Integrated Renewable Energy Strategies

Introduction

We look at two examples in which integrating multiple, new technologies yield synergies that make renewable energy particularly attractive.  Note: this is a fast-moving field.  I expect this article to be outdated very soon.

Vehicle-to-Grid Technologies

A friend asked me if having a lot of Electric Vehicles (EV’s) on the road might cause the US carbon footprint to increase.  After all, most of America’s electricity is generated from coal-fired power plants.  I’d like to counter that point of view by arguing that an integrated approach to transportation, energy storage, energy distribution, and energy production would have fantastic, positive effects. 

The carbon footprint of electricity generated for transportation is a valid concern; although it’s been over-stated by EV detractors.  The concern is not helped by the fact that Big Coal is using the latest set of oil shocks in its lobbying efforts for greater production at lower levels of environmental protection.  There is no such thing as “Clean Coal” – especially when you take into account the environmental costs of coal mining and distribution operations. 

One of the exciting developments that are technologically feasible today is the notion of “Vehicle-To-Grid” (aka V2G) interconnection.  The idea is that millions of EV’s would be parked in garages overnight and (ideally) at a charging station while their owners are at work in the daytime and these millions of EV’s represent a gigantic, distributed energy storage system.  When the sun shines and the wind blows, we can feed the grid and the vehicles connected to it with “clean” energy.  

V2G uses technology very similar to grid-tied PV arrays .  When a vehicle is being charged, the owner incurs a cost.  When the charged battery in a vehicle is used to supply energy to the grid and thus balance loads w/ supply, the owner receives a credit.  Costs & credits are reconciled at monthly (or whatever) intervals. 

This scenario allows means that fewer conventional power plants can be run at constant output.  This is the most efficient and least polluting mode of operation.  V2G could greatly reduce – perhaps eliminate – the need for “spot providers” of electrical energy.  Spikes in energy demand raise costs as well as pollution levels.  Imagine a vastly decentralized population of EV’s that can act as a gigantic flywheel on the grid. 

DC Power Transmission

Another exciting development is with very high voltage DC power transmission.  As you know, we usually distribute electricity via high voltage AC because that’s got a lot less I2R loss than low voltage DC.  New technologies are already being deployed that allow lower loss transmission of very high voltage DC.  This is exciting because states such as Wyoming, Colorado, Nebraska, and New Mexico have huge wind & solar resources but low population (and low water supplies).  If we could transfer the electricity to where it’s needed and do that efficiently, we’d bring a lot of revenue to states that could use it while tapping a vast, non-polluting energy source. 

Finally, Arizona and southeastern California have enough sun to generate electricity using “concentrating solar” technology at an almost cost-competitive basis with conventional sources (actually I think that if you removed subsidies & tax breaks on coal and natural gas, concentrating solar would already be cost-competitive).  Concentrating solar uses mirrors to track the sun and focus the sun’s energy on pipes containing a material with a high heat capacity.  The heated material is then used to generate steam to run turbines to generate electricity.  These facilities are proven to work with low maintenance for decades. 

Coupling these with HV DC transmission and V2G storage would allow these sources to reach population centers and serve the needs of our population at night when the sun isn’t shining. 

Conclusion

These are just the technologies that we know about and could deploy now.  I’ve left off research topics such as compressed air storage in underground caverns.  Yes, in an overly simplistic scenario, a lot of EV’s on the road could have negative consequences for our carbon footprint.  Execution of a sane – patriotic, even – energy policy would have quite the opposite effect. 

Imagine the US jobs created if we as a country put the sort of resources that are currently going into subsidizing polluting industries into development and deployment of renewable energy technologies.  Imagine the positive effects on our foreign policy and our balance of trad

© Michael C. Glaviano 2009 - 2016