Carbon Reduction and Grid Storage Via a CNG/Hybrid Smart Car

Recently the Earth’s Atmosphere has reached a carbon dioxide level that has passed 400 parts per million (ppm), a point the Earth has not reached in over 3 million years. We need to curb the emission of carbon dioxide into the atmosphere and one possibility is to reduce the amount of carbon that is emitted through transportation. Our research involves the development of a smart car system designed to combine distributed generation, electric vehicles, and energy storage into a dispatchable source of electricity. This system is designed around a series-electric hybrid vehicle using the built in battery pack and generator. Our research creates a system that combines a series-electric hybrid vehicle with a smart-charging system, a compressed natural gas (CNG) conversion for the gasoline-fired engine, and a grid synchronous inverter. We have named this platform the CNG/Hybrid/Smart Car. People require an automobile for transportation in many parts of the world and creating an energy generator that uses a more environmentally friendly carbon energy source inside the car can solve many of our energy and transportation issues simultaneously.

Not only is natural gas a less carbon intensive transportation fuel than gasoline, it is also more cost effective on a $/mile basis. The prices for natural gas are significantly reduced in recent months and will likely remain low due to the new fracking technologies and the large deposits found in the Marcellus Shale of the Northeastern US as well as many similar deposits around the world. The Locational Marginal Price (LMP) of electricity is set by the overseeing RTO. LMP typically varies significantly from region to region and also by the time of day. At peak energy usage hours, the cost of generating electricity from our CNG/Hybrid/Smart Car platform from natural gas can be up to $0.18 / kWh cheaper than generated energy from the RTO. Running the natural gas generator at these hours qualifies the vehicle as a generator and will create a source of revenue (capacity and energy) and can eventually pay for a significant part of the car and its modifications. Initial modeling using current LMP data from PJM, as well as the current and projected costs of gasoline and natural gas show that such a system will pay for a significant portion of its cost within its useful lifetime. A vehicle that generates a revenue stream is unheard of to this point in time. Further economic analysis using @RISK Monte Carlo software will be demonstrated in our paper that show the range of costs and benefits associated with our system.

The CNG/Hybrid/Smart Car that we are developing will also become the most economical energy storage system available for the electric power grid. The vehicle will be able to store and distribute electricity and because of its onboard reserve of CNG will be able to provide significantly more electrical energy when there is a demand for it. Leveraging high LMP prices to our benefit, our system will use times when electricity is cheapest to charge the battery pack of the vehicle and compress gas to fill the CNG storage tank. When electricity is most expensive and demand support is required on the grid our car can discharge the battery pack once again turning a profit for its owner while supporting the power grid. Charging and discharging a battery pack, one that is already a necessary part of the vehicle, will also make the system environmentally friendly through storage of excess energy rather than wasting energy. In the future, a large number of these series-electric hybrid vehicles can be combined to better address the issue of grid storage on a large scale.

An additional benefit to this CNG/Hybrid/Smart Car system is that it can be used both as a backup generator and can increase the grid-stiffness of intermittent renewable generation systems like wind and photovoltaic systems. In the event of a grid outage the generator can be utilized as a backup power device to generate electricity. The vehicle operator can use natural gas to generate electricity until the grid comes back online in a more environmentally friendly and cost effective manner than common gasoline or diesel generators. Renewables have an inherently lower reliability than conventional grid power device. For example, photovoltaic systems are impacted clouds and night time and wind power generation ceases when the wind subsides. Augmenting a renewable energy power plant with a system similar to our CNG/Hybrid/Smart Car System will make the power plant a dispatchable and reliable source of energy. This way renewables can be dispatched or used for baseload as opposed to only being used when available.

Combining CNG or natural gas with a distributed generation system will provide benefits in multiple ways. First the emissions produced from a natural gas generator are fewer than the emissions produced by a coal burning fossil fuel power plant. Second a CNG/Hybrid/Smart Car replacing a gasoline burning car with have 90% fewer CO emissions and 25% fewer CO₂ emissions than a gasoline-based car. Third, using such a system in distributed generation will mean that the electricity will have less distance to travel to be used. This will remove losses inherent to power transmission in transmission lines, distribution lines, and transformers. This higher overall efficiency will mean less fuel must be burned for the same energy decreasing more costs and emissions. Finally, using a battery pack with renewables and the CNG/Hybrid/Smart Car will lead to fewer emissions over the lifetime of the generator.

One of the National Academy of Engineering’s Grand Challenges for Engineering is to make solar energy economical and to have a high penetration of solar energy into the US power grid. The CNG/Hybrid/Smart Car that we have been developing will positively impact the deployment of renewable power through increasing economics and system reliability. Combining the CNG/Hybrid/Smart Car with solar power generation, specifically photovoltaics, will make a more cost-effective, environmentally friendly, and reliable system than either one alone. Because of this, one of the our concurrent research strategies is to build the system as a pad mount where there is no car, but only the natural gas generator, a battery pack and the inverter to interface with the grid. This device will have significantly lower cost and more rapid payback. A third research strategy which we are working collaboratively with another university on is mounting the CNG generator/inverter system (and possibly a battery pack) onto a military-grade trailer. Making the generator portable would have applications in disaster areas where the power grid is down and in expeditions where no power infrastructure exists. Our fourth and final research approach is using the core technology as a cogeneration setup utilizing the waste heat to generate hot water in commercial and residential applications to increase the overall efficiency of the system and reduce the effective carbon emission per utilized energy even further.

                The power generation system that we propose as the core to these four technology options will use natural gas as a more environmentally friendly, cheaper, and more sustainable option than coal, gasoline or gasoline. Natural gas has fewer carbon emissions than coal and gasoline making it a better option in terms of environmental consequences. The current state of natural gas extraction in the United States has resulted in very low costs. The research and development of our CNG/Hybrid/Smart Car and CNG generator/inverter system platforms will reduce the use of coal for electricity and gasoline for transportation and offer a radically new paradigm for reducing carbon emissions over present technology options. The fact that such a system is not only a more sustainable option in terms of the environment but provides a very favorable set of economic benefits to its owner could lead to wide market adoption. The systems we are developing may become a potential solution to the issues of grid storage, economic and reliable renewable energy systems, and cheaper, more accessible transportation and electricity.