Similarly, renewables-based generation, energy storage, and grid analytics/software are the three sisters of the Smart Grid – leveraging the synergies of their technologies to achieve greater reliable electricity yield than each technology could independently produce.   These three technologies can deliver their combined benefits for utility-scale generation as well as distributed generation and microgrids.  

Renewables, the first sister, are categorized as intermittent or steady-state sources of electrical energy.  Wind and solar are intermittent.  Geothermal and hydro (in most cases) are steady-state.  While steady-state is easier to manage, it’s not as well-distributed or readily accessible for most countries.  Solar and wind have distinct advantages in the fact that the sun shines everywhere and the wind is usually not too picky about where it blows.  Solar has great flexibility in where it can be placed –rooftops everywhere can be potential sites for distributed generation.  But intermittency is a vexing problem for planners and grid managers because it is vital to grid health to minimize fluctuations of energy.  Clouds passing over solar panels or temporary drops in wind create those fluctuations.  This is where the second sister comes into play. 

Innovations in battery technologies are transforming energy storage into cost-competitive solutions that partner well with intermittent renewables like wind and solar to deliver steady state power.   There are new technologies that overcome concerns of energy density, flammability, toxicity, and achieve grid-parity pricing.  Energy storage is the second sister of the Smart Grid.  Stationary and mobile (EV) forms of energy storage can play significant roles in utility scale and distributed generation utilizing solar and wind, because it can be deployed to smooth out temporal or weather-based fluctuations.  Renewables and energy storage deliver a potent synergy, but a third sister is needed to help manage these assets as they are integrated into transmission or distribution grids.

Grid analytics and grid management software are needed to manage increasing numbers of renewable generation and energy storage assets.  Utilities are building out IP-enabled networks to accommodate bi-directional communications, and this activity opens up opportunities for remote realtime monitoring and management of these new assets anywhere in the grid.   Realtime management of dispersed assets needs software to organize grid management activities.   It also requires analytics to provide proactive intelligence about conditions and predictive performance of grid networks and devices.  Grid analytics and management software enhance the reliability of electricity on the grid – a valuable synergy with renewables and energy storage. 

These technologies will accelerate the delivery of the benefits of the Smart Grid, but today exist as separate solutions.  Could a three sisters solution for the Smart Grid be the next brilliantly synergistic American innovation?  Like the Native Americans of the past, system integrators who specialize in distributed generation and microgrids can play a key role in creatively combining these technologies into solutions that fully leverage their synergies.  These solutions could also be exported globally to address developed and developing world energy needs.

Storage is the topic of this week’s blog.  Energy storage is defined in the Smart Grid Dictionary as “Banking electricity in batteries or other storage devices for transmission and distribution at a future point in time.  Storage can take electrochemical or non-electrochemical forms.  Energy storage is used for grid stabilization, grid operational support (frequency regulation services, contingency reserves, voltage support, and black start), power quality and reliability, load shifting, and compensating for the variability of renewable energy sources.  Energy storage is a key component of the Smart Grid.”   

As this definition notes, energy storage traditionally served an important role in power quality and bridging, ensuring continuity of power and service.  We are also accustomed to seeing batteries (plus generators) for specific applications, such as back-up power for telecommunications and networking gear, computer centers, and hospitals.  Those UPS (Uninterruptible Power Supply) devices that you see in offices are another source of battery power. 

Energy storage is undergoing a tremendous expansion into new venues, such as our homes and garages, and new applications for balancing energy generated through intermittent renewables like solar and wind energy.  Indeed, many experts consider it a vital component to most renewable energy sources to ensure that there is sufficient electricity to meet demand.  While solar energy is available during the day at times of peak demand, it is affected by weather patterns that could reduce or preclude electricity production.  Wind is most reliably available at night, producing electricity during off-peak hours.  Utility-scale energy storage allows all of these energy sources to be harvested and used when needed.  This is time-shifted generation, and it really changes the game for renewables.   Time-shifted generation is based on the premise that you charge your batteries when that power source is available, and discharge that stored electricity into the grid when it is needed.    

This premise presents an interesting challenge to utilities and public utility commissions in the USA.  Their calculations for setting appropriate tariffs are based on definitions of traditional generation, transmission, and distribution assets.   These assets traditionally only serve one functional purpose as their names indicate.  But energy storage can be treated as a generating asset when it is contributing electricity to the grid, and as a consumption point when it is recharging.  Thus, energy storage doesn’t easily fall into the existing rate cases.  The Federal Energy Regulatory Commission (FERC) is considering if they should develop a policy about storage to provide guidance to utilities and regulatory agencies.    

One of the biggest concerns is competition and cost recoveries involved in classification of assets.  Aside from utilities, investors also have concerns about the viability of investments they could make in energy storage.  A favorable or unfavorable regulatory climate, or one that is a 50 state patchwork of different asset treatments could have serious implications for the scope and pace of successful Smart Grid deployments. 

The push for distributed generation moves the issue outside of the traditional utility footprint too. Distributed generation means distributed energy storage too, and some of it will be located at what was once just the point of consumption.   And then, of course, some of it will be on wheels too, in electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs). 

And finally, there are discussions about energy storage from the carbon credits perspective – is it “clean energy” when it is discharging into the grid even if its source was a dirty fossil fuel?  Or does the source of its original charge determine its “green-ness”? 

Energy storage has tremendous benefits to a Smart Grid, but it does require serious study to classify it properly for asset, emissions, investment, and regulatory purposes.  Without agreed definitions, confusion will inject delay and detours on the path to a cleaner and more secure energy future.

Smart Grid Rule #5:  You know you have a Smart Grid when energy storage is nationally defined as a specific asset class, with guidance about cost recovery and carbon emissions treatments.

What makes a home its own micro grid?  It takes the following (and presumes that the utility has smart meters and the complex systems in place to support a two-way flow of electricity and communication):

• An alternative energy source of electricity production like solar panels on your roof
• An energy storage capability – the home battery
• Internal communicating technology that has contact with all appliances that use electricity – could be a wired or wireless technology
• HEMS (home energy management system) software that manages home electricity use and communicates with the preferred utility in real-time about pricing and billing

Let’s talk about the micro grid’s home battery.  This is an energy storage device that doesn’t look like the batteries in a flashlight.  Based on today’s technologies, it will be much bigger – say the size of an average refrigerator – that will evolve over time into a more compact unit (remember the incredible shrinking cell phones?)  It can store the cheapest energy – whether you create that through your own generating capacity or buy electricity from the utility at the lowest price point.  It kicks into action based on the agreement you set up with the utility.  You might voluntarily disconnect from the utility grid when electricity is expensive to purchase or when your generating capacity can handle your home load.  The utility may ask you to disconnect when this type of demand response program eliminates the need to fire up a peaker plant, or to mitigate the loss of transmission or distribution capabilities due to planned or unplanned events (maintenance vs. accident).  Your home is its own “island”, which is a term used by utilities to describe this distributed generation concept.  How long your home remains islanded from the larger grid is based on your utility agreement as well as you home battery duration, your management of that stored energy, how much electricity you can continue to generate on your own, and the cessation of conditions that caused the utility to island your home.

I like this entire concept, but want to emphasize that the battery needs to be managed by the HEMS system.  I want the home battery management system integrated to my HEMS software so that I have one terminal (internet-enabled TV, computer, whatever) that tells me the health of my home battery, how much capacity it has for energy and power (its duration), how long it will take to fully recharge again, and recommend if I should buy power from the utility to recharge it (and at what cost) rather than use my own generating capacity.  Thus when it is nestled in a standard home utility closet or garage, it must be regularly updating its status with my HEMS software so I don’t discover that the battery isn’t working properly during a power outage.     

Energy storage is a key component of the smart grid whether we’re talking about utility-scale storage or home-based storage.  The simplicity by which any energy storage solution is managed is a key contributor to its adoption rate by homeowners – especially those of us who like plug and play instead of interpreting technical installation manuals. 

There is a lot of conversation about whether or not the home battery drives away every morning – is it an electric vehicle (EV) or plug-in hybrid electric vehicle (PHEV) instead of a stationary device.  That’s the topic of next week’s blog.