V2Green is a local Seattle greentech company started, in part, by UW grad Seth Bridges (left in photo above). V2Green is based on a rather clever idea, it provides electrical grids the opportunity to store and draw power from plug-in electrical vehicles.
From the V2Green website:
V2Green technology enables the flow of energy between electric vehicles and the grid to be adaptively managed, balancing real-time grid conditions with the need to charge individual vehicles.
The benefits are clear. Smart charging allows the existing grid to support electric transportation. Utilities, eager to increase their use of renewable energy and encourage off-peak charging, are expected to offer vehicle owners economic rebates. The resulting lower cost of ‘electric fuel’ will drive plug-in vehicle sales and encourage auto makers to further their investments in clean-energy transportation.
Ultimately, V2Green solutions support a reduction in fossil fuel consumption—decreasing the greenhouse gas emissions that cause climate change and diminishing the nation’s dependence on foreign oil.
These notes are from a talk given by Seth Bridges to an embedded systems class at the University of Washington on February 23rd, 2009.
Opening Slides
Is an electric vehicle any different than any other appliance that you would have in your house? On the face of it, maybe not. However, you don’t use the vehicle while it is plugged in–if you are, you’re probably doing something wrong. Air conditioners, pool pumps, refrigerators–even if you turn them all on–does the system fall over? No, it doesn’t. So, what happens when we plug in one more thing.
The average vehicle gets 4 miles / kWh. For the year, it’s about 3,000 kWh / yr (for 12,000 miles / yr). The average household is 10,000 kWh / year. So, is this a problem? Well, maybe no. Especially if you are charging at night; the problem is, however, if you plug in during the day or even at 4pm when you get back from work.
CA gives people $250 a year for installing a system that allows the utility to remotely control A/C. The rebate program is driven by Southern California Edison (link). How much would people expect to receive for taking part in GridPoint. Shows iPhone application. You need a way to opt-out, most certainly.
Grid 101: Reducing Peak Demand
One of the big things you have to think about is peak demand. If you plug in your car, you draw 10-15 amps. GM and Ford are saying that plug-in cars will have substantial charging requirements, something that makes them look like an air conditioner. The cost to run a coal plan, 2 cents per kw/hr. Natural gas 8-10 cents kw/hr. At the maximum peak demand, it can cost upwards of $10,000 per kw/hr. Last summer, CA hit 50 GW on August 11th (or thereabouts) and their capacity is 56GW. They were within 10% of maximum. This is why utilities are scared of thousands, or even millions, of plug-in cars. They can’t build that infrastructure fast enough. Our system allows utilities to control load on the electric grid by adjusting charge rate on PHEV vehicles. Eventually we will send power back into the grid from the vehicle battery system in order to minimize excessive loads on the power grid.
Grid 101: Real-time balance
Generally, there is no storage in the grid–that is why every moment they are balancing supply and demand. It’s really expensive to take a gas turbine to move it off its most efficient point; every time you take it down or modify it, you are wasting natural gas. If we can somehow save energy and match load via plug-in vehicle batteries, it would be a tremendous benefit. There is a lot of inefficiencies in the system to just provide real-time balance–there are systems on standby, long-term standby, etc.
Grid 101: Renewables Integration
Due to emerging state/federal regulations, 15-20% of all new generation will have to be renewable. This sounds pretty good; everyone likes wind and solar. However, these resources are variable. A 1MW wind turbine won’t put out 1MW all day, you can predict these things in aggregate but it’s challenging. If you have a cloud that moves over a 1MW solar farm and you lose around 1MW off the grid, that’s a big problem. If you could, for example, take your cars or water heaters to schedule load and charge only when wind and solar are pushing out more electricity, that would be most efficient. Is this feasible?
Opportunity: Manage Your Load
The Tesla requires 80 amps at 240. You need special box in your house to charge it. The neighborhoods that have Priuses will likely upgrade to Teslas (or cars like that). Power draw of everyday appliances: water heater is 4kW, TV is 150 watts, pool pump is 1-2kW. As long as you can drive your car, you’re not going to care when you drive it. The Chevy Volt is talking about 16volt battery pack, which they will probably use only 10 so they get long lifetime. It costs a lot of money for a charge cycle. Lithium Ion is about $2 per Wh–for the car though, people already have an incentive to buy batteries.
The technology that is in more sophisticated drive trains can absolutely drive 20kW right out the door. GM and Ford though don’t want this to mess up warranties–the 100,000 mile warranties.
Challenge: Manage Your Load
It takes lots of communication. Today, we have 130 cars. We get to most of them by using Verizon and AT&t, cellular modem contracts. It costs a lot of money to send data on that network, this won’t scale. Some of our customers have their own networks, like 100-200 bytes a day to the house. What does it cost to push a byte out, that has been an increasing point of pain. How do you send less bytes? How do you send bytes more cheaply? Unlike a water heater, the car gets up and goes away. At the end of the day, between the hours of 10-6, I will have X amounts of MW. This is about machine learning and predictive analytics. The better you are at this, the more money you can make.
V2Green Connectivity Module
Shows embedded system picture. Now on 3rd version of hardware. This piece of hardware communicates with cars (Priuses, etc.). It does the normalization. It might be serial port or CANN bus. Has GPS and data logging. Provides high grade energy monitoring. AC power supply, it can pull from vehicle or pull from wall. Uses everyday components. Atmel and 64 Mbit external flash. Lots of data logging. Up to 2/samples per second. Flexible communications daughtercard to support wifi, internal cellular, zigbee.
Open Source: Key Software Building Blocks
They use open source software but don’t release their software so they choose carefully.
FreeRTOS: simple, small preemtive scheduler (highly recommends it)
IwIP: a lightweight TCP/IP stack
axTLS: memory efficient TLS1 implementation
