be true in some part for solar and wind, but it might be necessary to transmit 10% over very far distances. This would require a power line, able to transport about 600 GW and with a length of 10,000 km. 

This assumptions are very rough, but it is helpful to start with a plausible range, additional demands are then simple multiplications of the result. If we assume that the power line has a voltage of one million Volts, the current through this line is 600,000 Ampere and we don't want to loose more than 20% of the energy within the line. 

With these assumptions, the resistance of the line has to be in the range of R=U/I = 200kV/600kA = 0,3 Ohm. Knowing this, we can lookup in the table of material properties the necessary material demand. Only cooper and aluminium seem to be sufficient, aluminium is much cheaper, so we take aluminium. The electrical resist of aluminium is 28.2 nΩ·m. The diameter of the 10,000,000 m wire has therefor 1 m², quite thick, but able to transport a significant amount of our global electricity demand on a intercontinental distance.
Sources of electricity in the year 2050, estimated by China State Grid.

How expensive is that cable?

To get an idea of the price, we have to know the raw material price of aluminium. At the moment, aluminium sells for 2000 $/t, with limited deviations from that value. Our power line needs 27.000.000 tons of aluminium, because the density is 2700kg/m³. The pricetag is 14 G$, not that bad, if we consider the impact to the global power supply.
A real cable will be at last ten times as expensive as this first assumption, because we have to include an isolation, that can keep one million Volt, but even a price of 140 Billion $ is small compared to the equipment, that is necessary to produce the power.

To produce 600 GW of power, even the cheapest wind power converter at the best suitable places around the arctic circle would cost 600 Billion $.

Impact of a global Grid

A global grid would be a tremendous step to a reliable energy supply. We can compare the solution with the alternative path of large scale storage. The necessary storage for 600 GW over 10 hours needs a capacity of 6000 GWh. This could be done by ultra cheap Lithium Batteries with a price tag of 300$/kWh or 1,800 Billion $ for the required amount. Using the Hydraulic Rock Storage HRS technology, the price could be reduced to 600 G$.

A global grid would use the oceans to wire the continents. The ocean floors are a relatively save place to wire the world, as we already know from the internet fiber optic cables. Another advantage is the international law, the floor of the ocean is not under the same dispute as the land surface and it seems much easier to get a permit to roll out the cables there.

When a country like China takes the lead to interconnect the continents with electric cables, this would change the way, we think about local generation of power. But keep in mind, today, our energy supply system is intercontinental over the ocean, the supertankers distribute comparable amounts of energy over the ocean. 

Freitag, 10. Juli 2015

The End of Fire

The End of the Fire Era

About half a million years ago, mankind started to manage the energy of fire. The first use of open fire was for heat production and cooking. Since three thousand years fire could be kept in a stove to use the energy more efficient. During the 17 Century, the incredible story of mechanical energy production by the use of fire within steam engines and internal combustion machines began.
This glorious historical period will come to an end, very soon!

What is wrong with fire

There are at least three big problems when we use fire to generate useful energy.
  1. The fuel is expensive and not sustainable
  2. The conversion into useful energy is dirty and has high losses
  3. The atmosphere can't absorb infinite amounts of carbon
All these disadvantages are a good reason to extinguish the fire for ever. But is this possible and is this part of a long term trend?

Have a look into the flames. 

To ignite a fire without tools is one of the most demanding tasks man can solve and only very few of us did this ever complete. On the other side, it is the process that happen more often than any medium scale process we can think about. After some calculation* we find:

 mankind ignites 7 Billion  fires every second 

With other words, for every person on the planet earth we ignite every second a fire and extinguish it within a fraction of a second again. And none of this fires is seen because it happens within the engines of our cars.
Other fires burn in large power plants and in the heating system of our home, we don't see them even. Fire has lost its visibility. And this might be a first signal, that fire is disappearing.
Another place where flames appeared was the ignition of cigarettes, even this type of fire seems to disappear, no smoking in restaurants, in office building, in airplanes and only some lost desperadoes at the entrance of some buildings remind us of the old days.

Why fire

All the little and large fires in our engines have only one reason, they should generate mechanical energy and this energy is sometimes converted to electrical energy. This is possible due to the thermodynamic law of physics. But this law tell us, that the efficiency is always low and needs always a cold reservoir like a river or fresh air. This is the reason, that most of the energy is lost in heat, leaving the car through the exhaust pipe or the radiator. The situation in large conventional power plants is similar.
The famous Durango Silverton narrow gauge steam train.
Since Benjamin Franklins work in the 19. Century, we are aware, that electricity is the ultimate useful medium for energy. We can convert electricity in just any service we can imagine. About 60% of the electrical energy ends up in an electric motor to move people, cool air, transport stuff and cut wood.
Not one of this tasks requests a fire, but we had no other solution till now, so we used a fire to solve the problem.

Fire is Unhealthy

There is just no single technology that produces as much unhealthy substances as fire. There exist people who inhale the smoke intentional, but most of us try hard to avoid the smoke. We have this smoke detectors on the ceiling and we have different filters in our cars and in coal power plants.
Smoke detector, we try to avoid smoke
When we look to China, a day in Peking is like smoking a packet of cigarettes. But even if we live in modern industrialized countries we have to inhale nano particles of all kind due to the burning of gas, oil and coal. To give an exact value of lost live due to fire is very difficult, but it surpasses nuclear power by many orders of magnitude.

No fire no harm

If we extinguish all the fires and even the nuclear type of fire that feeds less than three percent of our global energy demand, we can save the planet and the people.
World energy consumption
World energy consumption, only hydro and renewable
don't burn and generate smoke of different kinds. Source Wikimedia

Although it seems impossible to expand the small renewable branch in the picture above, it could get reality, because this branch is growing exponential:
growth of PV
The blue dots show the installed PV in the world, the dotted line is a 25% growth
Exponential means, the growth rate is constant and the growth rate of PV is about 25% per year. If this continues for another 15 years, the whole earth can be powered by solar energy. Today we have installed 5000 GW of fire powered power stations, within 20 years we have more than 10000 GW of PV on earth. Read this: Is 100% PV possible?

A second trend is, that electricity is stored in batteries. We are used to mobile phones which need every night a charging. Many of our appliances like screw driver and tooth brush use batteries.
The next big step is the electric car, the definite way to extinguish fire. The visionary Elon Musk buildt a car with batteries from the laptop. Today TESLA sells the model S on a ever growing rate.
More batteries will come. As far as I know no other factory type expands faster than the battery production plants with the Giga Factory on top. Read also: Storage Maters.
Largest production site ever for a small product! Source TESLA
More than 50 GWh of batteries should leave the Giga Factory every year. But this is not sufficient to meet the demand of 90 000 GWh of storage for a clean future. Complete new technologies like the Hydraulic Rock Storage are invented, which can store many GWh in one site with very low environmental impact.

Will fire stay  

We will never extinguish fire for ever, because people like fire.
We love fire

But hidden fire for old machinery invented in the 19. Century will go forever, even hydrogen. It was a funny time of smoking stem engines and high factory chimneys. A world of dark snow in the winter and dirty ash.

Have a clean time.

Samstag, 16. Mai 2015

Is 100% Photovoltaic possible?

The World powered by the Sun

Today, photovoltaic electricity is only a small fraction of the global electricity production. The volume seems to be one percent in the year 2015. If we do a very simple extrapolation and imagine, that all these PV modules were installed in 2014 and we continue this installation speed, than we need another 99 years, to have a 100% emission free PV world. But this is simply not the way the world goes round.
I will try to extrapolate the situation, based on data from the MIT report "The Future of Solar Energy" [1]

Analyse the past of Photovoltaic

If we wont to understand the future, it is very useful, to look into the past, not only to understand the development, but also to understand the error which occurred by predicting the future. 
The Energy Information Administration (EIA) and the International Energy Agency (IEA) predict since 10 years the global PV installations in a published outlook. The first outlook from 2006 predicted for the year 2030 a global installation of 100 GW. This volume was already matched in the year 2011, only five years after the report was published! Ok, one wrong shot can be excused.
In the year 2011, the EIA predicted 150 GW until 2020. Again a failure, already in 2014 we have reached 180 GW of solar. 
The MIT analysed all predictions and compiled them to a very nice picture:
Figure 1: Different predictions and the reality, source MIT [1] page 137
In the early time, the predictions of the IEA had an exponential growth, that is a good guess, because most of the time, new products grow in that type. The only problem was at that time, the growth factor was to small, for example see IEA 2008 prediction in figure 1. Today things have gone worse with the prediction from the IEA. Not only is the factor to small, the prediction includes a reduction of the production of PV itself. This seems hard to understand.(An in depth analysis was done by Christian Breyer, paper PDF)
Things go even more strange, when we look at the price predictions of PV. The EIA predicted the development of the PV price till the year 2030. It should be mentioned, that it is a very difficult task to predict a price of any product for more than 20 years. But this failure is very illuminating.
Figure 2: Price prediction by EIA IEO 2009 of PV and observed results. [1] page 137
The EIA IEO 2009 outlook predicted, that the capital cost of PV in the year 2030 will drop to 4$/W.
Actually, the price even for residential systems dropped to this value already in the year 2014. It should be noted, that the price for residential PV systems in Germany was at the same time at 2$/W.
The price for utility PV systems reached only two years after the report was published the predicted value for 2030, 4$/W. 
All this information should be available to the EIA today. It irritates me, why the EIA does not change the prediction about the deployment of PV although they can observe the rapid price drop obviously. (I am thankful for any helpful hint)

Is there enough material for a large roll out of PV 

One possible reason, to be pessimistic about the global roll out of PV might be the scare elements used in PV systems. Today almost all PV systems use Silicon to convert sunlight into electricity. The MIT analysed the production of different raw materials, essential for the production of SI-PV-modules. 
To set up a PV system we need concrete and steel to mount the panel in the direction of the sun. Glass, aluminium and plastic are necessary to protect the silicon cell, cooper and more plastic is necessary to transport the power away.
Figure 3: Commodity materials required for PV. [1] page 131
Today, all these commodity are produced in a volume, that no real bottle neck will occur. In figure 3, we can see, that the steel production of 9 days is sufficient, to mount all PV panels for 5% of the global electricity production, within half a year, the steel production is sufficient for a 100% conversion to PV.
The least available material in this consideration is glass. For a 100% PV world, we need the glass production of 20 years. But glass production is in no way a limiting factor. The necessary raw material is sand, an endless resource.
The solar cell itself consists of a silicon waver and some silver, are they rare?
Figure 4: The annual production and requirement for a solar future. [1] page 135
In figure 4 we see, that silver might get a little problem, because we need an amount of silver that is produced within 30 years. It should be mentioned that new technologies of production can reduce the necessary mass of silver very strong. Other elements, like Ga are only necessary if we would use GsAs cells in our PV systems what is not widely the case. 
We conclude, the raw material is no show stopper for a PV future.

My prediction of PV growth

Compiling all this information, I come to a quite different prediction than the IEA. My simple, but till today best guess is, that the exponential growth will continue, but at a lower rate. 
Figure 5: Long term trend of PV installation.
In figure 5 we see the global installation of PV shown as a black curve in this logarithmic plot. In the year 1992, we had only 100 MW of PV installed, ten years later, 2002 it was 1000 MW, Today it is about 200 000 MW!
Update to Figure 5 including the growing power demand, wind and the latest figures available 2016.
If the growth rate continues at 25%, as seen within the last three years, we will reach 100% PV not long after the year 2030. Remember, today we have a global power plant pool of 5300 000 MW, sufficient to power half the world. Even if we expect, that the future is fair to all people, we need "only" 10 000 000 MW to bring electricity in every home on this planet, long before 2050.  

One problem remains: Storage

Without an affordable storage system, PV can only bring electricity during sunny daytime. For a complete conversion, we need about 90 000 GWh of storage [2].
One solution for residential systems may be the power wall from Tesla, but I am not convinced, that this makes sense on a large scale. For large scale, I recommend the Gravity Storage!


[1] The Future of Solar Energy, 2015 Massachusetts Institute of Technology, ISBN (978-0-928008-9-8)
[2] Elon Musk predicts (minute 18) during the presentation of the power wall 90 000 GWh of required storage. https://youtu.be/yKORsrlN-2k