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.

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. 

PV Price in the Future

Massive Price Drop in PV Systems

The future will be solar if the price of photostatic (PV) systems drops. There is a new research result about the future of the PV price online, done by Fraunhofer ISE [1], that gives surprising insights. I will discuss the results in this blog post.

Learning from experience

The first silicon PV cell date back to 1950s and since the 1980s there is a global market and production worth mentioning. Since then, the price of PV cells was constantly dropping. The interesting thing is, there is a mathematical law, that describes this drop. To keep it short, this law tells us, that every time, the production of PV doubled, the price fell about 20%. 

The actual development is shown in the graphic:

Development of PV module price since 1980 [1]

To understand this plot, be aware, the right axis is the accumulated produced capacity of PW measured in GW. It starts with 0.001 GW (=1 MW) and ends with 100.000 GW. To cover this vast range, the scale is logarithmic. The first price tag dates back to 1980, where we had to pay more than €20 per watt. The price is adjusted for inflation to the level of 2014, an exchange rate of one Euro gives $1.25 is in use. The last price tag is for 2014 and is in the range of €0.5 to €0.7 for large-scale PV power plants. 

Learning Curve

It is not surprising, that the actual price in different years is not always precise on the long-term trend curve, that shows a drop of 20,9% per year, due to market effects. 

The big question is, how will this learning curve develop in the future? There are three scenarios, a very conservative one, that tells us, only 19% drop with another doubling of the installed PV base, a medium scenario with 20.9% drop and a progressive one with 23%. However, the result will always be a sharp drop of the PV panel price, if the installed base grows in the future. 

Below a price of €0.2/W, there seems to be another limitation of the pure raw material cost. To me´, this limitation seems a little artificial, because of the price of this raw materials, like silicon or glass, could also drop if the production volume grows far beyond today's volume. 

It should be mentioned, that a capacity of 100.000 GW PV installation is equivalent to a surface of one million square kilometers, this is the size of a country like Egypt or Texas and California combined!

How expensive is electricity in the future?

The price of a PV panel is not the only part of the cost drivers in solar power. To break the price down to a kWh of electricity at the grid feed in, we have to include other cost drivers. 

Price of different elements for real-world PV grid-scale sites. [1]

The first surprising thing is, that the PV-modules are no longer the main cost driver, as shown in the figure above. The cost of mounting, connecting and planning top already this cost. The paper from ISE does not cover "Red tape", this will hopefully drop in the future, but nobody knows.

Another significant part of the cost drivers are the inverter, they produce AC from the DC, generated by the PV cell. The price of this inverter follows a similar law of price drop by market volume as the PV panels.

Price per kWh

To calculate the price of a kWh of electricity itself, we have to take the solar radiation and the capital cost into account. There is a calculation method, the levelized cost of electricity (LCOE). It includes capital cost and maintenance of the PV power site. If you are a geek, you can do the math with the following formula:

Calculation of the levelized cost of electricity (LCOE). [1]

The interesting result is, that one of the main factors for electricity from PV is not only the sun but the interest or discount rate. Today, we live in a world with very different interest rates. A strange effect is, if we look at the globe, the countries with high insulation have often very high-interest rates. For example, Germany has a low insulation but also a low-interest rate, Spain has a relative high insulation but a significantly higher interest rate. The result is, the price of PV energy is much more similar as we first guess.

PV power price depends on the cost of capital. [1]

Long-term development

To look into the future beyond 2020 is very difficult, but the gathered information gives us some hints. The first thing is, PV electricity price will drop due to the learning effect resulting from the growing market. The market is growing because PV electricity gets cheaper and is competitive with all other electric power sources. The long-term price in the scenario of ISE is in the range of  2 ct/kWh. 

The share of the market will be beyond 30% in 2050. 

But there is an obstacle on the path to solar. The sun shines only at daytime and only if there are no clouds. This results in a strong request for energy storage. One solution is the new concept of Hydraulic Rock Storage (HRS) as developed by the Heindl Energy in Germany. 

Energy storage using the Hydraulic Rock Storage. [2]

Combining a cheap storage with a storage price of 3 ct/kWh and PV in the range of 2 ct/kWh gives a long-term price for electricity over the whole day, only a fraction is stored, for less than 5 ct/kWh in most regions of the world.

Reference:

[1] Fraunhofer ISE (2015): Current and Future Cost of Photovoltaics. Long-term Scenarios for Market Development, System Prices and LCOE of Utility-Scale PV Systems. Study on behalf of Agora Energiewende. http://www.agora-energiewende.org/service/publications/

[2] Heindl Energy, Hydraulic Rock Storage, http://heindl-energy.com/