Renewable Redundancy

SUBHEAD: Off the grid. Drilling deeper into renewable energy issues. By Stoneleigh on 09 August 2009 in The Automatic Earth - http://theautomaticearth.blogspot.com/2009/08/august-9-2009-renewable-redundancy.html The Automatic Earth has received quite a number of viable renewable energy questions lately, particularly with regards to my own personal energy strategy. People have also asked why I work in grid connections for renewable energy (which I'll from now on refer to as RE), given that I do not believe we are going to see a wholesale societal conversion to renewable power as fossil fuels deplete (see Renewable Power - Not in Your Lifetime). Someone even suggested I was facilitating something I knew would not work. That, however, is not the case. Please allow me to explain.

image above: Solar photo-voltaic panel array in residential yard.

From http://www.livingoffgrid.org Renewable power will never be able to run an energy-profligate industrial society such as the one most of us have grown up in, due to, among other reasons,

• low energy density,
• low EROEI,
• intermittency,
• lack of energy storage capacity,
• mismatched supply and demand profiles,
• poor grid infrastructure,
• inability of distributed renewable energy to sustain grid operational parameters,
• looming financing difficulties,
• receding horizons,
• inability to scale up RE production before the credit crunch puts the brakes on
• etc. etc.

Still, that does not mean RE has no value. On the contrary, it has the potential to be extremely valuable to those who install it while it is still possible to do so, although debt must be avoided and, as several readers have pointed out, maintenance may well be a significant problem as parts and expertise may not be locally available. It is a matter of knowing what renewable power can and cannot do and making the most of the latter while not pinning our hopes on the impossible. It reminds me of a passage I came across, which ran something like this: Grant me the strength to change what I can, the serenity to accept what I cannot change, and the wisdom to know the difference. There is an important distinction to make between grid-tied and stand-alone RE systems. For household-scale RE systems I think grid connection generally makes little sense. Some jurisdictions pay a premium for renewable power, especially if it is generated by very small systems, and this may tempt some people. Here in Ontario for instance, rooftop solar less than 10kW will be paid about 80 cents/kWh (about 10 times what is paid for conventional energy sources). However, the income will be taxable and the ability to earn an income may also result in an increase in property taxes. In Ontario this is not yet the case, but only because the property tax agency (MPAC) is reactive, not proactive. It is entirely possible that homeowners could make very little money after tax. In addition, premium payment programs may require renewable generators to sell all the power they produce to the grid and then obtain their own supply back from the grid, with no potential for storage and use of their own power during blackouts. This is a serious compromise to make, as back-up power is a major advantage of owning renewable power generation. If the only advantage is to be the -potential- money made, and most of that could be clawed back in taxes, then there would be little point in installing a system. A grid connection could also allow power generated to be commandeered without payment ‘for the public good’ in times of crisis. This is unlikely to happen soon, but as mains power becomes increasingly unreliable in a collapsing economy, circumstances may change. The premium payments that are supposed to be guaranteed for 20 years could easily be repudiated if they become a political liability. For larger systems, such as farm-based or community power projects, a grid connection may well be necessary in order to make best use of the generation potential in supplying a larger area. For instance, a farmer supplementing his dairy manure with off-farm organic wastes could generate 500kW from methane produced through anaerobic digestion, and this would exceed farm-load considerably. He could use a grid connection to supply many close neighbours, and be paid a premium price for his power. Taxes would still be an issue though, as would the debt that most would need to incur in order to finance the construction of such a project. Grid reliability is likely to be much reduced in the future, but even unstable areas generally have some power, so exporting power to neighbours could still be viable intermittently. The importance of storage, of gas or electricity or both, would increase significantly under those circumstances. Alternatively a farmer could design a smaller system using only his own on-farm waste streams to supply only his own load. It would be harder to find the money for construction without an income stream, and some components would have to be oversized in order to cover demand peaks, further adding to the cost. A farmer who could afford to do this would have a secure source of power, assuming at least some maintenance expertise and access to parts, and could therefore be able to continue producing food - and electricity-. Of course, finding someone who could afford to buy his produce could be difficult, as it was during the Great Depression, but not producing food has its own obvious consequences. There is no guarantee that building an RE project will provide what the owner is looking for, given all the confounding factors approaching once the credit crunch resumes, but doing nothing is risky too. People will have to choose the risks they feel they can live with. In general, minimizing demand before attempting to provide supply is a good idea. For a stand-alone project, supplying only the essentials will be most cost-effective. Obtaining spare parts in advance and learning how to install them independently is highly advisable. Building a robust system with as few moving parts and complex components as possible would be best, but complex components are hard to avoid. Energy storage will be an essential component. Back-up power will probably be called for. Cash reserves for maintenance costs would help, assuming parts and expertise are available, which they probably will be in some areas and not in others. In some ways renewable power is best regarded as a bridge between our current comfortable reality and a much less comfortable lower energy future. For those who can afford them (a small minority unfortunately), these systems can buy some time to make mental and physical adjustments to a new reality. Our own 3kW solar array is not grid connected. It will continue to operate in a stand-alone manner, feeding the battery bank that runs the essential loads 24/7. It was installed for the power, not in order to produce an income. The essentials (well pump, sump pump, circulating pumps for the outdoor wood furnace and the solar thermal system, fridge, freezer, security system, minimal lighting) are powered from the batteries through the inverter. We have six 4V Rolls Surrette 4ks-25ps connected in series, which provide 1350 amphrs of battery storage. They are manufactured specifically for solar and other renewable energy applications, with dual-container construction, a ten year warranty and up to a twenty year life span. We can charge the batteries from the panels, or from a gas generator, or from a diesel generator run by the tractor, or with the mains. The batteries are meant to keep these essentials running for at least four days of no sun, no mains and no generator. The next most important things (geothermal back-up system, furnace fan, microwave, another freezer, ceiling fans, and a few sockets) are wired into a generator panel. We can run those from the mains or with a generator if we have fuel for it. If we have no mains power, no fuel and no sun for more than four days, we can still keep warm, heat water and cook using a 1928 kitchen wood range and two supplementary wood stoves. We can also run radiators connected to the outdoor wood furnace, so we can distribute the heat from outside using only the circulating pump rather than the furnace fan, as the furnace fan is too large a load to run off a renewable energy system. We also have two bicycle powered generators and portable battery packs that we can use to power incidental things if necessary. Independence in the face of great uncertainty over energy supply comes from flexibility and a degree of redundancy. Redundancy is important as one does not know quite what one will be facing, what resources will be available when, and how long one may have to cope alone. Having more than one way of doing the essentials expands the range of circumstances one can handle. There needs to be more than one way of doing essential things, so that one can adapt to changing circumstances quickly. RE investments probably need to be made sooner rather than later, as they would tend to fall into the category of items that will not be available later, although there could be a period where they may be cheaper for those who have managed to preserve purchasing power as liquidity. The need to make such investments at today’s high prices will unfortunately restrict the number of people who are able go the RE route without taking on debt. While one could argue that such an investment will only make one a target for confiscation or vandalism, vulnerability will depend greatly on local circumstances. These risks are real, but will not be equal everywhere, and risk cannot be avoided no matter what people choose to do. We are simply moving into a high-risk world that all of us will find acutely uncomfortable.

see also:

Ea O Ka Aina: Redundancy Redundancy 8/7/09