Saturday, October 17, 2015

New Trends in Battery Storage

Allow me to report the newest trends in battery storage from the German market, one of the pioneering markets in terms of renewable energy.
Next to trending residential home storage systems in the size of approx. 5 kWh combined with intelligent energy management systems, bigger commercial and industry battery storage systems in the size of 15 kWh up to MWh-range are now entering the market.
These XXL battery storage systems - realized with different technologies - can be used:
(a) to stabilize a local grid infrastructure, (b) for peak-shaving (cutting the peaks of volatile renewable energy supplies, such as solar and wind), (c) for arbitrage (optimization of difference in supply price and feed-in tariff, and (d) as uninterruptable power supply (USV).
The newest trend is virtual large-scale clustered swarm storage, where several smaller distributed battery storage systems are combined into a network structure via mobile connection.

Internationally, not only company Tesla is venturing in this area, also other big car manufacturers are joining in, e.g. Daimler, battery producers, e.g. German company Varta and French company Saft, and technology providers, such as SMA, Siemens, Bosch, Younicos, BYD etc.
Further regional energy providers, e.g. Lichtblick in Hamburg, and many start-up ventures.

Let's think about Podcars. If we are going to deploy and integrate battery storage into a Podcar system design, the following points could be considered:
- we could subdivide the looped podcar infrastructure in power cells, which are interlinked with each other. This would keep the overall system more robust and resilient. In this way, the multiple cells can load balance for peak shaving, price optimization and emergency backup. A local grid connection might still be needed to keep costs for battery storage at an acceptable limit. A feed-in tariff stucture would decrease the payback time period significantly.
- continous power monitoring from central station. A virtualized large-scale clustered swarm storage network could be deployed, which interlinks power cells and looped podcar nodes.
- a decision on battery technology has to be made, e.g. Vanadium Redox-Flow Technology, Lithium technologies or traditional "dinosaur" lead gel batteries (low price and matured technology).

Thursday, October 15, 2015

Building a Solar Canopy

When we are talking about how to canopy solar-powered podcar guideways with solar PV modules, we are actually talking about Building-Integrated PhotoVoltaic systems (BIPV) (see also scenario 1 in my last post Energy Aspects).

In the following you can see some impressions of different vendors' products and imagine how these technologies would look like on a podcar guideway.
Because of copyright reasons I provide here the direct web links without favoring the one over the other vendor. The links below are picked at random.

Examples for flexible, elastic modules:

A good source for reading more about BIPV is for example:
Energizing Archictecture: Design and Photovoltaics by Claudia Lüling
available for example here


Wednesday, October 14, 2015

Energy Aspects

In the following I want to sketch some important aspects when it comes down to power (real scale) podcars.

Basic considerations looking at the power consumption side:
  • First, max. energy consumption of fully loaded podcar per defined distance should be estimated (I assume that there is not much valuable empiric data existent so far)
  • Operating hours per day and time of operation should be considered (in terms of matching consumption with solar PV generation onsite)
  • Additional power loads for the guideway and stations (control electronics, electric lighting, ticketing system etc.) have to be put into the equation
Basic considerations looking at the power generation side:
  • If possible, 100% energy generation from renewable energy sources: Power can and should be produced from versatile renewable energy sources in a hybrid generation approach, e.g. solar and wind, to optimize energy supply and to minimize disruptions or dependency on backup systems (grid or battery storage). Ideally, the energy is generated locally where it will be consumed. This saves overhead costs for distribution.
  • Centralized or decentralized energy production: It has to be decided in the design phase, if energy should be generated locally or remotely or both. 
Two scenarios: 
1) Energy is produced in a decentralized way by mounting solar PV modules locally on top of the guideway. In this case, shortages in the power supply (evening and night times, cloudy sky) must be compensated reliably by power from the grid or from battery storage. Ideally, the then purchased grid power should come from renewable sources only. In a potential power surplus case (full sunshine at noon, no or few podcars used), a (REFIT-) scheme should be in place to repay the surplus power fed to the grid. Otherwise, it can be stored in batteries.
2) Energy is produced centrally at a (remote) solar and/or wind farm and then distributed to the podcar system. A question here would be, if power can be distributed locally or via the grid. A power purchase agreement would be an option. 

Example calculation:
Let's assume in scenario (1) that we can build 300 Wp solar PV per 1 m length of guideway, then this would equal to the theoretical value of 300 kWp per km or approx. 480 kWp per mile. This is nearly half a mega watt per mile under optimal (test) conditions.

Next steps:
When we have the value for the energy consumption of a fully loaded podcar, we can then calculate how many podcars we can power on a certain distance (minus additional loads). We can also determine how big the battery storage must be, depending on operational hours, solar climate and grid-connection or not.

Example calculation using PVWatts Calculator
Example calculation for 300 kWp solar PV system (installed along 1 km Podcar track) for location Mountain View, California, assuming solar PV modules facing South, fixed installation with 20 degrees tilt angle, and 14% total system losses. Initial Cost and CoE to be verified. Further assumed PV incentive of $0.09/kWh.

These values can be compared to get an idea of the cost-effectiveness of this system. However, system costs, system financing options (including 3rd party ownership) and complex utility rates can significantly change the relative value of the PV system.

Sunday, October 11, 2015


We are indeed living in an interesting time. With the IT-revolution apparently never stopping, we are facing currently a change in the energy sector from fossil fuels to renewable energies. The next revolution in the transportation sector is already on its way…

IT is in the middle of a transition from the so-called 2nd platform to the 3rd platform. What does this mean?
First, the (r)evolution went from mainframes (1st platform) to the personal computer and the Internet (which is the 2nd platform). Now, we face the shift from PCs to Mobile Devices with millions of apps and billions of users coming with an enormous hunger for data resources. The megatrends transforming the IT industry are big data, cloud, social networking and mobility.

Imagine this: The information growth in the Digital Universe is expected to reach 44 Zettabytes in 2020. To put this into perspective: Think of a grain of sand equal to one Megabyte, then one Zettabyte is equivalent to a beach stretching around the coasts of China and India!
And this is only one Zettabyte...
After the Zettabyte comes only the Yottabyte, before it goes into weird names.

This is, why I gave this blog the name (R)Evolution³. To describe the ongoing trifold (r)evolution in the IT, energy and transportation sectors, and how they reinforce each other. 

Solar-powered podcars bring all these innovations together: a computerized, suspended or supported, elevated transportation system, powered by solar energy combined with reliably managed, stored and secured data.