Big Picture of Energy Generation 2030

Electric Energy Generation till 2030

We can read every day about the change in the energy market. We hear about the year 2050, a time when most of our politicians are no longer with us. 

But is the Big Change to renewables so far away? 

There is only one way to understand the change, and that is, read the data we have. And I did this and present them here. The source is from BP energy statistics, you can download the data there.

Solar and Wind

I concentrate on two sources of energy solar power and wind power. Both are renewable and have the potential to power our civilization. I take the sum of both to get a more smooth picture because there is some change between wind and solar shares, that obscure the real change. The result in a logarithmic graph can show us the long-term trend:

Figure 1: (click to enlarge) red: global electric power consumption; blue: global installed solar and wind power; yellow: global mean power from solar and wind. Data source: BP

The mean global electric energy consumption is about 2000 GW, shown as the red dots, which align in the plot and show a constant growth of 3%.

All installations of wind and solar power are shown as blue dots and have an astonishing constant growth over the last 20 years in the range of 22% per year. 

The mean energy production of this fluctuating sources is much smaller as the installed capacity due to the fact, that the sun does not shine at night and the wind does not always blow. A good estimate based on data from BP shows a factor of five between the blue and yellow line. This means the wind and solar production is only 20% of the time as strong as on the nameplate. Of course, this is a statistical value and may differ between different installations.

The most interesting point is somewhere at 2030, the yellow line crosses the red line, in other words, the generated electric energy over one year from solar and wind power is larger than the electric demand in 2030!

Could this be true  

Today (end 2017), only 2% of the global electricity is from solar power, but remember only 1% was from solar power 3 years ago. In 2020 we will see 4%, 2023 we see 8%, 2026 there are 16% and 2029 32% and 2032 64%, this is the rule of exponential growth, as we all have seen in electronics. 

Figure 2: Solar energy share in different countries and the world. Source: IEA PVPS, shown in pv-magazin.

The remaining 36%, oh sorry I did not include wind power in this very short estimation!

But there is one thing, that may stop this trend. It is not the price of photovoltaics because photovoltaics is now below 3ct/kWh and thereby cheaper than any other energy source. There is a so-called learning curve that gives in the future even lower prices due to high production volumes.

The roadblock could be energy storage!

If we find no way to store the energy cheap and on the huge scale, we cannot go far beyond 50% of fluctuating renewable energy in the electric grid. And the storage demand is in the range of 24 h global electricity production, 60,000 GWh!

To imagine this number using batteries, think about the Gigafactory built by Elon Musk. If it reaches full capacity it may supply 100 GWh of batteries a year. If we install all the batteries in the grid, we need 600 years until we have enough storage. This works only out when the batteries have a lifetime of at least 600 years. 

Figure 3: Gravity Storage, a large-scale electricity storage system.

We need new ideas, my concept of a Gravity Storage may show a way out of this problem. One Gravity Storage site can store up to 8 GWh of energy, and we don't need expensive raw materials only rock and water.

But this is another story. 

LCOS Levelized Cost Of Storage

LCOS the price for stored Energy

Comparison of storage costs

Comparing the costs of energy storage is anything but easy. This is because known storage media such as batteries, pumped storage, gravity storage or compressed air have very different prices and efficiencies.
In this post, I would like to explain the LCOS comparison procedure, which is used internationally, and point out the calculation problems.

Where the costs arise

A webinar about LCoS and bulk storage.

At first glance, many people see only the purchase price (CAPEX) for a storage device. But even this is not a trivial decision, let's just think of a pumped storage reservoir that needs to be built. Perhaps ten years from the investment decision to the first electricity supply, a time when a lot of money is spent. Wouldn't it have been possible to invest the money better during this time, perhaps with a 5% interest rate?
To take this effect into account, the discounted price for the future is determined. In a simple case, a storage device that costs 1000 dollars, but can first be used after one year, would cost ~1050 euros.

When the storage facility is in operation, running costs (OPEX) are incurred, e.g. for maintenance and operation, but also for renting the space. If there is a battery storage unit in the house and requires 1 m² of space, you have to allocate the rental costs per month, about $5/m², so that the storage unit alone causes 5*12 = $60 rental costs per year!

A power storage device is never 100% efficient. Since the electricity that is stored is not free of charge, even if the opposite is often claimed, the costs of electricity lost during storage must be considered. For example, if you have a LiIon battery that takes electricity from your own PV system, you can charge assuming 10 ct/kWh for the electricity and a storage efficiency of 90%, measured on the alternating current side. As a result, 10 ct costs are incurred per storage cycle in a 10 kWh storage system due to the internal power loss.

For many calculations, however, the lost interest rate is one of the most expensive but also the most difficult to understand parameter. When making an investment decision, every company wants a return on investment that is higher than the return it would receive from the bank. Since every investment is supposed to generate a profit and is subject to uncertainties, a calculated return is assumed, which appears to be relatively high, currently often 8%.
Consider that a storage facility could break down, in the future, there could be another demand or a much cheaper storage facility could come onto the market. In each of these cases, the expected repayment would be risking and the entrepreneur would be "insured" with a planned return.

Exact calculation 

For an exact calculation of the costs of storing one kWh of electricity (or 1 MWh, the usual unit in the electricity market) one must, therefore, know many factors in advance. The most important ones are:

• Electricity price of the electricity to be stored (P_elec-in)
• The efficiency of the storage system (u (DOD))
• The purchase price of the storage system (CAPEX)
• Storage device lifetime (N Storage device lifetime in years)
• Number of storage cycles (#cycles)
• Expected return (r interest rate)
• Operating costs (O&M) 

If you have all these figures collected, you can make a first simple calculation:

                   All costs
Costs per kWh = --------------- 
                  stored power

As simple as this formula may seem, it becomes complicated if future revenues and expenses are used correctly from a financial point of view. Then, for example, a kWh that you store in 5 years becomes smaller than expected, since you have to discount everything for the future (keyword: interest rate).

This discounting can be described by a sum formula which reads as follows:

The detailed formula for calculating the storage costs according to the Apricum calculation.

I assume that most people will be awed by the sight of this formula. But, strictly speaking, it does not say more than I have mentioned so far, only in one, for mathematically experienced people, plain way

Evaluation of LCOS with examples

Practically speaking, you can enter such a formula in Excel with a little patience and then start to calculate. I did this together with experts from the Imperial College in London, especially Mr. Schmidt[1], and determined the results for some systems.

Comparing important storage systems gives the following results:

Comparison of LCOS for different storage systems[1]

The graph shows that Gravity Storage and Compressed Air storage have almost the same initial cost (CAPEX) but the storage costs for a Gravity Storage System are lower because the efficiency is higher there and therefore less power (P-elec) has to be stored in the system to have the same amount of power available later.

The following assumptions were made for the estimation above:

Data used for the calculation above (click to magnify). [1]

How strong the impact of the yield (interest rate) is, can be seen if you calculate with 4% interest rate instead of 8% interest rate as shown above.

Change in LCOS at 4% interest rate. [1]

Although all other costs are unchanged, the storage costs for some systems, such as Pumped Hydro are significantly lower. However, the costs of batteries remain relatively high. What is the reason for this? The reason for this is due to the construction period, while battery systems can be connected to the grid within one year, systems with a construction period of several years require a lot of capital upfront until the first revenues are generated. If interest rates are low, this is less important.

Conclusion

I hope it has become clear at this point that the calculation of storage costs, especially if they are an investment of a company, is not easy to determine, but that there are known procedures for accurately calculating these costs.

Many private users of battery systems will rarely make such a calculation, it is often about the good "feeling" to have a store for one's own electricity, but unfortunately, this cannot be reflected in an investment decision.

Read more Global Demand for Energy Storage

Comments:

CAPEX = capital expenditures (capital costs)

LCOS = Levelized Cost of Storage

OPEX = operating expenditures (operating costs)

Sources:

[1] Schmidt, 2017, report: Levelized cost of storage.

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, 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 during 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 this 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; the 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 Musk's 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 afterward energy is produced clean, without CO2 and at a low cost.

I think: we can do it!

Sources:

[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

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. Besides 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 stop the carbon problem and limit the exhaustion of the scare fossil 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 these let's look into the near history.

The 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 fluctuating 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 seems 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 happened 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

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

We don't know the exact possible amount of energy demand that can be shifted to other times but an optimistic guess might be, that 50% of the demand can be shifted in a way that the storage demand is halved.

Assuming this, we need only one day of storage if a smart grid and a continent-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 contains 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 this seems to be more within practical reach, than a bure battery solution.  

References

 [1] Jens Tambke, Lueder von Bremen, Länderübergreifender Ausgleich für die Integration Erneuerbarer Energien. 

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 powertrain 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 legal 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 during its operational phase of approximately 200,000 miles (ca. 321,869 km), may sum up to $30,000 (depending on local tax) and is often more expensive as the whole car. In addition, no one knows during car purchase how the gas price will develop. The money ends up in the pockets of the oil companies and oil states, not in the automotive industry!

Summarized, the major carmakers only can 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 earth elements are not necessary, which can only be found in hybrid cars like the Toyota Prius (46 kg!).

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 $ 11.000.000.000 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 substantially 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 an 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 an 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 appears 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. A 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 easily reachable by a battery and beyond the lifespan 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 of 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.

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

It would not be new in the history of innovation that industry does 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 like 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 January 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. 

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, the 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 superconductor" (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. 

These 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 lose 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 aluminum seem to be sufficient, aluminum is much cheaper, so we take aluminum. The electrical resistance of aluminum 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 an 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 aluminum. At the moment, aluminum sells for 2000 $/t, with limited deviations from that value. Our power line needs 27.000.000 tons of aluminum because the density is 2700kg/m³. The price tag is 14 G$, not that bad if we consider the impact on 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 safe 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 for 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 the 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. 

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, then 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 analyzed 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 too 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 got 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 rollout of PV 

One possible reason, to be pessimistic about the global rollout 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 analyzed 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, aluminum and plastic are necessary to protect the silicon cell, copper and more plastic are necessary to transport the power away.

Figure 3: Commodity materials required for PV. [1] page 131

Today, all these commodities are produced in a volume, that no real bottleneck 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 wafer 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, in 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!

References:

[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

Storage Maters

Fuel is Stored Solar Energy

We live in a world, where the energy we consume was stored eons ago by nature. The conversion efficiency of solar energy into oil was really lousy, only a fraction of the solar radiation was converted to biological mater, only a fraction was laid down into the ground and only a fraction is now available. If we do the math, we find, that less than one billionth (10E-9) of the solar energy, which reached the earth within the last 100 million years, is stored in our fuel resources. This leads to the idea that we can do better than nature! Using solar radiation energy conversion systems like photovoltaic or concentrated solar power, we end up near 20% conversion rate, which is sufficient for economic land use and by a factor of 100 better than plants, who only convert 0.1% of the energy in usable fibers or sugar. It should be mentioned, plants need water and solar cells love deserts! Resulting in no competition of land use if we are smart and don’t plant for energy but plant for food.

The Storage Problem Remains

There remains a problem, storage! Storage was never an easy business, but if solved it changed the world. Inventing hey, for example, was necessary to conquer the northern hemisphere, where in wintertime is no food for the livestock. Storing information in books was the breakthrough for the industrial age and unlimited computer storage capacity is essential for our information age.   

The upcoming renewable power age lacks efficient and cheap storage capacity for electricity. Knowing this, we could visit the known technologies and there potential to solve the problem if further developed. Best known to the public are batteries. This is, by the way, a big problem, because our politicians, driven by their simple mind and the public, believe in batteries. Batteries are fine for mobile applications like cell phone and laptop. Cars using batteries are still expensive, but it may be within the reach of our technology to power them by batteries. Things get much more difficult if we want to use batteries for grid-scale applications.
Batteries are expensive and need some more or less rare and expensive metals, they use processes which are not perfect rechargeable, this is the reason that batteries run out of business after a few thousand charging cycles. All this does not matter, if we use a mobile phone, live time is limited, the price of the battery is not the main value of the device and we don’t care to much on the environmental impact on the small scale that is involved.

Grid-Scale Storage is Different

If we need storage for large scale, and grid technology is always about GW and TWh, values, which are trillion (10E12) times above the mobile phone and laptop scale. This is, by the way, easy to guess, as long as billions of consumers are out there. There are three different questions, how expensive is the storage capacity, how many times can we recharge it, and how efficient is the process. The reason why price matters is we can only earn a limited amount of money on every charging cycle. If the battery life is already finished, before we have earned enough money to pay for the battery itself, it is useless to buy the battery at all.  The situation for the efficiency is in some way similar. If we have to pay more for the energy to charge the battery as we earn during discharge, the system doesn´t work either. The problem of efficiency is not the core problem of batteries, but of many other storage concepts. Batteries suffer from the price per storage capacity. 

Why Batteries don´t Work

Price of storage capacity for many batteries is above 200$/kWh, even for the very simple and widely used lead-acid battery. Lithium-based systems are often above 1000$/kWh although prices were dropping during the last two decades. Let´s do a simple calculation; our battery should be charged every day, as it makes sense in solar power systems. During nighttime, the price of power should be 10ct/kWh more expensive as at daytime. If we discharge the battery, we earn 10ct every day and within six years we have a return on our investment into the lead-acid battery. But this does not hold due to the fact, that our battery dies after about 1000 cycles. Using the Lithium system, things are even worse, we have to wait about 30 years for the return of our invest without any interest rate, this does not attract many investors.

More Storage Technologies

We visit other techniques of storage in the next blog posts

• Methane
• Pumped Hydro
• Hydraulic Hydro Storage