Analyzing Distributed Energy – Living Off the Grid in Emergency Situations
In the aftermath of Hurricane Sandy, people all over the east coast of the U.S. are asking themselves what they can do to lessen their reliance on centralized energy systems for their electricity, heat and transportation needs. As climate change brings the potential for more intense and frequent extreme weather events, the desire for alternative energy options is becoming more prevalent. Few experts doubt that the energy regime of the future will bear little resemblance to our current system, but what technologies are available and economically viable today?
CleanEdison explored the practicality of a few of the leading candidates and found that today’s technology can provide all the electricity, heat and transportation needs during a power grid failure. However, continued investment is needed to make these technologies truly economically viable for mainstream application.
Grid-Tied Emergency Solar Panels with Battery Backup
Solar proponents have long envisioned the day when residential solar systems could truly be mini power plants. If the home used its own electricity when it could, sold excess electricity to the grid when it wanted, and stood on its own when it needed, installations would spring up across the nation. Initially, PV systems were installed for many off-grid applications. However, according to the International Renewable Energy Council (IREC), in the last decade, and especially in the last several years, grid-connected installations have become the largest sector for PV installations. Most of these installations are on the customer-side of the meter, although the last three years have seen an explosion of utility scale systems. On the other hand, off-grid systems have become such a small section of the industry that data on them is generally not counted in IREC and EIA reports.
As impressive as the growth of solar PV installations have been, grid-tied systems are only as reliable as the grid itself; without a functioning grid, they produce no energy and the dream of residential energy independence goes out the window. But large scale disasters, such as Hurricane Sandy or the Fukishima nuclear disaster in Japan have a way of focusing attention back on the idea of mixing grid-tied solar PV with battery back-up on the residential level.
Today, solar installers are willing to provide this type of system, but there is almost unanimous agreement that it is not worth it. This is because the cost of current batteries adds about 40 percent to the initial cost of the system and almost doubles the price over the lifetime of the system. Furthermore, while the panels themselves will last 25-30 years, most batteries on the market will only last 5-7 years before needing to be replaced. The problem is exacerbated by the fact that the 30 percent federal tax credit for residential renewable energy does not cover storage systems and batteries.
Some companies haven’t given up hope, finding creative ways to take advantage of incentives that do cover energy storage systems and combining those with solar installations. The most prominent example of this is the partnership between Tesla and Solar City which, according to IDC Energy Insights, have filed more than 70 installation permits in the Pacific Gas & Electric territory of California, most of which are 5 kw residential projects.
The companies are requesting subsidies from California’s Self-Generation Incentive Program. To qualify for that program as an energy storage system, there must be 4 kwh of storage for every kw of generation. That means that each 5 kw system must have 20 kwh of storage. For homeowners, this plan would help pay for 1/3 of the cost of the system. Customers would save additional costs through ime-of-use (TOU) utility costs in California, where costs are more expensive at hours of high-demand and less expensive when there is less demand.
Using maximum power point tracking (MPPT), these systems are fully automated to charge the battery at night during off-peak times, discharge, recharge during the solar producing hours and discharge again, all based on time-of-use power sourcing. All said and done, the plan in California will bring the dream of mixing cheap grid-connection with security of battery storage for unexpected blackouts and major disasters for about $6,000 on top of the installation, around the same as an advanced hard-wired generator would cost.
Of course, all this stands on federal incentives for PV, state subsidies for energy storage and residential time-of-use utility rates. Still, given the fact that there was over a $50 billion price tag on Hurricane Sandy, 60 percent of which was from lost business, supporting this type of solution should be seriously considered.
Geothermal Ground Source Heat Pumps
Geothermal energy, in the form of a ground source heat pump, does not produce any electricity and cannot be expected to keep business running after a super-storm like Hurricane Sandy. But for many of those affected by the storm, more immediate concerns about their access to space heating and hot water is the driving factor towards looking into alternatives to their current system. Around the world, although ambient temperatures change wildly from day-to-day, the temperature only a few feet below the earth’s surface remains relatively constant. This stable temperature can be harnessed to provide heat in the winter and cooling in the summer for less money than other forms of space heating.
Unfortunately, these systems do require a small amount of electricity, so if the grid is down, you will need a battery-backed solar array or a small generator. On the other hand, in a major hurricane like Sandy, there is no concern of damage to the geothermal system, as it is housed entirely underground. Furthermore, as opposed to furnaces, which run on gas that can be shut down by the utility or even leak into the flood water caused by hurricanes, ground source heat pumps use water or other non-toxic liquids to transfer heat from the ground to the house.
Even when there is not a major disaster that knocks out the power, geothermal energy is generally a good idea for homeowners (although less so in high-density areas such as Manhattan). Geothermal systems represent a savings to homeowners of 30to 70 percent in heating costs, and 20to 50 percent in the cooling costs of conventional systems. The systems require little maintenance and the underground pipe of the system carriers up to a 50-year warranty. Also, the $9,000 price tag is a lot more reasonable for most people than the $25,000 to buy the equipment for a solar array.
Though geothermal technology doesn’t get the recognition of the other renewable energy technologies such as solar and wind, it saw high growth rates this decade as well, although the growth slowed in 2009 due to the recession.
Electric Vehicle Security and Plug-in Hybrid Vehicles
In addition to the lack of power and heat in many areas affected by Hurricane Sandy, an ongoing problem has been the lack of available gasoline. In the New York Metropolitan area, 38 percent of gas stations still did not have gasoline available 10 days after the storm. This lack of transportation fuel has caused problems with government and community relief efforts as well as people’s ability to get back to work, even when the lights went back on. This is in addition to already sensitive feelings about the price of gasoline, climate change and the country’s reliance on volatile international oil markets.
Electric vehicles offer the promise of relieving the pressure that people face when forced to fill up at the pump, as well as an alternative for the gasoline shortage that still plagues the east coast. Of course, these vehicles have drawbacks due to their infancy as an industry. Many consumers still have “range anxiety” about running out of electricity without anywhere to charge it. In areas with strong government support such as California, Oregon and New York, this is becoming less and less of an issue. Companies have developed and continue to improve the charging times of public charging stations that work like gas stations for conventional cars and there has been a steady expansion of these systems to support the growing number of plug-in hybrid and electric vehicles.
Obviously, these vehicles require a working electrical grid that might be compromised in the aftermath of storms like Hurricane Sandy. That is, unless we develop grid-connected solar with battery backup. With this system, electric vehicles owners could produce enough energy to charge their vehicles overnight. If this is the plan, homeowners would need a slightly larger array (an extra three 200 w solar panels should be enough) or will have to ration electricity use when the grid is down. In either case, for most electric vehicle/solar PV combinations, you will have around a 14-year payback. While this might seem like a long time, the payback period for an electric vehicle without a PV installation is more like 50 years.
Conclusion: Off-Grid Power Solutions Provide Added Security
It is entirely possible with today’s technology to be independent of the centralized electricity and transportation systems that we take for granted until they are gone. These solutions do come with high upfront costs that must be taken into account, but unlike conventional energy technologies, there are very few on-going costs, so the systems are cheaper in the long run. Furthermore, in the event of a natural disaster such as Hurricane Sandy or the Fukishima Nuclear disaster, these distributed energy forms allow for autonomous energy production and self-reliance.
Government incentives and policies will play an important role part in the continued development of these technologies. While tax credits and other direct subsidies are important, a renewed sense of urgency for basic research into developing energy storage technologies will have the largest impacts down the road.
For the present, those in states such as California, with subsidies for energy storage and utilities that offer time-of-use rates, homeowners should be able to get battery backup for their solar systems for about the same price as a conventional generator. Having a battery backup system to a solar array opens the opportunity for further money-saving and disaster resistant systems such as geothermal heat pumps and electric vehicles. In any case, the threat of more severe weather events in our future will likely lead towards developing more independent energy production.
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