If you had to pick one word to sum up the key imperative for the smart grid industry at the close of 2011, it would have to be “integration.”

That word means different things when taken in different contexts, of course. But whether we’re talking about corporate acquisition activity in the smart grid space or the increasing pressure on utilities and vendors to tie together formerly separate systems in a working whole, it’s a useful concept to apply to some of the most important smart grid trends we’ve seen over the past year, as well as the challenges the industry faces in the year to come.

So how have the driving smart grid trends of 2011 set the stage for integration challenges to come? Here’s a quick recap:

1.) Corporate M&A Yields Investor Exits, But Have They Yielded Value to the Industry?

Take the massive number of corporate acquisitions in the smart grid industry in 2011. While M&A is a good way for investors in smart grid startups to realize a return on their investments, it’s also a huge challenge for the corporate buyers to integrate the technology they’ve acquired in a way that helps it realize its true and full value to the grid, to utilities and to their customers.

While it’s difficult to measure the overall value of smart grid M&A in dollar terms, given that so many deals were for undisclosed amounts, the biggest ones add up to billions. Those include Toshiba’s $2.3 billion purchase of smart meter giant Landis+Gyr, Schneider Electric’s $2 billion acquisition of Telvent, and General Electric’s $3.2 billion purchase of Converteam.

Schneider, GE, ABB and Siemens -- the Four Horsemen of the Power Grid, if you will -- have been the major buyers this year, with Siemens stepping up its comparatively lackluster acquisition roster by buying eMeter, a big independent player in smart meter data management software, earlier this month. On the demand response front, French grid giant Alstom bought UISOL, and Johnson Controls bought EnergyConnect, while U.S. demand response market leader EnerNOC added M2M Communications and Energy Response to its long roster of acquisitions.

It will take some time to assess how these acquisitions played out in the marketplace. It’s taken Cisco more than a year to turn its acquisition of wireless mesh startup Arch Rock into a deployment with smart meter partner Itron. Constellation Energy is still working on transitioning customers of demand response provider CPower, which it bought in Sept. 2010, to its new Virtuwatt program.

2.) Smart Meters Are Getting Up and Running -- or Facing Consequences

On the smart meter front, the integration challenge facing utilities is to prove that millions of newly deployed smart meters can actually provide all the value claimed for them -- and do it quickly enough to forestall the growing backlash from consumers and regulators over the costs of installing them.

Let’s take the example of Pacific Gas & Electric, the poster child for problems with smart meters. Sure, the Northern California utility has been busy coming up with ways to allow customers to opt out of having smart meters installed at their homes. But it’s also been turning on smart meter functions, like outage detection, which play an integral role in justifying the cost of deploying them through improvements to service that benefit utility and customer alike. (Of course, on the futuristic concept of hooking smart meters up to smart home energy devices, PG&E and the industry as a whole are expecting that to take several more years.)

Will PG&E and the other utilities with growing smart meter-customer relations issues get their networks running right? With tens of millions of smart meters being pushed into the field (helped along by billions in federal stimulus grants), we’re finally getting a chance to see whether or not they work. Some in the industry are predicting widespread failures of today’s systems, while others are predicting a more piecemeal process of replacing parts and rethinking architectures. 

Either scenario would mean increased costs for smart meter deployments already being paid for by increased customer rates -- and that’s not going to be OK with state utility regulators. Illinois lawmakers just passed a bill that would tie future profits of utilities ComEd and Ameren to proving that their $3.2 billion in smart grid plans actually live up to their promises of reducing outages, energy theft, power delivered to inactive meters and bad debt. State utility commissions in Maryland, Hawaii, Michigan and Indiana are ordering utilities to reduce customer rate increases for smart grid projects.

3.) Demand Response Shifting Models, Waiting for Payday

We’ve been saying for years that demand response -- the decades-old industry of getting big power users to turn down their power use to help utilities manage peak demands on their grids -- is due for a shakeup. The idea is that the emergence of the smart grid writ large will slowly give utilities and their customers ways to match power demand and grid needs in a way that would bypass aggregators like EnerNOC and Comverge.

Well, it hasn’t happened yet -- and with the DR market aiming its sights more and more toward faster and more automated forms of shaving power use, it’s not clear that the specialist middleman role is going to go anywhere anytime soon. Take October’s news of Mid-Atlantic grid operator PJM accepting two new projects from startups Viridity Energy and Enbala, that promise to reply to power reduction orders within four seconds, rather than in the hour-ahead or day-ahead timeframes more common in the industry. EnerNOC’s new 150-megawatt DR project with the Alberta (Canada) Electric System Operator is aimed at fast response to deliver stability to an entire regional grid system.

Fast-response is part and parcel with the broader concept of automated demand response, which has seen continual development over the course of 2011. OpenADR, the emerging standard for automating demand response, is being deployed by Honeywell in the U.S., China and Europe, and being tested by lots of other companies both for commercial and residential applications.

At the same time, 2011 was the year that gave the demand response industry some important regulatory boosters that could radically change the way that 'negawatts' are compensated in energy markets. In March, the Federal Energy Regulatory Commission ordered the nation’s grid operators to come up with market rules to compensate demand response on an equal footing to power generators. Next year should see some important developments on that front.

4.) The Smart Grid Back-Office Moves to the Cloud

While utilities spend most of their smart grid project money on the hardware deployed in the field, the ongoing costs and benefits of operating that gear relies on a well-planned and well-integrated back-office software system to manage it all. If utilities can’t or won’t invest in making that happen, there will be plenty of IT providers willing to rent it to them.

That’s the upshot of the move toward cloud computing platforms for smart grid functions that we’ve seen emerge over the course of 2011. Early in the year, Verizon said it would provide a cloud platform for eMeter’s meter data management services. Itron’s work with IBM, SAP and Teradata to set up a meter data warehousing and analytics system for Southern California Edison could expand to other settings. IBM and Oracle are both touting flexible cloud offerings to manage the changeable data needs of utilities.

In November, General Electric announced its first smart-grid-as-a-service client, the municipal utility of Norcross, Ga., and is hoping to expand that service to the thousands of smaller utilities across the country. SAIC is working on a similar cloud service for smart meter management, and Lockheed Martin is trying a demand response cloud offering for rural electric co-ops. 

On the smart-grid-to-smart-device front, we’ve got a host of vendors providing cloud-based platforms, including Tendril, Digi International and Honeywell. And let’s not forget the role of IT giants like IBM, Cisco and Microsoft in creating “smart city” IT infrastructures based in the cloud -- lots of cities need to manage electricity, gas and water as part of city services.

5.) Managing the Grid and Managing Markets Converge

All the technology for managing the flow of power on the grid ought to be combined with the technology for managing how it’s paid for. While energy procurement and planning has long been a part of the business operations of utilities and big-power-using companies, we’re seeing the technology and business processes behind that integrating with smart grid in some interesting and new ways.  

Take ABB’s $1 billion purchase of Ventyx in 2010, which has essentially given the Swiss grid giant a new software arm. Since then, Ventyx has been absorbing ABB’s grid operations software into its portfolio of power market management and generation-distribution planning and analysis tools, as well as new acquisitions like utility workforce management software vendor Obvient Solutions.

Two recent announcements from ABB/Ventyx highlight the dual nature of its offerings. The first, a new model-based Volt/VAR optimization application for its distribution grid management software, can help utilities manage grid voltages for efficiency and peak power reduction. The second, a transmission flow and outage data analysis engine, helps pinpoint and predict how congestion on certain transmission lines affects wholesale electric pricing.

Marrying grid operations and market operations could give smart grid technology providers new inroads into both utilities and the customers that pay for their power. To take the example of a key ABB rival, Schneider Electric’s $268 million purchase of Summit Energy in March gave it access to Summit’s client base, which represents $20 billion in annual power sales. Those customers are now targets of Schneider’s broader energy efficiency systems and services business -- and its $2 billion purchase of Telvent has given it a lot of utility-facing technologies to connect those customers to. 

A similar example comes from Alstom acquisition UISOL, which makes the software that runs demand response and market programs for big U.S. grid operators PJM, Midwest ISO and California ISO -- in other words, roughly half the DR capacity of the United States. UISOL also provides demand response software for a half-dozen utilities, including Las Vegas-based NV Energy. Alstom, obviously, has the grid technologies to connect both utilities and grid operators to their customers.