Thanks to a rise in smart grid investments, the attention being shown to smart grid technology companies has grown significantly in the last year.

Large companies – names like General Electric, Siemens AG, Cisco Systems Inc. and International Business Machines – are watching these small startups with an eye toward winning lucrative work from utility companies and government entities.

As Reuters reported last summer, several of these smart grid companies have technology and expertise that should prove to be valuable in helping upgrade the “massive but aging” electric supply system in the United States.

It will be interesting to keep track of the players in this space. Here are several smart grid technology companies that have attracted attention recently:

GridNet – This software company was acquired by Cisco in March 2010. GridNet builds software that sends data about electricity usage from meters to utilities.

CPower – This demand response company received funding from Intel (through its venture arm, Intel Capital) in 2009 and it was subsequently acquired by Constellation Energy last fall. Terms were not disclosed.

Ventyx – This Atlanta-based smart grid software company was acquired by Swiss engineering group ABB in May 2010.

Eka Systems — This company is a wireless smart grid developer based in Germantown, Md. The company was acquired last year by Cooper Industries Plc for an undisclosed amount.

Akuacom – This San Rafael, Calif.-based demand response firm was acquired last year by Honeywell International. The company’s demand response system helps reduce electricity use at peak times.

Greenbox SRS – This home energy management startup firm was acquired in 2009 by Silver Spring Networks. The Web-based technology helps utility customers measure their home’s energy usage.

Gridpoint – This Arlington, Va.-based software firm builds applications for utilities and other companies optimize energy consumption. The company has also been featured in several books including Thomas L. Friedman’s bestseller, Hot, Flat and Crowded.

Tendril Networks – This energy management software, hardware and services company is based in Boulder, Colo., and helps utilities communicate with their customers. The company last fall announced that it would be working with Lockheed Martin on a comprehensive demand response management system.

Areva T&D, Inc. — This company is working on platform for integrating smaller-scale energy sources into the electric grid.

Boeing Company – Not a smart grid company per se but company received $10 million from the U.S. Department of Energy in November for electricity distribution management system that would allow for integration of greater amount of customer-owned energy resources.

ABB Inc. – Raleigh, N.C. company that received money from U.S. Department of Energy in November to build a real-time monitoring, control and health management system to improve grid reliability and efficiency.

Varentec, Inc. – Another company that received money from the U.S. Department of Energy in November. This North Andover, Mass., company got $2 million for research and development of a ways to integrate renewable resources into the electric grid.

On-Ramp Wireless, Inc. – The fifth company on the list of those receiving money in November from the U.S. Department of Energy, On-Ramp Wireless is developing a wireless grid sensor and faulted circuit indicator capable of monitoring underground and other hard-to-reach distribution circuit locations.

Landis+Gyr – This Swiss smart meter manufacturer recently signed a deal to deliver 600,000 smart meters to a Finnish utility company, Oulu Energy.

Comverge Inc. – Norcross, Ga., company that manufactures and designs energy management systems. In November, Comverge closed on a 5-year $15 million convertible loan to fund general working capital and other corporate purposes.

Are there other smart grid technology companies we should know about? Please leave us a note in the comments below.