Daily Archive for December 5th, 2011

Low-cost energy storage devices for developing countries

The race to create low-cost energy storage devices has spurred many start-up companies like Ballast Energy, a company founded by MIT graduates Bryan Ho (PhD, 2011) and Bryan Ng (SM, 2008) earlier this year.  I had the opportunity to pick their brains about the challenges and potential impact of energy storage devices, their technology, and their experience as entrepreneurs.

1. What are the main problems with the electrical grid now?

Currently there is very little energy storage on the grid in the U.S.  Fundamentally, that means that electricity must be consumed immediately as it’s being generated.  This leads to a lot of synchronization problems and results in a very inefficient grid.  The U.S. has even built additional power plants to account for the occasional spike in energy use during peak hours.  These expansive power plants are needed very infrequently and are very expensive to fire up.

Developing countries face the same problem, but the challenges are exacerbated because their electrical grids are not as robust as those in the U.S., and there are many issues associated with local grid access, particularly in remote villages.  Furthermore, there often are not enough generators to provide energy during peak hours, so the power just goes out when energy demand is high.

2. What is an energy storage device and how does it help?

The purpose of an energy storage device is to provide a layer of buffering between energy generation and consumption, allowing people to use electricity in a manner that is much more efficient.  For the U.S., this means that we don’t need to continue building power plants that are rarely used and expensive to fire up.  Furthermore, electricity can be cheaper because it can be stored during low-demand times to be used during times of peak demand.  The development of energy storage devices is also critical alongside the ongoing development of renewable energy sources, since energy storage can smooth out intermittencies in solar and wind generation.  In developing countries, energy storage devices mean fewer power outages where there is a grid, and more efficient power usage in remote villages that can generate their own electricity through renewable energy.

3. What kinds of technologies are used for energy storage devices and how does your technology fit in?

Energy storage devices can be categorized by their energy storage mechanisms.  There are pumped hydro devices that pump water to be run through a turbine when energy is needed.  It requires a lot of space and there hasn’t been a new installation in decades. Secondly, there are compressed air devices, which can operate both below and above ground.  The concept is similar to that of pumped hydro but it’s done with air instead of water.  Third, there are electrochemical batteries, which can be divided into static and flow batteries, including lead-acid, Li-ion, Na-ion, liquid metal, etc.  There are many more, including devices based on gravity, flywheels, and capacitors.

One major problem with large-scale energy storage devices is the cost.  Current options for large-scale lithium-ion batteries involve stringing together a tractor-trailer full of smaller batteries to construct one large battery.  These methods are inefficient and expensive due to packing material costs.  Ballast Energy is looking into redesigning and reengineering electrochemical batteries specifically for the grid.

4.  What criteria do energy storage devices have to have to be used in the U.S. and in developing countries?

Depending on the application and mission of for the storage, the criteria for energy storage devices may vary.  Furthermore, commercial applications in urban areas have many of the same criteria as anything we’d purchase in the U.S.  Often what people have in mind when thinking of “applications in the developing world,” are off-grid applications in slums or rural areas.  In that case, the batteries need to be stable (doesn’t need a lot of maintenance and are more tolerant to less strictly controlled environments), inexpensive, distributable, and ideally have a long lifetime.

5. Can you put “low-cost” in context?

It depends on the type of application because not all types of power or energy usages are priced equally.  For the market that we’re targeting, which is energy or bulk storage where the charge/discharge rate is 1-6 hours, batteries currently cost $600+ per kilowatt-hour (kWh).  The price will go down over time, but Ballast is targeting $200-$250 kWh immediately.

6. Do you have any advice for aspiring MIT entrepreneurs?

MIT has a tremendous amount of resources, including intelligent and passionate people, competitions like the $100K or IDEAS, equipment, and programs/classes/clubs like iTeams, VMS, Ventureships, and Energy Ventures.  There are many opportunities for students to get involved with start-up companies and ventures, and vice versa.  Take advantage of these resources and don’t be afraid to ask questions or ask for help.