Silver Spring Networks has added another $15 million to its fourth round of funding to help it expand its reach in the smart meter networking field, VentureWire reported Wednesday. The $15 million investment comes on top of $75 million in series D funds the Redwood City, Calif.-based startup raised in October (see Silver Spring Grabs $75M). Venture firm Kleiner Perkins Caufield and Byers led the round, VentureWire reported. Previous investors have included Foundation Capital, JVB Properties and Northgate Capital. Add that to the nearly $70 million in venture capital, debt financing and warrants raised since 2007 (see Green Light post and VentureBeat post), and that's a lot of money for Silver Spring to expand its "Smart Energy Network." That now includes about 500,000 smart meters from companies such as Itron, General Electric and Landis+Gyr, embedded with the company's devices, which communicate to one another and utility access points via meshed radios using Internet protocol (IP)-based networking. Silver Spring expects to have about 2 million meters with its devices installed in place by year's end. With large-scale contracts with utiltiies including Pacific Gas & Electric Co. (5 million customers), Florida Power & Light (4.5 million customers) and Pepco Holdings Inc. (1.9 million customers), Silver Spring is set to install its devices in millions more meters over the coming years. Competitors in the field include smart meter makers that provide networking and communications themselves — Itron, GE, Landis+Gyr, Sensus and Elster are the big ones — as well as rival networking providers such as Aclara, Trilliant, Eka Systems and SmartSynch. Those companies use different means of carrying data for energy management and control between utilities and customers via the smart meter — and whether they utilize open standards or should be deemed proprietary is a topic of some debate (see Smart Grid: A Matter of Standards). No doubt all of these companies will be vying for a piece of the $4.5 billion in grants for smart grid projects contained in the stimulus package signed into law last month (see Obama Signs Stimulus Package). That funding is tied to using open standards when available and appropriate.